Heart rate recovery of individuals undergoing cardiac rehabilitation after acute coronary syndrome

Heart rate recovery is useful for evaluating the recovery of exercise tolerance in patients with heart failure and atrial fibrillation

This study aimed to examine the factors that contribute to improvement of exercise tolerance in patients with heart failure (HF) and atrial fibrillation (AF) following cardiac rehabilitation. Our hypothesis is that parasympathetic values are important for recovering exercise tolerance in those patients. We included 84 consecutive patients with HF and AF (mean age: 69 ± 15 years, 80% men). All of the patients underwent a cardiopulmonary exercise test and had pre and post 5 month cardiac rehabilitation assessed. After 155 ± 11 days and 44 ± 8 sessions, 73 patients (86%) showed an increase in peak oxygen uptake (VO₂) and VO₂ at the anaerobic threshold. In univariate linear regression analysis, the % change in heart rate recovery, plasma B-type natriuretic peptide levels, resting heart rate, and the minute ventilation /carbon dioxide output slope were significantly related to that of peak VO₂ (p < 0.01, p = 0.03, p = 0.02, p < 0.01, respectively). Stepwise multivariate linear regression analysis showed that the % change in heart rate recovery was independently related to that of peak VO₂ (p < 0.05). Our results suggest that heart rate recovery is closely associated with recovery of exercise tolerance in patients with HF and AF after CR.

Physical activity and cardiac autonomic dysfunction in patients with chronic obstructive pulmonary disease: a cross-sectional analysis

BACKGROUND

The cardiac autonomic function in patients with chronic obstructive pulmonary disease (COPD) has been poorly studied.

OBJECTIVES

We aimed to 1) describe the cardiac autonomic function assessed by heart rate recovery (HRR) and chronotropic response (CR) during a 6-min walk test (6MWT) and afterward and 2) estimate the association of physical activity with HRR and CR in COPD patients.

METHODS

This cross-sectional analysis included 320 patients with mild to very severe COPD. Physical activity (steps, time in any/moderate-to-vigorous/vigorous physical activity, intensity and sedentary time) was measured during 1 week by accelerometer. CR and HRR were measured during a 6MWT and 5 min after, respectively, and their association with physical activity parameters was estimated by multivariable linear regression models.

RESULTS

Patients were 82% male and had a mean (SD) age 68 (8) years, post-bronchodilator FEV1 57 (18) % predicted, and walked a mean of 7716 (4139) steps/day. HRR was slow until 5 min after the 6MWT; the mean (SD) was 15 (10), 22 (11), 25 (12), 25 (12) and 27 (12) bpm after 1, 2, 3, 4 and 5 min, respectively). The mean CR was 35% (16). After adjusting for relevant confounders, time in vigorous physical activity was significantly associated with a fast decrease in HRR (p=0.044) and an increase in CR (p=0.021). We found no independent association for other physical activity parameters.

CONCLUSION

A cardiac autonomic dysfunction is present in patients with mild to very severe COPD and is inversely related to the practice of vigorous physical activity.