Background
Progress in the management of myocardial infarction has contributed to the increased population of patients with asymptomatic left ventricular dysfunction or congestive heart failure. These patients are at high risk of sudden cardiac death. Factors that worsen this prognosis include exacerbation of coronary artery disease and acute coronary syndrome. We aimed to define and compare risk factors of acute coronary syndrome and sudden cardiac death as well as the cumulative incidence of both in patients after myocardial infarction with asymptomatic left ventricular dysfunction or congestive heart failure during a 2-year follow-up period.
Material and Method
We enrolled 320 patients who survived the first 2 to 3 weeks after first ST-elevated myocardial infarction. Seventy-one patients who developed acute coronary syndrome and 38 who experienced sudden cardiac death were analyzed.
Results
In patients with asymptomatic left ventricular dysfunction, the only independent predictor of sudden cardiac death was male sex. Diabetes was the only predictor for acute coronary syndrome. In patients with chronic heart failure, low heart-rate variability was the strongest independent predictor of sudden cardiac death. Increased mean 24-hour heart rate was the most powerful predictor of acute coronary syndrome. The cumulative incidence of acute coronary syndrome and sudden cardiac death was most strongly associated with a total cholesterol level >200 mg/dL and increased QT-interval dispersion.
Conclusions
Predictors of acute coronary syndrome and sudden cardiac death differ in patients after myocardial infarction with asymptomatic left ventricular dysfunction or chronic heart failure and are inconsistent at different stages of development of chronic heart failure.

Keywords: Poland - epidemiology, Myocardial Infarction - physiopathology, Multivariate Analysis, Models, Cardiovascular, Incidence, Heart Failure - physiopathology, Death, Sudden, Cardiac - epidemiology, Aged, 80 and over, Acute Coronary Syndrome - epidemiology, Survivors, Ventricular Dysfunction, Left - physiopathology