Twenty-two patients with heart disease performed a standard isometric exercise, sustained handgrip, during the course of diagnostic cardiac catheterization. During handgrip an increase in mean arterial pressure (average 87 to 104 mm Hg) was noted in all patients. Coronary sinus blood flow and myocardial O 2 consumption increased (average 45%) in all patients so monitored. Systemic vascular resistance increased in 19 patients, in contrast to the response reported in normal volunteers. The relation between left ventricular stroke-work index and LVEDP (left ventricular function curve) during the control state and during the fourth minute of sustained handgrip provided a simple estimate of left ventricular reserve and correlated well with the New York Heart Association functional classification of the patient studied. Patients with good reserve had a rise in stroke-work with little or no change in LVEDP. Patients with poor reserve had a fall in stroke-work together with a substantial rise in LVEDP. It is concluded that the stress imposed by sustained handgrip provides a simple test for the evaluation of left ventricular reserve.
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.
