Wave-intensity analysis: a new approach to coronary hemodynamics

Abstract

In 10 anesthetized dogs, we measured high-fidelity left circumflex coronary (PLCx), aortic (PAo), and left ventricular (PLV) pressures and left circumflex velocity ( U LCx; Doppler) and used wave-intensity analysis (WIA) to identify the determinants of PLCx and U LCx. Dogs were paced from the right atrium ( control 1) or right ventricle by use of single ( control 2) and then paired pacing to evaluate the effects of left ventricular contraction on PLCx and U LCx. During left ventricular isovolumic contraction, PLCx exceeded PAo, paired pacing increasing the difference. Paired pacing increased ΔPX(the PLCx-PAo difference at the PAo-PLV crossover) and average dPLCx/d t ( P < 0.0001 for both). During this time, WIA identified a backward-going compression wave (BCW) that increased PLCx and decreased U LCx; the BCW increased during paired pacing ( P < 0.0001). After the aortic valve opened, the increase in PAo caused a forward-going compression wave that, when it exceeded the BCW, caused U LCx to increase, despite PLV and (presumably) elastance continuing to increase. Thus WIA identifies the contributions of upstream (aortic) and downstream (microcirculatory) effects on PLCx and U LCx.