Clinical decisions in patients following myocardial infarction

Usefulness of exercise testing shortly after acute myocardial infarction for predicting 10-year mortality

Previous studies on the prognostic value of exercise test variables after acute myocardial infarction (AMI) are limited methodologically and have yielded inconsistent results. This study determined whether 6 exercise test variables (systolic blood pressure, ST-segment depression or elevation, exercise capacity, arrhythmias, and angina pectoris) after controlling for age and sex, enhance 6 clinical variables (digoxin, previous AMI, history of systemic hypertension and angina, Killip class, and stress) as predictors of cardiovascular death and act as independent predictors as well. The present study followed 258 patients for 10.6 years, each of whom had AMI between 1977 and 1980 and an exercise test before hospital discharge. By 1988, 71 of the 258 patients had died, 56 of cardiovascular causes. This study is unique because exposure and outcome variables are clearly defined and follow-up was complete and longer than in previous studies. Multivariate survival analysis using an exponential model was tested to evaluate the conditional effects of the exercise test and clinical variables and to control for confounders. The model combined the exercise test and clinical variables. Results are reported with hazard ratios (HR) and 95% confidence intervals (CI). For important clinical risk predictors, the HRs with CIs are: digoxin use, HR 4.0 (CI 1.8, 8.5); history of prior AMI, HR 2.4 (CI 1.2, 4.7); history of systemic hypertension, HR 2.5 (CI 1.3, 4.5); angina, HR 2.4 (CI 1.3, 4.5); and stress, HR 4.2 (CI 2.2, 7.9).(ABSTRACT TRUNCATED AT 250 WORDS)

Recognition and management of asymptomatic patients with left ventricular dysfunction

In recent years there have been encouraging developments in the therapy for congestive heart failure. Vasodilator therapy, as an adjunct to digitalis and diuretics, has made a major impact. Vasodilator therapy results in improved left ventricular (LV) ejection fraction, improved functional capacity, and enhanced quality of life. When an angiotensin-converting enzyme (ACE) inhibitor is used, several studies published since 1988 show that these improvements are accompanied by improved survival. Yet many questions remain. Principal among these is how to approach the patient who has significantly depressed LV function, but is asymptomatic or has only minimal symptoms. In these patients the prognosis cannot be based on New York Heart Association (NYHA) functional class, but must reflect objective measurements of ventricular function. Any intervention should be specifically designed to improve survival, since functional capacity and quality of life are apparently unimpaired. On the other hand, there are no data at present to suggest that intervention in these patients will improve survival. This article considers the evaluation of such asymptomatic patients and potential therapeutic approaches. These are the use of cardiac glycosides, the use of ACE inhibitors, or their combination. Circumstantial evidence supporting their use in this select patient population is considered. It is stressed that any decision to intervene therapeutically in the asymptomatic patient must be made by the physician on an individual basis.

Noninvasive and invasive testing after myocardial infarction

Recurrent myocardial ischemia, moderate to marked depression of left ventricular systolic function, and late-occurring or recurrent cardiac arrhythmia indicate increased risk for patients with acute myocardial infarction. Some patients, on the basis of high risk and/or unsuccessful response, will be early candidates for early aggressive diagnostic and therapeutic procedures. Others will have clinical indicators of increased risk during hospitalization that warrant diagnostic coronary arteriographic assessment before discharge. Still other patients with low risk clinical characteristics can be further stratified by predischarge or early postdischarge stress testing for myocardial ischemia, left ventricular functional reserve, and/or likely occurrence of arrhythmias. Some stratified to low risk patients will be treated only with secondary prevention measures. Others at higher risk will undergo more aggressive evaluation and subsequent medical or surgical therapy.