Outcome of dual-chamber pacing for the pacemaker syndrome

Symptomatic hypotension induced by VVI pacing (ventricular paced, ventricular inhibited) is characteristic of the pacemaker syndrome. Recent observations indicate that it is due to atrioventricular dyssynchrony. Since 1980, we have used the approach of converting the ventricular pacing to a dual-chamber pacing system in patients with this syndrome. The clinical course, hemodynamics, and response to dual-chamber pacing were evaluated in nine patients with the pacemaker syndrome whose ages ranged from 41 to 78 years. The indication for initial implantation of a pacemaker was symptomatic sinus node dysfunction in eight patients and intermittent Mobitz II block in one patient. One patient had a history of heart failure. The mean cardiothoracic ratio was 0.44. After initial implantation of a VVI pacemaker, all patients had syncope or near-syncope (mean duration, 10 months; mean frequency, one episode per month) despite normal pacemaker function. Eight of the nine patients had a symptomatic decrease in systolic blood pressure of greater than 20 mm Hg and ventriculoatrial conduction during VVI pacing. Dual-chamber pacing was instituted in all nine patients. This mode abolished pacing hypotension and its related symptoms. During a mean follow-up of 10 months, no patient has had recurrent syncopal or near-syncopal attacks related to pacemaker function. Dual-chamber pacing is an effective approach for treatment of the pacemaker syndrome.