Left ventricular function and power distribution during ejection period in patients with cardiac diseases.

Abstract

Left ventricular (LV) power output (PW) distribution during ejection period, and its relation to LV function were analyzed in 22 patients with valvular disease or cardiomyopathy, and also in 5 controls.The PW was calculated from LV pressure and LV volume change by ventriculography at every 20msec of the ejection period.The controls and those with idiopathic non-obstructive hypertrophic cardiomyopathy showed a higher PW in the early phase of ejection period, followed by a gradual decrease. In the cases of idiopathic obstructive hypertrophic cardiomyopathy, aortic insufficiency, and mitral insufficiency, greater PW was generated widely over the ejection period, but the distribution was greater during the middle phase of the period. The idiopathic congestive cardiomyopathy and combined valvular disease developed a greater PW in the late phase of the period. The peak PW was observed during the phase of greater PW distribution in each disorder.Five controls (EF_??_60%, SWI_??_5600ml•mmHg/M2) showed a greater PW (49±4% of the total PW)in the early phase of ejection period, 9 with loaded but compensated LV function (EF_??_60%, SWI>5, 600) (41±10%)in the middle third, and 9 with failed LV function (EF_??_60%) (41±14%) in the late third.An index (2/3PW) of PW distribution correlated with EF (r=0.73, p<0.05). Heart rate, systolic blood pressure, and LV end-diastolic pressure were not different among patients with different levels of EF.Our investigation provides data which suggest that the main PW distribution probably shifts from the early to the middle phase adaptively to ventricular load, but may move from the middle to the late phase in cases of LV failure.