Mechanism of altered pattern of left ventricular filling with aging in subjects without cardiac disease.

The mechanism whereby aging, in the absence of cardiac disease, may alter the pattern of left ventricular (LV) diastolic filling is unknown. Accordingly, this study was designed to examine the factors that may be in part responsible for aging's effect on the pattern of LV diastolic filling. The LV end-diastolic pressure-volume relation was analyzed in 11 elderly subjects (68 +/- 5 years, mean +/- standard deviation) and 15 normal young adults (31 +/- 7 years) without coronary artery disease, systemic hypertension, LV hypertrophy or abnormality of LV systolic function. After catheterization, the subjects underwent pulsed Doppler analysis of mitral flow. All had normal 2-dimensional echocardiograms without LV or valvular dysfunction. Peak early filling velocity in the elderly subjects was decreased in comparison with that in young adults (61 +/- 14 vs 83 +/- 8 cm/s, p less than 0.001) and the ratio of early and late diastolic filling velocity was reduced (0.81 +/- 0.26 vs 1.88 +/- 0.40, p less than 0.001). The isovolumic relaxation time did not differ between the elderly and young subjects (158 +/- 20 vs 146 +/- 22 ms, difference not significant). In the elderly, LV end-diastolic pressure was increased (15 +/- 7 vs 11 +/- 4 mm Hg, p less than 0.05) despite a smaller end-diastolic volume index (60 +/- 16 vs 74 +/- 18 ml/m2, p less than 0.05), indicating a shift of the passive diastolic pressure-volume relation. It was concluded that early diastolic filling is reduced in normal aged subjects, even in the absence of coronary artery disease and systolic dysfunction. This altered pattern of diastolic filling may result from a shift of the passive LV diastolic pressure-volume relation.