Clinical and electrophysiological observations with disopyramide in drug-resistant and recurrent symptomatic arrhythmias.

Seventeen patients with recurrent symptomatic arrhythmias were treated with oral disopyramide (DP). Fifteen of the 17 patients had received other currently conventional anti-arrhythmic therapy, to which only 1 patient responded, yet 13 of these 15 patients with resistant arrhythmias responded to DP. Electrophysiological studies were performed on 9 patients. The most impressive electrophysiological findings were the depressant effect of DP on ventricular automaticity and its action in slowing conduction through the His-Purkinje system (including the bundle branches) without depressing sino-atrial rate and atrioventricular (AV) nodal conduction time. Retrograde ventriculo-atrial (VA) conduction was markedly prolonged in 4 patients with reciprocating supraventricular tachycardia (SVT), including 2 patients with Wolff-Parkinson-White syndrome. All 4 patients with reciprocating SVT appear to be cured of their arrhythmia, probably by this mechanism.