Mechanocardiographic assessment of left ventricular function in coronary artery disease.

Multiple regression analysis was used in order to evaluate the independent contribution and combined use of mechanocardiographic indices for assessing cardiac function in 23 patients with coronary artery disease. Three indices were derived from the quantitative displacement left apex cardiogram: the time from the onset of electrical depolarisation to the peak of the first derivative (t peak dD/dt) and the first derivative normalised for the amplitude ofthe displacement (dD/dt/D) using forD total and developed displacement. From the external carotid pulse the ratio pre-ejection period to the ejection time (PEP/ LVET) was calculated. Several invasive isovolumic and ejection phase indices of left ventricular function were calculated and used as dependent variables in the multiple regression analysis. The non-invasive indices were used as dependent variables. The index dD/dt/D of the left apex cardiogram was significantly partially correlated with all invasive indices and demonstrated the highest t values. For PEP/LVET the t values were smaller and not always significant. No signficant partial correlation was found for (t peak dD/dt). The combined use of PEP/LVET and dD/dt/D resulted in a better differentiation between normal and abnormal left ventricular function. It is concluded that quantitative apex cardiography is superior to systolic time intervals for assessing left ventricular function in coronary artery disease though both methods offer independent information and should be considered complementary.