Longitudinal myocardial dysfunction in healthy older subjects as a manifestation of cardiac ageing.

BACKGROUND: Abnormalities of longitudinal left ventricular (LV) contraction and relaxation may be early markers of cardiac disease. This study was designed to assess the relationship between long-axis LV function and age in healthy subjects.

METHODS: 118 healthy individuals aged 57 +/-19 years (range 20-90 years) with no evidence of cardiovascular disease under-went echocardiography with Doppler examination of transmitral flow. To assess longitudinal LV function, systolic (S(m)), early diastolic (E(m)) and late diastolic (A(m)) mitral annular velocities were measured using colour-coded tissue Doppler imaging.

RESULTS: The left atrium was enlarged (P<0.001) in subjects >/=60 years of age compared to those <60 years, but there were no differences in LV volumetric indices and ejection fraction. Peak E velocity was lower (P<0.001) and peak A velocity of transmitral flow was higher in older subjects (P<0.001) with a higher E/A ratio (P<0.001) and longer isovolumic relaxation time (P= 0.001) indicative of impaired ventricular relaxation. S m and E m mitral annular velocities decreased (P<0.001) and A m velocity increased (P=0.002) in the older group. E m velocity and E m /A m ratio showed a strong negative correlation with age (r= -0.80, P<0.001 and r=-0.78, P<0.001, respectively).

CONCLUSIONS: Global LV systolic function is preserved but the velocity of long-axis systolic shortening is depressed in older individuals, indicating selective impairment of the longitudinal component of systolic contraction. The decline in the velocity of early diastolic long-axis LV lengthening and the changes in the pattern of transmitral flow suggest impaired ventricular relaxation. These measures of cardiac function may be a useful index of normal cardiac ageing.