Atrial natriuretic peptide attenuates pacing-induced myocardial ischemia during general anesthesia in patients with coronary artery disease

Atrial natriuretic peptide (ANP) exerts a dilatory effect on coronary arter ies in humans. We investigated the effects of ANP on pacing-induced myocard ial ischemia during enflurane anesthesia in patients with coronary artery d isease (CAD). In 20 patients with CAD, myocardial ischemia was induced by a trial pacing before and after an iv infusion of ANP (50 mg.kg(-1).min(-1), n = 10) or placebo (n = 10). We studied the effects of ANP or placebo on pa cing-induced changes in central hemodynamics, myocardial blood flow and reg ional myocardial indices of lactate uptake (RMLU), and oxygen consumption ( RMVO2) and extraction (RMO2E). ST-segment depression was less pronounced du ring 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 mu mol/min during control pacing compared with -0.7 mu mol/min during pacing with ANP (P < 0.01). ANP did not affect pacing-induced changes in RMVO2, RMO2E, or the rate pressur e product. Placebo did not affect pacing-induced changes in ST-segment depr ession or RMLU. In conclusion, ANP attenuates ischemic ST-segment depressio n and lactate release during pacing-induced myocardial ischemia in patients with CAD. The antiischemic effect of ANP was not accompanied by any improv ement in the regional myocardial oxygen supply/demand relationship. Implica tions: We evaluated the effects of IV atrial. natriuretic peptide (50 ng.kg (-1).min(-1)) on pacing-induced myocardial ischemia during general anesthes ia in patients with coronary artery disease. In contrast to placebo, atrial natriuretic peptide attenuated ST-segment depression and myocardial lactat e production and improved left ventricular function during pacing-induced i schemia.