[Myocardial vitality: clinical correlates and diagnostic concepts]

Modern therapeutic options in ischemic coronary disease such as thrombolysis, coronary angioplasty, new emerging strategies in treating heart failure and secondary prevention have resulted in decreasing cardiac mortality over the last ten years. In the era of interventional cardiology a new focus of clinical interest is the process of transition from loss of contractile function to definitive necrosis of severely ischemic myocardium. The decision for bypass surgery or angioplasty in patients with compromised contractile function should be based on evidence of viable myocardium with some or full potential for functional recovery; otherwise prognostic benefit may be questionable or dubious. The clinical substrate of non-contractile, but viable myocardial tissue may be present in patient presenting with both stable and unstable angina, in cases of acute or chronic myocardial infarction and in the setting of congestive heart failure resulting from ischemic cardiomyopathy. Various diagnostic methods are theoretically useful to assess residual myocardial viability both in hibernating myocardium (contractile down-regulation) and post-ischemic stunned (reperfused) myocardial tissue. Myocardial viability is confirmed both in presence of systolic wall motion or systolic wall thickening as evidenced from (contrast or radionuclide) left ventricular angiograms or echograms. Moreover, myocardial tissue perfusion by thallium-201 or other radioactive perfusion agents as documented by uptake of tracer is considered clear evidence of viability; however, lack of uptake of perfusion agents may not always exclude viable myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)