How to Treat High-Risk Post Myocardial Infarction Patients Based on MADIT and Other Recent Trials

Abstract

Noninvasive tests for risk assessment and empiric selection of drug therapy have long been used in managing high-risk patients after myocardial infarction. Risk stratification using ventricular function is effective in predicting overall survival but less valuable with respect to defining sudden cardiac death risk [1, 2]. Newer approaches such as heart rate variability, while promising, are yet to be widely evaluated in clinical practice [3]. Empiric drug therapy is less attractive. Therapy with class 3 antiarrhythmic agents after myocardial infarction in high risk patients has been abandoned due to unfavorable clinical studies. Only β-blocking agents remain of proven benefit; but patient acceptance, compliance and tolerance are problematic. Less than 50% of patients actually receive such agents in clinical trials. In patients with depressed ventricular function, better acceptance exists for angiotensin-converting enzyme inhibitors [3]. Yet, in a meta-analysis of all ACE inhibitor trials, Garg and Yusuf noted the incidence of sudden death was unaltered [4]. In the CHF-STAT study, there was 19% incidence of sudden death at two years in the placebo arm despite such therapy [5]. Addition of amiodarone has conferred no improvement [5–7]. In the same trial, it was 15% in patients randomized to amiodarone at two years. In fact, after myocardial infarction, prophylactic amiodarone may or may not have shown arrhythmic death reduction but did not improve overall survival [8]. This suggests, yet again, that only the mode of death was altered. Based on these unsuccessful strategies, it has been suggested that risk stratification and treatment by whatever method chosen, noninvasive or invasive and pharmacologic or nonpharmacologic respectively, will fail to establish a reasonable balance between patients submitted to the screening, evaluation and treatment algorithm and the additional mortality benefit conferred by the strategy [9].