AGE DEPENDENCY OF LEFT-VENTRICULAR DIASTOLIC FUNCTION IN PRESSURE-OVERLOAD HYPERTROPHY

Objectives. We sought to evaluate whether age is a determinant of left ventricular (LV) pressure overload hypertrophy and whether diastolic function influenced the aging process. Background. The adaptation of t he left ventricle to chronic pressure overload is a complex process of hormonal, structural and hemodynamic factors. Different responses in the elderly patients have been described. Methods. LV biplane cineangi ography, micromanometry and endomyocardial biopsies were carried out i n 57 patients with pure or predominant aortic stenosis, Patients were classified into a senior (<60 years, mean age +/- SD 46 +/- 10 years, n = 35) and an elderly (>65 years; mean age 70 +/- 4 years, n = 22) st udy group. LV systolic function was evaluated from biplane ejection fr action and midwall fractional shortening, whereas diastolic function w as assessed from the time constant of LV pressure decay, peak filling rate and the constant of myocardial stiffness. Biopsy samples were exa mined morphometrically for interstitial fibrosis, fibrous content, mus cle fiber diameter and volume fraction of myofibrils. Results. Gender distribution and the severity of aortic stenosis were comparable in th e two patient groups. LV peak systolic and end-diastolic pressures wer e significantly higher in the elderly than in the senior group. LV eje ction fraction and midwall fractional shortening were comparable in th e two groups. The time constant of relaxation and the myocardial stiff ness constant were greater in the elderly than in the senior group whe reas the early peak filling rate was significantly reduced in the elde rly group. Interstitial fibrosis was increased, although not significa ntly (p < 0.06), and fibrous content,vas enhanced (p < 0.001) in elder ly patients with respect to the senior group. There was a linear corre lation between age and myocardial stiffness (r = 0.55, p < 0.0001) and an inverse relation between age and early peak filling rate (r = 0.52 , p < 0.0001). Conclusions. In the presence of a comparable degree of aortic valve stenosis, elderly patients (>65 years) present with more severe LV hypertrophy than do senior patients (<60 years). Therefore e lderly patients have a more pronounced impairment of LV diastolic func tion, whereas systolic function is preserved. Thus, there is an age de pendency of LV pressure overload hypertrophy that can be explained by the longer duration of pressure overload or an exhaustion of the adapt ation process in the elderly. (C) 1997 by the American College of Card iology