Adams-Stokes seizures due to ventricular tachydysrhythmias in patients with heart block: prevalence and problems of management.

One hundred and twelve patients with heart block and chronic tendency to syncope were ECG-monitored during syncope. Ventricular tachycardia and/or fibrillation (VT-VF) was observed as the cause of syncope in 11 patients: in 6 of 20 patients with chronic third degree A-V block, in 3 of 65 with paroxysmal A-V block and in 2 of 27 with S-A block. The R-R interval preceding the escape beat which initiated VT-VF varied between 1.2 and 2.2 seconds. The cerebral attacks were amenable to long-term pacemaker treatment. However, relapses of VT-VF were observed during pacing with a low rate of 55 per minute and during short interruptions in pacing, as produced by intermittent pacemaker failure or threshold determination. In one patient, supplementary treatment with a beta-blocking agent had to be given to suppress exercise-induced attacks of VT-VF after pacemaker implantation.