Measurements of variations in resting coronary flow velocity

Abstract

The recent development of intracoronary Doppler catheters has allowed the measurements of coronary flow velocity and coronary flow reserve. To assess the presence of spontaneous variability in resting coronary flow velocity, which should be taken into account in investigation the effects of various interventions on the coronary circulation, the authors studied 20 syndrome X patients (group 1), 8 patients with coronary artery disease (group 2), and 10 heart transplant patients (group 3) who were undergoing coronary flow reserve studies. With a standard femoral approach a 3.6F intracoronary Doppler catheter was positioned in the proximal left anterior descending coronary artery.The coronary flow velocity was measured over a fifteen-minute period with the patient in the supine position and breathing normally. There were no significant changes in the coronary flow velocity during the study in all three groups. These results demonstrate that under resting conditions, with stable heart rates and mean arterial pressures, the coronary flow velocity remains relatively constant and any changes observed under these conditions as a result of any intervention are likely to be related to the intervention.