Abstract： Coronary artery disease (CAD) is the leading cause of cardiovascular death in the Chinese population.Coronary angiography is the golden standard for the diagnosis of CAD and coronary tortuosity (CT) is a common coronary angiographic finding,however,little work has been done on clinical manifestation and significance of CT.It was hypothesized that CT may be associated with angina pectoris and abnormal exercise stress test in patients without CAD,1 but weather CT can lead to cardiac ischemia has not yet been clarified.The purpose of this study was to determine the impact of CT on myocardial perfusion defects.