Regional coronary hemodynamic responses to cold stimulation in patients without variant angina.

The responses to cold in patients with exertional chest pain were studied by measuring coronary sinus and great cardiac vein flows, aortic and left ventricular pressure and diameters of epicardial and small (0.4 to 1.0 mm) intramyocardial coronary arteries before and after the left hand of 18 such patients was immersed in ice water. Coronary sinus and great cardiac vein flows were used as indexes of total and anterior left ventricular flows. Coronary sinus flow minus great cardiac vein flow was used as an index of inferior left ventricular flow. Perfusion of left ventricular regions was considered potentially "normal" or "abnormal" according to the presence or absence of 50 percent or greater stenosis of luminal diameter in the coronary artery supplying a given region. With cold stimulation, increases occurred in heart rate (6 beats/min), mean aortic pressure (22 mm Hg) and left ventricular end-diastolic pressure (8 mm Hg) (all p less than 0.05). Left ventricular flow in normally perfused regions increased as resistance decreased. Left ventricular flow in abnormally perfused regions increased slightly and resistance increased. Regional left ventricular flow increased more, and changes in resistance differed in normally and abnormally perfused regions. Coronary arterial diameter decreased only minimally (6 percent) in both normal and abnormal left ventricular regions. These data show that cold stimulation increases coronary resistance in abnormally perfused left ventricular regions. Cold stimulation-related increases in coronary resistance do not appear to be caused by coronary arterial "spasm."