NONINVASIVE COMPUTERIZED ASSESSMENT OF LEFT-VENTRICULAR PERFORMANCE AND SYSTEMIC HEMODYNAMICS BY STUDY OF AORTIC ROOT PRESSURE AND FLOW ESTIMATES IN HEALTHY-MEN, AND MEN WITH ACUTE AND HEALED MYOCARDIAL-INFARCTION

Aortic root pressure and flow data can be used to assess left ventricu lar (LV) performance and properties of the systemic arterial tree. The calibrated subclavian arterial pulse trace was combined with echocard iographic imaging and Doppler velocity recordings to obtain noninvasiv e estimates of aortic root pressure and flow in 8 healthy subjects (gr oup A), 12 patients with recent myocardial infarction (group B), and 8 with healed myocardial infarction and a dilated left ventricle (group C). The pressure and flow data were transferred to a computer and pro cessed in specially designed software, including a new procedure for e stimation of 3-element windkessel model parameters. There were no sign ificant group differences for either aortic root pressure estimates or heart rate. In groups B and C, stroke and cardiac indexes were lower and total peripheral resistance higher than in group A. There were no group differences in the model estimates of total arterial compliance, whereas the characteristic impedance was greater in group C than in A , indicating a less compliant aorta in C. Both LV total and steady pow er were less in groups B and C than in A, whereas no group difference was found for percent oscillatory power. The reproducibility for recor ding was good for the aortic root pressure estimates, and lower for th e derived parameters (stroke and cardiac indexes, windkessel model par ameters and LV power), whereas that for interpretation was generally g ood. This method provides a unique noninvasive access to important par ameters of LV function and the systemic circulation.