RESUMO
OBJECTIVE: Because hibernation is considered a down-regulation of contractile function in response to reduced regional myocardial perfusion, hibernating myocardium is expected to be supplied by a critically stenosed or even occluded coronary artery. Thus, high-dose dobutamine has been postulated to cause ischemia and reworsening of myocardial function (biphasic response), whereas myocardium that demonstrates sustained improvement with high-dose dobutamine should not be supplied by a significantly stenosed vessel. This study evaluates the type of dobutamine response-biphasic versus sustained improvement-of dyssynergic myocardium in relation to its angiographically documented blood supply. METHODS: In 38 patients (5 women; mean age 60 +/- 9 years) with chronic coronary artery disease and impaired left ventricular ejection fraction (