A transient regional inbalance between oxygen demand and supply usually results in myocardial ischemia whose signs and symptoms can be used as a diagnostic tool. Myocardial ischemia results in a typical “cascade” of events in which the various markers are hierarchically ranked in a well-defined time sequence . The flow heterogeneity, especially between subendocardial and subepicardial perfusion, is the forerunner of ischemia, followed by the metabolic changes, by the alterations in the ventricular diastolic relaxation, by the regional dyssynergy, and only at a later stage by electrocardiographic changes, global left ventricular dysfunction, and pain (Fig. 1).
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