The infarcted myocardium Simply dead tissue, or a lively target for therapeutic interventions

Time for primary review 32 days. It has been known for many years that infarction of the heart induces prominent alterations of cardiac structure. The most apparent is the scarring of the infarct. Structural changes after infarction are, however, not limited to the infarcted area, but also extend into the non-infarcted myocardium. Changes in the non-infarcted myocardium include hypertrophy of the cardiomyocytes, growth of the capillary network, and an increase in interstitial collagen. Cardiac structure is a major determinant of function, which is depressed after myocardial infarction (MI). After infarction, both short term and long term compensatory or regulatory mechanisms are activated. Often these mechanisms also affect cardiac structure. Although activation of these compensatory mechanisms may be beneficial early after infarction, they may have adverse effects, when activation is continued for a longer time. Indeed, pharmacological treatments that block the long term activation of these compensatory mechanisms, like angiotensin converting enzyme inhibitors (ACEI) that block the renin—angiotensin system (RAS), have been shown to improve cardiac function after infarction. Although we know that cardiac function and structure are closely related and do indeed both change after infarction, it is largely unknown what the exact structural component is that causes the reduction in cardiac function after infarction. Also it is not clear which structural component should be targeted for effective pharmacotherapy after infarction. In this review we attempt to clarify the structural alterations after infarction. We and others have focused for many years on the potential importance of changes in the vital non-infarcted myocardium and, indeed, found several alterations in cardiac structure after infarction and effects thereon of drugs that improved cardiac function. However, recent data in animal studies and humans point to the importance of the infarct itself as a potential target for intervention. The infarct appears to be more than … * Corresponding author. Tel.: +31-43-387-6631; fax: +31-43-387-6613 jclatlpat. azm. nl