Hypertrophic cardiomyopathy is classically defined as a diastolic disease with normal systolic function. Long axis left ventricular function is an important and sensitive determinant of global ventricular function but its assessment is often difficult and complex. Tissue Doppler imaging of the mitral annulus allows the study of long axis left ventricular function.
47 patients with non-obstructive hypertrophic cardiomyopathy and 45 healthy volunteers, matched by age and sex, were studied with pulsed tissue Doppler imaging of the 4 sides of the mitral annulus (septal, lateral, inferior, anterior) in 4 and 2 chamber views. In each wave (systolic-s, rapid filling-e, atrial contraction-a) we analyzed velocities, time intervals and velocity-time integrals, as well as heterogeneity and asynchrony. Data were compared among the different sides in each group, between groups and with conventional Doppler data.
In contrast to normal subjects, hypertrophic cardiomyopathy patients showed: 1--Systolic function: lower velocities, longer systolic time intervals (isovolumic relaxation time, time to peak s, ejection time), higher systolic asynchrony (time to peak s, ejection time, systolic time) and lower s/shortening fraction ratio. These changes occurred despite normal indices of global systolic function. 2--Diastolic function: lower velocities (much lower rapid filling velocity, lower atrial contraction velocity, lower septal e/a), higher e/a heterogeneity index, longer protodiastolic times (isovolumic relaxation time and time to peak e), higher diastolic asynchrony (time to peak e) and lower e wave integral. Hypertrophic cardiomyopathy patients also showed higher average number of annular sides with e/a < 1 per patient and higher percentage of e/a < 1, mainly on the septal side.
This study shows that: 1--Tissue Doppler imaging allows the detailed analysis of long axis left ventricular function in hypertrophic cardiomyopathy patients. 2--Long axis systolic function is abnormal in this disease, even in the presence of normal indices of global systolic function. 3--Long axis diastolic function is deeply disturbed in hypertrophic cardiomyopathy, at ventricular and atrial levels. 4--Long axis dysfunction occurs in annular sides contiguous to hypertrophied and non-hypertrophied walls, highlighting the role of other factors in its pathophysiology.