Effects of isometric exercise and heart rate on left ventricular filling pattern assessed by pulsed Doppler echocardiography.

Abstract

Left ventricular filling pattern was assessed by pulsed Doppler echocardiography at rest and during handgrip exercise in 33 healthy middle-aged subjects. The peak mitral flow-velocities during the early rapid filling phase (E) and during late (atrial) filling (A) were measured and the ratio of these peak flow-velocities (E:A ratio) was calculated. The E:A ratio was inversely related to age (r = -0.50), heart rate (r = -0.47) and septal thickness (r = -0.36) at rest. Exercise caused a significant (P less than 0.001) decrease in E:A ratio as a result of an increase in the peak A velocity. No significant change in the peak E velocity was observed during exercise. The exercise E:A ratio was related to heart rate (r = -0.53), but not to resting E:A ratio or age, since the decrease in E:A ratio tended to be less in the older subjects. Our study shows that isometric exercise augments the relative contribution of atrial contraction of left ventricular filling and this increase may 'mask' minor changes in resting transmitral flow pattern associated with, e.g. ageing. Secondly, in addition to age, heart rate must be taken into account when studying populations with different heart-rate levels or interventions associated with simultaneous heart rate changes.