September 27, 2011 (Cleveland, Ohio) — A simple exercise program tailored to the patient's functional limits can improve the survival prognosis for patients with abnormal heart-rate recovery (HRR), results of a new study show [1].
HRR, the difference between a person's heart rate at peak exercise and one minute into recovery postexercise, is an easily derived variable that has been shown in earlier studies to predict overall mortality in patients with cardiovascular disease, according to Dr Michael Jolly (Cleveland Clinic, OH) and colleagues. An HRR value <12 beats per minute is considered abnormal. Small studies have shown that cardiac-rehabilitation regimens can restore patients' HRR to normal, but Jolly et al's study, published in the October 4, 2011 issue of Circulation, is the first to show that restoring heart-rate recovery to normal can lead to survival benefit, according to the authors.
"These are people whose cardiac autonomic nervous system is malfunctioning, and the fact that you can do something to change that really has an impact on mortality," coinvestigator Dr Leslie Cho (Cleveland Clinic) told heartwire . "Until now, everyone knew that abnormal heart-rate recovery was a bad thing, but there was nothing to make it better."
We're putting a million stents in people, but we're not doing cardiac rehab, which actually has mortality benefit.
The study evaluated 1070 consecutive patients who underwent exercise stress testing before and after completion of a physician-supervised 12-week exercise program based on the established protocols from the American Association of Cardiovascular and Pulmonary Rehabilitation (AACVPR). Of 544 patients with abnormal baseline HRR, 225 (41%) had normal HRR after completing the rehabilitation program. The patients were followed for an average of 8.1 years, during which there were 197 deaths. Among the patients with an abnormal HRR at baseline, those who still had an abnormal HRR at the end of the program had a higher predicted mortality, adjusted for multiple variables (hazard ratio 2.15, p<0.001). Patients with abnormal HRR at baseline but normal HRR at the end of the program had survival rates similar to those of the group with normal HRR before and after cardiac rehabilitation (p=0.143).
More People Could and Should Take Advantage of Cardiac Rehab
In the program, the patients exercised on a treadmill, stationary bike, seated step machine, or elliptical trainer three times a week for 30 to 50 minutes at 50% to 80% of their predicted maximum heart rate, plus warm-up and cool-down periods. The patients were encouraged to exercise until feeling symptoms even if they reached 85% of their heart rate. Researchers documented their vital signs, symptoms, ECG changes, and arrhythmias at each stage during exercise and recovery.
Cho said that designing the exercise rehab program around the patient's specific functional limitations, as recommended by the AACVPR, is critical to the program's chances of success. "If you exercise people, but it's not really improving their functional status, that doesn't help with their autonomic nervous system. But if you improve their functional status like we do by designing an individualized, tailored program, then that really has an impact."
Unfortunately, only about 20% of cardiovascular-disease patients eligible for rehabilitation programs in the US take advantage of them, even though every insurance program covers it, Cho said. "Physicians have not pushed it a lot in patients, and patients don't want to do things unless their physician tells them how wonderful it is," she said. "It's really a shame that cardiac rehab isn't used more. We're putting a million stents in people, but we're not doing cardiac rehab, which actually has mortality benefit."
The 59% of patients in the study whose HRR did not normalize following the rehab program were probably hindered by heart failure, peripheral disease, or other factors that prevented them from exercising intensely enough to "retrain" their heart rate, she said. "So the next question will be whether doing a longer duration of exercise training in that population can improve heart recovery."
Heartwire from Medscape © 2011 Medscape, LLC
Cite this: Exercise Rehab Ups Survival in Abnormal Heart-Rate Recovery - Medscape - Sep 28, 2011.
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