The differing prognostic utility of exercise radionuclide ventriculography in coronary artery disease patients with and without prior myocardial infarction

Previous studies have documented the prognostic utility of left ventricular ejection fraction response to exercise primarily in populations without prior myocardial infarction. We undertook a study to assess the prognostic utility of exercise left ventricular ejection fraction and segmental wall motion response during exercise radionuclide ventriculography in coronary artery disease patients with and without prior myocardial infarction. Methods. We examined the comparative prognostic utility of left ventricular ejection fraction and segmental wall motion response during upright bicycle exercise radionuclide ventriculography in 419 coronary artery disease patients with (n=217) and without (n=202) prior myocardial infarction using univariate and multivariate hierarchical regression analyses. Results. During an average followup period of 61 months, 96 patients (23%) suffered cardiac events, including 55/217 (25%) of the patients with prior myocardial infarction and 41/200 (21%) of the patients without prior myocardial infarction (p=ns). Both cumulative Kaplan-Meier survival analyses and stepwise hierarchical Cox survival analyses demonstrated that peak left ventricular ejection fraction <55% was a significant predictor of cardiac events in patients without prior myocardial infarction (p=0.04), whereas an exercise wall motion worsening score ≥ 2 was a significant predictor in patients with a prior myocardial infarction (p=0.0001). Conclusions. The prognostic utility of exercise radionuclide ventriculography variables differ according to the presence or absence of prior myocardial infarction. Global function, assessed by peak left ventricular ejection fraction, adds the greatest prognostic information in patients without prior myocardial infarction, whereas regional function, assessed by exercise wall motion worsening, is the best predictor among patients with prior myocardial infarction.