Indications for and results of implanting cardiac pacemakers

Abstract

Implantable pacemakers have decreased the mortality and morbidity of patients with cardiogenic syncope (Morgagni-Adams-Stokes disease). When atrioventricular block is absent, the differential diagnosis of cardiogenic syncope, simple syncope, carotid sinus syndrome, syncope with aortic stenosis, cerebrovascular insufficiency and epileptic states in the elderly may be difficult. The occurrence of bundle branch block in a patient with syncope should raise the suspicion of Morgagni-Adams-Stokes attacks, but could be a miscue if relied on unduly. At the Mayo Clinic internal pacemakers have been implanted in thirty-eight patients primarily for uncontrolled episodes of syncope. At the time of surgical treatment, the dominant atrioventricular relationship was established as complete block in seventeen; 2:1 heart block in eleven; normal sinus rhythm in nine; and atrial fibrillation with episodes of ventricular standstill in one. There were four hospital deaths. Eight patients required reoperation. When only an occasional episode of cardiogenic syncope has occurred, the decision to implant the presently available pacemaker is difficult and a trial of medical management is warranted. Numerous electrocardiographic phenomena occur but are primarily of theoretical interest. We have observed no deaths unequivocably attributable to stimulation of a pacemaker when atrioventricular conduction was present.