Acute effects of aerobic exercise on the blood pressure of patients after coronary artery bypass grafting.

BACKGROUND: Coronary artery bypass grafting a frequent surgical procedure to treat coronary heart disease, uses the patient's own veins or arteries to bypass narrowed areas and restore blood flow to heart muscle. Cardiac rehabilitation follows this procedure and includes psychological and nutritional support along with the regular practice of physical exercises. OBJECTIVE: The aim of this study was to investigate the acute effects of the aerobic exercise on the blood pressure of patients after coronary artery bypass grafting. METHODS: After 30 days of surgical procedure, 14 patients were assigned to the aerobic exercise group (exercise on the cycle ergometer for 35 minutes), while 8 patients were assigned to the control group (absolute rest for 35 minutes). Blood pressure was measured by a digital automatic device before and after 24 hours of the experiment in both groups. RESULTS: Systolic (P = 0.639) and diastolic (P = 0.103) blood pressures were similar between CG and AEG at baseline. Regarding intragroup differences, no significant changes were observed after 24 hours for SBP in the CG (P = 0.999) and AEG (P = 0.244). On the other hand, significant changes were found for DBP after 24 hours for the CG (P = 0.007) and AEG (P = 0.015). When CG and AEG were compared after 24 hours, no significant differences were found for SBP (P = 0.999) and DBP (P = 0.054). CONCLUSIONS: We found decreased diastolic blood pressure in the aerobic exercise group when the results for pre-training and post-training were compared. However, to support our findings further research is needed, preferably using randomized controlled trials.

Acute Response to Aerobic Exercise on Autonomic Cardiac Control of Patients in Phase III of a Cardiovascular Rehabilitation Program Following Coronary Artery Bypass Grafting.

OBJECTIVE: The aim of the present study was to investigate the acute response to aerobic exercise on autonomic cardiac control of patients undergoing coronary artery bypass grafting (CABG). METHODS: The study sample consisted of eight patients (age: 58.6±7.7 years; body mass index: 26.7±3.5 kg.m2) who underwent a successful CABG (no complications during surgery and/or in the following weeks). To assess heart rate variability (HRV), participants remained in a supine position with a 30-degree head elevation for 20 minutes. Electrocardiographic signal (protocol with three derivations) was collected from 600 Hz sample rate to obtain beat-to-beat intervals (R-R interval). This assessment was performed before, after one hour and after 24 hours of the exercise session. All patients underwent a 35 minutes aerobic exercise session (AES) (low-moderate intensity) on the cycle ergometer. RESULTS: Significant differences were found in the time domain, with positive changes in root mean square of successive RR interval differences (rMSSD) (ms) (parasympathetic component) (one [P=0.017] and 24 hours [P=0.007] post-session). In the frequency domain, we found a significant difference in high frequency (HF) (ms2) (parasympathetic component) (one hour [P=0.048] post-session). The low frequency (LF)/HF ratio (sympathetic and parasympathetic components with a predominance of the sympathetic component) reached statistical significance only 24 hours (P=0.018) post-session. Additionally, the largest effect size was observed only for the LF/HF ratio at one (d=-0.8) and 24 hours (d=-1.3) after one AES. CONCLUSION: The practice of (acute) aerobic exercise improved autonomic cardiac control in patients undergoing CABG.

Acute response to aerobic exercise on autonomic cardiac control of patients in phase iii of a cardiovascular rehabilitation program following coronary artery bypass grafting

Abstract Objective: The aim of the present study was to investigate the acute response to aerobic exercise on autonomic cardiac control of patients undergoing coronary artery bypass grafting (CABG). Methods: The study sample consisted of eight patients (age: 58.6±7.7 years; body mass index: 26.7±3.5 kg.m2) who underwent a successful CABG (no complications during surgery and/or in the following weeks). To assess heart rate variability (HRV), participants remained in a supine position with a 30-degree head elevation for 20 minutes. Electrocardiographic signal (protocol with three derivations) was collected from 600 Hz sample rate to obtain beat-to-beat intervals (R-R interval). This assessment was performed before, after one hour and after 24 hours of the exercise session. All patients underwent a 35 minutes aerobic exercise session (AES) (low-moderate intensity) on the cycle ergometer. Results: Significant differences were found in the time domain, with positive changes in root mean square of successive RR interval differences (rMSSD) (ms) (parasympathetic component) (one [P=0.017] and 24 hours [P=0.007] post-session). In the frequency domain, we found a significant difference in high frequency (HF) (ms2) (parasympathetic component) (one hour [P=0.048] post-session). The low frequency (LF)/HF ratio (sympathetic and parasympathetic components with a predominance of the sympathetic component) reached statistical significance only 24 hours (P=0.018) post-session. Additionally, the largest effect size was observed only for the LF/HF ratio at one (d=-0.8) and 24 hours (d=-1.3) after one AES. Conclusion: The practice of (acute) aerobic exercise improved autonomic cardiac control in patients undergoing CABG.