42 Dialogues in Cardiovascular Medicine - Vol 1. N° 1  .1996 Summaries of Ten Seminal Papers his landmark paper by Bolli on the clinical relevance of myocardial stunning is the first attempt to build a bridge between laboratory and real clinical conditions. Clinically, stunning is the mechanical dysfunction that persists after reperfusion despite the absence of irrever- sible damage and restoration of normal or near-normal coronary flow. Implicit in this definition is that stunning is fully reversible provided the myocardium has sufficient time to recover. Thus, the contractile abnormality must be reversible and the dysfunctional myocardium have a normal or near-normal flow, points not always easy to determine in the clinical setting. Major clinical situations in which myocardial stunning may occur: a) Stunning after ischemia induced by percutaneous transluminal coronary angioplasty (PTCA).  This clinical condition best resembles the experimental setting for stunning. Brief ischemia associated with simple, uncomplicated PTCA is usually not sufficient to cause long-lasting systolic abnormalities, even after multiple balloon inflations, but it may induce persistent diastolic abnormalities resulting in decreased left ventricular compliance. The exact incidence, severity, and duration of these diastolic abnormalities are unknown, but they are well tolerated provided the contractile reserve is intact. However, myocardial stunning can occur in less favorable situations, eg, in patients with baseline left ventricular dysfunction, unstable angina, severe simple-vessel disease, and complicated PTCA. b) Stunning in unstable angina  is often associated with reversible wall motion abnormalities. Although consistent with stunning, these abnormalities could also be caused by hibernation and/or ongoing silent ischemia. Precise diagnosis of stunning requires concomitant measurement of regional function and flow and determination of the time course of the contractile abnormalities. As patients with proximal left anterior descending coronary artery lesions and persistently negative T waves on precordial leads often exhibit improvement in wall motion, this could be considered good evidence for stunning in unstable angina. c) Stunning in variant angina.  Single episodes of variant angina promptly treated with vasodilators usually do not cause stunning, probably because they are too short. However, if coronary spasm persists, stunning results, which, if not resolved, can pose a threat to life. d) Stunning after acute myocardial infarction (AMI).  In AMI, improvement of systolic and diastolic function or myocardial salvage by reperfusion does not occur immediately after reflow - a good demonstration of stunning. Sequential measurements of regional left ventricular function are thus needed to clearly define the time course of stunning in AMI. e) Stunning after exercise-induced angina.  Although some echocardiographic observations suggest that exercise- induced ischemia may result in prolonged contractile abnormalities, this does not appear to be clinically significant. The occurrence and severity of postexercise stunning probably depend on the intensity and duration of exercise and on the severity of the coronary inflow restriction. f) Stunning after cardiac surgery.  Transient depression of ventricular contractility due to stunning is very common after cardiopulmonary bypass, and is usually reversible within 24 to 38 hours. In high-risk patients subjected to cardiac surgery, stunning can pose a crucial clinical problem which needs treatment and, if possible, prevention. g) Stunning after cardiac transplantation.  There is considerable evidence that cardiac function is reversibly depressed in the first hours or days after transplantation, which may complicate the postoperative management of these rather unstable patients. In conclusion, Bolli’s hypotheses about myocardial stunning in humans have all been proven in clinical practice. Though he also hinted that repetitive stunning might cause a chronic condition similar to “hibernation,” the clinical distinction may not be vital, as in both cases reperfusion is required - to improve flow in hibernation and coronary reserve in repetitive stunning. Thus, the real clinical issue is whether the left ventricular abnormality is reversible or not. T Myocardial “stunning” in man R. Bolli Circ Res. 1992;86:1671-1691.