Systemic Hemodynamic and Myocardial Metabolic Effects of Isoproterenol and Angiotensin After Open-Heart Surgery
Cardiovascular dynamics and metabolism after open heart surgery were studied in 10 patients before and after infusion of angiotensin and isoproterenol. Patients with rheumatic mitral disease showed marked lowering of cardiac index with elevation of systemic vascular resistance in the control state while those with aortic disease demonstrated less depression of cardiac index and normal resistance. The group with mitral disease also showed lower coronary blood flow and much higher coronary vascular resistance than the aortic patients. Angiotensin caused further depression of cardiac index and marked increase in pressure work. Isoproterenol augmented cardiac index but did not affect pressure work significantly. Both agents increased oxygen consumption significantly by increment in coronary flow (isoproterenol) or by widening of myocardial oxygen extraction (angiotensin). Isoproterenol is favored over angiotensin in low output states after cardiac surgery as a means of meeting oxygen demands as well as the response of cardiac index.
- Received April 16, 1970.
- Accepted June 29, 1970.
- © 1970 American Heart Association, Inc.