Atrial Natriuretic Peptide Attenuates Pacing-Induced Myocardial Ischemia During General Anesthesia in Patients with Coronary Artery Disease

Abstract

Atrial natriuretic peptide (ANP) exerts a dilatory effect on coronary arteries in humans.We investigated the effects of ANP on pacing-induced myocardial ischemia during enflurane anesthesia in patients with coronary artery disease (CAD). In 20 patients with CAD, myocardial ischemia was induced by atrial pacing before and after an iv infusion of ANP (50 mg [center dot] kg-1 [center dot] min-1, n = 10) or placebo (n = 10). We studied the effects of ANP or placebo on pacing-induced changes in central hemodynamics, myocardial blood flow and regional myocardial indices of lactate uptake (RMLU), and oxygen consumption (RMVO2) and extraction (RMO (2) E). ST-segment depression was less pronounced during pacing with ANP compared with control pacing (-0.09 +/- 0.01 vs -0.24 +/- 0.02 mV; P < 0.001). RMLU decreased to -11.1 [micro sign]mol/min during control pacing compared with -0.7 [micro sign]mol/min during pacing with ANP (P < 0.01). ANP did not affect pacing-induced changes in RMVO (2), RMO2 E, or the rate pressure product. Placebo did not affect pacing-induced changes in ST-segment depression or RMLU. In conclusion, ANP attenuates ischemic ST-segment depression and lactate release during pacing-induced myocardial ischemia in patients with CAD. The antiischemic effect of ANP was not accompanied by any improvement in the regional myocardial oxygen supply/demand relationship. Implications: We evaluated the effects of IV atrial natriuretic peptide (50 ng [center dot] kg-1 [center dot] min-1) on pacing-induced myocardial ischemia during general anesthesia in patients with coronary artery disease. In contrast to placebo, atrial natriuretic peptide attenuated ST-segment depression and myocardial lactate production and improved left ventricular function during pacing-induced ischemia. (Anesth Analg 1999;88:279-85)