Resting blood flow in hypocontractile myocardium: resolving the controversy.

The question of whether reductions in blood flow occur under resting conditions in viable nonischemic myocardium in patients with coronary artery disease has been debated for 3 decades. Some early measurements reported reductions in resting left ventricular flow that seemed difficult to attribute to admixture of scar tissue with normally perfused myocardium.1,2 Others failed to show differences between apparently normal individuals and coronary patients.3,4 Transient defects in resting Tl scans observed in the late 1970s supported the concept of relative hypoperfusion of viable nonischemic myocardium. They were “usually associated with severe coronary artery disease but normal or only mildly abnormal left ventricular wall motion”5 and often were less pronounced after bypass graft surgery.6