Contractility of the hypertrophied human left ventricle in chronic pressure and volume overload.

Nine patients with normal left ventricles (C), 10 patients with pressure load (PL) due to predominant aortic stenosis, and 9 patients with predominant volume load (VL) due to aortic incompetence were studied by left ventricular high-fidelity pressure measurements and cineangiography. Peak measured velocity of the contractile elements (Vpm) used as index of contractility and left ventricular muscle mass (LMMI) were determined. The patients with PL and VL were matched with respect to LMMI. In PL LMMI was 241 +/- 41 and in VL 254 +/- 42 gm. per square meter. Both were sizably increased (P smaller than 0.001) as compared to LMMI in C (89 +/- 24 gm. per square meter). Vpm was 1.41 +/- 0.20 ML per second in C. In PL and VLVpm was reduced to 1.05 +/- 0.26 (P smaller than 0.01) and to 1.07 +/- 0.33 ML per second (P smaller than 0.02). Vpm in PL was not different from Vpm in VL. Heart rate showed no major difference in the three groups. It is concluded that in two groups of patients with predominant PL and VL matched with respect to LMMI left ventricular contractility was depressed to a similar extent regardless of the stimulus to hypertrophy.