atrial fibrillation".) Myocardial necrosis Minimal myocardial necrosis, particularly of the epicardium, may occur as a result of high-energy shocks. This is typically asymptomatic and is manifested by small rises in serum CK-MB and troponin levels. In contrast, substantial elevations of either CK-MB or troponin following electrical cardioversion, or the development of chest pain suggestive of angina, suggests the presence of myocardial injury from causes unrelated to the procedure. As such, we do not routinely monitor cardiac enzymes following electrical cardioversion in asymptomatic patients. Although the cause is unknown, it has been suggested that myocardial necrosis may be due to the sustained depolarization of a critical mass of myocardial cells [40]. The risk of myocardial https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 11/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate necrosis appears related to the amount of energy delivered with each shock rather than to the number of shocks, although many repeated shocks may lead to myocardial damage and scarring. In one study of 30 patients who underwent cardioversion, an increase in serum CK-MB was seen in only two patients, despite substantial release of CK from skeletal muscle [56]. Furthermore, the small release of CK-MB in this report cannot be considered diagnostic for myocardial damage since the total CK from skeletal muscle includes approximately 1 percent CK-MB [57]. (See "Troponin testing: Clinical use".) The desire for improved specificity in the diagnosis of myocardial injury has led to measurement of the serum troponin levels. Among 38 patients undergoing elective cardioversion, only three patients had minimal elevations of troponin I (0.8 to 1.5 mcg/L), suggesting subtle myocardial injury [44]. Two other studies, however, reported no elevations in troponin T following cardioversion [45,58]. Myocardial dysfunction Global left ventricular dysfunction due to myocardial stunning may be seen in patients with cardiac arrest who have undergone successful cardiopulmonary resuscitation. This is related in part to defibrillation, but is also a result of the arrhythmia itself and due to the absence of cardiac output and coronary blood flow during the period of arrest with resultant ischemia. Myocardial dysfunction due to stunning may reverse within the first 24 to 48 hours after cardiac arrest. It is routine to image the heart and evaluate ventricular function shortly after a patient suffers a cardiac arrest to determine if there is evidence of structural heart disease. This evaluation should not be delayed. However, it is important to recognize that ventricular dysfunction may be transient and that imaging should be repeated within a few days if ventricular dysfunction is present immediately after the arrest [59]. In animals, the severity of postresuscitation myocardial dysfunction is related, in part, to the energy used for defibrillation [60]. Further support for this observation comes from another animal study comparing biphasic and monophasic waveforms for reversion of ventricular fibrillation [61]. Although lower-energy biphasic waveforms were as effective as higher-energy monophasic waveforms for restoration of sinus rhythm, there was less myocardial dysfunction after defibrillation with the use of biphasic waveforms. The process of electrical cardioversion may transiently injure or "stun" the atria as well [62,63]. Pulmonary edema Pulmonary edema is a rare complication of cardioversion, which is probably due to transient left atrial standstill or left ventricular dysfunction. It is unrelated to the amount of energy used. Pulmonary edema may be more common in patients with AF associated with valvular heart disease or left ventricular dysfunction. In this setting, the return of atrial https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 12/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate systole after cardioversion can result in a significant elevation in left atrial pressure and pulmonary edema [64]. Transient hypotension Transient hypotension can occur for several hours after cardioversion. Most patients require no therapy; if necessary, the fall in blood pressure usually responds to fluid replacement [65]. Although the mechanism is not certain, the hypotension may be related to vasodilation or the use of sedation during the procedure. Cutaneous burns Following cardioversion or defibrillation, skin burns occur in 20 to 25 percent of patients and are more likely with improper technique and placement of electrodes [66]. The risk of burns is less with the use of biphasic waveforms and the use of gel-based pads [67]. The use of steroid cream, silver sulfadiazine cream, or topical ibuprofen reduces the pain and inflammation [68,69]. INTERNAL CARDIOVERSION/DEFIBRILLATION Technique and efficacy Internal or intracardiac cardioversion is an effective technique for patients in whom external cardioversion has failed to restore sinus rhythm. However, the need for internal cardioversion has been greatly diminished due to the efficacy of biphasic waveform defibrillators and the availability of ibutilide in restoring sinus rhythm. In addition, given the invasive nature of the procedure, specialized training is required to perform internal cardioversion. An ACC/AHA task force on clinical competency has published recommendations for technical and cognitive skills needed to perform internal direct current cardioversion ( table 3A-B) [70]. Internal cardioversion can be performed in various ways: Using a preexisting ICD to deliver a clinician-directed shock. Using epicardial wires placed during surgery or internal paddles applied directly to the epicardium in a patient with a sternotomy [71]. Two defibrillation electrodes are placed in the right atrium and coronary sinus or in the right atrium and left pulmonary artery, respectively, and then intracardiac shocks are delivered by an external defibrillator. Internal cardioversion complications Although internal cardioversion is an effective approach for restoring sinus rhythms in patients with AF refractory to pharmacologic or external electrical cardioversion, one study reported that complications occurred in 19 percent of patients, including low cardiac output from ventricular stunning, pericardial effusion, and a brief https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 13/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate period of ventricular asystole requiring ventricular pacing [72]. Another report of 25 patients found that 36 percent developed transient bradycardia, related to sinus and atrioventricular nodal depression, requiring temporary ventricular pacing [73]. Shocks of up to 20 joules did not affect the function of permanent pacemakers. Implantable cardioverter-defibrillators ICDs are in widespread use in patients with a history of sustained ventricular tachycardia or ventricular fibrillation and also for primary prevention in selected patients. In patients with an ICD, internal cardioversion can be attempted by a cardiologist using the device programmer to deliver the shock. The advantage of using the ICD is that it avoids the risk of a skin irritation from an external shock and the small chance of damage to the ICD system from the shock. The disadvantage of using the ICD is that it consumes some of the battery in the device and does not always work for cardioversion of atrial arrhythmias. Indications for and efficacy of ICDs are discussed in detail elsewhere. (See "Implantable cardioverter-defibrillators: Overview of indications, components, and functions" and "Primary prevention of sudden cardiac death in patients with cardiomyopathy and heart failure with reduced LVEF".) SOCIETY GUIDELINE LINKS Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Atrial fibrillation" and "Society guideline links: Arrhythmias in adults" and "Society guideline links: Ventricular arrhythmias" and "Society guideline links: Supraventricular arrhythmias".) INFORMATION FOR PATIENTS UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." th th The Basics patient education pieces are written in plain language, at the 5 to 6 grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more th th sophisticated, and more detailed. These articles are written at the 10 to 12 grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon. Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 14/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate variety of subjects by searching on "patient info" and the keyword(s) of interest.) Basics topics (see "Patient education: Heart failure and atrial fibrillation (The Basics)") Beyond the Basics topics (see "Patient education: Cardioversion (Beyond the Basics)" and "Patient education: Implantable cardioverter-defibrillators (Beyond the Basics)") SUMMARY AND RECOMMENDATIONS Definitions Electrical cardioversion and defibrillation are commonly performed procedures in the management of patients with cardiac arrhythmias. Elective outpatient cardioversions are routinely performed on patients with persistent atrial fibrillation (AF) to restore sinus rhythm ( movie 1). Cardioversion is the delivery of energy that is synchronized to the QRS complex, while defibrillation is asynchronous delivery of a shock randomly during the cardiac cycle. (See 'Introduction' above.) Energy selection When available, a biphasic defibrillator is preferred due to greater efficacy. Nearly all available external defibrillators now use a biphasic waveform. However, it is still important to fully understand the type of waveform that is delivered when using an external defibrillator. The energy selection recommendations in this topic are in joules and are for defibrillators that use a standard biphasic waveform. Lower energies can be used with defibrillators that use a truncated biphasic waveform. (See 'Energy selection' above.) Once an arrhythmia has been identified, the most important factor in the likelihood of a successful cardioversion or defibrillation is the choice of the initial energy level to be delivered to the patient. To increase the likelihood of initial shock success and reduce the duration of sedation, a higher initial energy may be considered. The following are suggested initial energy requirements for monophasic and biphasic waveforms (see "Basic principles and technique of external electrical cardioversion and defibrillation", section on 'Energy selection for cardioversion and defibrillation'): For AF, 120 to 200 joules ( algorithm 1) For atrial flutter, 50 to 100 joules For ventricular tachycardia with a pulse, 100 joules For ventricular fibrillation or pulseless ventricular tachycardia, 200 to 360 joules ( algorithm 2) Efficacy External cardioversion and defibrillation have been used in the treatment of a variety of arrhythmias, with variable results depending on the chronicity of the arrhythmia, https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 15/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate triggers for the arrhythmia, and the patient s overall clinical condition. The term "failed cardioversion" can indicate failure to restore sinus rhythm at all, or an immediate recurrence of the arrhythmia. It is important to differentiate these two failure mechanisms because different approaches can be used to address each type of failure. (See 'Efficacy' above.) Atrial fibrillation or atrial flutter Electrical cardioversion success rates approach 100 percent in patients with atrial flutter or AF of short duration and no structural heart disease, while the success rates are much lower in patients with chronic AF and concomitant mitral valve disease. (See 'Atrial fibrillation' above and 'Atrial flutter' above.) Ventricular tachycardia Electrical cardioversion is usually successful in the acute treatment of ventricular tachycardia. If a distinct QRS and T wave are identified, synchronized cardioversion can be attempted. In contrast, synchronized cardioversion may be impossible or hazardous if distinct QRS complexes are not identified. As such, under these circumstances, asynchronous defibrillation should be used. (See 'Ventricular tachycardia' above.) Ventricular fibrillation Defibrillation is the only definitive treatment for ventricular fibrillation (VF), with high success rates when performed promptly. However, the success rate falls substantially as the duration of ventricular fibrillation increases, probably due to myocardial ischemia, acidosis, and other metabolic changes. For these reasons, defibrillation as soon as possible has been considered to be the standard of care for VF ( algorithm 2). (See 'Ventricular fibrillation' above.) Complications While electrical cardioversion and defibrillation are generally well tolerated, complications may occur. Most complications are self-limited (eg, changes in the electrocardiogram, hypotension related to sedation and/or vasodilation) or relatively benign (eg, skin irritation). However, providers should be aware of potential life- threatening complications such as post-cardioversion arrhythmias and thromboembolism. (See 'Complications' above.) Internal cardioversion Internal or intracardiac cardioversion is an effective technique for patients in whom external cardioversion has failed to restore sinus rhythm. The need for internal cardioversion has been greatly diminished due to the efficacy of biphasic waveform defibrillators in restoring sinus rhythm. Given the invasive nature of the procedure, specialized training is required to perform internal cardioversion. (See 'Internal cardioversion/defibrillation' above.) https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 16/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate ACKNOWLEDGMENT The UpToDate editorial staff acknowledges Ramsey Wehbe, MD, who contributed to earlier versions of this topic review. Use of UpToDate is subject to the Terms of Use. REFERENCES 1. Strzelczyk TA, Kaplan RM, Medler M, Knight BP. Outcomes Associated With Electrical Cardioversion for Atrial Fibrillation When Performed Autonomously by an Advanced Practice Provider. JACC Clin Electrophysiol 2017; 3:1447. 2. Kirchhof P, Eckardt L, Loh P, et al. Anterior-posterior versus anterior-lateral electrode positions for external cardioversion of atrial fibrillation: a randomised trial. Lancet 2002; 360:1275. 3. Botto GL, Politi A, Bonini W, et al. External cardioversion of atrial fibrillation: role of paddle position on technical efficacy and energy requirements. Heart 1999; 82:726. 4. Ramirez FD, Fiset SL, Cleland MJ, et al. Effect of Applying Force to Self-Adhesive Electrodes on Transthoracic Impedance: Implications for Electrical Cardioversion. Pacing Clin Electrophysiol 2016; 39:1141. 5. Walsh SJ, McCarty D, McClelland AJ, et al. Impedance compensated biphasic waveforms for transthoracic cardioversion of atrial fibrillation: a multi-centre comparison of antero-apical and antero-posterior pad positions. Eur Heart J 2005; 26:1298. 6. Dahl CF, Ewy GA, Warner ED, Thomas ED. Myocardial necrosis from direct current countershock. Effect of paddle electrode size and time interval between discharges. Circulation 1974; 50:956. 7. Warner ED, Dahl C, Ewy GA. Myocardial injury from transthoracic defibrillator countershock. Arch Pathol 1975; 99:55. 8. Link MS, Atkins DL, Passman RS, et al. Part 6: electrical therapies: automated external defibrillators, defibrillation, cardioversion, and pacing: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010; 122:S706. 9. Saliba W, Juratli N, Chung MK, et al. Higher energy synchronized external direct current cardioversion for refractory atrial fibrillation. J Am Coll Cardiol 1999; 34:2031. https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 17/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate 10. Oral H, Souza JJ, Michaud GF, et al. Facilitating transthoracic cardioversion of atrial fibrillation with ibutilide pretreatment. N Engl J Med 1999; 340:1849. 11. Sung RJ. Facilitating electrical cardioversion of persistant atrial fibrillation by antiarrhythmic drugs: update on clinical trial results. Card Electrophysiol Rev 2003; 7:300. 12. Babbs CF, Yim GK, Whistler SJ, et al. Elevation of ventricular defibrillation threshold in dogs by antiarrhythmic drugs. Am Heart J 1979; 98:345. 13. Troup PJ, Chapman PD, Olinger GN, Kleinman LH. The implanted defibrillator: relation of defibrillating lead configuration and clinical variables to defibrillation threshold. J Am Coll Cardiol 1985; 6:1315. 14. Tacker WA Jr, Niebauer MJ, Babbs CF, et al. The effect of newer antiarrhythmic drugs on defibrillation threshold. Crit Care Med 1980; 8:177. 15. Van Gelder IC, Crijns HJ, Van Gilst WH, et al. Effects of flecainide on the atrial defibrillation threshold. Am J Cardiol 1989; 63:112. 16. Gurevitz OT, Ammash NM, Malouf JF, et al. Comparative efficacy of monophasic and biphasic waveforms for transthoracic cardioversion of atrial fibrillation and atrial flutter. Am Heart J 2005; 149:316. 17. Page RL, Kerber RE, Russell JK, et al. Biphasic versus monophasic shock waveform for conversion of atrial fibrillation: the results of an international randomized, double-blind multicenter trial. J Am Coll Cardiol 2002; 39:1956. 18. Khaykin Y, Newman D, Kowalewski M, et al. Biphasic versus monophasic cardioversion in shock-resistant atrial fibrillation:. J Cardiovasc Electrophysiol 2003; 14:868. 19. Wyse DG, Waldo AL, DiMarco JP, et al. A comparison of rate control and rhythm control in patients with atrial fibrillation. N Engl J Med 2002; 347:1825. 20. Van Gelder IC, Hagens VE, Bosker HA, et al. A comparison of rate control and rhythm control in patients with recurrent persistent atrial fibrillation. N Engl J Med 2002; 347:1834. 21. Fuster V, Ryd n LE, Cannom DS, et al. ACC/AHA/ESC 2006 Guidelines for the Management of Patients with Atrial Fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Revise the 2001 Guidelines for the Management of Patients With Atrial Fibrillation): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. Circulation 2006; 114:e257. 22. Niebauer MJ, Brewer JE, Chung MK, Tchou PJ. Comparison of the rectilinear biphasic waveform with the monophasic damped sine waveform for external cardioversion of atrial https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 18/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate fibrillation and flutter. Am J Cardiol 2004; 93:1495. 23. Gallagher MM, Guo XH, Poloniecki JD, et al. Initial energy setting, outcome and efficiency in direct current cardioversion of atrial fibrillation and flutter. J Am Coll Cardiol 2001; 38:1498. 24. Mortensen K, Risius T, Schwemer TF, et al. Biphasic versus monophasic shock for external cardioversion of atrial flutter: a prospective, randomized trial. Cardiology 2008; 111:57. 25. Faddy SC, Powell J, Craig JC. Biphasic and monophasic shocks for transthoracic defibrillation: a meta analysis of randomised controlled trials. Resuscitation 2003; 58:9. 26. Morrison LJ, Dorian P, Long J, et al. Out-of-hospital cardiac arrest rectilinear biphasic to monophasic damped sine defibrillation waveforms with advanced life support intervention trial (ORBIT). Resuscitation 2005; 66:149. 27. Martens PR, Russell JK, Wolcke B, et al. Optimal Response to Cardiac Arrest study: defibrillation waveform effects. Resuscitation 2001; 49:233. 28. Stothert JC, Hatcher TS, Gupton CL, et al. Rectilinear biphasic waveform defibrillation of out- of-hospital cardiac arrest. Prehosp Emerg Care 2004; 8:388. 29. Tovar OH, Jones JL. Electrophysiological deterioration during long-duration ventricular fibrillation. Circulation 2000; 102:2886. 30. Cobb LA, Fahrenbruch CE, Walsh TR, et al. Influence of cardiopulmonary resuscitation prior to defibrillation in patients with out-of-hospital ventricular fibrillation. JAMA 1999; 281:1182. 31. Wik L, Hansen TB, Fylling F, et al. Delaying defibrillation to give basic cardiopulmonary resuscitation to patients with out-of-hospital ventricular fibrillation: a randomized trial. JAMA 2003; 289:1389. 32. VOGEL JH, PRYOR R, BLOUNT SG Jr. DIRECT-CURRENT DEFIBRILLATION DURING PREGNANCY. JAMA 1965; 193:970. 33. Schroeder JS, Harrison DC. Repeated cardioversion during pregnancy. Treatment of refractory paroxysmal atrial tachycardia during 3 successive pregnancies. Am J Cardiol 1971; 27:445. 34. Waller C, Callies F, Langenfeld H. Adverse effects of direct current cardioversion on cardiac pacemakers and electrodes Is external cardioversion contraindicated in patients with permanent pacing systems? Europace 2004; 6:165. 35. Gould L, Patel S, Gomes GI, Chokshi AB. Pacemaker failure following external defibrillation. Pacing Clin Electrophysiol 1981; 4:575. 36. Levine PA, Barold SS, Fletcher RD, Talbot P. Adverse acute and chronic effects of electrical defibrillation and cardioversion on implanted unipolar cardiac pacing systems. J Am Coll Cardiol 1983; 1:1413. https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 19/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate 37. Manegold JC, Israel CW, Ehrlich JR, et al. External cardioversion of atrial fibrillation in patients with implanted pacemaker or cardioverter-defibrillator systems: a randomized comparison of monophasic and biphasic shock energy application. Eur Heart J 2007; 28:1731. 38. Eysmann SB, Marchlinski FE, Buxton AE, Josephson ME. Electrocardiographic changes after cardioversion of ventricular arrhythmias. Circulation 1986; 73:73. 39. Van Gelder IC, Crijns HJ, Van der Laarse A, et al. Incidence and clinical significance of ST segment elevation after electrical cardioversion of atrial fibrillation and atrial flutter. Am Heart J 1991; 121:51. 40. Chun PK, Davia JE, Donohue DJ. ST-segment elevation with elective DC cardioversion. Circulation 1981; 63:220. 41. Zelinger AB, Falk RH, Hood WB Jr. Electrical-induced sustained myocardial depolarization as a possible cause for transient ST elevation post-DC elective cardioversion. Am Heart J 1982; 103:1073. 42. Kok LC, Mitchell MA, Haines DE, et al. Transient ST elevation after transthoracic cardioversion in patients with hemodynamically unstable ventricular tachyarrhythmia. Am J Cardiol 2000; 85:878. 43. Reiffel JA, Gambino SR, McCarthy DM, Leahey EB Jr. Direct current cardioversion. Effect on creatine kinase, lactic dehydrogenase and myocardial isoenzymes. JAMA 1978; 239:122. 44. Allan JJ, Feld RD, Russell AA, et al. Cardiac troponin I levels are normal or minimally elevated after transthoracic cardioversion. J Am Coll Cardiol 1997; 30:1052. 45. Neumayr G, Hagn C, G nzer H, et al. Plasma levels of troponin T after electrical cardioversion of atrial fibrillation and flutter. Am J Cardiol 1997; 80:1367. 46. Reddy RK, Gleva MJ, Gliner BE, et al. Biphasic transthoracic defibrillation causes fewer ECG ST-segment changes after shock. Ann Emerg Med 1997; 30:127. 47. Ambler JJ, Deakin CD. A randomized controlled trial of efficacy and ST change following use of the Welch-Allyn MRL PIC biphasic waveform versus damped sine monophasic waveform for external DC cardioversion. Resuscitation 2006; 71:146. 48. Waldecker B, Brugada P, Zehender M, et al. Dysrhythmias after direct-current cardioversion. Am J Cardiol 1986; 57:120. 49. DeSilva RA, Graboys TB, Podrid PJ, Lown B. Cardioversion and defibrillation. Am Heart J 1980; 100:881. 50. LEMBERG L, CASTELLANOS A Jr, SWENSON J, GOSSELIN A. ARRHYTHMIAS RELATED TO CARDIOVERSION. Circulation 1964; 30:163. https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 20/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate 51. PELESKA B. CARDIAC ARRHYTHMIAS FOLLOWING CONDENSER DISCHARGES AND THEIR DEPENDENCE UPON STRENGTH OF CURRENT AND PHASE OF CARDIAC CYCLE. Circ Res 1963; 13:21. 52. Cohen TJ, Scheinman MM, Pullen BT, et al. Emergency intracardiac defibrillation for refractory ventricular fibrillation during routine electrophysiologic study. J Am Coll Cardiol 1991; 18:1280. 53. Gr nberg T, Nuotio I, Nikkinen M, et al. Arrhythmic complications after electrical cardioversion of acute atrial fibrillation: the FinCV study. Europace 2013; 15:1432. 54. Elhendy A, Gentile F, Khandheria BK, et al. Safety of electrical cardioversion in patients with previous embolic events. Mayo Clin Proc 2001; 76:364. 55. Bjerkelund CJ, Orning OM. The efficacy of anticoagulant therapy in preventing embolism related to D.C. electrical conversion of atrial fibrillation. Am J Cardiol 1969; 23:208. 56. Ehsani A, Ewy GA, Sobel BE. Effects of electrical countershock on serum creatine phosphokinase (CPK) isoenzyme activity. Am J Cardiol 1976; 37:12. 57. Lindberg K, Lundin A, Nordlander R, et al. Detection of acute myocardial infarction by a new, sensitive and rapid method for determination of creatine kinase B-subunit activity. Eur Heart J 1980; 1:327. 58. Goktekin O, Melek M, Gorenek B, et al. Cardiac troponin T and cardiac enzymes after external transthoracic cardioversion of ventricular arrhythmias in patients with coronary artery disease. Chest 2002; 122:2050. 59. Kern KB, Hilwig RW, Rhee KH, Berg RA. Myocardial dysfunction after resuscitation from cardiac arrest: an example of global myocardial stunning. J Am Coll Cardiol 1996; 28:232. 60. Xie J, Weil MH, Sun S, et al. High-energy defibrillation increases the severity of postresuscitation myocardial dysfunction. Circulation 1997; 96:683. 61. Sun S, Klouche K, Tang W, Weil MH. The effects of biphasic and conventional monophasic defibrillation on postresuscitation myocardial function. J Am Coll Cardiol 2001; 37:1753. 62. Grimm RA, Stewart WJ, Maloney JD, et al. Impact of electrical cardioversion for atrial fibrillation on left atrial appendage function and spontaneous echo contrast: characterization by simultaneous transesophageal echocardiography. J Am Coll Cardiol 1993; 22:1359. 63. Omran H, Jung W, Rabahieh R, et al. Left atrial chamber and appendage function after internal atrial defibrillation: a prospective and serial transesophageal echocardiographic study. J Am Coll Cardiol 1997; 29:131. https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 21/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate 64. Gowda RM, Misra D, Khan IA, Schweitzer P. Acute pulmonary edema after cardioversion of cardiac arrhythmias. Int J Cardiol 2003; 92:271. 65. Resnekov L. High-energy electrical current and myocardial damage. Med Instrum 1978; 12:24. 66. Ambler JJ, Sado DM, Zideman DA, Deakin CD. The incidence and severity of cutaneous burns following external DC cardioversion. Resuscitation 2004; 61:281. 67. Ambler JJ, Deakin CD. A randomised controlled trial of the effect of biphasic or monophasic waveform on the incidence and severity of cutaneous burns following external direct current cardioversion. Resuscitation 2006; 71:293. 68. Ambler JJ, Zideman DA, Deakin CD. The effect of prophylactic topical steroid cream on the incidence and severity of cutaneous burns following external DC cardioversion. Resuscitation 2005; 65:179. 69. Ambler JJ, Zideman DA, Deakin CD. The effect of topical non-steroidal anti-inflammatory cream on the incidence and severity of cutaneous burns following external DC cardioversion. Resuscitation 2005; 65:173. 70. Tracy CM, Akhtar M, DiMarco JP, et al. American College of Cardiology/American Heart Association Clinical Competence Statement on invasive electrophysiology studies, catheter ablation, and cardioversion: A report of the American College of Cardiology/American Heart Association/American College of Physicians-American Society of Internal Medicine Task Force on Clinical Competence. Circulation 2000; 102:2309. 71. Liebold A, Wahba A, Birnbaum DE. Low-energy cardioversion with epicardial wire electrodes: new treatment of atrial fibrillation after open heart surgery. Circulation 1998; 98:883. 72. Mansourati J, Larlet JM, Salaun G, et al. Safety of high energy internal cardioversion for atrial fibrillation. Pacing Clin Electrophysiol 1997; 20:1919. 73. Prakash A, Saksena S, Mathew P, Krol RB. Internal atrial defibrillation: effect on sinus and atrioventricular nodal function and implanted cardiac pacemakers. Pacing Clin Electrophysiol 1997; 20:2434. Topic 983 Version 47.0 https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 22/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate GRAPHICS Protocol for direct current cardioversion (CV) for atrial fibrillation (AF) when performed autonomously by a mid-level provider and when sedation is administered by anesthesiologist Pre-procedure 1. Obtain medical history that includes the indication for CV and review records. 2. Document that NPO status is at least 6 hours prior to procedure. 3. Confirm appropriate anticoagulation unless onset of AF is <24 to 48 hours: For warfarin, document therapeutic INRs (>2.0) for last 4 weeks. For non-warfarin oral anticoagulants, confirm no doses missed for last 4 weeks. Document therapeutic INR and/or NOAC dose within 12 hrs. Perform TEE if OAC has not been therapeutic for at least 4 weeks prior to procedure or if there is a history of prior atrial thrombus. 4. Complete ECG to confirm presence of AF or flutter. 5. Obtain consent: review indications, discuss risks and benefits, including potential skin irritation, stroke, abnormal rhythms, and inform patient of the role of each care team member. 6. Interrogate any CIED before CV. 7. Review case with supervising physician. Procedure 1. Apply cardioversion skin pads using anterior-posterior or base-apex placement. 2. Connect the pads to a synchronized biphasic defibrillator. 3. Complete a Time-Out procedure pursuant to hospital policy. 4. Anesthesia team provides deep sedation. 5. Select initial shock energy: AF begin at 200 to 360 joules. Atrial flutter begin at 50 to 100 joules. Atrial tachycardia begin at 50 joules. 6. If sinus rhythm was restored but there is an IRAF: Resynchronize defibrillator and repeat CV at same energy. If IRAF continues, contact supervising physician. Consider ibutilide 1 mg IV over 10 minutes with repeat CV after 10 additional minutes. https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 23/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate Post procedure 1. Perform ECG. 2. Interrogation of any CIED post procedure. 3. Document post procedure note including appropriate discharge medications. 4. Continue anticoagulation for a minimum of 4 weeks. 5. Update family or friends accompanying patient. 6. Ensure follow-up is arranged. NPO: nothing by mouth; INR: internal normalized ratio; NOAC: non-vitamin K oral anticoagulants; TEE: transesophageal echocardiography; OAC: oral anticoagulant; ECG: electrocardiogram; CIED: cardiac implantable electronic device; IRAF: immediate reoccurrence of atrial fibrillation; IV: intravenous. Original gure modi ed for this publication. From: Strzelczyk TA, Kaplan RM, Medler M, Knight BP. Outcomes Associated With Electrical Cardioversion for Atrial Fibrillation When Performed Autonomously by an Advanced Practice Provider. J Am Coll Cardiol 2017; 3:1447. Table used with the permission of Elsevier Inc. All rights reserved. Graphic 121196 Version 1.0 https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 24/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate Options for hands-free pacemaker/defibrillator pad positioning Positioning options for hands-free pacemaker/defibrillator pads showing anterior/lateral positioning (left) and anterior/posterior positioning (right). Graphic 103268 Version 2.0 https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 25/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate Defibrillation waveforms in implantable cardioverter- defibrillators Figure A shows the monophasic, exponentially decaying pulse was the waveform used in the first generation of ICDs. Figure B shows the biphasic waveform, which is generated with a single capacitor by switching the output polarity during discharge. Each division is 2 milliseconds. ICD: implantable cardioverter-defibrillator. Graphic 51842 Version 3.0 https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 26/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate Adult tachycardia with a pulse algorithm 2020 update Reprinted with permission. ACLS Provider Manual. Copyright 2020 American Heart Association, Inc. Graphic 130747 Version 10.0 https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 27/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate Adult cardiac arrest algorithm https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 28/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 29/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate Reprinted with permission. Highlights of the 2020 American Heart Association Guidelines for CPR and ECC. Copyright 2020 American Association, Inc. Graphic 129983 Version 9.0 https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 30/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate The effect of antiarrhythmic agents on cardioversion energy requirements Antiarrhythmic agent Energy requirement Lidocane Increased or no change Quinidine Increased Phenytoin Increased Amiodarone Increased Flecainide Increased Ibutilide Decreased Graphic 81781 Version 3.0 https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 31/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate 12 lead ECG of atrial flutter The 12 lead electrocardiogram (ECG) of atrial flutter shows a regular rhythm with a narrow QRS complex. Flutter waves are present, best seen in leads II, III, and aVF (*). In this ECG, the flutter waves are negative in leads II, III, and aVF, and positive in lead V1. One flutter wave is obvious between the QRS complexes, while the second one is superimposed on the terminal portion of the QRS complex; hence there is 2:1 atrioventricular nodal block, which is the most common presentation for atrial flutter. Reproduced with permission by Samuel Levy, MD. Graphic 75931 Version 3.0 https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 32/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate Reentrant circuit of typical atrial flutter within the right atrium Schematic representation of reentrant circuit (red arrow) of typical (type 1) atrial flutter. The reentrant impulse rotates in a counterclockwise direction around the tricuspid annulus. The crista terminalis (CT) and eustacian ridge (ER) serve as lines of block, preventing the impulse from short-circuiting the annulus. Ablation is performed in the isthmus between the IVC and TA, which is an obligatory part of the circuit. SVC: superior vena cava; CS: coronary sinus; IVC: inferior vena cava; FO: foramen ovale Graphic 52904 Version 5.0 https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 33/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate Cognitive skills necessary to perform internal DC cardioversion Physicians should have knowledge of the following: Cognitive and technical skills for performing intracardiac electrophysiologic study Principles of intracavitary cardioversion with catheter technology, catheters, chest electrodes, or whatever variant the operator plans to use Indications and complications associated with transvenous catheterization and with the intracavitary delivery of DC shock The safe delivery of DC shock and the limit of energy that can be delivered via electrode catheters The use of conscious sedation or, when appropriate, anesthesia The use of intravenous antiarrhythmic medications Cognitive skills necessary for external DC cardioversion Data from Tracy CM, Akhtar M, DiMarco JP, et al. Circulation 2000; 102:2309. Graphic 57223 Version 2.0 https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 34/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate Technical skills necessary to perform internal DC cardioversion Competency in performing diagnostic cardiac electrophysiology studies Ability to place electrode catheters in appropriate locations for intracardiac synchronization and DC cardioversion Familiarity with the catheter characteristics, synchronization, and DC cardioversion equipment Ability to confirm the timing and energy of the shock for safe shock delivery Adequate electrocardiographic and rhythm monitoring equipment Ability to handle complications, including the use of temporary pacing and defibrillation Proficiency in the appropriate use of sedation during procedures, including airway management Data from Tracy CM, Akhtar M, DiMarco JP, et al. Circulation 2000; 102:2309. Graphic 65048 Version 2.0 https://www.uptodate.com/contents/cardioversion-for-specific-arrhythmias/print 35/36 7/6/23, 2:50 PM Cardioversion for specific arrhythmias - UpToDate Contributor Disclosures