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Effects of beating- versus arrested-heart revascularization on cardiac autonomic regulation and arrhythmias
Jurij M Kalisnik1, Viktor Avbelj, Roman Trobec
1Department of Cardiovascular Surgery, University Medical Center Ljubljana, Ljubljana, Slovenia. jurij-matija.kalisnik@mf.uni-lj.si
Insights
Off-pump coronary artery bypass grafting (CABG) better preserves cardiac autonomic regulation and reduces arrhythmias compared to on-pump CABG. Beating-heart surgery leads to faster recovery of heart rate and autonomic function post-operation.
Area of Science:
- Cardiology
- Autonomic Nervous System Regulation
- Cardiac Surgery
Background:
- Cardiac surgery can disrupt autonomic regulation, increasing arrhythmia risk and sudden cardiac death.
- Coronary artery bypass grafting (CABG) techniques, on-pump versus off-pump, have differential impacts on cardiac autonomic function.
Purpose of the Study:
- To compare the effects of on-pump and off-pump coronary artery bypass grafting (CABG) on cardiac autonomic regulation and postoperative arrhythmias.
Main Methods:
- 57 patients undergoing CABG were divided into on-pump (28) and off-pump (29) groups.
- Electrocardiographic recordings and breathing data were collected preoperatively and on postoperative days 4, 7, and 28.
- Analysis focused on heart rate variability, arrhythmias, and sympathetic/parasympathetic modulation.
Main Results:
- Both CABG groups showed significant declines in heart rate variability indices (total, low-frequency, high-frequency power).
- Off-pump CABG demonstrated better preservation of total and high-frequency power at 7 days post-surgery.
- The on-pump group experienced a higher incidence of arrhythmias on postoperative day 7.
Conclusions:
- Coronary artery bypass grafting significantly impairs cardiac autonomic regulation.
- Beating-heart (off-pump) revascularization better preserves autonomic modulation post-CABG.
- Factors beyond autonomic regulation may contribute to arrhythmias and delayed heart rate recovery after on-pump CABG.
Background:
Altered autonomic regulation after cardiac operations precipitates cardiac arrhythmias, affects repolarization, and increases the risk of sudden cardiac death. We sought to clarify how the 2 different techniques of coronary artery bypass grafting (CABG), namely conventional CABG using cardiopulmonary bypass (on-pump) and beating-heart CABG without cardiopulmonary bypass (off-pump), affect cardiac autonomic regulation and arrhythmic disturbances postoperatively.
Methods:
We included 57 consecutive patients, 28 in the on-pump group and 29 in the off-pump group. The electro-cardiographic recordings were performed on the preoperative day and the fourth, seventh, and twenty-eighth day after operation. Fifteen-minute digital recordings were taken; one channel was used to record electrocardiogram and the other breathing. Detailed analyses of arrhythmia, heart rate, and heart rate variability indices were performed on respective days to assess sympathetic and parasympathetic modulation of the heart and relate it to detected arrhythmic disturbances.
Results:
Total power, low-frequency power, which indicates baroreceptor-mediated sympathetic modulation, and high-frequency power, indicating parasympathetic vagal modulation, declined significantly in both groups after CABG (P < .001); however, 7 days after CABG, total and high-frequency power were better preserved in the off-pump group. Mean RR interval was longer in the off-pump group at 7 (P= .006) and 28 days (P= .008) after surgery. The total incidence of arrhythmic events was higher in the on-pump group on the seventh day (P = .017, adjusted odds ratio = 8.6, 95% confidence interval 1.4-80.3).
Conclusions:
The results show profound impairment of cardiac autonomic regulation after CABG, showing better preserved cardiac autonomic modulation 7 days after beating-heart revascularization. Evidence suggests that slower restoration of heart rate and increased incidence of arrhythmic events after CABG using cardiopulmonary bypass are the result not only of impaired cardiac autonomic regulation but also of the involvement of additional factors of nonautonomic origin.
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