Assessment of right ventricular contractile function in patients with left ventricular dysfunction by a simplified echocardiographic subtraction method.

: A simplified version of the modified echocardiographic subtraction method for measuring right ventricular (RV) volume was used to assess the indices of RV contractile function, the end-systolic pressure-volume (RV Emax) ratio and the +dP/dt(max)-end-diastolic volume (EDV) relationship. RV volumes determined by the simplified subtraction method and the modified subtraction method were compared in 18 patients. Subsequently, RV contractile function was assessed in 13 patients with normal left ventricular (LV) function (control group: ejection fraction > 56%, as determined by left ventriculography), and 10 patients (group F; five with myocardial infarction, three with dilated cardiomyopathy, two with ischemic cardiomyopathy) with depressed LV function (ejection fraction < or = 55% by left ventriculography). During the application of lower body negative pressure of -20 mmHg, B-mode echocardiograms (apical four-chamber view) and RV or pulmonary artery pressure were recorded simultaneously. The regression equation between RV volumes obtained by the simplified subtraction method and the modified subtraction method was y = 0.99x + 4.5, and the correlation coefficient (r) was 0.985 (p < 0.001). The RV Emax of group F was not significantly less than that of the control group (0.40 +/- 0.16 vs 0.44 +/- 0.17 mmHg/ml, not significant). The correlation coefficients of RV Emax in each group were large (control group 0.92 +/- 0.09, group F 0.90 +/- 0.07). The +dP/dtmax-EDV ratio of group F was significantly less than that of the control group (2.05 +/- 0.74 vs 3.40 +/- 1.85 mmHg/ml.sec, p < 0.05). The correlation coefficient of the +dP/dtmax-EDV ratio was 0.91 +/- 0.06 in the control group and 0.85 +/- 0.15 in group F. The indices of RV contractile function could be assessed using the simplified subtraction method. RV function in patients with LV dysfunction appeared to be depressed.