Modulation of cardiac autonomic nervous activity early after cardioversion of atrial fibrillation by biphasic waveform.

Background: Imbalance of cardiac autonomic nervous modulation might prominently contribute to early relapses of atrial fibrillation (AF) after cardioversion (CV). The biphasic (Bi) waveform is more effective than the monophasic (Mo) waveform in CV of AF. Whether these waveforms have different effects on autonomic modulation early after CV is unknown.