Prevention of Left Ventricular Remodeling After Myocardial Infarction.

Abstract

Postinfarction left ventricular remodeling begins early after acute myocardial infarction and may continue for months to years afterward. Early re-establishment of flow in the occluded artery is associated with smaller left ventricular cavity volumes and reduced remodeling. Acute percutaneous coronary intervention (PCI) or thrombolytic therapy (for patients more than 1 hour away from a catheterization facility) as early as possible after symptoms is critical. Late reperfusion (PCI more than 12 hours after infarction) may prove useful, and this will be determined by the results of ongoing clinical trials. Recurrent MI is reduced by antiplatelet agents (aspirin in most patients) and by 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors. Intravenous nitroglycerin may limit early (initial 24 hours) dilatation following infarction, but long-term use in asymptomatic patients is not efficacious. Beta- adrenergic receptor antagonists and angiotensin-converting enzyme (ACE) inhibitors have independent efficacy in attenuating the early and late phases of remodeling. The combined use of a beta-blocker and an ACE inhibitor has greater efficacy than either agent alone, provided they are tolerated hemodynamically. Although angiotensin II receptor antagonists have similar efficacy to ACE inhibitors and have fewer side effects, the angiotensin II receptor blockers should be reserved for patients intolerant to ACE inhibitors. In patients requiring diuretic therapy, spironolactone is preferred because of its salutary properties regarding extracellular matrix remodeling, specifically in reducing fibrosis. Surgical revascularization with or without associated mitral valve repair is useful in selected patients with severe ischemic mitral regurgitation or hibernating myocardium. New therapies directed at modulating the remodeling process may focus on manipulating the components of the extracellular matrix to reduce the deleterious impact of this process.