Myocardial Stunning: An Overview

Over the past two decades, we have challenged the belief that transient ischemia is benign with little functional sequelae following resolution of ischemia. The phenomenon of prolonged postischemic contractile dysfunction, or of myocardial stunning, has been developed and is under investigation using multiple experimental and clinical models. Classifications of myocardial stunning have been suggested and include single and multiple reversible ischemic episodes, partially reversible episodes, and global ischemia. More challenging is the understanding of the mechanisms of myocardial stunning, including free radical protection, excitation-contraction uncoupling, altered calcium flux, microvascular dysfunction, and impaired energy production and use. Finally, advances have been made in the clinical arena, including development of new more sensitive technologies to detect dysfunction, and development of potentially important therapies, including free radical scavengers, adenosine-regulating agents, and calcium channel blockers. In this brief overview, we focus on myocardial stunning, including a historical perspective of coronary occlusion, and definition, classification, and clinical implications of myocardial stunning.