The changes in coronary blood flow in response to intracoronary injection of 3 ml of 76% Renografin were studied in 47 patients using the thermodilution technique for continuous measurement of coronary sinus blood flow. Within seconds after left coronary injection, an increase in coronary sinus flow began which peaked at an average of 53% above control in 5-10 seconds. There was a corresponding decrease in coronary resistance. Flow returned to control level in almost all patients within one minute of injection. Twenty-four of 35 patients had no change in coronary sinus flow in response to right coronary injection. This can be explained by the fact that most of the venous flow from the right coronary artery returns in such a way that it cannot be measured by the coronary sinus catheter. Of the eleven patients who did show an increase, seven had angiographically documented right to left collaterals, suggesting that the increase in flow was the result of vasodilatation of the left coronary bed by contrast arriving via the right to left collaterals. The percent changes in flow and resistance in response to left coronary injection were isgnificantly greater in the 13 normals than in the 34 with obstructive disease of the left coronary artery (P lessthan 0.01). Flow rose 70 plus or minus 27% (mean plus or minus standard deviation) in the normals versus 46 plus or minus 25% in the patients with coronary artery disease, while resistance fell 44 plus or minus 9% versus 33 plus or minus 11%. The differences, however, were not sufficient for these changes to be of value in the assessment of the degree of impairment of the coronary arterial bed in the individual patient.
Ten men with stable angina pectoris not fully relieved by optimal doses of propranolol (mean 218 mg daily) were given a single oral dose of 120 mg verapamil or a placebo on alternate mornings; the order of treatment was double blind.
SUMMARY Eleven men with coronary artery disease were studied to determine whether they would manifest inappropriate coronary vasoconstriction in response to mental stress. Mental stress was induced by having the patient perform difficult mental arithmetic in time with a clicking metronome. Aortic blood pressure and thermodilution coronary sinus blood flow were recorded continuously before and during the mental arithmetic. For the group, heart rate rose from 70 to 82 beats/min, systolic blood pressure rose from 161 to 181 mm Hg and diastolic blood pressure rose from 71 to 78 mm Hg. Coronary resistance decreased by 16%. The index of myocardial oxygen consumption rose by 40%, and there was an equivalent rise in coronary sinus blood flow of 41%, with no change in coronary arteriovenous oxygen difference.Because the increase in myocardial oxygen consumption was accompanied by a proportional increase in coronary sinus blood flow, a decrease in coronary resistance and no change in myocardial oxygen extraction, we conclude that the response of patients with coronary artery disease to at least moderately severe mental stress is not characterized by abnormal coronary vasoconstriction.THE PRESENT STUDY was carried out in men with ischemic heart disease to define the response of the human coronary vasculature to mental stress. In particular, we were seeking evidence for the existence of an abnormal vasomotor response (inappropriate coronary vasoconstriction) to mental stress. Mudge et al.' reported inappropriate coronary vasoconstriction in patients with coronary artery disease during exposure to cutaneous cold. The present study was designed to determine whether a similar response occurred with mental stress.
MethodsEleven men ages 40-62 years who were undergoing cardiac catheterization and coronary arteriography as potential candidates for coronary bypass surgery were studied without prior sedation. All medication was discontinued 48 hours before the catheterization. Appropriate informed consent was obtained from each patient before the study. After standard right-heart catheterization, a #7 thermistor catheter (Wilton Webster Laboratories) was inserted into the coronary sinus for measurement of coronary sinus blood flow by the continuous thermodilution technique.2 The catheter was positioned under fluoroscopic guidance so that the external thermistor lay 5-10 mm inside the coronary sinus ostium as visualized by injection of 2-3 ml of contrast medium. The recording of the coronary sinus temperature by the thermistor showed a steady temperature, reflecting an absence of contamination
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