Kirchhof et al. (Ref. 1) investigated the anterior-posterior versus anterior-lateral electrode positions for external cardioversion of atrial fibrillation. Currently, both electrode positions are recommended for external cardioversion in actual guidelines. In the study by Kirchhof et al. a randomised trial was initiated comparing the two positions with the endpoint of successful cardioversion.
108 consecutive patients with persistent atrial fibrillation underwent elective external cardioversion by a standardised step-up protocol with increasing shock strengths (50-360 J). Electrode positions were randomly assigned as anterior-lateral or anterior-posterior position.
If sinus rhythm was not achieved with 360 J energy, a single cross-over shock (360 J) was applied with the other electrode configuration.
External cardioversion of persistent atrial fibrillation was more likely to be successful when an anterior-posterior electrode position was used. Cardioversion was successful in the anterior-posterior compared with the anterior-lateral position in 50 out of 52 (96%) vs 44 out of 56 patients (78%), respectively (p<0,009). Cross-over from the anterior-lateral to the anterior-posterior electrode position was successful in 8 out of 12 patients, whereas cross-over in the other direction was not successful (n=2). In total, after cross-over cardioversion was successful in 102 of 108 randomised patients (94%).
These findings suggest that an anterior-posterior electrode position is more effective for external cardioversion of atrial fibrillation than an anterior-lateral electrode position.
The results of the present study:
This observation has significant impact on the practicable approach to the patients with persistent atrial fibrillation.
* Recommendations of the ACC/AHA/ESC 2001 are to start with external electrical cardioversion (EEC) or rapid action antiarrhythmic therapy (ibutilide) or longer action antiarrhythmic therapy (amiodarone).
It is emphasised that ECC after pharmacologic treatment reduced the risk of the recurrence of AF (but with the possible drug side-effects). A recurrence of AF after EEC should be treated with antiarrhythmic treatment followed by EEC. One can also opt for rate control with an anticoagulation treatment.
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