Effects of aging on left ventricular-arterial coupling in man: assessment by means of arterial effective and left ventricular elastances.

The ejection fraction (EF) is a load-dependent index of the systolic function of the left ventricle (LV), which depends on the 'functional' coupling of the LV with the arterial system, evaluated by the ratio between arterial effective elastance (Ea) to end-systolic left ventricular elastance. The spectrum of changes in LV and the arterial system during aging has not been studied by means of coupled analysis of elastances. Twenty-five normotensive healthy subjects aged from 22 to 68 years underwent hemodynamic and angiographic studies. The functional properties of the arterial system were evaluated in terms of Ea (end-systolic pressure/stroke volume), and the systolic function of the LV was approximated by the end-systolic pressure to end-systolic volume ratio (Elv). The result is that Ea increased linearly with age. Elv increased less than Ea. The positive relationship between Ea/Elv and age was close to statistical significance (r = 0.39, p = 0.07), suggesting that left ventricular-arterial coupling changes little with aging. Analysis of the relationship between EF and end-systolic stress showed that several points were situated at the lower part of the relationship in elderly subjects, suggesting a decrease in the intrinsic contractility of left ventricular muscle in some cases. Aging is characterized by a simultaneous increase in arterial system elastance and the systolic performance of the left ventricular pump, thereby preserving the transfer function of the arterial system as a whole. However, some aged subjects may depart from this rule, probably because of variability in the capacity to produce myocardial hypertrophy and/or altered inotropy of the muscle.