Tripodi D, McAreavey D. Long-term results of dual-chamber (DDD) pacing in obstructive hypertrophic cardiomyopathy. Evidence for progressive symptomatic and hemodynamic improvement and reduction of left ventricular hypertrophy. Circulation

Background We previously reported that 6 to 12 weeks of dual-chamber (DDD) pacing results in clinical and hemody-namic improvement in obstructive hypertrophic cardiomyopa-thy (HCM). This study examines the long-term results ofDDD pacing in obstructive HCM. Methods and Results DDD devices were implanted in 84 patients (mean age, 49±16 years) with obstructive HCM and severe drug-refractory symptoms. At a mean follow-up of 2.3+0.8 years (maximum, 3.5 years), the New York Heart Association (NYHA) functional class had improved signifi-cantly (1.6±0.6 versus 3.2--0.5, P<.00001). Symptoms were eliminated in 28 patients (33%), improved in 47 patients (56%), but remained unchanged in 7 patients (8%). Two patients died suddenly (97 % cumulative 3-year survival rate). In 74 patients with significant left ventricular outflow trac