Observations in patients with implanted pacemaker: III. Frequency of ventricular tachycardia as cause of Adams-Stokes attacks and rate of pacing required for its prevention

Abstract

Thirty-eight patients with Adams-Stokes syndrome were treated with implanted pacemakers. In 28 the mechanism of syncope could be determined. Ventricular tachycardia was observed in 19, that is, in about 68 per cent. Because of the great frequency of this arrhythmia and the grave prognosis attached to it, prevention of ventricular tachycardia is the chief problem in the treatment of Adams-Stokes syndrome. The use of sympathomimetic and cardiac-depressant drugs is contraindicated. Stimulation of the ventricle by an electrical pacemaker is the only promising method of treatment. Pacing at a rate of 60 per minute was effective in the long-term prevention of ventricular tachycardia in 15 out of 19 patients. In 3 patients, ventricular arrhythmias recurred on the day of implantation. Raising the rate of pacing from 60 to 80 per minute prevented further attacks in 2 patients. In the third patient, however, fatal ventricular fibrillation recurred on the day of operation, after the rate of pacing had been stepped up to 96 per minute. A fourth patient succumbed to ventricular fibrillation on the ninth postoperative day while function of the implanted pacemaker at a rate of 60 per minute was unimpaired. It is suggested that implantable pacemakers, in order to yield full benefit, should have an inherent pacing rate of 90 per minute. Provision should be made, if possible, for increasing the rate of the pacemaker so that its function may be adapted to changing needs.