External cardioversion of atrial fibrillation: role of paddle position on technical efficacy and energy requirements

Abstract

Aim-To define the eVect of defibrillator paddle position on technical success and dc shock energy requirements of external cardioversion of atrial fibrillation. Methods-301 patients (mean (SD) age 62 (11) years) with stable atrial fibrillation were randomly assigned to elective external cardioversion using anterolateral paddle position (ventricular apex-right infraclavicular area; group AL (151 patients)) or anteroposterior paddle position (sternal body-angle of the left scapula; group AP (150 patients)). A step up protocol was used, delivering a 3 J/kg body weight dc shock, then a 4 J/kg shock (maximum 360 J), and finally a second 4 J/kg shock using the alternative paddle location. Conclusions-An anteroposterior defibrillator paddle position is superior to an anterolateral location with regard to technical success in external cardioversion of stable atrial fibrillation, and permits lower dc shock energy requirements. Arrhythmia duration is the only clinical variable that can limit the restoration of sinus rhythm. (Heart 1999;82:726-730) Results-The

External Cardioversion in Patients With Persistent Atrial Fibrillation A Reappraisal of the Effects of Electrode Pad Position and Transthoracic Impedance on Cardioversion Success.

“…3,9,15) In contrast, our data revealed that even in patients with relatively long AF duration, eg, > 6 months (median 9 months), success rates were similar to those in patients of AF duration < 6 months. Therefore, our data suggest that DC treatment administered to control AF rhythm should not be overlooked when treating patients with prolonged AF duration.…”

“…Several studies suggest a higher cardioversion success rate when pads are positioned over the right parasternal area or sternal body and the left infrascapular area, rather than when electrode pads are conventionally positioned. [7][8][9][10] However, the differences in cardioversion success rate due to differing pad positions have not been confirmed by other studies. 5,6,11) Recently, a small, nonrandomized, and nonprospective study by Mehdiard, et al 11) suggested that improved DC cardioversion efficacy in patients with AF could be achieved by positioning pads under fluoroscopy to encompass as much atrial muscle as possible.…”

“…Previous studies comparing the relative efficacy of pad positions on AF cardioversion have yielded divergent results, with several studies indicating that position has no bearing on cardioversion success 5,6,11) and other studies showing that anteroposterior positioning achieves significantly improved results. [7][8][9][10]12) In the study by Mehdiard, et al 11) 360 J DC shocks with the electrode pads positioned anteroposteriorly (under fluoroscopic guidance) to cover the atrial mass as much as possible were able to successfully induce sinus rhythm in 8 of 15 patients who had failed cardioversion using a conventional pad position. The recent randomized study by Kirchhof, et al 12) also supported the advantage of an anterior-posterior position over the anterior-lateral position for external cardioversion of persistent atrial fibrillation.…”

“…Clinical predictors of cardioversion success: Several investigators concluded that AF duration was an important factor affecting the technical success of external cardioversion 9,11,14,15) with a lower success rate achieved if atrial fibrillation persisted for longer than 6 months. 3,9,15) In contrast, our data revealed that even in patients with relatively long AF duration, eg, > 6 months (median 9 months), success rates were similar to those in patients of AF duration < 6 months.…”

Part 6: Defibrillation

“…Twenty-two studies have compared specific cardioversion strategies (eg, monophasic versus biphasic defibrillators and different energy levels) administered by cardiologists in the hospital setting to patients with atrial fibrillation (both acute and chronic) (LOE 1 14,17,26,27,31,[102][103][104][105][106][107][108][109][110][111][112][113][114][115] ; LOE 2 116,117 ). Most of these studies documented that biphasic shocks were more effective than monophasic shocks for cardioversion.…”