Comparison of Exercise Test Responses in Patients with Normal versus Abnormal Heart Rate Recovery

Abstract

Recently, the decrement in heart rate (HR) after peak or symptom-limited exercise testing has been suggested as an “independent” predictor of mortality. A delayed decrease in HR at 1 -min post-exercise, denned as a reduction of 12 beats/min or less from the HR at peak exercise, signifies an abnormal response in patients not on ß-blocker therapy. PURPOSE: To evaluate the significance of an abnormal HR recovery within 1-min after maximal exercise testing relative to other test variables that are associated with prognosis. METHODS: Review of 685 diagnostic exercise tests using simultaneous myocardial perfusion imaging (MPI) with technetium 99m sestamibi or tetrofosmin. Stress testing employed a traditional or modified Bruce treadmill protocol with a ≥ 2-min cool-down walk; HR recovery was measured at 1 min after peak exercise. RESULTS: Forty-one of the 501 non-beta blocked patients (8%) demonstrated an abnormal HR recovery response at 1-min post-exercise. A comparison of age and selected test variables (mean ± SD) at peak exercise between the normal (n = 460) and abnormal (n = 41) recovery HR responders is shown in the table.TablePatients with an abnormal HR recovery were older, had a decreased MET capacity, maximal HR, % of age predicted HR and double product, and an increased prevalence of symptoms and fixed and reversible defects by MPI. CONCLUSION: These data suggest that patients not on ß-blocker therapy with a delayed decrease in HR at 1-min post-exercise, are likely to demonstrate other abnormal responses that are associated with adverse outcomes and increased mortality.