Myocardial tolerance to hypoxia is relatively limited. This means that severe ischemia will quickly lead to myocardial cell damage and subsequent loss of contractile function. In coronary heart disease revascularisation procedures aim at the prevention of myocardial cell necrosis or at least to reduce the amount of myocardium at risk. In case of myocardial infarction subsequent restoration of blood flow in the infarct related vessel may lead to better demarcation of the myocardial scar from adjacent normal myocardium. This is thought (though not proven) to improve diastolic and even systolic cardiac performance and to prevent ventricular arrhythmias. Usually the infarcted area becomes a mechanically stable scar over time, rupture of the infarcted region is a rare but mostly fatal event.