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Persisting symptoms despite permanent pacing. Incidence, causes, and follow-up.

Persisting symptoms, consisting of palpitations, dizziness, or syncope, were found in 49 of 570 consecutively followed patients (8.6 percent) with permanent pacemakers (PM). Among 540 patients with ventricular PM, 19 had syncope and 24 dizziness; among 30 patients with dual-chamber PM, five had palpitations and one dizziness. Symptoms were PM-related in 17, caused by tachyarrhythmias in 12, of noncardiac origin in 16, and of unknown origin in four patients. Holter monitoring was necessary for evaluating the persisting symptoms in 36 patients and helpful in 32 studies (89 percent). Symptoms were relieved in all patients with PM-related causes but only in 6/16 patients (38 percent) with syncope or dizziness of noncardiac origin despite various therapeutic measures. In patients with either documented tachyarrhythmias or unknown cause of syncope or dizziness, antiarrhythmic drugs led to symptomatic improvement in 11 of 12 treated patients during an average follow-up of 15 months. We concluded that: (1) persistent syncope, dizziness, or palpitations occurred in 8.6 percent of 570 patients after PM-implantation; (2) symptoms were more frequent but less severe in patients with dual-chamber PM than in those with ventricular PM; (3) tachyarrhythmias as a possible cause of symptoms were found in 25 percent of patients; (4) symptomatic improvement was noted in 28 of 29 patients when a PM-related cause or tachyarrhythmias were treated.