The Multifarious Spectrum of Ischemic Left Ventricular Dysfunction: Relevance of New Ischemic Syndromes

Ischemic heart disease, once limited to a number of well defined entities such as angina of effort, unstable angina, and myocardial infarction, must now be regarded as a much more complex and elusive entity. Silent ischemia was the first of the new ischemic syndromes to be described. Recently, three further new syndromes have been added, namely stunning, hibernation and preconditioning. All three have one common theme—they can be related to ischemia and reperfusion. In stunning, there is post-reperfusion mechanical dysfunction that recovers. In hibernation, there is prominent contractile dysfunction, apparently out of proportion to the reduction in coronary flow, and the recovery upon reperfusion is good. In preconditioning, severe ischemia followed by reperfusion protects against subsequent ischemia which may modify the severity of ischemic damage in the other ischemic syndromes. Ischemic LV dysfunction as found in post-infarct patients and in the absence of any simple relation to reperfusion, can be either diastolic or systolic or both in nature. In ischemic LV diastolic dysfunction without major systolic dysfunction, calcium antagonists may be appropriate therapy which could point to a role for abnormalities in the regulation of cytosolic calcium. It is proposed that there is potentially a mixed post-infarct syndrome, which may comprise one or more of the new ischemic syndromes (silent ischemia, stunning, hibernation, and preconditioning), as well as a varying degree of systolic and/or diastolic dysfunction. The basis of the systolic dysfunction is, at least in part, post-infarct LV remodeling. Several of these entities could overlap in the same patient. The term “mixed post-infarct ischemic syndrome” is suggested to describe this condition.