Abstract 3259: The Use of a Low Tilt Biphasic Waveform Lowers the Defibrillation Threshold for the Internal Cardioversion of Atrial Fibrillation
Purpose: Conventional defibrillators used for the internal cardioversion of atrial fibrillation (AF) employ high tilt waveforms generated by a capacitor based discharge. We have developed a biphasic waveform with low tilt. This was compared with a conventional waveform of equivalent duration (6/6ms) and voltage.
Methods: Patients were randomised to receive either the low tilt waveform or a conventional waveform. Defibrillation electrodes were positioned in the right atrial appendage and distal coronary sinus. Peak voltage was increased in a stepwise progression from 50V to 300V. Shock success was defined as return of sinus rhythm for ≥ 30 seconds.
Results: The low tilt waveform resulted in successful termination of persistent AF in 10 of 13 cases (77%) at a mean voltage of 223V versus the conventional waveform in 2 of 12 cases (17%) at a mean voltage of 270V (p = 0.002). In patients with induced AF the mean voltage for the low tilt waveform was 90V and for the conventional waveform was 158V (p=0.005).
Conclusions: The low tilt biphasic waveform was more successful for the internal cardioversion of both persistent and induced AF. This waveform could be useful for the termination of both persistent and induced AF during ablation procedures in order to restore sinus rhythm at a low voltage.