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Effects of ouabain on coronary and systemic vascular resistance and myocardial oxygen consumption in patients without heart failure

1978; Elsevier BV; Volume: 41; Issue: 1 Linguagem: Inglês

10.1016/0002-9149(78)90137-6

1879-1913

Henry DeMots, Shahbudin H. Rahimtoola, John H. McAnulty, George A. Porter,

Nitric Oxide and Endothelin Effects

The effect of digitalis glycosides on vascular resistance varies from one vascular bed to another and is also related to the hemodynamic state of the patient. To determine whether the rate of infusion is also a determinant of the vasoactive response the effect of various infusion rates of ouabain on the coronary and systemic beds was examined and the associated changes in myocardial oxygen consumption in patients without heart failure were quantitated. A 10 second and 2 minute infusion of ouabain (15 μg/kg body weight) produced 18.1 ± 5.6 percent and 7.5 ± 1.7 percent increases in mean arterial pressure and 23.7 ± 9.8 percent and 17.6 ± 7.5 percent increases in systemic vascular resistance, respectively (P <0.05 for each). A 15 minute infusion produced no statistically significant change in either variable. Coronary vascular resistance increased 13.4 ± 5.2 percent (P <0.05) after a 10 second infusion but did not change during or after a 15 minute infusion. The 10 second infusion was also associated with transient deterioration of myocardial lactate metabolism. Thirty minutes after ouabain administration mean arterial pressure had returned to control levels, but myocardial oxygen consumption remained increased by 12.5 ± 3.9 percent (P <0.025), indicating that ouabain produces a net increase in myocardial oxygen demand in patients without heart failure. Rapid intravenous administration of ouabain produces systemic and coronary arteriolar constriction that may lead to clinical deterioration. These effects can be avoided by slower delivery of the drug. Even in patients without heart failure, the increase in myocardial oxygen consumption with full digitalization is small.