CCU Rotation: Elective Direct Current Cardioversion in Atrial Fibrillation – Should we do it?

Atrial fibrillation (Afib) is the most common sustained cardiac rhythm disturbance, and has an increasing prevalence as our population ages. Although often associated with heart disease, Afib can also occur in many patients with no detectable heart disease (often called Lone Afib). Management of Afib consists of either rate control or rhythm control, and within rhythm control, two major strategies exist: pharmacologic cardioversion vs. direct current cardioversion. The rapid restoration of sinus rhythm in patients with Afib can prevent many of the short and long term consequences of persistent disease as hemodynamic impairment and thromboembolic events result in significant morbidity, mortality, and cost.

Elective direct current cardioversion has been studied in both ED and Cardiology literature. Cardioversion of stable patients without prior anticoagulation in the ED has also been proven to be safe and effective.

Indications:
•First episode
•Infrequent episode that does not spontaneously convert, with onset within past 48hrs (as determined by symptom onset)
•Infrequent episode that has been prolonged for longer than 48hrs with the patient currently therapeutically anticoagulated (INR >2.0)
•Worsening cardiac function due to Afib

Contraindications: notice that there is no mention of other co-morbidities as a contraindication
•Minimally symptomatic patients (specifically patients incidentally found to be in Afib based on ECG rather than symptoms)
•Age >80 (relative contraindication)
•Paroxysmal Afib, as patients generally spontaneously cardiovert and Afib is of short duration
•Uncorrected extrinsic causes of Afib (thyrotoxicosis, pericarditis, myocarditis, mitral stenosis)

Direct Current Cardioversion:
•Patients should ideally have been fasting for approximately 6-8 hours prior to the procedure; however, having eaten within the last 6-8 hours is NOT a contraindication
•Attaching pads to anterior/posterior (sternum and left scapula) has been proven to be more effective than anterior/lateral (apex and R infraclavicular).
•Short acting sedative should be given for patient comfort
•Initial shock of 200J (with biphasic waveform)
•Patients who convert to sinus rhythm should then be observed
oOne study proposed a 1hr observation period but there is no generally accepted standard length of time
•Once stable in sinus rhythm, patients should be given prompt Cardiology follow up, possibly within 1 week
oMost studies were retrospective and included only a 7 day follow up window

Outcomes
• Restoration of sinus rhythm found to be >90% ,
• Most common adverse reaction after cardioversion had to do with complications from procedural sedation
• Most common cardioversion-related reason for non-discharge was ventricular tachycardia that was brief and self-terminating
• Thromboembolic risk of cardioversion of Afib with a duration less than 48hrs is <1% o In most studies during which the follow up window was 7 days, there were no thromboembolic events or deaths o In the one retrospective study of a 30 day window, there were also no thromboembolic events or deaths reported. • AED return rate for relapsed Afib can range from 3-17%3, almost exclusively in the first month after cardioversion Considerations: • No ED study recommended giving anticoagulation before, during, or after the cardioversion o Current Cardiology guidelines, however, recommends: • If CHADS2 score= 0-1 and age <60, give ASA • If CHADS2 score= 0 and age 60-74, give ASA • If CHADS2 score= 1 and age >60, give anticoagulation
• If CHADS2 score> 1 at any age, given anticoagulation
• No ED study routinely administered antiarrhythmics before, during, or after cardioversion to prevent recurrence of Afib
o ACC/AHA/ESC guidelines recommend either a beta-blocker, or flecainide, propafenone, disopyrimide or sotalol before and after
o Alternatives included amiodarone or dofetilide

1. Botto GL, et al. External cardioversion of atrial fibrillation: role of paddle position on technical efficacy and energy requirements. Heart, 1999;726-730.

2. Von Besser K, Mills AM. Is discharge to home after emergency department cardioversion safe for the treatment of recent-onset atrial fibrillation? Ann Emerg Med, 2011; 58(6): 517-520.

3. Naccarelli G, et al. Restoration of sinus rhythm in atrial fibrillation. UpToDate. Ed. GM Saperia. April 16, 2012. http://www.uptodate.com/contents/restoration-of-sinus-rhythm-in-atrial-fibrillation?source=search
_result&search=cardioversion+atrial+fibrillation&selectedTitle=1%7E150#H8701654

4. Burton JH, et al. Electrical cardioversion of emergency department patients with atrial fibrillation. Ann Emerg Med, 2004; 44:20-30.

5. Stead LG, Vaidyanathan L. Rhythm control with electrocardioverision for atrial fibrillation and flutter. Ann Emerg Med, 2009; 54(4): 745-747.

6. Jacoby JL, et al. Synchronized emergency department cardioversion of atrial fibrillation saves time, money, and resources. J Emerg Med, 2005; 28: 27-30.

7. Fuster V, et al. ACC/AHA/ESC 2006 guidelines for the management of atrial fibrillation: a report of the American College of Cardiology/American Heart Association/the European Society of Cardiology Committee for Practice Guidelines developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. Circulation, 2006; 114: e257-354.

Above article by: Lani Lee MD

2 Comments on "CCU Rotation: Elective Direct Current Cardioversion in Atrial Fibrillation – Should we do it?"

  • Hey there- any reason you start at 200J biphasic? I seem to remember thinking that some of the guidelines say you can start as low as 50J, but that sometimes you need more or repeat w/ the lower levels. I have had experience starting about 100J and increasing for a second attempt at 200J if unsuccessful. Is there a good study regarding starting Joules? Thanks, –andrew s.

    • I came across a podcast that suggested starting at a higher current, in an effort to depolarize a “critical mass” of atrium – unlike with aflutter where there is only a circuit that needs to be interrupted and 50J would likely suffice. – Vince

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