Assessment of left ventricular function in coronary artery disease by impedance cardiography

Summary

Impedance cardiography (ICG) was obtained in 112 normal subjects and 90 patients with coronary artery disease (CAD) for assessing the clinical value of left ventricular function in patients with CAD. 17 cases with old myocardial infarction were examined by two-dimensional echocardiography (TDE) simultaneously. 12 parameters, including QZ/ZA₂, QZI, PEP/LVET, HI, CI, SI, A wave, C wave, O wave, X-O interval, A/C and O/C, were measured in this study. The results of the normal group were essentially similar to those reported in the literature. The parameters measured in CAD patients were abnormal, with remarkable significance as compared with those of normal group (P < 0.01).

QZ/ZA₂ is a new parameter proposed in the present study, which is closely correlated with PEP/LVET and QZI (r = 0.89, r=0.88), and also with EF and left ventricular wall motion index estimated by TDE (r=0.65, r = 0.77). It is easy to measure with remarkable accuracy.

Isovolumic contraction wave found in patients with myocardial infarction was considered to be due to asynergy of ventricular wall motion. The presence of C wave alternation and increase in A/C or O/C ratio may represent abnormal cardiac function.

We consider that ICG can be used for the assessment of left ventricular function in CAD patients.