EFFECTS OF AGING ON LEFT-VENTRICULAR RELAXATION IN HUMANS - ANALYSIS OF LEFT-VENTRICULAR ISOVOLUMIC PRESSURE DECAY

Background Some experimental studies in animals have shown that myocar dial relaxation is prolonged with aging. However, it is not known whet her aging alters ventricular isovolumic relaxation in human subjects. Methods and Results We analyzed high-fidelity left ventricular pressur es, measured by use of a catheter-tipped manometer, and biplane left v entriculograms in 55 normal subjects who underwent diagnostic cardiac catheterization but who were found to have normal cardiac anatomy and function. There were 38 men and 17 women, ranging in age from 20 to 77 years. Left ventricular isovolumic relaxation was assessed by the exp onential time constants of isovolumic pressure decay with (Tb) and wit hout (Tw) an asymptote pressure. Left ventricular volume, ejection fra ction, and wall thickness or mass were calculated from left ventricula r angiograms. Neither of the time constants of left ventricular relaxa tion correlated with age (Tb: r=.001 to .10, P=NS; Tw: r=.02 to .05, P =NS). Left ventricular systolic function (ie, ejection fraction and en d-systolic volume index), heart rate, and left ventricular wall thickn ess or mass, which are major hemodynamic determinants of left ventricu lar relaxation, were not significantly affected by aging. The multivar iate analysis of age and hemodynamic variables against the time consta nts of left ventricular relaxation also indicated that no significant relation was found between age and left ventricular relaxation. Conclu sions In the absence of coronary artery disease, systemic hypertension , left ventricular systolic dysfunction, or hypertrophy, left ventricu lar relaxation assessed by the time constant of isovolumic pressure de cay remains essentially unchanged with normal adult aging, at least un til the eighth decade.