Regional myocardial function by tissue Doppler in hypertrophic cardiomyopathy: the impact of obstruction

The conventional echocardiographic assessment of myocardial function in patients with obstructive hypertrophic cardiomyopathy (HOCM) is complex, because of the load dependency of this method. Tissue Doppler imaging (TDI) may improve this evaluation.

To compare regional myocardial function with TDI, between patients with hypertrophic obstructive cardiomyopathy (HOCM) and with non-obstructive forms of the disease (NOHCM).

26 patients with HOCM and 23 with NOHCM were studied with pulsed TDI. We studied longitudinal (8 left ventricular segments, apical views) and radial regional function (2 segments, short axis view), and analyzed velocities, time intervals, velocity-time integrals and heterogeneity and asynchrony indices and the meridional (basal-medial segments) velocity gradient in each wall. Data were compared within each group and between groups.

Compared to NOHCM, HOCM patients showed: systolic functions: a) longitudinal: similar velocities, time intervals and integrals; b) radial: higher meridional gradient, lower velocity-time integrals. Diastolic function: a) longitudinal: lower a, higher e and e/a tendency; lower e meridional gradient, higher percentage of septal and anterior wall segments with e/a > or = 1; b) radial: lower a velocities and integrals, shorter diagnostic time.

This study shows that in HOCM patients, the presence of obstruction and its associated load conditions have a different impact on systolic and diastolic regional myocardial function, in long and short axis, assessed with TDI. So, in HOCM patients: 1-Long axis regional systolic function is similar to the non-obstructive forms, suggesting relative load independence. 2-Long and short axis regional diastolic function is, in specific segments and parameters, different from the non-obstructive forms. These data should be taken into account in the assessment of regional myocardial function with TDI in HOCM.