Mid systolic septal deceleration in hypertrophic cardiomyopathy: clinical value and insights into the pathophysiology of outflow tract obstruction by tissue Doppler echocardiography.

H ypertrophic cardiomyopathy (HCM) is an inherited cardiac disorder characterised by abnormal left ventricular (LV) hypertrophy in the absence of severe aortic stenosis and hypertension. The presence of a dynamic gradient in the left ventricular outflow tract (LVOT) above 30 mm Hg at rest is associated with an increased mortality. Surgical myectomy or transcoronary ablation of septal hypertrophy (TASH) is indicated in patients with persistent symptoms and gradients . 50 mm Hg under resting or provoked conditions, despite medical treatment. We recently described a characteristic mid systolic septal deceleration (MSSD) pattern in the velocity trace of the basal septum obtained by tissue Doppler imaging (TDI), but the diagnostic value of the MSSD pattern in a larger patient population is still unknown.