Symptomatic Hypertrophic Obstructive Cardiomyopathy: The Role of Dual-Chamber Pacing

BACKGROUND AND PURPOSE: The management of symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM) has traditionally consisted of beta blockers and calcium channel blockers. Surgical treatment has been employed for operable patients who became refractory to medical therapy. However, associated complications, mortality rate, and recurrence of functional limitations have shifted the focus toward alternative therapy modalities. Recently, permanent dual-chamber (DDD) pacemaker has been introduced as an alternative treatment option. PATIENTS AND METHODS: This study comprises clinical, angiographic, echocardiographic, and electrophysiologic data obtained at a single center on 10 symptomatic patients with HOCM who received a DDD pacemaker after medical therapy failed to relieve symptoms. Presenting symptoms were exertional dyspnea and chest pain (60%), syncope (20%), and presyncope (20%). These symptoms were documented for 8.9+/-7.1 years before pacemaker implantation. All patients were in New York Heart Association functional class III or IV before pacemaker therapy. RESULTS: Placement of a permanent DDD pacemaker decreased the left ventricular outflow tract gradient from 83+/-44 mm Hg (range: 35-180 mm Hg) to 47.1+/-25.3 mm Hg (range: 10-75 mm Hg) in these patients. Within 1 to 30 months, follow-up found that the functional status of eight out of the 10 patients had improved to New York Heart Association class 0 or I. CONCLUSION: In selected patients with symptomatic HOCM who fail to respond to medical therapy, DDD pacemaker may offer a nonsurgical alternative treatment option. Large-scale multicenter, prospective, randomized trials are needed to establish the role of this modality in the treatment of hypertrophic obstructive cardiomyopathy.