Comparative prognostic value of radionuclide ventriculography at rest and during exercise in 100 patients after first myocardial infarction

Abstract

To assess the prognostic value of radionuclide ventriculography we followed 100 consecutive patients for two years after their first myocardial infarction. Ventricular performance as assessed by left ventricular ejection fraction was measured at rest one day before hospital discharge and again one, four and 12 months later at rest and during submaximal exercise. Left ventricular ejection fraction at discharge was below normal (<0.47) in 74 patients and correlated well with abnormality of regional wall motion. Low left ventricular ejection fraction (<0.30) observed in 25 patients was poorly predicted either clinically, radiologically, or electrocardiographically. Peak serum creatine kinase correlated well with left ventricular ejection fraction but there was significant difference between anterior (n=46) and inferior (n=54) infarction with relative sparing of left ventricular function after inferior infarction. Left ventricular ejection fraction after inferior infarction was significantly higher both for transmural and subendocardial infarction, reflecting a variable degree of right ventricular necrosis. Within two years of first infarction, angina had developed in 32 patients, left ventricular failure in 17, ventricular tachycardia or fibrillation in four patients, reinfarction in seven, and 17 died suddenly. Low resting left ventricular ejection fraction before discharge was associated with left ventricular failure, ventricular arrhythmia, and sudden death (10 patients). Of the remaining patients exercised one month after infarction 27 showed a significant fall (>5%) in left ventricular ejection fraction and 23 of these developed postinfarction angina, four suffered non-fatal reinfarction and five patients died. Radionuclide ventriculography with exercise testing thus identified 88% of patients who died suddenly in the first two years after infarction. This was superior to any of the coronary prognostic indices currently in use and more predictive than the conventional end points of exercise testing (chest pain or ST segment depression) used either separately or in combination.