This is Workshop 7, Electrocardiographic Electrophysiologic Correlations, Atrial Fibrillation Clinical Scenarios and Syndromes. I'm Jeanne Poole from the University of Washington. Here are my disclosures. Okay, case one, a 48-year-old female presents with frequent palpitations. She can recall infrequent episodes of fast heart rate in her teen years. Her ECG is shown. This is the really easy case, but it is such a classic great electrocardiogram. Successful ablation is most likely to be achieved from the left lateral wall, the right anterior free wall, or mid-septal, or accessed via the middle cardiac vein. Okay, middle cardiac vein. I'm sure everybody got that right. And there's a lot of different algorithms. And this one I'm showing you is simply the ARUDA algorithm. And in your other talks on accessory pathways, you will have gone over this. But if you just pop down to step two, if you have a completely negative delta wave in lead two, high sensitivity, high specificity, and positive predictive value that you will need to ablate within the coronary sinus or the MCB. Okay, 20-year-old male is in the ED with two hours of rapid palpitations and chest pressure. His ECG is shown in tracing one, which is on this slide. He's had several similar episodes in the past, but those did terminate spontaneously. His blood pressure right now is 105 over 70. He's given six milligrams of IV adenosine with no change, and then 12 milligrams of IV adenosine. And the tachycardia converts to the rhythm in tracing two, which I'll show you on the next slide. The patient continues to feel palpitations. Blood pressure is stable at 100 over 74. So you recommend the following acute treatment, intravenous procainamide, immediate DC cardioversion, intravenous verapamil, or intravenous amiodarone. So here is tracing two. And here are the questions again. And the answer is intravenous procainamide. So why is that? Well, the first rhythm shows ADRT, and the second rhythm is clearly pre-excited atrial fibrillation. The mechanism of the transition in the rhythms most likely was a direct effect of adenosine on accessory pathway conduction due to recovery of excitability due to the hyperpolarization effects and sodium channel reactivation associated with adenosine. The acute treatment for pre-excited AFib is IV procainamide or IV ibutylide if the patient is hemodynamically stable, or if unstable, DC cardioversion. This patient's blood pressure remains stable, and of the options, IV procainamide is the best choice, A. AV nodal blocking agents are generally to be avoided as accessory pathway conduction may be favored, and the non-dihydropyridine calcium channel blockers and digoxin may actually enhance accessory pathway conduction, and IV amiodarone is also contraindicated. Case three. A 30-year-old female has an ICD placed after her brother died suddenly in his sleep at age 12. The patient has not had appropriate ICD therapy, has remained normally active, echocardiogram is normal, and she has no other medical problems. Her ECG is shown in tracing one on the next slide. Based upon the information available, the most likely genetic mutation to explain the findings is MYH7, RYR2, PRKAG2, and CACNA1C. Here is the patient's tracing, and here are the choices. Okay, well the right answer is D. This was a case of ruling out everything else in order to come to the right answer. So this patient has an ECG with a prolonged QT interval. There's some T-wave inversion, V1 to V4. The T-wave inversion pattern you might have thought might be consistent with somebody with ARVC, but that was not given to you as an option, and the patient's echocardiogram was stated to be normal. Her brother died suddenly in his sleep, and sudden cardiac death during sleep is characteristic of long QT3 or Brugada syndrome, but these were also not given to you as options, and those are most commonly the SCN5A mutations. Mutations of MYH7, answer A, which encode for the beta-myosin heaving chain, are found in hypertrophic cardiomyopathy. ECGs and HCM can include significant alterations of the ST and T-wave segments and QT prolongation due to the LVH, but the patient has a normal echocardiogram. Mutations of the ryanodine receptor are associated with CPVT, answer B, and QT intervals are generally normal in CPVT, and arrhythmias most often occur related to activity. PRKAG2 mutations cause a syndrome of ventricular pre-excitation atrial fibrillation conduction defects and cardiac hypertrophy. So, by elimination, answer D is the best answer. A mutation in CACNA1C gene is associated with Timothy syndrome or long QT8. So, CACNA1C makes the voltage-dependent L-type calcium channel subunit alpha-1C protein. There are actually two forms of Timothy syndrome, type 1, which includes other classic findings such as syndactyly, other congenital defects, and craniofacial characteristics, which this patient does not have. Type 2 has fewer or none of those other associated physical findings, but a more severe arrhythmia presentation. Exercise relatedness is not a strong characteristic of Timothy syndrome, and there are many case reports describing cardiac arrest with sleep or auditory stimuli. Case 4. A 33-year-old male has a history of syncope occurring once every several years, with eight episodes over 15 years. The last two have occurred in the setting of a viral illness. Recently, he got up out of bed during the night to urinate. He passed out in the bathroom, falling and bruising his arm on the countertop. A recording and tracing one was obtained from an ILR interrogation, and what should you recommend? And the choices are tilt table test, single-chamber pacemaker, dual-chamber pacemaker, or conservative management. So this is the tracing. This is a continuous recording. Here again are the answers. Tilt table, single-chamber pacemaker, dual-chamber pacemaker, or conservative management. So the answer is conservative management, and it's often really difficult to look at these patients who have severe basal-vagal syncope because of the length of the cardio-inhibitory pause, but his do appear to all occur with a trigger that is consistent with basal-vagal syncope. Many of them are occurring with viral illnesses, which is a typical trigger, as well as standing up, sometimes having GI illnesses, or in the setting of a viral illness. Or in the setting of stress, like having blood drawn. A tilt table test is unlikely to provide any more information than you already got off of the ILR, and a pacemaker implant is not recommended based upon randomized studies. There are exceptions, however, in patients who experience significant repetitive injury. Answer C is wrong for the same reason as answer B. When pacemakers are used, however, a dual-chamber device is preferred to provide AV synchroning, and because patients may experience both sinus and AV nodal depression. Devices with specific algorithms directed at basal-vagal syncope are recommended. Conservative management with careful attention to fluids and mitigating the risk by counseling the patient, for instance, to rise up slowly, to not just pop out of bed in the middle of the night, sit for a while on the side of the bed, and anticipate triggering situations may prevent significant symptoms and avoid a pacemaker in a young person. This is an algorithm from the 2017 guideline document for the management of patients with syncope. You can see that conservative measures are 2A and 2B, as well as education, which is the class one indication. Pacemakers receive a class 2B indication. Case 5, a 40-year-old male with type 1 myotonic muscular dystrophy is referred for evaluation of an abnormal ECG. Two ECGs are available for review spaced six months apart. The patient is active and able to engage in normal activities of daily living. He has no history of syncope or near syncope. His echocardiogram shows normal LV function, 65%, and normal RB function. He undergoes an EP study, and the HV interval is 116 milliseconds. Program stimulation is performed, and BT is not induced. The best therapy now is a dual-chamber pacemaker, a subcutaneous ICD, conservative monitoring, or an implantable loop recorder. We'll go back up to the questions again. Dual-chamber pacer, subcutaneous ICD, continue to watch, or implant an ILR. Here are the ECGs. The patient is active and able to engage in normal activities of daily living. He has no history of syncope or near syncope. He has no history of syncope or near-syncope. He undergoes an EP study, and the HV interval is 116 milliseconds. Okay, best therapy is a dual-chamber pacemaker. So, this form of muscular dystrophy is characterized by conduction system disease, both sinus and AV nodal, as well as the patients can have a non-ischemic cardiomyopathy. This patient has a normal echocardiogram, however. And the two ECGs that were shown showed significant conduction abnormalities with the right bundle branch block on premature atrial beads and the left bundle branch block on tracing two. So the patient is clearly at high risk and demonstrating conduction system disease. In this disorder, connection system disease is progressive. If you're not sure what to do, you've knew an EP study to assess the HV interval will confirm the need for a pacemaker. So the patient meets criteria for a pacemaker and therefore answers C and D are wrong. Currently, the patient does not meet standard indications for primary prevention ICD given normal LV function and no inducible or sustained spontaneous VT. So for patients who do require a pacemaker and an ICD to be implanted at the same time without otherwise meeting standard ICD indications only has a level of recommendation of 2B. So thus a pacemaker is the best answer at this point. Some death in this disorder can be due to either conduction abnormalities or ventricular arrhythmias. And here for your reference, are the recommendations from the 2017 guidelines for the management of ventricular tachyarrhythmias and the 2018 guidelines for the evaluation and management of patients with bradycardia and cardiac conduction delay. On the left are recommendations for neuromuscular disorders. And on the right, you can see a summary of neuromuscular disorders and specific recommendations. Case six, the 23 year old females referred to you for evaluation of episodic near syncope while playing college basketball. The following ECG is obtained in tracing one of the following choices, the genetic mutation affecting which cardiac function is most likely to be associated with this ECG pattern. A, disruption of desmosomal proteins. B, abnormalities of nuclear and bullet proteins. C, increased calcium leak from the sarcoplasmic reticulum. D, loss of function of the voltage gated sodium channel. Here is the ECG. Here are the questions again. Here's the ECG. And here's the answer, disruption of desmosomal proteins. The other answers B, C and D refer to other entities that I explained here. So the correct answer is A, mutations encoding for desmosomal proteins are causative for ARVC. Three of the more commonly found mutations are the placofilin-2, desmoplakin and the placoglobin. So the ECG in patients with ARVC, as with the example that I provide, typically shows T wave inversions in the precordial leads which extend beyond B3. Other findings can of course include evidence of ventricular ectopy that have a left bundle branch morphology. A lot of these patients have a right bundle branch block or incomplete right bundle branch block and up to 30% there's an epsilon wave which was not present on this ECG that represents delayed activation to the right ventricle. Answer B referred to the lamin mutations. These are intermediate filament proteins which provide the scaffolding of the nuclear envelope and gene mutations affecting these proteins are implicated in familial dilated cardiomyopathy, Charcot-Marie-Tooth, Emory-Dreyfus and other syndromes. The ECG in these patients is really not very specific but can include abnormalities of conduction at any level and presence of supraventricular or ventricular arrhythmias. Answer C, mutations in the RYR2 or CASQ2 encode for the cardiac ryanodine receptor, near calcium release channel and the cardiac calsequestrin respectively destabilize the RYR2 calcium release channel complex in sarcoplasmic reticulum which results in spontaneous calcium release through the RYR2 channels. And this of course is CPVT. So the ECGs don't really show specific characteristics unless the patient has the binding of PVCs with the very classic bidirectional PVCs which really should make you suspect CPVT in such a patient as well as non-sustainability which is usually polymorphic and exercise related. D, loss of function of the voltage gated sodium channels caused by mutations of SCN5A found in Bregada syndrome. Loss of function in this channel leads to an unopposed ITO current. Patients with this disorder may display the characteristic ECG phenotype with coved ST elevations in B1 and B2. Case seven. A patient was started on a Sotal-Off for recurrent atrial fibrillation. She tolerated the medication well. Three weeks later, she had an episode of syncope and several lightheaded episodes. She was admitted to the hospital and the telemetry tracing is shown here. The best explanation for the finding is A, reverse use dependence. B, use dependence. C, artifact. D, pacing induced. So the right answer is A, reverse use dependence. Class III medications like Sotolol are potassium channel blockers resulting in prolonged QT intervals. The effect is heightened in the setting of bradycardia and pauses and that is reverse use dependence or answer A. This telemetry strip showed 2 to 180 block which caused the pauses and showed a prolonged QT interval. Use dependence is a characteristic of sodium channel blockers such as fluconide and propathenone which was answer B. The rhythm is neither artifact, answer C, or pacing induced as the patient does not have a pacemaker, answer D. Case eight, a 46-year-old female with dual chamber pacemaker for sinus node dysfunction has PAF for which she takes fluconide 50 milligrams BID. LBEF is 56%. She has a diagnosis also of HEF-PATH. She presents to the ED with a UTI and decompensated heart failure. Labs show an elevated white count, creatinine is 2.8, baseline it is 1.4, sodium is 124, potassium 3.6, BNP 1545. Recurrence of atrial fibrillation prompts an increase in the fluconide dose to 100 milligrams BID. She subsequently develops cardiogenic shock. Her ECG now is shown in tracing one. Immediate treatment should include A, synchronized cardioversion, B, IV sodium bicarbonate, C, IV amiodarone, or D, IV isoproteranol. So the answer is B, IV sodium bicarbonate. So this patient presents with decompensated heart failure from acute renal dysfunction due to her infection. Flecainide is a negative inotrope and can lead to worsened heart failure and shock. Flecainide toxicity can have a profound effect on the conduction system with a very wide QRS complex, in this case, a wide paste rhythm. So while flecainide metabolism is mostly in the liver by CYP2D6, anywhere from 10 up to 50% of it can be excreted unchanged in the kidney. So acute renal failure can result in significant flecainide toxicity. Acute treatment of flecainide toxicity or overdose is hypertonic saline, which can be given as sodium bicarbonate ampoules and IV isotonic sodium bicarbonate. Case now, a 35 year old woman with a history of substance abuse on chronic methadone is admitted after a presumed seizure with aspiration. She is now being treated with azithromycin, benatoin, methadone, and midazolam. Her admission ECG is shown in tracing one on the next slide. So which of the following drugs most likely explains the ECG? A, azithromycin, B, benatoin, C, methadone, or D, midazolam? And here is the electrocardiogram. We'll go back to the options. So the answer is C, methadone. The ECG obviously showed marked QT prolongation and methadone blocks IKR. It's well-known to be associated with TRASAD as well as sudden death. So answer is C. Now, although there are case reports of polymorphic VT and increased sudden death with azithromycin, the pro-arrhythmic potential is really rare unless there are other QT prolonging drugs that the patient also is on at the same time. The so-called seizure that the patient had was likely TRASAD and occurred before admission. So none of the post-admission medications can be the culprits. Now that's the end of this workshop. Thank you for your attention. This is workshop number seven, electrocardiographic EP correlations, atrial fibrillation clinical scenarios and syndromes. I'm Ed Gerstenfeld from the University of California, San Francisco. These are my disclosures and we'll jump right into the next set of questions for workshop seven. So patient with symptomatic paroxysmal atrial fibrillation is referred for ablation. RF ablation is performed using wide encircling lesions around the right pulmonary veins. After ablation, a circular mapping catheter is placed into the right superior pulmonary vein. Pacing from bipoles 11, 12 of the catheter is shown. The best conclusion from these tracings is, A, there's entry block, but not exit block. B, there's exit block, but not entry block. C, there's both entry and exit block. Or D, there's neither entry nor exit block. This is the tracing. Again, you can see surface leads 1AVF and V1. You can see a 20-pole circular mapping catheter, ablation catheter, and recordings from a decapolar catheter in the coronary sinus. When I say S, that means a stimulus. So there's two pacing stimuli, and these were the possible answers. So based on this tracing, again, you can take a few minutes. Feel free for any of these questions to pause, analyze the tracing, and then I'll go ahead with the answer. The correct answer is D, there's neither entry nor exit block. And again, when you're... It's important for clinical practice. If you're thinking about taking the boards, again, there's just not many questions you can write about catheter ablation of AFib. So differential pacing, looking at pulmonary vein entry and exit block is a favorite, a crowd favorite. So let's look at this tracing. On the left, right, you have pacing, and you can see locally that you're capturing atrial signal. So you have local capture, and although there's a long time delay, you have a positive P wave in V1, and you're accelerating that atrial rate to the rate of pacing, right? So you don't have exit block because you're capturing the pulmonary vein sleeve, and although there's a delay, you are exiting to the atrium, and you can see with the coronary sinus also, that's accelerating to the pace rate with proximal to distal activation. Now, after you stop pacing, you have a pause, and then you see these signals simultaneous with the V, right, and the question is, is that just a far-field V, or is that late entry into the pulmonary vein? Well, one is you're in... I told you you're in the right superior pulmonary vein, so you rarely will see a far-field V there. But even if you're not sure, use everything on the tracing, right? Look at this initial, but this is after the pacing stimulus, but here, there's, during pacing, on all these signals, right, there's no far-field V there. So since there's no far-field V there, this must be atrial signal, and there's just late entry into the vein that happens to simultaneously be on time with the QRS. So there is entry into the vein, there's exit out of the vein, and therefore, there's neither entry nor exit block. Moving on to case two, a 64-year-old man presents for ablation of recurrent tachycardia occurring after an atrial fibrillation ablation. Intracardiac catheters are placed in the superior vena cava and coronary sinus with the proximal electrodes at the ostium. Overdrive pacing is performed from the distal coronary sinus electrode during tachycardia. The right atrial activation map is also shown. The question is, if tachycardia is likely to terminate, with which of the following ablation lesions? A, linear ablation from the inferior vena cava to the tricuspid annulus, B, linear ablation from the left inferior pulmonary vein to the mitral annulus, C, linear ablation from the right superior pulmonary vein to the left superior pulmonary vein, D, a focal lesion on the right atrial septum, or E, a focal ablation inside the distal coronary sinus. Here we see the tracing. Again, surface CCG1, ABF and V1, 20-pole circular catheter, coronary sinus proximal to distal, where overdrive pacing, I'm even giving you the cycle length of the tachycardia during and after pacing. And on the right is an LAO view of a right atrial activation map. And again, these are the options. So go ahead and take a few seconds, may take some time to look through this tracing and think of the best answer. And for all these questions, the best possible answer, don't always look for the perfect answer. Okay, for this question, the correct answer is, B, linear ablation from the left inferior pulmonary vein to mitral annulus. Let's go and look at this tracing. First question, as I said, always are we accelerating the atrial rate? Whenever overdrive pacing, again, I try not to use the term entrainment until we know it's a macarangia tachycardia. So we're overdrive pacing. Are we accelerating the atrial rate to the paced rate? Again, if you use your calipers or you look at the electrogram to stimulus interval, it is constant. So we are in fact accelerating this next return beat. And then the following one is a little bit longer. In fact, I'm giving you, actually we're pacing here from the distal CS. So I'm giving you the post pacing interval is 242, tachycardia interval is 245. So within the circuit, because the PPI is within, I'd usually like 20 for these atrial tachycardias within 20 of the tachycardia cycle length. But there's an important observation here. Let's move over to this activation map. You know, there is a focal activation on a septum. Again, this is LAO, so this is a septum, but it's pretty broad. And it really, from a right atrial view, you know, this most likely with a broad septal early activation is just breakthrough of a left atrial tachycardia to a right atrium. Also, if we look at the color bar here on this map, we see that we have a hundred milliseconds of tachycardia. We know the tachycardia is 245. So clearly we don't have the tachycardia identified in this map. Now there is an important point here. And that is that we're pacing from the distal CS, but we don't have antedromic capture of those remaining CS electrograms, right? If we're pacing from one, two, why would we not be capturing or accelerating these electrodes right next to it, three, four, seven, eight, and nine, 10? You'd think you'd see them in front, but you don't, you actually see nine, 10 behind, right? This last stimulus actually captures this next electrode, nine, 10, and then activates the atrium for proximal to distal. So this is called downstream capture, right? And for this to happen, it means the coronary sinus has to be part of the circuit in a counterclockwise fashion. So we're activating the CS from proximal to distal. And that's why when we pace the distal CS, the proximal CS has already been activated. So we can't activate it antedromically. We basically have to go all around the atrium, get back to the proximal CS, and then reactivate it proximal to distal. So when you see this downstream capture, you're not capturing adjacent electrograms, but capturing the next one, that tells you it's a macro-re-entrant circuit, right? It was focal. We should be able to capture those adjacent electrograms. So it's a macro-re-entrant circuit. We know it's using the CS since we have downstream capture, and we know we're within the tachycardia cycle length. So this is mitral flutter. And we'll go back to these options. IVC intercuspid annulus obviously would work for a typical right atrial flutter. But in this case, we don't have right atrial flutter. In fact, we're in the circuit from the distal CS, which would not be consistent with that. Right superior to left superior pulmonary vein. So that would be useful for a roof-dependent flutter. Now we don't know that this isn't a figure of eight flutter, for example, using both the mitral annulus and the roof. But if it was, we still wouldn't expect it to terminate with a roof ablation alone. We'd need to terminate the mitral flutter. Focal lesion on the right atrial septum, that was a distractor from that activation map. Clearly, we didn't have a tachycardia circuit, the whole length of the circuit in the map. And it was broad, the fuse looked like left to right atrial breakthrough. Also, that would not be consistent with the downstream capture. And again, same thing, focal ablation of distal CS would not work for macular reentrant tachycardia. So the best option then is B. Okay, I think this is a Michaud paper if you want to look it up. But very important to understand this downstream capture lack of fusion. I do have an example, I think, here of a roof-dependent flutter. Again, proximal distal in the CS, but here we're again, we're overdrive pacing from the distal CS. But now you can see that we're actually capturing those electrograms antidromically. And so we know that the CS is not part of the circuit because we're clearly completely fused there. Okay, so just to counter an example of a roof-dependent flutter that's not using the mitral annulus as part of the tachycardia mechanism. And again, I say this many times, but try not to rely just on the 3D activation maps. At least some entrainment really is helpful to prove the tachycardia before you start ablating because sometimes these can be quite challenging to terminate. At least you're confident of the mechanism. Okay, case three, a 68-year-old woman with recent persistent AF is undergoing catheter ablation for paroxysmal atrial fibrillation. Wide area circumferential lesions are placed around the right and left pairs of pulmonary veins, followed by cardioversion to sinus rhythm. After completion of the ablation, the circular catheter is placed inside the left superior pulmonary vein. Paces performed from BIPOL 1112 on the circular mapping catheter. The findings are reproducible. And the best explanation for the tracing shown, entry block but not exit block, same options as question one, exit block but not entry block, both entry and exit, or neither entry nor exit. So let's look at this tracing. And these are the options. Again, you'll see a lot of these type of differential pacing type questions. So take a few seconds to look at this and then we'll go to the answer. Okay, so the correct answer for case three is, A, there is entry block but not exit block. And again, this is uncommon but can happen, which is why pacing maneuvers are useful. So you can see with pacing that you are capturing, in fact, the pulmonary vein sleeve. And these first two beats is looking at the P wave in V1 appear to be sinus, but then this third beat comes in early, right? It clearly comes in earlier than the sinus beats. And it has a positive inferiorly directed P wave in V1. So this pulmonary vein sleeve is actually exiting to the atrium. Again, this one does not exit. So it's intermittent exit, but you don't have complete exit block. I mean, is it possible that you had a simultaneous PAC when you're pacing? Suppose it's possible, but again, you see this little proximal activation is what you'd expect from when you're pacing the left superior pulmonary vein. P wave looks like that. So you likely have exit block or likely do not have complete exit block. If you have entrance block, again, you have only this far field signal in 1920. You see that far field signal also when you pace and bring in this stimulus. So you don't see these potentials that you see on the circulatory mapping catheter when you're pacing during sinus rhythm, both at the beginning and end of this tracing. So you do, in fact, have entrance block. You're not conducting into the signals. These are far field signals that you likely often see from the left atrial appendage, but they're not sharp like these paced electrograms. So you have entrance block, but you did not have complete exit block. Okay. This is just another example that might be asked as a question, where, again, you have a circulatory mapping catheter and a pulmonary vein, and do you have exit block here? You can see these dissociated potentials separated from sinus rhythms. You might initially think you have exit block, but if you look at other potentials on the circulatory mapping catheter, you do have evidence of entrance into the pulmonary vein that's at the rate of sinus rhythm. So sometimes you can have partial isolation of a segment of a pulmonary vein. So if part of it's associated, but part is not, you don't have a complete isolation of the vein. In fact, this is not pacing, this is sinus rhythm. So the real question should be entrance block. Do you have complete entrance block? And the answer would be no, in this case. Okay, case four, a 40-year-old woman undergoes electrophysiology study for palpitations. Atrial program stimulation induces a tachycardia. The mechanism of the tachycardia is atrial tachycardia, AV node re-entry, AV re-entry, or D, need more information. This is the tracing. So again, this is sinus rhythm, and you're inducing tachycardia with these, with program stimulations. You have two stimuli and then a premature, have the HISS labeled onset of a tachycardia. This is kind of classic EP type question, and the options are shown, atrial tach, AVNRT, AVRT, or need more information. And I'll give you a few seconds to examine this tracing. Okay, and the correct answer, hopefully many people got, was AV re-entry. And let's look at why that is. Again, sort of classic EP. So you induce the typical narrow complex tachycardia, although at the onset, there are two wide beats, and they're left bundle branch type beats in B1, right? This sometimes just happens with wobble at the onset of tachycardia. You can see from the first beat, there is a HISS and a narrow QRS, and you see that out. For all these beats, there's a HISS in front of the QRS. Right, so are these PVCs? Well, there's a HISS clearly in front of this QRS, a HISS in front. So these are not PVCs, but they're in fact left bundle aberrancy. And so very important when you see any sort of wide beats, to say, well, what happens during those wide beats? I'm only giving you one, during those wide beats. I'm only giving you one coronary sinus electrogram, so you can't really see what happens to the coronary sinus. But here with this black line, I'm showing you the local on the HISS catheter, VA interval with a wide QRS, right? And just looking, I mean, this is the same interval. So pretty obviously shorter with a narrow QRS than a wide QRS. So in a left bundle, aberrancy leads to a longer VA time that tells you that this has to be AVRT, right? Kumail's rule. And we know, in fact, not just that it's AVRT, but we have a left-sided accessory pathway. Again, if you looked at the CS activation, you would see that it's clearly eccentric, which is why I just gave you one CS electrogram. But VA Lanthans with a left bundle has to be accessory pathway and has to be a left-sided accessory pathway. Case five, 56-year-old with a post-infarction cardiomyopathy undergoes implantation of a primary prevention dual-chamber cardioverter defibrillator. He's maintained an aspirin, metoprolol, and licinopril. One month after implantation, he reports an ICD shock, prevents for evaluation. Potassium is 4.2, creatinine is 1.5. Electrograms from the episode are shown in the figure. The most appropriate next management step is A, coronary angiography. B, start amiodarone, 400 milligrams daily. C, start sotolol, 120 milligrams BID. D, refer for EP study. Or E, extend ATP, the atrial anti-tachycardia pacing from eight to 15 pulses. This is the intracardiac electrograms from that episode. I'm showing you labeling the atrial signal, the ventricular, and the marker channel. You can see here, so this is fib sensing, ATP, right, tachypacing, going back to sensing. And the options are angiography, amiodarone, sotolol, EP study, or extend ATP. Take a few seconds to look and think about that. And the correct answer for this question is, refer for EP study. Let's look at the tracing. Again, these ICD tracings are a lot of fun, and you can get a lot of information out of them, just like you can from an EP study, particularly paying attention to these times where you have ATP. So when ATP happens, again, it's like an EP study. So does it accelerate the A to the V rate? Well, again, if you take out your calipers, you'll see that certainly by the end here, these A's are faster, and then there's a longer pause. So this is like doing a program STEM during SVT. And we see when we come off pacing, not only have we accelerated the atrial rate, but the response to pacing is a V-A-V response, right? So that pretty much excludes an atrial tachycardia. If we look at the post-pacing interval, it's much longer. This is the same interval held over the tachycardia cycle, so it's much longer than the tachycardia cycle length. That much longer here, again, than the tachycardia cycle length here. That's also consistent with AVNRT. And we can see that the V-A time, which is this last paced V to A during overdrive pacing, is much longer during pacing than it is during tachycardia. You essentially have an A-N-V tachycardia with a V-A-V response and a short V-A time. This is most consistent with AVNRT. Again, patient has an ICD, he's getting therapies, and this is something that can be easily ablated. So rather than committing him to long-term drugs, going back to these options, MEO or Sotolol, no reason for coronary angiography, EP study to try and fix this makes the most sense. Okay, so remember to think about ATP similar to a mini-EP study when you're trying to interpret these electrograms. Okay, K6, I think this is our last one. A 46-year-old presents with recent onset fatigue, palpitations, a skin rash, and the ECG shown in figure 6-1, which I will show. Figure 6-2, top panel shows results of cardiac MRI, which shows an LVEF of 51% with a region of delayed enhancement in the basal inferior left ventricle. Figure 6-2, a bottom panel shows a PET scan with normal perfusion and FDG uptake in that same region, the basal intraceptal LV. And the next best management option is to place a dual-chamber pacemaker, a dual-chamber ICD, start prednisone and monitor, start doxycycline and monitor, or electrophysiology study with voltage mapping. This is the ECG, I'll give you a few seconds to look at that. This is the MRI up top showing that basal abnormality. And we have the FDG PET, which also shows a basal, normal perfusion, but an abnormality in uptake, the basal lateral wall. These are the questions, these are the options, dual-chamber pacemaker, dual-chamber ICD, prednisone, doxycycline, or EP study with voltage mapping. Give you a couple of minutes to think about that. Go ahead and pause and then restart when you're ready. Okay, and the correct answer for case 6 is place dual-chamber ICD. So we'll start with the ECG. Obviously here, as you can see with the P-waves, we have AV block, right? We have an atrial rate that's faster than the ventricular rate. The ventricular rate's slower and regular. There's no real relationship between the P-waves and the QRS. So this is AV block. And again, I tried not to be too subtle, but I have given an MRI perfusion abnormality and an FDG defect that this is cardiac sarcoid. You have AV block, you have an FDG abnormality. So then the question is, what should you do? Again, I think with an EF that's not normal, so 51% with a heart block and FDG uptake, that's cardiac sarcoidosis. And most everyone would agree that an ICD should be placed in not a pacemaker. You'd be studying with voltage mapping. Again, patient doesn't have a VT that we've been told about. So I'm not sure that's going to add much. Doxycycline was, you know, because I said the patient had a skin rash, sort of a distractor. We thought the heart block was due to Lyme disease. And then the remaining question is, do you go right to the dual chamber defibrillator or do you start prednisone? Because you know that may have a dramatic effect on sarcoid and may improve the conduction. And then do the ICD later. And again, just looking at the latest consensus document on cardiac sarcoid, says despite their potential reversibility of heart block, device implantations recommended upfront because reversibility is unpredictable. Also, if you start the prednisone first, that can limit wound healing. So they recommend putting the ICD in first and then starting prednisone. Again, starting the prednisone, you know, they're saying immunosuppression about two weeks once the wound is healed is still important because you'd like to avoid, you know, a hundred percent V pacing, which could worsen the cardiomyopathy. And often with prednisone, you can reverse the AV block and not make the, render the patient pacemaker dependent. So you would definitely start immunosuppression, but the recommendations according to the guidelines or the latest consensus document is go ahead and put the ICD in, let the wound heal, then start the immunosuppression. Okay, so that finishes up workshop. My questions for workshop seven. Hope you found this helpful and hope you're enjoying Core Concepts in EP. Thank you. This is Sam Asravatham, one of the electrophysiologists at Mayo Clinic, going to talk through some cases, AFib, SVT, and some common scenarios. No relevant disclosures for this session. So I'm going to start with a couple of questions. No relevant disclosures for these slides. I'm going to show you an intracardiac tracing. The patient has normal heart, sudden onset, sudden offset palpitation. Based on the tracing, I'd like you to think what's least likely. Is it typically renal re-entry, a right pre-wall accessory pathway, left atrial tachycardia, or junctional tachycardia? Coronary sinus is well seated with the distal CS electrodes on the mitral annulus. So distal CS, proximal CS, his bundle recording catheter, right atrial catheter, right ventricular catheter. So based on this, what's unlikely? Typically, VNRT, right pre-wall, left atrial tachycardia, junctional tachycardia. So pretty much the one you're not going to think about in this case is a right pre-wall accessory pathway. So why is this something we have to think? So whenever we see a V and an A together, we have very few conditions to think about. Mainly, it's going to be AV node re-entry. Circuit is very close to the compact AV node and nearby atrium. So you're able to simultaneously or near simultaneously get to the A and B. But we have a differential diagnosis, could be junctional tachycardia, although less common, possible with a very similar pattern. And we have to have a knowledge of some maneuvers to make that distinction. Atrial tachycardia is a possibility when A and B are together, but what it is is one A is taking a long time. And it so happens the PR interval, the AV interval approximates the rate of the tachycardia, the cycle length of A to A. So it looks like the A and B are together, but it's really this A that goes to the B. But why this is a somewhat mystery case is the distal CS is earlier than the prostenal CS. Certainly could be a left atrial tachycardia, but this could also be AV node re-entry or a junctional tachycardia. What it won't be is a right free wall early tachycardia like the right free wall accessory pathway, ORT, because the right atrial signals are clearly late or significantly later. So how does this happen when you have AV node re-entry and get CS activation that may be unusual, mid-CS early, distal CS early? For that, we have to think about the atrial part of the circuit of AV node re-entry. We know we go towards the AV node, back out from the AV node, and then you have to complete the circuit. At the very least, that circuit has to jump over this Eustachian ridge and tendon of toddaro. If there is block in these structures, Eustachian ridge, crista terminalis, then those are the patients who need left atrial myocardium to participate in the circuit to complete it. And when you have to get to the left atrium, then from the left atrium, you cannot go anywhere you like into the CS. You may drape down the septum and the proximal CS will be early, but if you go further into the atrium and then use one of the distal CS to LA connections to get into the CS, this will produce an eccentric or eccentric sequence where distal CS is earlier than proximal CS. Note, however, the fast pathway region just behind the tendon of toddaro will still be earlier than the distal CS. It's only when you look at the CS in isolation, it's confusing. It looks like, why is distal CS early? But what you'll notice if you put a catheter right at the fast pathway region, that will be even earlier than the distal CS. So let's switch chambers here. So I'm going to show you an endocardial RV unipolar voltage map. Patient has syncope palpitation, who's getting risk stratification and also possible inflation. I'm going to show you an area of low voltage and I'd like you to think what's least likely. So voltage here, this purplish is pretty normal voltage. Endocardial unipolar map. Red is very small voltage. RV endocardial unipolar map. What's least likely? ARVC, sarcoid, epicardial fat, poor tissue contact. Any of these may be possible, but what's least likely? Sarcoidosis is unlikely. So right ventricular cardiomyopathy, we have this fibro fatty kind of change from myocardium and that's often three wall. You can be out in the outflow tract three wall, can be near the tricuspid annulus. So this pattern of low voltage on the epicardial surface as suggested by unipolar endocardial map is consistent with, and probably the most important diagnosis to consider, right ventricular cardiomyopathy. But we also know the annulus has fat and sometimes that fat can be quite prominent when you get towards the outflow tract. And as a result of this fat, you may see a normal, slightly less, usually not this dramatic a difference of the amount of voltage in this area. And this is more important consideration when you do an epicardial map and you may not see small ventricular signals because the fat is separating your catheter from the myocardium. The poor tissue contact is a very important cause, even with unipolar mapping, for three wall having low voltage. We instinctively, we want to avoid perforation of the RV3 wall. So often contact is leased on the RV3 wall. So those are important things to consider. But first you would think ARVC, you're going to think, well, could it just be fat? And do I have good contact? Sufficient doubt that you will now do an epicardial map. Sarcoidosis tends to be a disease of the septum, can be anywhere, including the free wall, but it's prominently in the septum, conduction system area, just below the membranous septum is a common site for sarcoidosis. In the outflow tract, it's also septum, which is the posterior part of the RVOT. Whenever free wall is prominent problems, we think less of sarcoidosis. So this is a question to try and understand localization of catheter position in the sinuses of that cell. So I'll show a figure, patient has tachypalpitation. First, based on the signals alone, I want you to try and tell me, ablation catheter position, unlikely to be which, right sinus, non-coronary sinus, tricuspid annulus, tricuspid annulus of mid-septal or left mid-septal location, least likely. So ECG leads during tachycardia, is bundled recording catheter, ASV, CS. Right atrial, right ventricular, ablation catheter. You can see the relative timing of the ablation catheter to other signals. You can also notice the type of signals, VA, near field, far field. Spend another few seconds looking at this. And which is least likely, saying no, that's not it. This is very unlikely to be the right sinus of Valsalva. The reason is, the right sinus of Valsalva is right underneath the RVOT in front of the lung. So you'll get a large, near-field looking ventricular electrogram. And very rare to see any atrial electrogram. And if you do, it will be far-field and it will not be shown. So right sinus, the electrogram itself cannot look like this. And you can exclude that location just based on the electrogram. The left sinus can have B and A. The non-coronary sinus usually has A that's prominent. But when you're deep in the non-coronary sinus, you can pick up the neighboring LV myocardium as a far-field signal as well. So if you see B and A, it could be left sinus or non-coronary sinus. If you see only B, it's usually right sinus. If you see only A, it's usually non-coronary sinus. Now also take a look at fluoroscopy. LAO view, leftward orientation of the catheter. RAO view, posterior, posterior, behind the annulus. Leftward is either left sinus or non-coronary sinus. Posterior is non-coronary sinus. Or it's junction with the left coronary sinus. So right sinus, you'll see it here in the LAO, and it will be way up here, anterior, just underneath the RVOT. And that's why in the right sinus, you will record only ventricular electrograms. This kind of illustrates this figuratively. It's a cartoon description. Notice right sinus under the RVOT. Left sinus also a little under the RVOT, but next to mitral annulus, which means left atrium. Non-coronary sinus, like a finger poking in to the interatrial septum, mostly atrial signals. But when you go deeper in, you can pick up some far-field ventricular signals. Sometimes in heart disease, you'll get this kind of distortion, some preferential chamber enlargements, but still these relationships are pretty fixed. Non-coronary sinus, finger into the interatrial septum, right sinus underneath the right ventricular outpotent. So we'll switch arrhythmias here, patient with suspected pre-excitation. There's a delta wave, which I'll show you in the surface ECG, and we're going to do differential pacing, pacing from different sites in the atrium, CS, and then right atrium. CS and then right atrium. So ECG leads slurred upstroke. Look at the QRS. Pacing from left atrium, this is CS, right atrium. So this is classic maneuver for fasciculoventricular pathways. So if you have an accessory pathway, A to B connection, it's generally going to be right-sided or left-sided. If you pace close to the right side, right-sided pathways will have more pre-excitation. If you place close to the left side, like the CS, left-sided pathways will have more pre-excitation when compared to right-sided pacing. Septal pathways are either favoring right or left, and while the changes can be less dramatic, you will see some change. In addition to this maneuver for fasciculoventricular pathways, you will do some other things. You pace the A faster and faster until you get AV block, and you see no increase in pre-excitation. Standard pathways, the more you block in the AV node, the more pre-excitation you'll see. This doesn't happen with fasciculoventricular pathways. If you see AV with pacing or administration of adenosine, you will see no difference in the pattern of pre-excitation, even just before or after AV block. Why does this happen? Fasciculoventricular tracts are not really atrioventricular bypass tracts. You still go through the AV node. So whether you pace here or here, you block or you decrement, you reach this tract only after you go through the AV node. It's kind of like a breach in the normal insulation of the proximal bundle branches that you get to the V a little quicker than you normally would by going down here. Because you get there quicker, VR is shorter because you're reaching ventricle earlier than you get to the Purkinje network. You get the slurring of the upstroke because once you reach the hiss, it's not too long before you get to the V, the HV will be short. All things that suggest a pathway that these patients do not get tachycardia, you would put them on a treadmill. If you look at a holter, sleep, daytime, atrial pacing, differential pacing, no difference in the pattern of pre-excitation. Atrial fibrillation situation question. So patient has had wide area circumferential ablation, history of persistent AFib. A circumferential mapping catheter is placed in the right upper pulmonary vein. And the question you often have to ask yourself in a case like pulmonary vein isolation, do we have exit block? Do we have entrance block? Do we have both? Or do I need to do something to get more information? So here's the tracing. ECG, circumferential mapping catheter in the right upper pulmonary vein. Ablation catheter in the left atrium. Coronary sinus catheter. CS1 and 2 are distal, pacing from the distal CS. So can you tell from this tracing? Exit block, entrance block, both need information. So we need more information. Specifically, we should consider a maneuver with a pacing close to the vein. So here's the reason for the difficulty. If we see an ectopic beat and it doesn't get out to the atrium, we say it's exit block. The problem here that's a little confusing is, well, if there is exit block, there should be entrance block. An entrance block, when you pace the CS, you shouldn't see signals in the pulmonary vein, but you do. Could it be that this would have conducted out except it would have taken a long time and it just paced and came into the vein too quick? So not sure. Now, there is a way without doing any maneuvers to start reasoning this out. One of them is you notice the signals on the circumferential mapping character in the pulmonary vein are only partial. They're in one sector. And whenever you see in one sector and there's been no ablation inside the pulmonary vein, then look what that sector of electrodes is next to. And it could be signals from that neighboring site. Well, could it be that this patient had had ablation in the pulmonary vein? Very unlikely, because when you've got the ectopic, you see living tissue, electrograms throughout the entire circumference of the pulmonary vein microdia. So this should lead you to the suspicion that maybe these signals are from some neighboring structure. are from some neighboring structure. What is this pacing maneuvers principle? So we pace, we see whether we're getting inside the vein, but that same pacing wave front also gets to the right atrium. So if this mapping catheter is close to the SVC or neighboring right atrium, that may be what's picking up those signals. What you can do is pace the right atrium or the SVC wherever you pace, those signals will come earlier. So now when you pace, instead of seeing these signals of timing like this, if you see those signals pulled in, the ones that you're confused about, these signals, if you saw those pull in when you pace the right atrium or SVC, then you know they are right atrium or SVC origin. So here you can see the mapping catheter, circumferential mapping catheter, RSVV. Catheter and the SVC are in junction just inside the SVC. They're very close together, just anterior. That's why this sector of electrodes might pick up SVC activation. So critical moment, the space from that catheter and you see those signals disappear. They're pulled in and fused with the saturation artifact of the spacing site spike. So the origin of those signals is where you're pacing from. You should try to pace at low output and pace facing in the SVC away from where your lasso catheter is. So you don't get just far field capture of that site. So very important questions that come up in patients where we have pulmonary vein isolation, end points. When we lose all the signals and we see ectopics that clearly have exit blocks spontaneously, it's easy. But when it's confusing, remember the principle. See where those electrodes are facing and consider pacing from that neighboring structure to see if those signals are pulled in. Thank you very much for your attention.

palpitations

fast heart rate

ECG

ablation

procainamide

pre-excited atrial fibrillation

prolonged QT interval

syncope

arrhythmia

cardiomyopathy