Clinical implications: Reperfusion therapy, administered as early as possible after start of symptoms, has improved the prognosis in acute ST-elevation myocardial infarction. Still, however, many patients suffer large infarctions, subsequently with an increased risk of heart failure, arrhythmias, and death. In pilot studies, mechanical postconditioning has been shown to reduce infarct size and thus potentially improve prognosis. However, the effect of postconditioning must be confirmed in larger clinical trials before implemented in routine treatment.