Heart rate recovery in patients with heart disease
improved after phase 2 cardiac rehabilitation, improving all-cause mortality,
according to researchers.
Patients included in the study underwent exercise stress
testing before and after a phase 2 cardiac rehabilitation program and exercised
under physician supervision for 12 weeks. Exercise included a 10- to 15-minute
warm-up, 30 to 50 minutes of aerobic exercise and a 15- to 20-minute cool-down.
Researchers defined the primary endpoints as heart rate recovery and mortality.
Heart rate recovery was the difference between heart rate at peak exercise and
exactly 1 minute into the recovery period, according to researchers.
There were 1,070 patients who underwent exercise stress
testing, and 544 of the patients had abnormal heart rate recovery at baseline.
At baseline, the average value of heart rate recovery during stress testing was
13.2 ± 8.6 beats/minute vs. 16.6 ± 9.4 beats/minute after cardiac
rehabilitation. After rehabilitation, 41% of patients with abnormal heart rate
recovery had normal heart rate recovery, and patients who could not normalize
heart rate recovery had a higher predicted mortality rate (P<.001).
When looking at a multivariable model, researchers found
predictors that failed to improve heart rate recovery included older age
(OR=1.47; 95% CI, 1.23-1.75), lack of improvement in exercise capacity
(OR=0.70; 95% CI, 0.59-0.83), peripheral arterial disease (OR=3.02; 95% CI,
1.37-6.68) and prior congestive HF (OR=1.93; 95% CI, 1.12-3.32). After cardiac
rehabilitation, 89% of patients who had normal heart rate recovery at baseline
continued to have normal heart rate recovery vs. 41% of patients who achieved
normal heart rate recovery. Eleven percent of patients with normal heart rate
recovery developed abnormal heart rate recovery vs. 59% who maintained abnormal
heart rate recovery. Overall, 18% of patients died.