Usefulness of abnormal heart rate recovery on exercise stress testing to predict high-risk findings on single-photon emission computed tomography myocardial perfusion imaging in men.

Abnormal heart rate recovery (HRR) after maximal exercise treadmill testing predicts adverse cardiac outcomes, although whether abnormal HRR on exercise treadmill testing should prompt further diagnostic cardiac testing is unknown. The aim of this study was to determine the prevalence of high-risk stress single-photon emission computed tomography myocardial perfusion imaging (MPI) findings in patients with abnormal HRR. A total of 509 men who had been referred for exercise stress MPI and were without other abnormal exercise treadmill testing findings (ischemic electrocardiographic changes or exercise treadmill testing-induced angina) were included in this study. Abnormal HRR was defined as a decrease in heart rate <or=12 beats at 1 minute after maximal exercise. Overall, 11% had abnormal HRR. Patients with abnormal HRR had significantly more mild or greater coronary heart disease (summed stress score [SSS] >or=4, 49% vs 27%; p = 0.001), severe coronary heart disease (SSS >8, 36% vs 7%; p <0.001), left ventricular (LV) dysfunction (LV ejection fraction <50%; 25% vs 6%; p <0.001), and composite high-risk MPI findings (SSS >8 or LV ejection fraction <40%; 40% vs 9%; p <0.001) compared with those without abnormal HRR. On multivariate logistic regression analysis, abnormal HRR was found to be an independent predictor of mild or greater coronary heart disease (odds ratio [OR] 2.4, 95% confidence interval [CI] 1.4 to 4.3, p = 0.003), severe coronary heart disease (OR 5.5, 95% CI 2.7 to 11.0, p <0.001), and composite high-risk MPI findings (OR 4.3, 95% CI 2.1 to 8.6, p <0.001). In conclusion, abnormal HRR on exercise treadmill testing was associated with a high prevalence of abnormal and high-risk stress MPI findings, even in patients without other exercise treadmill testing findings that traditionally would prompt further testing. These findings suggest that further testing with stress MPI should be considered in patients with abnormal HRR on routine exercise treadmill testing.