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Heart rate (HR) recovery or HRR, calculated as HR at peak exercise – HR at 1 minute of active recovery, has been inversely associated with total mortality in large patient cohorts that include patients with heart disease and/or poor exercise capacity. To what extent HRR is important in prognosis in patients without heart disease who have normal exercise capacity is less certain
We retrospectively queried our exercise database for the time period 9–16–93 and 8–14–06 to identify patients without known heart disease and a “normal test” defined as achieving at least 85% of predicted peak HR, 100% of functional aerobic capacity (FAC), and a normal exercise EKG on a symptom–limited treadmill test using the Bruce protocol. Where a patient had multiple tests, we took the first test in the study period. We then established the Hazard Ratio of abnormal HRR (< 13 bpm) for total mortality using Cox Proportional Hazards regression.
65,535 exercise tests were performed during the study period. A total of 39,500 tests on 34,557 unique patients without known heart disease were identified. Age averaged 52.3 ± 11.7 years, 31.5% of patients were female, and 13,571 patients (39.3%) met the criteria for having a “normal test”. Overall mortality was low with 1277 deaths (3.70%) over follow–up of 12.3 ± 3.1 years. Abnormal HRR was seen approximately half as often in normal versus non–normal tests (17.6% versus 34.0%). In univariate analyses, abnormal versus normal HRR was associated with a higher mortality both in normal tests (3.43% versus 2.16%) and non–normal tests (7.74% versus 2.90%). However, results of Cox Regression adjusting for age, sex, body mass index, FAC, diabetes, hypertension, and use of a drug which lowers HR yielded a Hazard Ratio of 1.012 with 95% confidence limits of 0.783– 1.308 with p = 0.9259 in normal tests. In contrast, abnormal HRR remained a significant predictor of mortality in non–normal tests: Hazard Ratio = 1.424 with 95% CL of 1.237 – 1.638, p < 0.0001.
Abnormal HRR should not be considered a sign of poor prognosis when the exercise test is otherwise normal, though abnormal HRR does predict mortality in exercise tests that do not meet strict standards for being normal.
West, Room 3005
Sunday, March 10, 2013, 8:30 a.m.–8:45 a.m.
Session Title: Exercise and Health: New Insights
Abstract Category: 29. Sports and Exercise Cardiology: Diagnostic Testing: ECG Exercise or “The Older Athlete”
Presentation Number: 921–5
- 2013 American College of Cardiology Foundation