Directions for Research in the Post-Myocardial Infarction Patient with Left Ventricular Dysfunction

Abstract

Left ventricular dysfunction (LVD) in post-myocardial infarction (MI) patients is an important predictor of a poor prognosis. LVD may be asymptomatic in the post-MI patient, but it can also manifest as heart failure (HF) or sudden cardiac death. Early revascularization and pharmacologic therapy targeting coronary artery disease (CAD) and LVD reduce post-MI mortality as well as rates of HF and recurrent MI. However, despite dramatic gains in the treatment of post-MI LVD, there remains considerable room for improvement. The following is a brief summary of important areas of investigation addressing this goal. Improved Utilization of Proven Therapies Current acute HF syndrome registries highlight the importance of CAD as a therapeutic target. In the Acute Decompensated Heart Failure National Registry (ADHERE) database, CAD was documented in approximately 60% of patients, with a large proportion of patients classified as post MI. 1 Data from the Organized Program to Initiate Lifesaving Treatment in Hospitalized Patients with Heart Failure (OPTIMIZE-HF) registry show that patients with CAD and LVD had an early postdischarge (60-90 days) combined mortality and rehospitalization rate of 36.2%. 2 Similar results were seen in the Outcomes of a Prospective Trial of Intravenous Milrinone for Exacerbations of Chronic Heart Failure (OPTIME-CHF) study, in which HF patients with CAD had a higher 60-day mortality rate than patients with a nonischemic etiology. 3 As discussed elsewhere in this supplement, the current available data suggest that this patient population is not fully evaluated during hospitalization and is often managed by noncardiologists. Therefore, all the available therapeutic options are not uniformly implemented. These options include medical therapy (with -blockers, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, aldosterone antagonists, antiplatelet agents, and statins), revascularization procedures (percutaneous coronary intervention and coronary artery bypass graft surgery), cardiac surgery (mitral valve repair or replacement, and left ventricular aneurysmectomy), and device therapy (cardiac resynchronization therapy [CRT] and implantable cardioverter defibrillators [ICDs]). Studies investigating the complete assessment of therapeutic targets and implementation of proven therapies may improve outcomes in the post-MI patient with LVD. Systems for optimal use of proven therapies for post-MI patients with LVD must incorporate all locations of care and providers, including the emergency department, inpatient wards, specialty clinics, and primary care offices. Disease management programs for ambulatory HF patients have produced a statistically significant risk reduction in total mortality and significant reductions in the rates of all-cause and HF-related rehospitalization as well as improved cost savings. 4 Study of the utility of such programs in the post-MI patient with LVD may yield similar benefits. In addition to studies about early and complete implementation of potentially lifesaving therapies, investigations addressing the optimal titration of these therapies may improve outcomes. For instance, ambulatory HF patients monitored to achieve lower levels of serum brain natriuretic peptide through -blocker and angiotensin-converting enzyme inhibitor dose adjust