INTRODUCTION In acute myocardial infarction, effective and sustained reperfusion can salvage myocardium and improve survival and convalescence. Although there is no alternative to reperfusion when pursuing these treatment goals, some aspects of reperfusion may cause additional injury and, thus, constitute potential therapeutic targets. Reperfusion arrhythmia, myocardial stunning, reperfusion-induced microvascular damage, and reperfusion-induced myocardial necrosis are generally considered as the principle manifestations of reperfusion injury. There is, however, debate whether microvascular damage and expansion of the necrotic zone truly represent reperfusion injury or rather extension of the consequences of the ischemic insult into the reperfusion period.