Aims: External electrical cardioversion is the method of choice to terminate persistent atrial fibrillation. Whether the type of shock electrode affects cardioversion success is not known. We tested whether hand-held steel electrodes improve cardioversion outcome with monophasic or biphasic shocks when compared with adhesive patch electrodes.
Methods and results: Two hundred and one consecutive patients with persistent atrial fibrillation (147 male, mean age 63+/-1 years, duration of atrial fibrillation 6.3+/-1 months) were randomly assigned to cardioversion using either a sinusoidal monophasic or a truncated exponential biphasic shock wave form. The first half of patients were cardioverted using adhesive patch electrodes, the second half using hand-held steel paddle electrodes, and all patients using an anterior-posterior electrode position. Paddle electrodes successfully cardioverted 100/104 patients (96%) and patch electrodes 85/97 patients (88%, P=0.04). This effect was comparable to that of biphasic shocks: biphasic shocks cardioverted 102/104 patients (98%) and monophasic shocks 83/97 patients (86%, P=0.001). A beneficial effect of paddle electrodes was observed for both shock wave forms. After cross-over from an ineffective monophasic to a biphasic shock, cardioversion was successful in 198/201 (98.5%) patients. Unsuccessful cardioversion after cross-over (3/201 patients) only occurred with patch electrodes (P=0.07).
Conclusion: Hand-held paddle electrodes increase success of external cardioversion of atrial fibrillation in this trial. This increase is of similar magnitude as the increase in cardioversion success achieved with biphasic shocks. A combination of biphasic shocks, paddle electrodes, and an anterior-posterior electrode position renders outcome of external cardioversion almost always successful (104/104 patients in this trial).