Changes in left ventricular diastolic function 6 months after nonsurgical septal reduction therapy for hypertrophic obstructive cardiomyopathy

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 rig; 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.