WEBVTT 1 00:00:00.200 --> 00:00:02.720 Okay, so today we're going to go over anti rhythmics. 2 00:00:02.759 --> 00:00:06.240 This can definitely be one of the more complicated topics 3 00:00:06.280 --> 00:00:07.879 to learn in school. It can definitely be a lot 4 00:00:07.879 --> 00:00:09.880 more daunting compared to the other topics. So I did 5 00:00:09.919 --> 00:00:11.800 my best to break it down and probably throw in 6 00:00:11.839 --> 00:00:14.119 more tomonics than I've had in any other podcast, so 7 00:00:14.160 --> 00:00:16.879 hopefully that helps you. So before we get started, thank 8 00:00:16.920 --> 00:00:19.359 you as always for the really nice comments, the support 9 00:00:19.399 --> 00:00:21.719 for the channel. Everybody who reaches out and leaves a 10 00:00:21.800 --> 00:00:23.760 nice comment, I truly do appreciate it, So thank you 11 00:00:23.839 --> 00:00:26.199 so much. Let's go ahead and get started with anti rhythmics. 12 00:00:26.280 --> 00:00:28.239 So there's four main classes that you need to know, 13 00:00:28.399 --> 00:00:31.760 and that's your Class one sodium channel blockers, Class two 14 00:00:31.879 --> 00:00:35.880 Beta blockers, Class three potassium channel blockers, and class four 15 00:00:35.920 --> 00:00:38.719 calcium channel blockers. So if you ever forget which classes which, 16 00:00:38.759 --> 00:00:42.600 remember the sentence some block potassium channels, some block potassium 17 00:00:42.640 --> 00:00:46.960 channels the letters SBPC that helps you remember. Class one 18 00:00:47.079 --> 00:00:50.840 S sodium channel blockers, Class two B Beta blockers, Class 19 00:00:50.880 --> 00:00:54.840 three P potassium channel blockers CEE, Class four calcium channel blockers. 20 00:00:54.960 --> 00:00:56.880 All right, let's go ahead and get started. We're going 21 00:00:56.880 --> 00:00:59.600 to start with our sodium channel blockers, but before we do, 22 00:00:59.679 --> 00:01:02.960 I want to review, done done, the cardiac action potential, 23 00:01:03.000 --> 00:01:05.319 as it's the foundation to understand how this class works, 24 00:01:05.439 --> 00:01:07.439 as well as some of our other classes that will 25 00:01:07.480 --> 00:01:10.879 go over today. So the cardiac action potential is complicated, 26 00:01:10.920 --> 00:01:13.560 and to make it even more complicated, it varies depending 27 00:01:13.599 --> 00:01:15.359 on which part of the heart we're talking about. We 28 00:01:15.400 --> 00:01:17.680 have an action potential in our pacemaker cells as well 29 00:01:17.719 --> 00:01:20.239 as our cardiomyocytes in the cardiac muscle. But I'm going 30 00:01:20.280 --> 00:01:22.599 to try to make this as simple as possible. Let's 31 00:01:22.680 --> 00:01:25.719 first start with the action potential of the cardiomiocytes. Now, 32 00:01:25.719 --> 00:01:28.280 before breaking down each phase, there's a few simple key 33 00:01:28.319 --> 00:01:32.760 facts to keep in mind. First, there is five phases zero, one, two, three, 34 00:01:32.799 --> 00:01:35.560 and four. Next, there's three players in the game, three 35 00:01:35.560 --> 00:01:39.719 major ions sodium, calcium, and potassium, which are all positively charged, 36 00:01:39.959 --> 00:01:42.159 and finally, at rest. The inside of the cardiac cell 37 00:01:42.200 --> 00:01:45.799 sits at about negative ninety millivolts, making it relatively negative 38 00:01:45.799 --> 00:01:48.159 compared to the outside. All right, so let's break it down, 39 00:01:48.200 --> 00:01:50.840 starting with phase four, which I like to call the floor. 40 00:01:50.920 --> 00:01:53.560 Phase four is the floor. This phase is the resting 41 00:01:53.599 --> 00:01:56.599 membrane potential. The cell is electrically quiet. There is some 42 00:01:56.719 --> 00:01:59.319 leakage of ions, but overall, to keep it simple, just 43 00:01:59.359 --> 00:02:02.200 remember phase four as the floor as not much as happening, 44 00:02:02.239 --> 00:02:04.920 and it's a pretty flat phase. Then comes phase zero. 45 00:02:05.079 --> 00:02:08.199 This is where the action starts fast. Sodium channels open 46 00:02:08.280 --> 00:02:11.479 up and sodium rushes into the cell, causing the inside 47 00:02:11.479 --> 00:02:14.960 to become rapidly more positive. This phase causes this rapid 48 00:02:15.000 --> 00:02:18.800 depolarization and creates this sharp upstroke on the graph. Phase zero, 49 00:02:18.919 --> 00:02:22.360 just remember, is all about sodium and depolarization. Next to 50 00:02:22.479 --> 00:02:26.919 Phase one, brief but important moment sodium channels close and potassium, 51 00:02:27.000 --> 00:02:29.439 the party pooper as we'll call him, begins to exit 52 00:02:29.479 --> 00:02:31.840 the cell. This leads to a slight dip in the 53 00:02:31.879 --> 00:02:36.039 membrane potential known as initial repolarization. Phase two. Potassium keeps 54 00:02:36.080 --> 00:02:38.680 leaving like the party pooper he is, but calcium starts 55 00:02:38.680 --> 00:02:40.919 to enter the cell at the same time, which essentially 56 00:02:40.960 --> 00:02:43.319 balances things out, and that's why Phase two is known 57 00:02:43.319 --> 00:02:46.879 as the plateau phase. Ultimately, though, the calcium channels eventually 58 00:02:46.879 --> 00:02:50.199 close and potassium of course keeps leaving, leading to a 59 00:02:50.319 --> 00:02:53.520 rapid drop and repolarization, which is phase three. This big 60 00:02:53.520 --> 00:02:56.000 old drop, and then eventually the cell returns to its 61 00:02:56.080 --> 00:02:58.960 negative resting state and more back at phase four the floor. 62 00:02:59.240 --> 00:03:01.080 So to sum it up, phase four is the floor 63 00:03:01.159 --> 00:03:04.240 resting state. Phase zero is the sodium fueled upstroke to 64 00:03:04.280 --> 00:03:08.800 start the party rapid depolarization. Phase one initial repolarization. Party 65 00:03:08.840 --> 00:03:12.000 pooper potassium starts to leave. Phase two. Calcium saves the 66 00:03:12.080 --> 00:03:15.159 day and rushes into balance out potassium's exit. Phase three, 67 00:03:15.199 --> 00:03:18.240 Calcium eventually gets shut down in potassium like the party pooper, 68 00:03:18.280 --> 00:03:21.439 e is keeps leaving big drop and repolarization. Okay, so 69 00:03:21.479 --> 00:03:23.639 now that we have a general understanding, let's start with 70 00:03:23.680 --> 00:03:26.719 our class one sodium channel blockers. So the meds in 71 00:03:26.719 --> 00:03:29.000 this class, while there is a lot of them, they're 72 00:03:29.039 --> 00:03:32.439 broken into subsections making it even worse. Class one A, 73 00:03:32.639 --> 00:03:35.599 one B, one C. I know, learning anti rhythmics really 74 00:03:35.639 --> 00:03:38.240 sucks that, I feel you. I do have anomonic though, 75 00:03:38.280 --> 00:03:40.120 so we'll go over that in just a minute. So 76 00:03:40.280 --> 00:03:44.560 Class one A is disopyramid quinidine procanamide, Class one B 77 00:03:44.759 --> 00:03:48.560 is lytoicane and mixilotine, and class one C is flecinide 78 00:03:48.560 --> 00:03:51.199 and propaphenome. So how the heck can you remember all 79 00:03:51.199 --> 00:03:54.159 of those they all sound different and weird. Well, there's 80 00:03:54.159 --> 00:03:56.960 a tried and true mnemonic that goes, double quarter pounder, 81 00:03:57.039 --> 00:04:01.240 lettuce mao fries please, double quarter pounder, let mayo fries please. 82 00:04:01.599 --> 00:04:03.759 Know this mnemonic really well, as it's not only going 83 00:04:03.800 --> 00:04:05.360 to help you remember the meds in this class, but 84 00:04:05.560 --> 00:04:08.080 also some additional mnemonics that I have thrown in. So, 85 00:04:08.080 --> 00:04:10.759 starting with your Class one A drugs, double quarter pounder 86 00:04:10.919 --> 00:04:15.080 DQP stands for disopyramid, which is the d. Q stands 87 00:04:15.080 --> 00:04:18.279 for quinidine, and P stands for procaanamide. Now I've got 88 00:04:18.279 --> 00:04:20.160 a little twist to this mnemonic that's going to help 89 00:04:20.199 --> 00:04:22.959 you remember a key feature of these one A drugs 90 00:04:22.959 --> 00:04:26.279 that you cannot forget. Picture your double quarter pounder not 91 00:04:26.279 --> 00:04:29.360 on a regular hamburger bun, but instead, remember it's stuffed 92 00:04:29.399 --> 00:04:31.920 inside of a foot long hot dog bun. A double 93 00:04:32.040 --> 00:04:34.079 quarter pounder and a foot long hot dog bund. It 94 00:04:34.199 --> 00:04:36.560 sounds odd now, but trust me, it's going to make 95 00:04:36.600 --> 00:04:38.879 sense and help you soon. Okay, Next our Class one 96 00:04:38.920 --> 00:04:42.759 B drugs lettice mayo stands for lytokane and mixilotine. And 97 00:04:42.759 --> 00:04:45.759 then finally our Class one C meds, fries please, which 98 00:04:45.800 --> 00:04:49.040 is flecanide and propaphenone. So once more double quarter pounder 99 00:04:49.120 --> 00:04:52.879 disopyramid quinidine and procanamide Class one A. Remember it's on 100 00:04:52.920 --> 00:04:55.439 a foot long hot dog bun lettice mayo, which is 101 00:04:55.519 --> 00:04:59.079 lytokine and maxilotine class one B. And then fries please 102 00:04:59.160 --> 00:05:02.120 flecanide and propafenone class one CE. So that's how you 103 00:05:02.120 --> 00:05:04.040 remember the meds in this class. Now let's talk about 104 00:05:04.040 --> 00:05:06.759 how they work on that cardiac action potential we discussed 105 00:05:06.759 --> 00:05:09.639 before of the cardiomyocytes. So if we think about our 106 00:05:09.680 --> 00:05:12.519 cardiac action potential we talked about before, where do we 107 00:05:12.560 --> 00:05:15.160 think the main area of impact would be? When did 108 00:05:15.240 --> 00:05:18.680 sodium the party animal join in? So phase zero, right, 109 00:05:18.759 --> 00:05:22.000 our big spike depolarization. So when we add a sodium 110 00:05:22.079 --> 00:05:25.480 channel blocker to a patient within arrhythmium, we decrease sodium 111 00:05:25.519 --> 00:05:27.600 influx and it's kind of like cutting the gas to 112 00:05:27.639 --> 00:05:29.560 the engine and slowing things down a bit. And by 113 00:05:29.600 --> 00:05:33.079 slowing phase zero depolarization, we slow conduction velocity and this 114 00:05:33.160 --> 00:05:36.959 can suppress ectopic beats, interrupt re entrance circuits, helping to 115 00:05:37.000 --> 00:05:39.399 restore normal rhythm. Now here's where it gets a little tricky. 116 00:05:39.480 --> 00:05:41.879 So these meds are all sodium channel blockers, but they 117 00:05:41.959 --> 00:05:45.319 all impact sodium in varying degrees. Some are potent sodium 118 00:05:45.399 --> 00:05:48.480 channel blockers, some are weak sodium channel blockers. Some even 119 00:05:48.519 --> 00:05:51.879 block potassium. So let's make this as simple as we 120 00:05:51.920 --> 00:05:54.839 possibly can. So starting with our class one SEA drugs, 121 00:05:54.959 --> 00:05:57.480 which bind the tightest and the longest, making them the 122 00:05:57.560 --> 00:06:01.279 most potent sodium channel blockers, causing the steepest reduction in 123 00:06:01.360 --> 00:06:04.000 the phase zero upstroke. And even though they stretch out 124 00:06:04.000 --> 00:06:06.360 our phase zero upstroke, they don't really change the action 125 00:06:06.439 --> 00:06:09.439 potential duration. The action potential duration, by the way, is 126 00:06:09.480 --> 00:06:11.800 just a total time it takes for a cardiaccel to 127 00:06:11.800 --> 00:06:15.120 complete one cycle, so from phase zero depolarization to the 128 00:06:15.240 --> 00:06:18.000 end of phase three repolarization. Next is our class one 129 00:06:18.040 --> 00:06:21.839 A drugs, which produce intermediate BLOCKA, producing a moderate slowing 130 00:06:21.920 --> 00:06:25.480 of phase zero, but most importantly, they also block potassium. 131 00:06:25.519 --> 00:06:29.199 Sneaky little guys. So this lengthens the effective refractory period 132 00:06:29.199 --> 00:06:33.439 and the action potential duration, resulting in QT prolongation, which 133 00:06:33.480 --> 00:06:35.240 is going to cost some issues. We'll go into more 134 00:06:35.279 --> 00:06:37.639 depth about in just a few minutes. And then finally 135 00:06:37.639 --> 00:06:39.639 we have our class one B drugs. They bind and 136 00:06:39.680 --> 00:06:42.360 release very quickly, so their effect on phase zero slope 137 00:06:42.399 --> 00:06:45.279 is minimal. They also decrease the refractory period a bit too, 138 00:06:45.279 --> 00:06:47.920 which can shorten the action potential duration. So I have 139 00:06:47.959 --> 00:06:50.240 an easy way for you to remember the different subclasses 140 00:06:50.279 --> 00:06:53.319 and their strength of impact on the sodium channel simply 141 00:06:53.360 --> 00:06:56.000 by remembering the more salt in the food, the more 142 00:06:56.040 --> 00:06:59.639 it blocks sodium. So remember our mnemonic double quarter pounder, lettuce, 143 00:06:59.680 --> 00:07:02.639 male fries please. So out of all of these, which 144 00:07:02.680 --> 00:07:05.560 has the least amount of salt? Double quarter pounder, lettuce, 145 00:07:05.600 --> 00:07:08.160 mao or fries please? And this isn't a trick question. 146 00:07:08.279 --> 00:07:10.000 Just think about the foods and think about what has 147 00:07:10.000 --> 00:07:12.199 the least amount of salt. So, lettuce and mao right, 148 00:07:12.279 --> 00:07:15.879 so Class one B lytoicanum oxilotine have the least sodium 149 00:07:15.959 --> 00:07:19.040 channel blocking activity. Next, which of these foods has the 150 00:07:19.079 --> 00:07:22.240 most salt the fries? Right? So fries please. Class one 151 00:07:22.319 --> 00:07:25.959 C fleckanide and propafenone exert the most potent sodium channel 152 00:07:25.959 --> 00:07:29.319 blocking among the Class one agents, which finally leaves us 153 00:07:29.319 --> 00:07:31.759 with our double quarter pounder Class one A, which has 154 00:07:31.920 --> 00:07:35.199 moderate amount of sodium. So these meds diso pyramid quinidine 155 00:07:35.240 --> 00:07:38.560 and procaanamide have moderate sodium channel blocking activity, so that's 156 00:07:38.560 --> 00:07:40.720 how I remembered it. There are other mnemonics, but the 157 00:07:40.759 --> 00:07:43.560 salt thing just made sense for me and worked. Okay, 158 00:07:43.600 --> 00:07:44.920 So the next thing that I want to go over 159 00:07:45.040 --> 00:07:46.959 is a few high old things to know about each 160 00:07:47.000 --> 00:07:49.839 of these meds, starting with our Class one A sodium 161 00:07:49.920 --> 00:07:52.519 channel blockers. So Class one A, remember is double quarter 162 00:07:52.519 --> 00:07:56.240 pounder diso pyramid quinidine procanamide. Now, before I told you, 163 00:07:56.279 --> 00:07:58.879 remember this double quarter pounder is on a foot long 164 00:07:58.920 --> 00:08:01.759 hot dog bund, you probably already have an idea of 165 00:08:01.800 --> 00:08:04.759 why I said that. So all Class one A drugs 166 00:08:04.759 --> 00:08:08.600 are notorious for prolonging the QT interval. So things like 167 00:08:08.600 --> 00:08:12.000 torsade to point, a dangerous form of polymorphic vtach are 168 00:08:12.079 --> 00:08:14.759 possible with these medications. And that's because, like we went 169 00:08:14.759 --> 00:08:17.680 over before, in addition to blocking sodium channels, they also 170 00:08:17.759 --> 00:08:21.399 block potassium, prolonging the action potential. And they're the only 171 00:08:21.439 --> 00:08:24.480 subclass of sodium channel blockers that do this. So Class 172 00:08:24.519 --> 00:08:27.079 one A drugs you have to know they can prolong 173 00:08:27.439 --> 00:08:30.079 the QT interval, so very important and very likely to 174 00:08:30.120 --> 00:08:32.399 test question. So the way that you're going to remember 175 00:08:32.440 --> 00:08:35.200 that is thinking back to our pnomonic again, same mnemonic 176 00:08:35.240 --> 00:08:37.799 over and over. So double quarter pounder on that foot 177 00:08:37.799 --> 00:08:42.240 long hot dog bund. So we remember double quarter pounder, disopyramid, quinidine, 178 00:08:42.279 --> 00:08:45.159 and procanamide. You're always going to remember that double quarter 179 00:08:45.159 --> 00:08:48.039 pounder is on a foot long hot dog bund. And 180 00:08:48.039 --> 00:08:50.799 that's because all of these drugs can pro long the 181 00:08:50.879 --> 00:08:53.639 QT interble. So that double quarter pounder oddly on this 182 00:08:53.720 --> 00:08:56.399 foot long hot dog bund helps you remember Class one 183 00:08:56.399 --> 00:08:59.360 A drugs prolong the QT interval, nice and simple, don't 184 00:08:59.360 --> 00:09:02.120 forget it. Let's talk about quinidine first. Now, I know 185 00:09:02.159 --> 00:09:03.840 we just said all of the meds in Class one 186 00:09:03.879 --> 00:09:07.120 A prolonged the QT interval, but quinidine really prolongs the 187 00:09:07.200 --> 00:09:09.799 QT intervle Quinidine has historically been one of the most 188 00:09:09.799 --> 00:09:12.480 common causes of drug induced to side to point, and 189 00:09:12.519 --> 00:09:14.200 the only reason it isn't still at the top of 190 00:09:14.200 --> 00:09:16.200 the list today is simply because we don't use it 191 00:09:16.240 --> 00:09:18.559 much anymore. It has a poor side effect profile and 192 00:09:18.600 --> 00:09:21.960 they're safer meds. There is still some utilization in recurrent 193 00:09:22.039 --> 00:09:25.360 vtach in Brugatta syndrome and short QT syndrome. And I'll 194 00:09:25.360 --> 00:09:27.039 give you a second to think about why we might 195 00:09:27.120 --> 00:09:29.759 use this drug to treat short QT syndrome. Yeah, so, 196 00:09:30.440 --> 00:09:32.440 but overall it's usually not going to be a top pick. 197 00:09:32.519 --> 00:09:34.200 With that being said, you still got to know it 198 00:09:34.200 --> 00:09:37.039 because in addition to potentially causing towards to point, it 199 00:09:37.080 --> 00:09:39.279 has a unique side effect that's often tested on. So 200 00:09:39.320 --> 00:09:41.639 the highest deel thing you need to know about quinidine 201 00:09:41.679 --> 00:09:45.039 is that it can cause something known as sensinism. Weird name, 202 00:09:45.080 --> 00:09:47.360 but the backstory may help you to remember it. So 203 00:09:47.440 --> 00:09:49.960 there is this tree called these Sinschona tree native to 204 00:09:50.000 --> 00:09:53.159 the Andes. It produces bark that's rich in alkaloids. This 205 00:09:53.240 --> 00:09:55.639 bark is not only the source of quindine but also 206 00:09:55.679 --> 00:09:58.159 the source of quinine, which you're probably familiar with for 207 00:09:58.200 --> 00:10:00.559 its treatment of malaria. So both of the meds which 208 00:10:00.600 --> 00:10:02.720 come from the same tree share a side effect from 209 00:10:02.720 --> 00:10:06.279 their plant origin, sensianism, which can cause a constellation of 210 00:10:06.320 --> 00:10:11.120 symptoms tinatus, hearing loss, confusion, and delirium, visual disturbances. And 211 00:10:11.200 --> 00:10:13.759 we call this sentianism as it's named after the tree. 212 00:10:13.759 --> 00:10:16.240 It's derived from the Sinchona tree. So hopefully that little 213 00:10:16.240 --> 00:10:19.279 backstory helps you to remember quinidine can cause sentianism and 214 00:10:19.360 --> 00:10:21.879 of course torsade to point. Next drug from Class one A, 215 00:10:22.039 --> 00:10:25.600 it's much higher yield, and that's procanamide. Procaanamide is another 216 00:10:25.639 --> 00:10:28.360 effective anti arrhythmic drug that's again limited by its side 217 00:10:28.360 --> 00:10:30.679 effect profile. And there's two things you need to know 218 00:10:30.720 --> 00:10:33.840 about procanamide that are very high yield, wolf Parkinson White 219 00:10:33.919 --> 00:10:36.559 and lupis. Let's talk about that. So procaanamide can be 220 00:10:36.639 --> 00:10:39.600 used to treat arrhythmias associated with Wolf Parkinson White syndrome. 221 00:10:39.679 --> 00:10:41.879 This is a popular exam question, so you need to 222 00:10:41.919 --> 00:10:45.080 know it. Next, this drug can cause lupus like syndrome 223 00:10:45.200 --> 00:10:48.799 or drug induced lupis. So chronic administration of procainamide can 224 00:10:48.879 --> 00:10:51.320 lead to lupus like syndrome. So these patients will have 225 00:10:51.720 --> 00:10:54.919 similar symptoms to those seen in lupus, rash, arthritis, et cetera. 226 00:10:55.279 --> 00:10:56.879 So these are the two things that you need to 227 00:10:56.919 --> 00:11:00.000 know about procanamide. They can treat Wolf Parkinson White arrhythmias 228 00:11:00.240 --> 00:11:02.600 and it can cause drug induced lupis. So how do 229 00:11:02.639 --> 00:11:05.559 you remember that? So instead of remembering it as procanamide, 230 00:11:05.759 --> 00:11:09.519 remember it as protrainamide. Every time you hear procanamide, I 231 00:11:09.519 --> 00:11:12.639 want you to think protrainamide and have this picture in 232 00:11:12.679 --> 00:11:15.320 your head of this big train rolling down the tracks. 233 00:11:15.480 --> 00:11:17.399 At the front of the train, the conductor is a 234 00:11:17.519 --> 00:11:20.279 wolf with bright white fur. That's your cue for wolf 235 00:11:20.320 --> 00:11:23.799 Parkinson White. And this train is circling in this continuous loop, 236 00:11:24.000 --> 00:11:27.240 which will help you remember loopis like syndrome. So procanamide 237 00:11:27.600 --> 00:11:30.120 is protrainamide. Think of a train being driven by a 238 00:11:30.120 --> 00:11:33.600 white wolf wolf Parkinson white circling in a continuous loop. 239 00:11:33.720 --> 00:11:36.200 Loopis like syndrome. And then our last drug in the 240 00:11:36.360 --> 00:11:40.600 Class one A class is disopyramid, which instead I used 241 00:11:40.600 --> 00:11:44.679 to remember as drysopyramid dr wide dry because the only 242 00:11:44.720 --> 00:11:46.480 thing I think you should know about this drug is 243 00:11:46.639 --> 00:11:49.720 it'll dry you out as it causes anticholinergic side effects, 244 00:11:49.799 --> 00:11:52.159 which is the most common adverse drug reaction. So it 245 00:11:52.159 --> 00:11:56.000 can cause dry mouth, dry eyes, urinary hesitancy, constipation, So 246 00:11:56.080 --> 00:11:59.080 avoid this in patients that have glaucoma, my asthenia, gravists, 247 00:11:59.080 --> 00:12:03.759 et cetera. Instead of disopyramid, remember dry soopyramid dr y 248 00:12:04.120 --> 00:12:07.080 to remember the anticholinergic side effects. Okay, next is our 249 00:12:07.080 --> 00:12:09.960 class one B. What are the Class one B drugs? 250 00:12:09.960 --> 00:12:13.759 Remember Class one B lettice, male lytocane, and maxillotine. So 251 00:12:13.879 --> 00:12:17.279 starting with lytocine. Lytocane, when administered intravenously, can be used 252 00:12:17.279 --> 00:12:21.080 for the treatment of ventricular arrhythmias. Most common ADR is 253 00:12:21.120 --> 00:12:24.519 going to be CNS toxicity. And then we have mixilotine, 254 00:12:24.519 --> 00:12:27.200 which is essentially an oral version of lytocine. It can 255 00:12:27.240 --> 00:12:30.200 also cause CNS toxicity, but because it's a POMD, we 256 00:12:30.240 --> 00:12:33.919 often see GI problems. Nausee of vomiting or heartburn not important. 257 00:12:34.080 --> 00:12:36.639 What you should know about these two meds is when prescribed, 258 00:12:36.679 --> 00:12:39.840 it will be for fast and failing ventricular tissue. So 259 00:12:39.840 --> 00:12:41.320 if you're going to use these meds, it will be 260 00:12:41.600 --> 00:12:46.759 fast ventricular rhythm so ventricular tachycardia ventricular fibrillation and or 261 00:12:46.879 --> 00:12:50.600 on failing or a schemic tissue so schemic arrhythmias after 262 00:12:50.639 --> 00:12:53.559 a myocardial infarction. And that's because the Class one B 263 00:12:53.679 --> 00:12:58.360 meds preferentially bind sodium channels in the depolarized and inactivated state, 264 00:12:58.360 --> 00:13:02.240 which are common in aeschemic myocardium and during tacharrhythmias. So 265 00:13:02.279 --> 00:13:05.200 drugs like maxilotine can be used for rhythmia suppression. Posts 266 00:13:05.200 --> 00:13:08.559 demi lytokin can be used in our ACLS algorithm. So 267 00:13:08.720 --> 00:13:11.639 main takeaway Class one B. Remember use these drugs in 268 00:13:11.759 --> 00:13:16.279 fast and failing ventricular tissue, ventricular tacharrhythmias and POSTMI. Okay, 269 00:13:16.320 --> 00:13:18.679 that finally leaves us with our class one C drugs. 270 00:13:18.759 --> 00:13:22.519 Class one C remember fries please, which is flecinide and propathenone. 271 00:13:22.559 --> 00:13:25.519 So these drugs can be used in both ventricular arrhythmias 272 00:13:25.559 --> 00:13:29.759 and superventricular arrhythmias like atrial fibrillation atrial flutter. There's something 273 00:13:29.799 --> 00:13:31.639 known as the pill in the pocket approach, which is 274 00:13:31.679 --> 00:13:34.679 a form of pharmacologic cardioversion. Basically, a patient has a 275 00:13:34.759 --> 00:13:37.120 history of aphib is that home feels an episode coming on, 276 00:13:37.200 --> 00:13:38.919 they can pop one of these combined with an av 277 00:13:39.039 --> 00:13:41.000 NOTAB blocking agent like a beta blocker, going to get 278 00:13:41.039 --> 00:13:43.120 themselves back in rhythm. So that's cool. But really the 279 00:13:43.159 --> 00:13:45.240 most important thing to know about the subclass, and what 280 00:13:45.279 --> 00:13:47.360 I want you to remember is that these drugs are 281 00:13:47.519 --> 00:13:51.480 contraindicated in patients with structural heart disease. Like POSTMI, They're 282 00:13:51.519 --> 00:13:54.039 only to be used in patients with structurally normal hearts. 283 00:13:54.360 --> 00:13:57.399 Using these drugs and patients with structural heart disease, cornary 284 00:13:57.480 --> 00:14:00.240 arter disease, et cetera can lead to sudden cardiac death 285 00:14:00.360 --> 00:14:02.679 quite the opposite of the class one B drugs. We 286 00:14:02.759 --> 00:14:04.679 just went over where that was one of their primary 287 00:14:04.679 --> 00:14:07.399 indications and a very easy test question. So how can 288 00:14:07.399 --> 00:14:10.039 you remember that Class one B drugs are good post 289 00:14:10.080 --> 00:14:13.039 DEMI and class one C drugs are bad post demi. 290 00:14:13.519 --> 00:14:15.559 So back to the same mnemonic again. I told you 291 00:14:15.600 --> 00:14:16.919 to remember it. So if you just had a heart 292 00:14:16.960 --> 00:14:19.399 attack and you're ordering some dinner, you're going to substitute 293 00:14:19.440 --> 00:14:22.000 your fries for a salad, right, So remember that Class 294 00:14:22.000 --> 00:14:24.879 one B let us mayo good post DEMI and class 295 00:14:24.879 --> 00:14:27.919 one C fries please no good post am I. Remember 296 00:14:27.960 --> 00:14:30.360 after a heart attack, swap the fries out for a salad. 297 00:14:30.440 --> 00:14:32.960 So that's your sodium channel blockers quick recap. Drugs in 298 00:14:33.000 --> 00:14:35.679 this class are remembered by the demonic double quarter pounder. 299 00:14:35.799 --> 00:14:39.279 Let us mao fries please double quarter pounder, disopyramid, quinityde 300 00:14:39.320 --> 00:14:42.000 and prokanamide that's your Class one A. Let us mao 301 00:14:42.159 --> 00:14:44.799 lytokane and mixilotine that's your Class one B. And then 302 00:14:44.879 --> 00:14:48.480 fries please fleckenide and propafenone Class one C. These drugs 303 00:14:48.480 --> 00:14:51.000 slow down the influx of sodium during phase zero. And 304 00:14:51.080 --> 00:14:52.960 remember the more salt in the food, the more it 305 00:14:53.039 --> 00:14:55.960 blocks sodium channels. Remember your double quarter pounder is on 306 00:14:56.080 --> 00:14:58.039 a foot long hot dog bund To help you remember 307 00:14:58.080 --> 00:15:01.519 your Class one A drugs can prolong the QT interval, torsad, 308 00:15:01.600 --> 00:15:06.240 et cetera. Remember quinidine can cause synchronism. Procanamide aka protranamide. 309 00:15:06.240 --> 00:15:08.440 Remember your white wolf driving the train on a loop 310 00:15:08.480 --> 00:15:11.879 track Wolf Parkinson White and lupis Class one B letacanum, 311 00:15:11.919 --> 00:15:15.000 oxilotine use on your fast and filling ventricular tissue. And 312 00:15:15.080 --> 00:15:18.559 Class one C fleckanide and propafenone. Most importantly, remember these 313 00:15:18.639 --> 00:15:22.320 drugs are contraindicated with structural heart disease postami, et cetera. 314 00:15:22.600 --> 00:15:25.080 Remember after an MI, I swap your fries out for 315 00:15:25.080 --> 00:15:28.039 a salad. That's your sodium channel blockers. Next, let's talk 316 00:15:28.039 --> 00:15:31.120 about Class two, which are beta blockers. You're probably already 317 00:15:31.120 --> 00:15:33.240 familiar with this class as we use these meds for 318 00:15:33.320 --> 00:15:36.000 hypertension as well as a number of other indications. And 319 00:15:36.039 --> 00:15:38.320 if you ever forget which med class is part of 320 00:15:38.360 --> 00:15:41.559 Class two, remember B is the second letter of the alphabet, 321 00:15:41.600 --> 00:15:43.919 and beta blockers which start with a B are our 322 00:15:44.000 --> 00:15:46.600 Class two agents. So these drugs, in addition to their 323 00:15:46.639 --> 00:15:51.080 anti hypertensive properties, also have anti arrhythmic properties. Luckily, remembering 324 00:15:51.120 --> 00:15:53.039 the names of these meds is a whole lot easier 325 00:15:53.039 --> 00:15:55.519 compared to your sodium channel blockers, because all of these 326 00:15:55.559 --> 00:15:59.080 drugs end in LOL, like a tenelol, propranolol, Carbada law, 327 00:15:59.080 --> 00:16:02.360 and mitoprolol. So all beta blockers end in l OL, 328 00:16:02.799 --> 00:16:07.320 and most but not all end in ol l ol L. 329 00:16:07.759 --> 00:16:10.080 And here's something important that I want you to recognize. 330 00:16:10.120 --> 00:16:12.159 If you see a beta blocker that does not end 331 00:16:12.200 --> 00:16:15.279 in olol, you need to know that this is going 332 00:16:15.320 --> 00:16:17.759 to be a unique or let's say a fancy beta 333 00:16:17.759 --> 00:16:19.879 blocker that does something a little extra. So if a 334 00:16:19.960 --> 00:16:23.000 beta blocker does not end in olol, it's usually because 335 00:16:23.039 --> 00:16:26.879 it has extra properties beyond standard beta blockade, like alpha 336 00:16:26.879 --> 00:16:29.440 blockade that we see in Carvata law and Libata law, 337 00:16:29.720 --> 00:16:34.080 which end in ilol and alo l respectively, or potassium 338 00:16:34.120 --> 00:16:37.279 channel blockade that we see in sodolol, which ends in alol. 339 00:16:37.639 --> 00:16:39.879 So when you see a beta blocker, check the suffix. 340 00:16:39.960 --> 00:16:43.320 If it ends in olol like mitopralaw, it'll lack primarily 341 00:16:43.360 --> 00:16:46.120 through standard beta blockade. If it ends a little differently 342 00:16:46.200 --> 00:16:49.399 like lo betalall alol. You'll know it has some additional 343 00:16:49.399 --> 00:16:52.399 properties beyond standard beta blockade. Now, how do these drugs work? 344 00:16:52.480 --> 00:16:54.919 So for that, let's look back at our cardiac action 345 00:16:55.000 --> 00:16:57.200 potential again, but this time we're going to be looking 346 00:16:57.240 --> 00:17:00.120 at our cardiac action potential of our pacemaker cells. So 347 00:17:00.200 --> 00:17:02.679 this is a little different. This action potential only has 348 00:17:02.840 --> 00:17:06.359 three phases, phases zero, three, and four. So let's start 349 00:17:06.359 --> 00:17:08.960 with phase four, which before we called the floor as 350 00:17:09.000 --> 00:17:11.279 this was almost a flat period with not much happening. 351 00:17:11.519 --> 00:17:13.400 But now in phase four it's a little different. You're 352 00:17:13.400 --> 00:17:16.079 going to notice there's this little upward slope, and that's 353 00:17:16.079 --> 00:17:18.640 because in phase four we now have this slow leak 354 00:17:18.680 --> 00:17:22.279 of sodium sneaking through these pacemaker channels. This is sometimes 355 00:17:22.359 --> 00:17:24.960 called the funny current. In addition, and very important, during 356 00:17:25.000 --> 00:17:28.400 phase four, we also have calcium influx, which is first 357 00:17:28.480 --> 00:17:31.359 through T type calcium channels and then a little later 358 00:17:31.400 --> 00:17:34.799 on through L type calcium channels, which ultimately depolarized the 359 00:17:34.799 --> 00:17:37.839 membrane to its threshold potential. Next this phase zero, where 360 00:17:37.880 --> 00:17:41.519 we have calcium continuing to enter through, producing a slower 361 00:17:41.599 --> 00:17:44.440 upstroke than the fast sodium driven spike of our cardio 362 00:17:44.519 --> 00:17:47.599 myocytes we were talking about before. And then finally phase three, 363 00:17:47.640 --> 00:17:51.559 which is repolarization, follows as calcium channels close and guess 364 00:17:51.599 --> 00:17:54.839 who starts to leave yet potassium, the party pooper flows out, 365 00:17:54.880 --> 00:17:57.279 which brings us back to phase four once more. And 366 00:17:57.400 --> 00:18:00.119 as you can see, I didn't mention phase one one 367 00:18:00.200 --> 00:18:02.359 or two, and that's because our pacemaker cells lack a 368 00:18:02.440 --> 00:18:04.920 distinct phase one or two. All right, So, now that 369 00:18:04.960 --> 00:18:08.359 we understand the pacemaker action potential, how do beta blockers 370 00:18:08.440 --> 00:18:11.960 influence this to help treat arrhythmias? Well, indirectly by preventing 371 00:18:12.000 --> 00:18:15.759 epinefrin and nore epinefrin from binding to the beta receptors. 372 00:18:15.839 --> 00:18:17.960 So how the heck does that help us treat arrhythmias 373 00:18:18.000 --> 00:18:20.039 and how does that impact the action potential? So in 374 00:18:20.079 --> 00:18:24.279 the heart, we have beta receptors, primarily beta one adrenergic receptors, 375 00:18:24.400 --> 00:18:27.079 and when catechola means like EPI and nor epi bind 376 00:18:27.160 --> 00:18:30.359 to these receptors, this long chain of events occurs. First, 377 00:18:30.400 --> 00:18:35.000 the enzyme IDENTL cyclosis activated, which converts ATP into CIMP. 378 00:18:35.519 --> 00:18:40.200 CIMP activates pKa, which phosphorulates L type calcium channels, causing 379 00:18:40.240 --> 00:18:42.880 them to open leading to an influx of calcium. Ugh, 380 00:18:43.519 --> 00:18:45.319 So what do you need to actually remember from that? 381 00:18:45.640 --> 00:18:47.519 So all you really need to know is that when 382 00:18:47.559 --> 00:18:50.440 EPI and nor rep bind to these receptors, a bunch 383 00:18:50.440 --> 00:18:52.799 of stuff happens which leads to more calcium in the cell. 384 00:18:53.160 --> 00:18:56.039 So if we block these receptors, we block these beta 385 00:18:56.039 --> 00:18:59.799 receptors with a beta blocker, we block epianore epi from binding, 386 00:19:00.079 --> 00:19:02.920 which ultimately slows the influx of calcium. And this is 387 00:19:02.960 --> 00:19:07.039 primarily at the end of phase four, which decreases that slope, 388 00:19:07.119 --> 00:19:09.160 which makes it take longer for the cell to reach 389 00:19:09.160 --> 00:19:12.359 the action potential threshold. So we have a decrease slope 390 00:19:12.400 --> 00:19:15.240 of phase four in our pacemaker cells. So in turn, 391 00:19:15.279 --> 00:19:17.720 the SA node is going to fire less often and 392 00:19:17.799 --> 00:19:20.880 the AV node is going to conduct more slowly, both 393 00:19:20.880 --> 00:19:23.440 of which help control heart rate and are especially useful 394 00:19:23.480 --> 00:19:27.039 in treating tacharithms like atrofibrillation. Now, beta blockers also have 395 00:19:27.119 --> 00:19:30.240 effects on non pacemaker cells like our cardiomyocytes, and in 396 00:19:30.319 --> 00:19:34.480 these cells, by decreasing calcium influx, they decrease cardiac contractility, 397 00:19:34.519 --> 00:19:37.799 decreasing oxygen demand for these cells. So this is really 398 00:19:37.839 --> 00:19:40.720 a lot of info, but really, here's the main takeaway 399 00:19:40.799 --> 00:19:42.920 in the simple recap of what you should know in 400 00:19:43.039 --> 00:19:45.839 just a few words. So, beta blockers stop EPI and 401 00:19:45.880 --> 00:19:49.920 nor epi from binding, which indirectly decreases calcium influx, which 402 00:19:49.960 --> 00:19:52.480 flattens our phase four slope. So that's what I think 403 00:19:52.519 --> 00:19:54.519 you should know. Now, what are the common indications for 404 00:19:54.559 --> 00:19:56.720 this class of drugs you should know? Of course, beta 405 00:19:56.720 --> 00:19:59.519 blockers are used in a number of different conditions, but 406 00:19:59.559 --> 00:20:01.759 when it comes us so they're anti rhythmic indications. The 407 00:20:01.799 --> 00:20:04.599 one you should know is for rate control in atrial 408 00:20:04.640 --> 00:20:09.000 fibrillation and atrial flutter. They can also be used in SVT, postmat, 409 00:20:09.160 --> 00:20:11.880 et cetera. But please remember rate control in a fib 410 00:20:11.920 --> 00:20:14.559 and a flutter. That's the most common and most important. Okay, 411 00:20:14.599 --> 00:20:16.359 So now I want to go over some extra tips 412 00:20:16.359 --> 00:20:18.799 for beta blockers and of course a whole bunch of demonics. 413 00:20:18.880 --> 00:20:21.160 So first, not all beta blockers are the same. We 414 00:20:21.240 --> 00:20:24.319 have cardio selective beta blockers that primarily just block the 415 00:20:24.319 --> 00:20:26.640 beta one receptors in the heart, and then we have 416 00:20:26.799 --> 00:20:29.799 non selective that also block beta two receptors which can 417 00:20:29.839 --> 00:20:32.839 be found in smooth muscle cells GI tract uterus. But 418 00:20:32.920 --> 00:20:35.799 most importantly in the lungs, where they can induce broncho 419 00:20:35.839 --> 00:20:39.440 dilation when stimulated. Remember the demonic beta one primarily found 420 00:20:39.440 --> 00:20:41.640 in the heart. You have one heart, beta two, which 421 00:20:41.680 --> 00:20:43.480 can be found in the lungs. You have two lungs, 422 00:20:43.599 --> 00:20:45.279 which just helps you to remember it. Now, there's a 423 00:20:45.319 --> 00:20:47.160 bunch of beta blockers, so how the heck can you 424 00:20:47.200 --> 00:20:50.279 remember which are cardio selective and which are non selective. 425 00:20:50.640 --> 00:20:53.319 Remember that a beam of light is selective to just 426 00:20:53.359 --> 00:20:56.400 one area. A beam B, E, A M is selective 427 00:20:56.440 --> 00:20:58.680 to just one area, So if the beta blocker starts 428 00:20:58.680 --> 00:21:02.839 with a BA or M, it's cardio selective. So B EA, M, 429 00:21:03.119 --> 00:21:07.480 B stands for bisoprolol or a bitaxilol. E stands for esmolol, 430 00:21:07.880 --> 00:21:10.440 A stands for a tenolol or asputle all, and then 431 00:21:10.720 --> 00:21:13.240 M stands from a toprolall. So you really don't even 432 00:21:13.279 --> 00:21:15.359 need to remember all of the specific names. All you 433 00:21:15.440 --> 00:21:17.799 need to remember is that a beam is a direct 434 00:21:17.839 --> 00:21:19.880 or selective light, Meaning if a beta blocker in the 435 00:21:19.920 --> 00:21:22.400 question starts with A B, E, A or M, it's 436 00:21:22.440 --> 00:21:24.920 cardio selective. So if they ask you a question like 437 00:21:25.000 --> 00:21:27.119 you decide to treat this patient with a beta blocker 438 00:21:27.160 --> 00:21:30.480 who has a history of mild to moderate at bronchospastic disease, 439 00:21:30.640 --> 00:21:32.920 which would be the preferred beta blocker to use. So 440 00:21:33.000 --> 00:21:34.640 all you need to do is find when that starts 441 00:21:34.680 --> 00:21:37.519 with beam b EA m as. The cardio selectivity makes 442 00:21:37.559 --> 00:21:39.680 this a safer drug for this population. So this is 443 00:21:39.720 --> 00:21:41.839 great for exam knowledge, but for real life, what you 444 00:21:41.839 --> 00:21:45.000 should know is that even cardio selective agents can exert 445 00:21:45.039 --> 00:21:47.759 some inhibition of beta two receptors at high doses. So 446 00:21:47.759 --> 00:21:51.319 if you had a patient with severe or decompensated bronchospastic disease, 447 00:21:51.519 --> 00:21:53.599 you don't want to avoid all beta blockers in these patients, 448 00:21:53.640 --> 00:21:56.240 selective and non selective. Okay, Next, I want to segue 449 00:21:56.240 --> 00:22:00.400 into anomodic to help you remember the contraindications slash warnings 450 00:22:00.440 --> 00:22:02.480 of this class of drugs. So to help you remember 451 00:22:02.480 --> 00:22:06.039 the common and most tested on remember the demonic ABCD. 452 00:22:06.359 --> 00:22:11.920 ABCD stands for asthma, bradacardia, cardiogenic shock and diabetes asthma 453 00:22:11.960 --> 00:22:15.319 braidacardia cardiogenic shock diabetes. So let's break them down. A 454 00:22:15.480 --> 00:22:17.599 stands for asthma, which we just talked about, so I 455 00:22:17.640 --> 00:22:20.160 won't go into great detail, but beta blockade with non 456 00:22:20.160 --> 00:22:24.119 selective agents prevents bronchodilation, so non selective beta blockers should 457 00:22:24.160 --> 00:22:27.400 be avoided in susceptible patients asthma et cetera, and in 458 00:22:27.440 --> 00:22:29.720 severe disease, you really want to avoid all beta blockers, 459 00:22:29.920 --> 00:22:33.640 even the selective agents. Next B stands for bradacardia. These 460 00:22:33.680 --> 00:22:36.920 mens have negative chronotropic effects. They slow the heart rate, 461 00:22:37.160 --> 00:22:41.640 so they're relatively contraindicated in symptomatic bradacardia, sinus nod dysfunction, 462 00:22:41.759 --> 00:22:44.119 and in patients with second or third degree av block 463 00:22:44.319 --> 00:22:47.599 unless a pacemaker's present C stands for cardiogenic shock or 464 00:22:47.640 --> 00:22:52.079 severely decompensated heart failure. So while beta blockers improve survival 465 00:22:52.160 --> 00:22:55.640 in stable chronic heart failure, initiation should be avoided in 466 00:22:55.799 --> 00:22:59.920 severe acute de compensation or cardiogenic shock, as in these states, 467 00:23:00.000 --> 00:23:02.440 the heart depends on the sympathetic drive the beta one 468 00:23:02.440 --> 00:23:05.720 stimulation to maintain output, which beta blockers shut down. So 469 00:23:05.839 --> 00:23:09.240 blocking beta one receptors reduces contractility and heart rate, which 470 00:23:09.279 --> 00:23:12.160 can worsen shock. Finally, the D stands for diabetes. This 471 00:23:12.200 --> 00:23:14.680 is more of a caution rather than a contraindication, but 472 00:23:14.720 --> 00:23:17.279 one that's important to know. So beta blockers can mask 473 00:23:17.440 --> 00:23:21.720 hypoglycemia symptoms like sweating anxiety, which are mediated by epinephrine, 474 00:23:21.720 --> 00:23:24.599 which they block. They also may delay recovery from insulin 475 00:23:24.599 --> 00:23:30.079 induced hypoglycemia by blunting epinephrin's effect on gluconeogenesis and glycogenolysis. 476 00:23:30.160 --> 00:23:32.480 Although the studies are a bit more conflicting in this area, 477 00:23:32.599 --> 00:23:35.359 but the main takeaway use these in caution with diabetics. 478 00:23:35.359 --> 00:23:37.400 All right, that's your beta blockers. Quick recap of the 479 00:23:37.519 --> 00:23:40.680 juicy details are class two antierrhythmics. Remember the second letter 480 00:23:40.680 --> 00:23:43.160 of the alphabet is B, and beta blockers which start 481 00:23:43.160 --> 00:23:45.720 with a B are r Class two antierythmics. All drugs 482 00:23:45.720 --> 00:23:49.000 in this class end in lol and most end in olol. 483 00:23:49.279 --> 00:23:51.839 The ones that don't got something special about them. Beta 484 00:23:51.880 --> 00:23:54.240 blockers block epian or EPI from binding to our beta 485 00:23:54.240 --> 00:23:58.279 one receptors in the heart, indirectly decreasing intracellular calcium influx, 486 00:23:58.519 --> 00:24:01.200 decreasing the slope of phase four. The main indication I 487 00:24:01.200 --> 00:24:03.680 would know is rate control in a fib and a flutter. 488 00:24:03.880 --> 00:24:08.079 Remember your cardio selective beta blockers with beam bisoprolol, bitaxilaw 489 00:24:08.160 --> 00:24:12.279 asmolol atenolol, aceputle law, metoprol law. Finally, remember your common 490 00:24:12.319 --> 00:24:18.680 contraindication slash warnings for beta blockers ABCD, asthma, bradacardia, cardiogenic shock, diabetes. 491 00:24:18.880 --> 00:24:21.160 That's your beta blockers. We're halfway there. Let's talk about 492 00:24:21.160 --> 00:24:25.599 our class three antiarithmics. Next are potassium channel blockers. There's 493 00:24:25.599 --> 00:24:30.880 a few different drugs in this class, amiodorone, dronetarone, ammutilide, dofeedolide, sodolol. Honestly, 494 00:24:30.920 --> 00:24:33.599 you should really just focus on amiodorone and maybe sodolol. 495 00:24:33.759 --> 00:24:35.440 But there is a nomonic to help you remember all 496 00:24:35.480 --> 00:24:37.720 of them if you choose to. And the mnemonic is 497 00:24:37.839 --> 00:24:40.640 and I'm sorry for this, but thenomonic is AIDS ai 498 00:24:40.759 --> 00:24:47.079 DS AIDS stands for a amiodorone, I, abutilide, d do feedolide, slash, dronetarone, 499 00:24:47.119 --> 00:24:50.400 and s sotolol. And to further help solidify this demonic 500 00:24:50.440 --> 00:24:52.839 and help you remember that the AIDS mnemonic is associated 501 00:24:52.880 --> 00:24:55.960 with potassium channel blockers, you can remember the sentence can't 502 00:24:56.000 --> 00:24:59.759 cure aids with potassium can't cure aids with potassium with 503 00:25:00.079 --> 00:25:02.039 can't and cure spelled with a K instead of C 504 00:25:02.240 --> 00:25:04.839 to help you remember the chemical symbol for potassium. I 505 00:25:04.880 --> 00:25:07.759 apologize it's not the most appropriate nomonic in dynomonics from 506 00:25:07.759 --> 00:25:09.799 here on out. Well, you'll see, all right, So how 507 00:25:09.839 --> 00:25:11.400 do these drugs work. Well, for that, we need to 508 00:25:11.440 --> 00:25:14.200 go back to our cardiac action potential of the cardiomyocytes 509 00:25:14.240 --> 00:25:17.079 we were discussing before, the one with five phases. So 510 00:25:17.119 --> 00:25:19.720 remember potassium, the party pooper who kept leaving the party 511 00:25:19.759 --> 00:25:23.480 and ultimately in phase three just flooded out, leading to repolarization. Well, 512 00:25:23.480 --> 00:25:24.960 what if we had a drug that could come in 513 00:25:25.000 --> 00:25:26.960 and just block the door and not let him out 514 00:25:27.039 --> 00:25:29.799 during phase three, making him just hang around. Well, that's 515 00:25:29.799 --> 00:25:33.119 our potassium channel blockers are class three drugs which block 516 00:25:33.240 --> 00:25:37.960 potassium eflux during phase three, prolonging phase three repolarization. So 517 00:25:38.039 --> 00:25:41.200 these drugs bind and inhibit potassium channels, meaning we have 518 00:25:41.319 --> 00:25:44.279 less potassium leaving the cell, which leads to a slower 519 00:25:44.359 --> 00:25:48.759 rate of repolarization, prolonging the action potential and effective refractory period. 520 00:25:49.119 --> 00:25:51.920 And this increase in the refractory period helps because this 521 00:25:52.039 --> 00:25:54.799 essentially lengthens the period of time the cell can kind 522 00:25:54.839 --> 00:25:57.079 of hang out before being stimulated again, we give it 523 00:25:57.119 --> 00:26:00.359 a little breathing room which helps interrupt re entrant arrhythmia. Now, 524 00:26:00.400 --> 00:26:03.920 the problem with prolonging things, prolonging the action potential in particular, 525 00:26:04.359 --> 00:26:05.960 is we get a new problem. And I'll give you 526 00:26:05.960 --> 00:26:08.240 a second to think about what that problem may be. 527 00:26:08.599 --> 00:26:11.319 What was another med class or subclass we talked about 528 00:26:11.319 --> 00:26:14.640 that also blocked potassium. It involved a foot long hot 529 00:26:14.640 --> 00:26:17.920 dog bund. That's right, our Class one A sodium channel blockers, 530 00:26:18.039 --> 00:26:20.079 the double quarter pounder on a foot long hot dog 531 00:26:20.119 --> 00:26:22.680 bund also blocked potassium and they led to the same 532 00:26:22.680 --> 00:26:25.680 issue we'll go over now, which is prolonged QT interval 533 00:26:25.720 --> 00:26:28.000 with the potential of developing towards sad de point, so 534 00:26:28.039 --> 00:26:30.440 a significant adverse effect that you need to be aware 535 00:26:30.440 --> 00:26:32.920 of for these medications. Of note, this is much less 536 00:26:32.920 --> 00:26:35.799 common with amiodorone androneterone compared to the other meds in 537 00:26:35.799 --> 00:26:37.880 this class. But you need to remember your Class three 538 00:26:37.880 --> 00:26:40.880 potassium channel blockers can prolong the QT interval, and so 539 00:26:41.000 --> 00:26:43.119 can your Class one A sodium channel blockers we went 540 00:26:43.160 --> 00:26:45.440 over before. Please remember this as it will likely be 541 00:26:45.480 --> 00:26:47.640 tested on all. Right, moving on, what are the indications 542 00:26:47.640 --> 00:26:51.279 for our class three drugs, So some indications are atrial fibrillation, 543 00:26:51.400 --> 00:26:55.240 atrial flutter, ventricular tachycardia. Amiodorone, really, the only one you 544 00:26:55.240 --> 00:26:57.960 should focus on is a powerful anti arrhythmic used for 545 00:26:58.039 --> 00:27:01.440 both atrial and ventricular arrhythmia, limited only by its side 546 00:27:01.440 --> 00:27:04.519 effect profile or only, It's most often prescribed to prevent 547 00:27:04.599 --> 00:27:08.920 atrial fibrillation and ventricular arrhythmias. Intravenously. It's used in critically 548 00:27:08.960 --> 00:27:12.000 ill patients with a fib to restore sinus rhythm, control 549 00:27:12.079 --> 00:27:15.920 ventricular rate, or convert ventricular arrhythmias, and like letocaine, it 550 00:27:15.960 --> 00:27:18.400 also plays a key role in our ACLS protocol. So 551 00:27:18.440 --> 00:27:20.680 let's talk a bit more about amiodorone, because I feel 552 00:27:20.720 --> 00:27:22.279 like if you're going to get a question about a 553 00:27:22.279 --> 00:27:25.160 class three anti arrhythmic, it's going to be on amiodorone, 554 00:27:25.200 --> 00:27:27.960 and not only that, amiodorone is just a really cool drug. 555 00:27:28.200 --> 00:27:32.240 So first, remember amiodorone as AM three odorone instead of 556 00:27:32.319 --> 00:27:36.680 am eodorone. Remember am three odorone as in the number three. 557 00:27:36.839 --> 00:27:38.920 So a year from now, when you forget all about 558 00:27:38.920 --> 00:27:40.599 this lecture and you get a test question that has 559 00:27:40.599 --> 00:27:43.400 amiodorone on it, and you forget everything about it. If 560 00:27:43.440 --> 00:27:46.319 you always remember it as AM three odorone instead of 561 00:27:46.359 --> 00:27:50.119 am eodorone, you'll never forget it's a class three anti arrhythmic. Now, 562 00:27:50.119 --> 00:27:52.640 on that note, even though this medication is classified as 563 00:27:52.640 --> 00:27:55.759 a class three anti arrhythmic as it does block potassium channels, 564 00:27:56.039 --> 00:27:59.160 it also blocks sodium channels like a class one, beta 565 00:27:59.160 --> 00:28:02.640 adrenergic recept like a class two, and calcium channels like 566 00:28:02.640 --> 00:28:06.119 a class four. Pretty crazy. Dronetarone, another class three drug 567 00:28:06.119 --> 00:28:09.319 which is structurally similar to amiodorone, just lacking the iodine group, 568 00:28:09.559 --> 00:28:12.720 also blocks all four channels. So maybe not super high yield, 569 00:28:12.720 --> 00:28:15.279 but pretty cool. Okay. Next, let's cover potentially the highest 570 00:28:15.279 --> 00:28:18.640 sealed thing to know about amiodorone, and that's its adverse effects. So, 571 00:28:18.720 --> 00:28:22.160 amiodorone is highly lipid soluble, so it accumulates in all 572 00:28:22.160 --> 00:28:24.200 different tissues throughout the body, which is part of the 573 00:28:24.200 --> 00:28:27.160 reason it has so damn many side effects. Oral amiodorone 574 00:28:27.160 --> 00:28:29.680 has a super long half life hangs around for up 575 00:28:29.680 --> 00:28:31.720 to one hundred plus days in some cases, so this 576 00:28:31.799 --> 00:28:33.880 is probably the highest heeled thing to know about amiodorone. 577 00:28:33.920 --> 00:28:36.240 It's adverse effects, So how do you remember the adverse 578 00:28:36.279 --> 00:28:39.480 effects of amiodorone. Well, unfortunately, all of the class three 579 00:28:39.519 --> 00:28:42.279 and four drug demonics are inappropriate and it's not on purpose, 580 00:28:42.319 --> 00:28:44.720 it's just what works out with the letters. So I'm sorry, 581 00:28:44.759 --> 00:28:46.960 but all right, So if the adverse effects, remember taking 582 00:28:46.960 --> 00:28:52.279 amiodorone is a bitch. Taking amiodorone is a bitch. Which 583 00:28:52.319 --> 00:28:56.559 stands for blue skin, interstitial lung disease, thyrotoxicity, coronal deposits 584 00:28:56.640 --> 00:29:00.680 of patotoxicity. So starting with b amiodorone can cause blue skin. 585 00:29:00.839 --> 00:29:03.920 Amiodorone can cause a bluish gray discoloration of the skin, 586 00:29:04.200 --> 00:29:06.759 sometimes called blue man syndrome. This is going to be 587 00:29:06.799 --> 00:29:10.960 most prominent on the face. There's other skin issues photosensitivity, hyperpigmentation, 588 00:29:11.039 --> 00:29:13.440 but don't forget the blue skin. Next eye stands for 589 00:29:13.480 --> 00:29:17.880 interstitial lung disease. Amiodorone induced pulmonary toxicity is found in 590 00:29:17.960 --> 00:29:20.359 up to five percent of patients. Most common form is 591 00:29:20.400 --> 00:29:23.400 interstitial pneuminitis. So before you start a patient on amiodorone, 592 00:29:23.440 --> 00:29:25.960 you should obtain a baseline chest X ray to ensure 593 00:29:26.000 --> 00:29:29.559 there isn't any evidence of existing interstitial lung disease. Next 594 00:29:29.599 --> 00:29:32.559 is probably the most important one, and that's thyroid toxicity 595 00:29:32.799 --> 00:29:36.640 thyroid toxicity, so amiodorone contains high amounts of iodine. That's 596 00:29:36.640 --> 00:29:39.799 actually the reason the name Amiodoron contains the letter's iod 597 00:29:40.000 --> 00:29:43.000 It's suited the fact amiodorone contains two iodine atoms per 598 00:29:43.039 --> 00:29:46.079 molecule in its chemical structure, and since iodine is a 599 00:29:46.160 --> 00:29:49.480 key substrate for thyroid hormone synthesis, this iodine load can 600 00:29:49.480 --> 00:29:53.759 disrupt thyroid function, leading to either hypo or hyperthyroidism. Thyroidys 601 00:29:53.839 --> 00:29:56.079 function is actually one of the most common complications of 602 00:29:56.119 --> 00:29:58.960 amiodoron therapy and because of this, patient should have baseline 603 00:29:58.960 --> 00:30:02.160 thyroid function tests such as TSH before starting the medication 604 00:30:02.200 --> 00:30:05.440 and should be monitored periodically during treatment. Next is the C, 605 00:30:05.680 --> 00:30:09.680 which stands for cornial microdeposits. So these microdeposits occur and 606 00:30:09.720 --> 00:30:12.880 the majority of patients taking amiodorone. They're typically benign and 607 00:30:12.880 --> 00:30:16.640 don't affect visual acuity. They result from amourone being secreted 608 00:30:16.680 --> 00:30:19.799 into the tiers by the lacrymal glands and gradually accumulate 609 00:30:19.799 --> 00:30:23.160 on the cornial surface, but generally resolve after discontinuation of 610 00:30:23.160 --> 00:30:25.160 the drug. And then finally we have H, which stands 611 00:30:25.200 --> 00:30:28.039 for patotoxicity. So around twenty five percent of patients taking 612 00:30:28.039 --> 00:30:32.400 amiodorone will have a transient rise and serum aminotransfhrase concentrations 613 00:30:32.599 --> 00:30:35.359 our liver function tests so ast ALT can go up. 614 00:30:35.400 --> 00:30:38.400 Most patients are asymptomatic, Habititis occurs in fewer than three 615 00:30:38.400 --> 00:30:41.480 percent of patients, and cirrhosis and hepatic failure are rare. 616 00:30:41.559 --> 00:30:43.480 So have this tear checklist of the many organs you 617 00:30:43.519 --> 00:30:46.599 will need to check before starting amiodorone. Baseline LFT should 618 00:30:46.599 --> 00:30:49.359 be attained prior to initiation, as well as checking during therapy. 619 00:30:49.400 --> 00:30:51.759 All right, so remember taking amiodone, as you can tell, 620 00:30:51.880 --> 00:30:58.319 is a bitch. Blue skin, interstitial lung disease, thyrotoxicity, cornial deposits, hepatotoxicity. 621 00:30:58.640 --> 00:31:00.839 One other class three met I want to briefly mention 622 00:31:00.920 --> 00:31:03.480 before we wrap up. This class is SODOLOL. So before 623 00:31:03.480 --> 00:31:05.599 I tell you why this med is unique, I want 624 00:31:05.640 --> 00:31:07.920 you to think and look at the name and think 625 00:31:07.960 --> 00:31:12.240 about what's unique about it. It's spelled so ta l 626 00:31:12.319 --> 00:31:15.039 O L so first it ends in LOL, so it's 627 00:31:15.039 --> 00:31:17.400 a beta blocker. But remember what we talked about before 628 00:31:17.440 --> 00:31:21.240 with beta blockers. If they end in olol, traditional beta 629 00:31:21.279 --> 00:31:24.079 blocker anything else, we know they have some additional properties. 630 00:31:24.319 --> 00:31:27.319 So sodolol ends in a lool, so we know there's 631 00:31:27.400 --> 00:31:29.839 more than just traditional beta blockade with this MED. And 632 00:31:29.880 --> 00:31:31.839 in this case it's pretty obvious as we're talking about 633 00:31:31.880 --> 00:31:34.880 potassium channel blockers right now, so we know sodolol also 634 00:31:34.960 --> 00:31:38.559 has potassium channel blocking abilities in addition to beta blockade, 635 00:31:38.599 --> 00:31:40.680 and that's why it's considered a Class three MED. But 636 00:31:40.799 --> 00:31:42.799 later on, when you see this on an exam question, 637 00:31:42.839 --> 00:31:45.000 you'll likely remember it's a beta blocker due to the 638 00:31:45.119 --> 00:31:47.160 lol at the end, but it's easy to forget it's 639 00:31:47.160 --> 00:31:49.839 also a potassium channel blocker. So because of that, I 640 00:31:49.920 --> 00:31:53.359 used to remember it instead of sodolol as so potolol. 641 00:31:53.680 --> 00:31:57.240 Instead of sodolol, remember it as so potolol so ptalol. 642 00:31:57.359 --> 00:31:59.920 The pot helps me remember that in addition to be 643 00:32:00.119 --> 00:32:03.799 a beta blocker, it's also a pot potassium channel blocker, 644 00:32:04.000 --> 00:32:06.799 So instead of sodolol, remember it as sopotolol. All right, 645 00:32:06.839 --> 00:32:09.319 that's our Class three anti rhythmics remember the meds by 646 00:32:09.319 --> 00:32:14.960 remembering the mnemonic aids aids amiodorone abutilid doftolide slash droneterone 647 00:32:15.000 --> 00:32:18.000 and sodolol. You can't cure aids with potassium. Remember they 648 00:32:18.039 --> 00:32:22.160 block potassium e flux during phase three, prolonging phase three repolarization. 649 00:32:22.480 --> 00:32:25.240 These drugs can prolong the QT interval with the potential 650 00:32:25.279 --> 00:32:28.519 of developing torsades. The highest yield meant to know is amiodorone. 651 00:32:28.519 --> 00:32:31.559 Remember instead of am eodorone, remember it as am three 652 00:32:31.599 --> 00:32:34.039 odorone to help you remember it's a class three anti arrhythmic. 653 00:32:34.279 --> 00:32:36.799 To remember the super high yield adverse drug reactions, remember 654 00:32:36.839 --> 00:32:42.279 taking amiodone is a bitch blueskin, interstitial lung disease, thyrotoxicity, 655 00:32:42.319 --> 00:32:46.240 corneal deposits, patotoxicity. And finally, remember sotolol is a beta 656 00:32:46.240 --> 00:32:48.839 blocker as well as a class three potassium channel blocker. 657 00:32:48.880 --> 00:32:52.039 Remember it as sopotolol instead of sodolol. Let's move on 658 00:32:52.079 --> 00:32:54.640 to our final class class four drugs next. So our 659 00:32:54.640 --> 00:32:57.279 class four drugs are calcium channel blockers. So in this 660 00:32:57.319 --> 00:32:59.720 class it's much easier as there's only two mets to 661 00:32:59.759 --> 00:33:02.359 know and that's verrapimil and doltize them. And if you 662 00:33:02.359 --> 00:33:04.640 need help remembering these two meds are Class four meds 663 00:33:04.640 --> 00:33:07.720 and I'm sorry another inappropriate nomonic, but remember the sentence. 664 00:33:08.119 --> 00:33:11.640 Four nication leads to venereal disease. Four nication helps you 665 00:33:11.680 --> 00:33:14.839 remember class four venereal disease which starts with the vee 666 00:33:15.039 --> 00:33:17.480 and d I. Help your remember of rapimil and dultize them, 667 00:33:17.519 --> 00:33:20.039 which also start with vee and d I. Four nication 668 00:33:20.319 --> 00:33:22.720 leads to veneeral disease. Helps you remember your class four 669 00:33:22.759 --> 00:33:25.240 meds of rapamil and do tie them now. The next 670 00:33:25.279 --> 00:33:27.319 question you might ask yourself is class four meads are 671 00:33:27.359 --> 00:33:29.400 calcium channel blockers. And we know there's a bunch of 672 00:33:29.440 --> 00:33:32.359 calcium channel blockers, So why are we only listing two meds? 673 00:33:32.559 --> 00:33:34.640 What about all of the other calcium channel blockers like 674 00:33:34.759 --> 00:33:37.079 m lodopene, ni fetipene, et cetera. Why are we only 675 00:33:37.119 --> 00:33:39.559 discussing del tiem and vrapimil. So for that, we need 676 00:33:39.559 --> 00:33:42.200 to quickly review the different types of calcium channel blockers 677 00:33:42.200 --> 00:33:44.480 and what they do. So there's two different types of 678 00:33:44.519 --> 00:33:49.880 calcium channel blockers non dihydropyridine and dihydropyridine non dehydropyridine are 679 00:33:49.960 --> 00:33:52.680 deltizem and veropimil, which will go over more in a moment, 680 00:33:52.960 --> 00:33:57.119 and dihydropyridine are all of the others, and lodopene, ni, fetipene, nicardipene, 681 00:33:57.160 --> 00:34:00.400 et cetera. The nice part about this is dihydropyridine ends 682 00:34:00.400 --> 00:34:03.920 in IE, and so do all of the dihydropuritine calcium 683 00:34:03.960 --> 00:34:07.880 channel blockers M lodopene i E, nipetipene i E, et cetera. 684 00:34:08.239 --> 00:34:11.440 The non dihydropyridine meds are the non I E meds 685 00:34:11.480 --> 00:34:13.639 don't tie them, and verrapimel that do not end in 686 00:34:13.679 --> 00:34:15.880 in E. It's a nice easy way to differentiate the two, 687 00:34:15.960 --> 00:34:18.400 So to keep this brief, both of these subclasses inhibit 688 00:34:18.440 --> 00:34:20.800 the L type calcium channels on cells, which will go 689 00:34:20.800 --> 00:34:22.880 over in more detail in a second. But the big 690 00:34:22.880 --> 00:34:27.039 difference is that dihydropyridines are I in E meds, AM, lodopen, niphetipene, 691 00:34:27.039 --> 00:34:30.440 et cetera primarily target the calcium channels on vascular smooth 692 00:34:30.480 --> 00:34:33.239 muscle tissue, so they're great for treating hypertension as they 693 00:34:33.239 --> 00:34:37.400 cause vasodielation of these vessels, reducing systemic vascular resistance, but 694 00:34:37.480 --> 00:34:40.719 exert minimal direct effects on the myocardium. That's where our 695 00:34:40.800 --> 00:34:43.320 non dihydropyuridine meds come in. The ones that do not 696 00:34:43.440 --> 00:34:45.800 end in in E don't tie them verrapiml. These meds 697 00:34:45.840 --> 00:34:48.519 do the same they inhibit L type calcium channels, but 698 00:34:48.559 --> 00:34:51.280 they are more selective for the pacemaker and non pacemaker 699 00:34:51.360 --> 00:34:53.920 cells of the heart, making them useful for the arrhythmias 700 00:34:53.960 --> 00:34:55.880 will go over. So let's talk a bit more about 701 00:34:55.880 --> 00:34:59.000 how these non dihydropyridine meds work. Are Class four agents, 702 00:34:59.199 --> 00:35:00.760 so the main effect is going to be on the 703 00:35:00.760 --> 00:35:03.760 pacemaker action potential. So, like we were talking about before, 704 00:35:03.800 --> 00:35:07.599 the pace maker action potential only has three phases, phase zero, three, 705 00:35:07.639 --> 00:35:10.440 and four. And let's just do a quick recap because 706 00:35:10.480 --> 00:35:13.280 it's a tough subject and why not. So Phase four, remember, 707 00:35:13.400 --> 00:35:16.159 is a slow sodium leak through the funny current, with 708 00:35:16.280 --> 00:35:19.480 calcium entering first through our T type calcium channels and 709 00:35:19.519 --> 00:35:22.239 then later on through our L type calcium channels to 710 00:35:22.280 --> 00:35:25.199 push us through to reach the threshold potential. Phase zero 711 00:35:25.360 --> 00:35:29.159 is the slower calcium driven upstroke of depolarization, and then 712 00:35:29.239 --> 00:35:32.559 finally phase three is repolarization as calcium channels close and 713 00:35:32.639 --> 00:35:35.719 potassium the party pooper he is flows out. So unlike 714 00:35:35.719 --> 00:35:39.400 beta blockers which indirectly affected calcium channels by blocking EPI 715 00:35:39.400 --> 00:35:43.119 and nor epi. Calcium channels directly impact calcium channels and 716 00:35:43.199 --> 00:35:45.719 have an impact on phase four and zero, so they 717 00:35:45.760 --> 00:35:48.760 decrease calcium entering during phase four and zero, so we'll 718 00:35:48.760 --> 00:35:51.440 have a decrease in the slope of phase four and zero, 719 00:35:51.760 --> 00:35:53.840 slowing things down so the heart gets a little bit 720 00:35:53.880 --> 00:35:56.199 more breathing room. And just like in beta blockers, they'll 721 00:35:56.239 --> 00:35:59.599 decrease firing of the s A node, decrease conduction velocity 722 00:35:59.639 --> 00:36:02.320 through the AV node, which helps to treat our arrhythmius. 723 00:36:02.440 --> 00:36:05.480 Like beta blockers, calcium channels also have effects on calcium 724 00:36:05.480 --> 00:36:08.840 influx and non pacemaker cells like our cardiac myocytes, decreasing 725 00:36:08.880 --> 00:36:11.599 the force generator during contractions, so they have an effect 726 00:36:11.599 --> 00:36:14.760 not only on cardiac conduction, but also cardiac contractility as well. 727 00:36:14.840 --> 00:36:17.719 So remember, calcium channel blockers block calcium channels just as 728 00:36:17.719 --> 00:36:20.159 the name states, which affects phase four and zero of 729 00:36:20.199 --> 00:36:23.519 the pacemaker cardiac action potential. Now, what arrhythmias do they treat? 730 00:36:23.519 --> 00:36:25.840 You might ask. Well, since they're similar to beta blockers, 731 00:36:25.960 --> 00:36:28.840 we will see some similarities. Fill tizim and verapamil are 732 00:36:28.840 --> 00:36:31.559 both used for acute and chronic ventricular rate control and 733 00:36:31.639 --> 00:36:35.280 atrial fibrillation and atrial flutter. They're also effective for superventricular 734 00:36:35.320 --> 00:36:38.639 tachycardia alongside a dentisine and can be used in multifocal 735 00:36:38.679 --> 00:36:41.639 atrial tachycardia, But the main indication to remember is rate 736 00:36:41.679 --> 00:36:44.440 control in a FIB and a flutter and SVT. All right, 737 00:36:44.440 --> 00:36:46.760 what else do we know about our calcium channel blockers. Well, 738 00:36:46.800 --> 00:36:48.880 of course you got to know the adverse drug reactions. 739 00:36:49.000 --> 00:36:51.519 So the three adverse effects you need to know for 740 00:36:51.639 --> 00:36:56.519 non dihydropyridan calcium channel blockers are constipation, cardiac block bradedcardia, 741 00:36:56.599 --> 00:36:59.639 which luckily is the initial of calcium channel blockers CCB. 742 00:36:59.840 --> 00:37:02.599 So starting with C, which is for constipation. This is 743 00:37:02.679 --> 00:37:04.960 pretty common and occurs in up to twenty five percent 744 00:37:05.000 --> 00:37:08.360 of patients. The next C cardiac block. These drugs may 745 00:37:08.400 --> 00:37:11.119 cause first, second or third degree av block and then 746 00:37:11.119 --> 00:37:13.480 finally b our last letter, these drugs may lead to 747 00:37:13.559 --> 00:37:16.079 sinus braidacardia, so you should avoid these drugs and patients 748 00:37:16.079 --> 00:37:19.039 who are using other av nodal blocking agents like beta blockers, 749 00:37:19.119 --> 00:37:22.079 patients with six sinus syndrome, or patients with underlying av 750 00:37:22.199 --> 00:37:24.719 NOD dysfunction. All right, that's our Class four anti arrhythmics 751 00:37:24.800 --> 00:37:27.440 are calcium channel blockers. Remember the meds in this class 752 00:37:27.440 --> 00:37:30.800 by remembering four nication leads to venarial disease Class four 753 00:37:30.920 --> 00:37:35.039 for rapamilandultizzem. Remember these are non dihydropurity in agents. They 754 00:37:35.079 --> 00:37:38.639 decrease calcium entering during phase four and zero indications rate 755 00:37:38.679 --> 00:37:41.679 control in a FIB and a flutter SVT. Remember your 756 00:37:41.719 --> 00:37:46.440 adverse drug reactions by remembering CCB constipation, cardiac block braidycardia. 757 00:37:46.679 --> 00:37:48.639 All right, if you're still with me, congrats. That was 758 00:37:48.679 --> 00:37:50.519 a lot. So that was your class one through four 759 00:37:50.519 --> 00:37:53.320 anti arrhythmics. I'm going to do a sixty second or 760 00:37:53.320 --> 00:37:55.960 so recap of the highest deal topics and demonics. Then 761 00:37:56.000 --> 00:37:58.000 we'll do a few quick questions to test your knowledge. 762 00:37:58.039 --> 00:38:00.360 So four classes of anti rhythmics to no Class one 763 00:38:00.440 --> 00:38:04.000 sodium channel blockers, Class two beta blockers, Class three potassium 764 00:38:04.039 --> 00:38:07.480 channel blockers, Class four calcium channel blockers. Remember them by 765 00:38:07.519 --> 00:38:12.119 remembering the sentence some blocked potassium channels SBPC. Starting with 766 00:38:12.159 --> 00:38:15.079 class one sodium channel blockers, which slow down the influx 767 00:38:15.119 --> 00:38:17.960 of sodium during phase zero, and remember the more salt 768 00:38:17.960 --> 00:38:20.599 in the food, the more it blocks sodium channels. Remember 769 00:38:20.599 --> 00:38:25.360 Class one has three subclasses. Class one A diso pyramid quinidine, procaanamide, 770 00:38:25.360 --> 00:38:29.000 Class one B lytokane and maxilotine. Class one C fleckinide 771 00:38:29.039 --> 00:38:32.679 and propaphenone. Remember your double quarter pounder lettuce mao fries. 772 00:38:32.760 --> 00:38:36.000 Please remember our Class one ameds double quarter pounder are 773 00:38:36.039 --> 00:38:38.239 on a foot long hot dog bund to help you 774 00:38:38.239 --> 00:38:41.000 remember the Class one A drugs prolong the qt intervle 775 00:38:41.039 --> 00:38:44.639 super important. Don't forget about procaanamide aka pro trainamide. Your 776 00:38:44.639 --> 00:38:47.079 white wolf driving a train on a loop track Wolf 777 00:38:47.119 --> 00:38:50.159 Parkinson white and lupis. Remember our Class one B meds 778 00:38:50.159 --> 00:38:52.960 are indicated for fast and failing tissue like post m I, 779 00:38:53.320 --> 00:38:56.360 but our Class one C meds are contraindicated post m I. 780 00:38:56.400 --> 00:38:58.719 Remember after a heart attack you swap the fries out 781 00:38:58.719 --> 00:39:01.360 for a salad. Next, Class two beta blockers. Remember the 782 00:39:01.360 --> 00:39:03.800 second letter of the alphabet is B, and beta blockers 783 00:39:03.800 --> 00:39:06.239 which start with a B are Class two antierrythmics. All 784 00:39:06.320 --> 00:39:08.880 drugs in this class end in LOL and most end 785 00:39:08.920 --> 00:39:12.079 in olol. The ones that don't got something special about them. 786 00:39:12.199 --> 00:39:14.920 Beta blockers block epianore EPI from binding to our beta 787 00:39:14.920 --> 00:39:18.199 one receptors in the heart, decreasing calcium influx, decreasing the 788 00:39:18.199 --> 00:39:20.519 slope of phase four. The main indication I would know 789 00:39:20.599 --> 00:39:22.440 is for rate control in a fib and a flutter. 790 00:39:22.639 --> 00:39:28.039 Remember your cardio selective beta blockers with beam bisoprolol, bataxilol, esmolol, atenolol, 791 00:39:28.199 --> 00:39:31.960 aceputle lul, and mitoprolol. Finally, remember your common contraindication slash 792 00:39:31.960 --> 00:39:36.840 warnings for beta blockers with ABCD, asthma, bradacardia, cardiogenic shock, diabetes, 793 00:39:36.920 --> 00:39:39.639 class three potassium channel blockers. Remember the meds by remembering 794 00:39:39.639 --> 00:39:45.239 the demonic aids aids amiodorone, a buttylid, dohedolide, troneterone, and sotolol. 795 00:39:45.400 --> 00:39:48.239 They block potassium E flux during phase three, leading to 796 00:39:48.320 --> 00:39:52.519 prolonged phase three repolarization. QT prolongation is an important adverse effect. 797 00:39:52.559 --> 00:39:55.559 To know. The highest yield med is amiodorone. Remember am 798 00:39:55.679 --> 00:39:57.719 three odorone to help you remember it's a class three 799 00:39:57.719 --> 00:40:01.039 anti arrhythmic and to remember these super highyield adrast drug reactions. 800 00:40:01.199 --> 00:40:06.800 Remember taking amyodoron is a bitch. Blue skin, interstitial lung disease, thyrotoxicity, 801 00:40:06.880 --> 00:40:11.000 coronial deposits of patotoxicity, and finally, remember sotolol is a 802 00:40:11.000 --> 00:40:13.679 beta blocker as well as a class three potassium channel blocker. 803 00:40:13.840 --> 00:40:16.880 Remember it as soapotolol pot to help you remember it 804 00:40:16.920 --> 00:40:20.079 also blocks potassium. Finally, our class fours. Remember the meds 805 00:40:20.079 --> 00:40:23.119 in this class by remembering fornication leads to venereal disease 806 00:40:23.440 --> 00:40:27.599 formication Class four veneal disease, verapamel and deltizem. Remember these 807 00:40:27.639 --> 00:40:30.920 are non dihydropurity in agents. They decrease calcium entering during 808 00:40:30.960 --> 00:40:34.119 phase four and zero in notal cells, prolonging phase four 809 00:40:34.159 --> 00:40:36.480 and zero indications, rate control in a FIB and a 810 00:40:36.519 --> 00:40:41.559 flutter SVT. Remember your adverse drug reactions by remembering CCB constipation, 811 00:40:41.679 --> 00:40:44.920 cardiac block, bradycardia. That's your anti rhythmics. Let's do five 812 00:40:45.000 --> 00:40:47.599 quick questions to test your knowledge. Question one, Which of 813 00:40:47.639 --> 00:40:50.679 the following anti rhythmic drugs has the most potent impact 814 00:40:50.880 --> 00:40:53.960 on blocking sodium channels in the myocardium leading to the 815 00:40:54.039 --> 00:40:57.840 greatest reduction in the slope of phase zero depolarization. Again, 816 00:40:58.079 --> 00:41:00.480 which of the following anti rhythmic drugs has the most 817 00:41:00.480 --> 00:41:03.599 potent impact on blocking sodium channels in the myocardium leading 818 00:41:03.599 --> 00:41:06.760 to the greatest reduction in the slope of phase zero depolarization. 819 00:41:07.079 --> 00:41:13.599 Choice A Lytokane B maxilatine, C flecanide, D disopyramid e 820 00:41:13.920 --> 00:41:20.199 verrapimil Again A Lytokane B maxilatine, C flecanide, D disopyramid 821 00:41:20.360 --> 00:41:29.400 e verrapim il. So that is going to be answer 822 00:41:29.519 --> 00:41:32.280 C flecanide. So which of these meds has the most 823 00:41:32.280 --> 00:41:35.599 potent sodium channel blocking activity. We have five choices, and 824 00:41:35.639 --> 00:41:37.519 one of them we can knock out right away answer 825 00:41:37.559 --> 00:41:40.360 ever rapimil. It is a class four calcium channel blocker, 826 00:41:40.519 --> 00:41:42.599 so let's eliminate that option. So then we're left with 827 00:41:42.639 --> 00:41:47.079 four choices Lytokane, maxilotine, flecanide, disopyramid, which are all sodium 828 00:41:47.159 --> 00:41:49.519 channel blockers. And if we remember the demonic all we 829 00:41:49.559 --> 00:41:51.679 have to do at this point is find the saltiest food. 830 00:41:52.000 --> 00:41:54.159 So let's think about the foods and how salty they are, 831 00:41:54.199 --> 00:41:56.960 which sounds ridiculous, but it works. So let us mayo 832 00:41:57.039 --> 00:41:59.000 we know has the least amount of salt, which has 833 00:41:59.039 --> 00:42:01.480 the weakest sodium channel blockade. That's our Class one B 834 00:42:01.599 --> 00:42:04.880 drugs double quarter pounder, moderate amount of salt, moderate sodium 835 00:42:04.920 --> 00:42:07.360 channel blockade which are Class one A drugs, and then 836 00:42:07.400 --> 00:42:09.639 finally the meds we should be looking for fries Please, 837 00:42:09.639 --> 00:42:12.800 which are the saltiest and have the strongest sodium channel blockade, 838 00:42:12.880 --> 00:42:16.480 are our class one C and since fries Please represents 839 00:42:16.519 --> 00:42:19.440 propaphenone and fleckanide, we have to look for these meds 840 00:42:19.440 --> 00:42:22.320 and luckily Flecaninde is present in the answer choices, so 841 00:42:22.360 --> 00:42:24.960 we know that answer C Flecanide is the correct choice, 842 00:42:25.039 --> 00:42:27.440 which is a Class one C agent exerting the most 843 00:42:27.440 --> 00:42:30.480 potent sodium channel blockade and has the greatest impact on 844 00:42:30.519 --> 00:42:33.480 reducing the slope Phase zero. Question two, a fifty eight 845 00:42:33.559 --> 00:42:35.679 year old man who has recently started on a new 846 00:42:35.719 --> 00:42:39.320 medication by his cardiologists presents to the emergency department. After 847 00:42:39.360 --> 00:42:43.000 beginning therapy, he reports episodes of dizziness and near syncopede. 848 00:42:43.079 --> 00:42:46.079 An ECG obtained in the emergency department shows a markedly 849 00:42:46.119 --> 00:42:50.400 prolonged qt interable followed by polymorphic ventricular tachycardia with a 850 00:42:50.519 --> 00:42:54.880 characteristic twisting of the QRS complexes around the isoelectric baseline. 851 00:42:55.000 --> 00:42:58.079 Which of the following medications is most likely responsible for 852 00:42:58.119 --> 00:43:05.599 this patient's presentation atacine B diltiaism C quinidine D maxilotine 853 00:43:05.920 --> 00:43:12.920 E metoprolol. Again a lytokine B DILTIAZM, c quinidine D, 854 00:43:13.320 --> 00:43:23.159 maxilotine E metoprolol. So that's going to be answer C quinidine. 855 00:43:23.199 --> 00:43:26.119 This question is describing a patient with prolonged QT and 856 00:43:26.280 --> 00:43:30.960 polymorphic ventricular tachycardia with twist and QRS complexes so torsa 857 00:43:31.079 --> 00:43:33.440 de point. So which medication class that we've covered today 858 00:43:33.480 --> 00:43:36.960 are most likely to cause prolonged QT and torsads And 859 00:43:37.000 --> 00:43:39.280 you've got to know this. That's your class three potassium 860 00:43:39.320 --> 00:43:42.119 channel blockers and your Class one A sodium channel blockers. 861 00:43:42.280 --> 00:43:44.159 So now that we know which drugs to look for 862 00:43:44.199 --> 00:43:46.639 in our answers, let's start with your potassium channel blockers. 863 00:43:46.679 --> 00:43:52.079 We remember those drugs with the mnemonic aids aids, amiodorone, beutilide, deftolide, dronetone, 864 00:43:52.079 --> 00:43:54.119 and sodolol. None of those meds are present in the 865 00:43:54.119 --> 00:43:56.760 answer choices. So next, let's search for our class one 866 00:43:56.760 --> 00:43:59.239 A drugs. Remember your double quarter pounder on a foot 867 00:43:59.239 --> 00:44:03.280 long hot dog on which represent disopyramid, prokanamide, and quinidine 868 00:44:03.400 --> 00:44:06.000 and quididine. We can see as answer ce A Class one, 869 00:44:06.039 --> 00:44:08.679 a drug that, as we discussed before, is notorious for 870 00:44:08.719 --> 00:44:11.840 prolonging the QT interble and causing torsades, is the most 871 00:44:11.920 --> 00:44:14.199 likely cause of this patient's presentation compared with the other 872 00:44:14.280 --> 00:44:17.199 medications and the correct answer for question two. Question three, 873 00:44:17.320 --> 00:44:19.280 a sixty four year old man was started on a 874 00:44:19.320 --> 00:44:22.199 new anti rhythmic medication several months ago. At a routine 875 00:44:22.239 --> 00:44:25.320 follow up, he reports new fatigue and notices bluish gray 876 00:44:25.320 --> 00:44:28.599 discoloration of the skin over his face. Laboratory studies reveal 877 00:44:28.599 --> 00:44:31.280 and elevated TSH, as well as an increase in serum 878 00:44:31.280 --> 00:44:35.960 aminotransphrase concentrations, AST and ALT. Which of the following medications 879 00:44:36.039 --> 00:44:38.199 was most likely initiated in this patient in the past 880 00:44:38.280 --> 00:44:44.199 few months. A dofetylide B sodolol, c amiodorone, D flecanide, 881 00:44:44.480 --> 00:44:51.000 e verapimil. Again, A dofetylide B sodolol, c amiodorone, D 882 00:44:51.280 --> 00:45:01.880 flecanide or e verapimil. So that's going to be answer 883 00:45:02.039 --> 00:45:05.440 c amioterone. So a correct answer is answer c amioterone. 884 00:45:05.480 --> 00:45:08.079 You better know this one. Remember, amiodorone messes with so 885 00:45:08.119 --> 00:45:10.159 many different organs in the body, and it's why there 886 00:45:10.159 --> 00:45:13.280 are so many monitoring parameters needed when initiating and continuing 887 00:45:13.280 --> 00:45:16.280 on this medication just X ray, thyroid function test, cerum, 888 00:45:16.320 --> 00:45:19.440 amino transferrase levels, et cetera. C Amiodone can cause a 889 00:45:19.559 --> 00:45:21.960 number of different adverse effects. The main ones though, are 890 00:45:22.000 --> 00:45:26.119 in the mnemonic b itch, because taking amiodon is a bitch. 891 00:45:26.440 --> 00:45:29.599 Blue skin which is seen in this patient, interstitial lung disease, 892 00:45:29.840 --> 00:45:32.639 thyrotoxicity which we see here as evident by the increase 893 00:45:32.679 --> 00:45:36.719 in TSHS, was the complaints of fatigue likely secondary to hypothidism, 894 00:45:36.800 --> 00:45:40.400 cornio deposit and then finally hepatotoxicity which we also see 895 00:45:40.400 --> 00:45:42.519 in this patient with the increase in ASD and AOT. 896 00:45:42.719 --> 00:45:46.159 So don't forget taking amiodone is a bitch. The other drugs, 897 00:45:46.159 --> 00:45:48.480 while they may have some adverse effects seen in this patient, 898 00:45:48.559 --> 00:45:51.800 like the hepatotoxicity, amiurone is the only one to potentially 899 00:45:51.800 --> 00:45:55.079 have all of these clinical manifestations. Question four. A seventy 900 00:45:55.159 --> 00:45:58.199 year old man with a history of hypertension and HR 901 00:45:58.360 --> 00:46:02.280 fibrillation presents to the clinic complaining of recurrent palpitations. His 902 00:46:02.320 --> 00:46:07.079 hemodynamically stable and his ECG confirms atrial fibrillation after failing 903 00:46:07.159 --> 00:46:09.840 other therapies, the patient is started on an oral medication 904 00:46:10.079 --> 00:46:14.880 that primarily prolongs phase three repolarization of the ventricular cardiac 905 00:46:14.920 --> 00:46:20.159 action potential, increasing the action potential duration and effective refractory period. 906 00:46:20.519 --> 00:46:23.320 Which of the following medications was most likely initiated in 907 00:46:23.360 --> 00:46:28.679 this patient? A Lytokane B metopol law, C do fetylide, 908 00:46:29.119 --> 00:46:35.079 D verapimil E maxilotine. Again A Lytokane B metopo law, 909 00:46:35.480 --> 00:46:45.840 C do fetolide, D verapimil or E maxilotine. So that's 910 00:46:45.840 --> 00:46:48.519 going to be answered, C do fetolide. So this is 911 00:46:48.800 --> 00:46:51.400 not an easy question, but let's break it down. So first, 912 00:46:51.440 --> 00:46:53.280 avoid all of the noise. The only part of this 913 00:46:53.400 --> 00:46:56.760 vignette that matters is the statement which drug in this 914 00:46:56.800 --> 00:47:01.400 list prolongs phase three repolarization, increasing action potential, duration, and 915 00:47:01.480 --> 00:47:05.000 effective refractory period, and by definition that is a potassium 916 00:47:05.039 --> 00:47:07.800 channel blocker, which in this case the only potassium channel 917 00:47:07.800 --> 00:47:11.000 blocker listed is de fedolided the d and aids the 918 00:47:11.039 --> 00:47:13.639 other meds. B. Motopol Law is a class two beta 919 00:47:13.639 --> 00:47:17.559 blocker which mainly affects phase four of pacemaker cells lytoicanum, 920 00:47:17.559 --> 00:47:20.360 oxilotine or lettuce and maomeds are Class one B sodium 921 00:47:20.440 --> 00:47:23.039 channel blockers which act on phase zero and Finally, d 922 00:47:23.199 --> 00:47:26.280 Verapamil is a class four calcium channel blocker which affects 923 00:47:26.320 --> 00:47:29.639 primarily phase four and zero of nodal cells. Question five, 924 00:47:29.719 --> 00:47:31.960 A sixty four year old man with a history of 925 00:47:31.960 --> 00:47:35.280 atrial fibrillation is being managed for rate control. He was 926 00:47:35.320 --> 00:47:38.880 previously prescribed a calcium channel blocker, which was discontinued due 927 00:47:38.880 --> 00:47:42.119 to intolerance. The treatment plan now shifts to a beta blocker. 928 00:47:42.199 --> 00:47:46.199 His medical history includes mild, well controlled asthma managed with 929 00:47:46.280 --> 00:47:49.599 occasional albuterol and hailer use. Which of the following beta 930 00:47:49.599 --> 00:47:52.360 blockers is the most suitable option for rate control in 931 00:47:52.400 --> 00:47:57.760 this patient? A proprano law B natlol C pindlelal D 932 00:47:58.000 --> 00:48:05.239 metopo law E timil again, A propranolol B naanilol C pindlelol, 933 00:48:05.719 --> 00:48:14.400 D metoprolol or E timilol. So that is going to 934 00:48:14.440 --> 00:48:17.280 be answered D metoprolol. So we have a patient with 935 00:48:17.320 --> 00:48:20.360 a history of a fib and mild bronchospastic disease. He 936 00:48:20.400 --> 00:48:22.760 didn't tolerate calcium channel blockers. Who are going to start 937 00:48:22.800 --> 00:48:25.360 him on a beta blocker non selective beta blockers hit 938 00:48:25.360 --> 00:48:27.559 both the beta one receptors in the heart as well 939 00:48:27.559 --> 00:48:30.599 as beta two in the lungs, which can cause broncho constriction, 940 00:48:30.880 --> 00:48:33.719 so these are not recommended in patients with bronchospastic disease 941 00:48:33.840 --> 00:48:36.199 like asthma. A selective agent, on the other hand, at 942 00:48:36.239 --> 00:48:39.199 lower doses will hit primarily beta one receptors and can 943 00:48:39.239 --> 00:48:41.760 be used with caution in this patient population. So the 944 00:48:41.760 --> 00:48:43.960 only question you need to ask yourself at this point 945 00:48:44.079 --> 00:48:47.119 is which is a cardio selective beta blockers in the answers, 946 00:48:47.320 --> 00:48:49.239 And the easy way to know is just to remember 947 00:48:49.280 --> 00:48:52.000 that a beam of light is direct and find a 948 00:48:52.000 --> 00:48:54.960 beta blocker that starts with B, E, A, or M. 949 00:48:55.079 --> 00:48:57.400 In this case, that would be metoprolol, which is a 950 00:48:57.400 --> 00:49:00.519 cardioselective agent, and the correct answer for this patient. All right, 951 00:49:00.519 --> 00:49:02.800 that was your anti rhythmics. Try not to be too overwhelmed. 952 00:49:02.840 --> 00:49:04.400 It is a lot, but try to just focus on 953 00:49:04.440 --> 00:49:06.800 the highest yield stuff and try to focus on the demonics. 954 00:49:06.800 --> 00:49:08.519 If you can try to remember those, you'll get through 955 00:49:08.559 --> 00:49:10.440 the exam and you'll be fine. Thank you so much 956 00:49:10.440 --> 00:49:12.239 for listening to the podcast, and thank you so much 957 00:49:12.239 --> 00:49:12.840 for the support