Elective Cardioversion: Influence of Paddle-Electrode Location and Size on Success Rates and Energy Requirements

Abstract

We compared the success rates and energy requirements of two electrode-paddle positions (anteroposterior vs. anterolateral) and different paddle sizes in the elective cardioversion of atrial arrhythmias. We prospectively studied 173 patients - 111 in atrial fibrillation and 62 in atrial flutter. The anterolateral paddles used were either two standard-size (8.5-cm diameter) paddles or one 13-cm diameter anterior paddle with one standard-size lateral paddle. The anteroposterior paddles used were either a standard-size or a 13-cm anterior paddle with 12-cm posterior paddle. Overall cardioversion success rates with either paddle position were similar (greater than 90 per cent). The larger paddles did not significantly reduce energy requirements for cardioversion of either arrhythmia. We conclude that anterolateral paddles are as effective as anteroposterior paddles for the elective cardioversion of atrial arrhythmias, and that there is no demonstrable advantage to using paddles that are larger than the standard size in either position.

Part 6: Defibrillation

“…Four studies support the anteriorposterior position (LOE 5), 26 -30 1 study supports the anterior-lateral position (LOE 5), 31 and 1 study supports the anterior-apex position (LOE 5). 32 Five studies (LOE 5) 16,[21][22][23][24] found no effect of electrode position on TTI. One study showed that paddles/pads should be placed under the breast tissue (LOE 5) 33 and 2 studies showed that hirsute males should be shaved before the application of pads (LOE 5).…”

“…Most studies evaluate cardioversion (eg, AF) or secondary end points (eg, TTI). Eleven studies (LOE 5) [15][16][17][18][19][20][21][22][23][24][25] found all 4 positions (anterior-apex, anteriorposterior, anterior-left infrascapular, anterior-right infrascapular) to be equally effective in defibrillation (for VF/pulseless VT) or elective AF cardioversion success. Four studies support the anteriorposterior position (LOE 5), 26 -30 1 study supports the anterior-lateral position (LOE 5), 31 and 1 study supports the anterior-apex position (LOE 5).…”

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

“…Pad position and cardioversion: The ventricular apex-right infraclavicular area has been the standard pad placement position for cardioversion, although it is known that the optimal electrode position should permit current passage through the entire atrial mass to attain cardioversion success. 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.…”

“…4) Because transthoracic impedance varies with electrode pad position, [5][6] different pad positions may result in differing cardioversion success rates. 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. In light of differing opinions and the lack of significant conclusive evidence, the relative effectiveness of different electrode positions on cardioversion success remains unclear.…”