Changes in Left Ventricular Diastolic Function 6 Months After Nonsurgical Septal Reduction Therapy for Hypertrophic Obstructive Cardiomyopathy

Abstract

Background —Nonsurgical septal reduction therapy (NSRT) decreases left ventricular outflow tract (LVOT) gradient and improves symptoms in patients with hypertrophic obstructive cardiomyopathy (HOCM). NSRT effects on LV/left ventricular diastolic function are currently unknown. Methods and Results —HOCM patients (n=29) had Doppler echocardiography at baseline and 6 months after NSRT to evaluate changes in LV volume, pre–A-wave pressure, early diastolic mitral annulus velocity (Ea) by tissue Doppler, and τ. At 6 months, a significant reduction in LVOT gradient (from 53.6±15 to 6±5 mm Hg; P <0.001) was accompanied by improvement in exercise duration (from 284±147 to 408±178 seconds; P =0.04) and New York Health Association class (from III to I; P <0.001). Pre-A pressure (18±6 to 14±5 mm Hg; P <0.01) and τ (62±8 to 51±8 ms; P <0.01) decreased, whereas Ea (5.8±1.8 to 8±1.8 cml/s; P <0.01) and LV end-diastolic volume (117±16 to 130±22 mL; P <0.01) increased. Conclusions —NSRT improves LV relaxation and compliance, which contributes to the symptomatic relief seen at 6 months.