Prognostic indexes for patients with ischemic heart disease enrolled in an exercise-centered rehabilitation program

Abstract

Indexes of prognosis were calculated for 610 postinfarction patients who participated in a vigorous exercise-centered rehabilitation program for an average of 36.5 ± 6.5 months (mean ± standard deviation), commencing 8.2 ± 11.7 months after infarction. Over this period, 23 (group F) had a fatal and 21 (group R) a nonfatal recurrence of infarction; the remaining 566 patients (group C [“control” group]) had no recurrence, although 12 of these patients died of unrelated causes. Recurrences in group R occurred 22.8 ± 17.6 months, and deaths in group F 19.6 ± 17.8 months after the patients had joined the exercise program. The most significant individual index of prognosis was noncompliance with the exercise program, observed in 47.8 percent of those with a fatal (F) recurrence, 57.1 percent of those with a nonfatal (R) recurrence and 0.7 percent of those in the control group; the risk ratio for the combined group F plus R was 22.6. Risk ratios were at the expected level for certain other traditional indicators of prognosis (persistent angina 2.01; aneurysm 2.05; enlarged heart 2.34; and polyfocal exercise-induced ventricular premature complexes 1.52). For three factors (S-T segment depression on exercise 0.2 mv or greater, serum cholesterol 270 mg/100 ml [7 mmol/liter] or greater and persistence of cigarette smoking), risk ratios (3.20,1.98, and 1.93, respectively) were somewhat higher than usually reported for postinfarction patients who do not exercise. However, because of the overall low fatality rate among patients (1.2 percent/year, with 0.7 percent/year in those free of S-T depression on exercise), the prognosis for patients with such risk factors remained at least as good as in comparable patients not receiving exercise rehabilitation. Age, hypertension ( 150 100 mm Hg or greater, 20.0 13.3 kPa ), persistence of resting electrocardiographic abnormalities and the results of physiologic tests had little influence on the prognosis of patients who exercise. However, a combination of S-T segment depression during exercise and a high serum cholesterol level yielded a risk ratio of 4.26. The apparent absence of risk from resting hypertension and from a high systolic blood pressure on exercise probably reflects the inability of patients with myocardial impairment to sustain a high systemic pressure.