Related Experiment Videos
Reduced heart rate variability in ischemic heart disease is only partially caused by ischemia. An HRV study before
B Wennerblom1, L Lurje, J Solem
1Department of Cardiology, Sahlgrenska University Hospital, S-413 35 Göteborg, Sweden. bertil.wennerblom@tripnet.se
Insights
Complete revascularization in angina patients partially restored heart rate variability (HRV), primarily vagal modulation. This suggests ischemia is a key factor, but not the sole cause, of reduced HRV in coronary artery disease.
Area of Science:
- Cardiology
- Autonomic Nervous System Function
- Ischemic Heart Disease
Background:
- Reduced heart rate variability (HRV) is linked to poor prognosis after acute myocardial infarction (AMI).
- HRV is also reduced in patients with uncomplicated coronary artery disease (CAD), with a suggested association with poor prognosis.
- The precise mechanism behind HRV reduction in CAD, particularly ischemia, remains unclear.
Purpose of the Study:
- To investigate the impact of complete revascularization via percutaneous transluminal coronary angioplasty (PTCA) on HRV in drug-free angina patients without prior AMI or other diseases.
- To determine if reducing ischemia through PTCA influences HRV in this specific patient group.
Main Methods:
- Twenty-four-hour Holter recordings were conducted in 48 angina patients and 41 controls at baseline, and 1 and 6 months post-PTCA.
- HRV was assessed during controlled respiration and cold pressure tests at baseline and post-PTCA in a subset of patients.
Main Results:
- Angina patients exhibited significantly reduced HRV parameters (mean RR interval, SD, rMSSD, pNN50, total power, low-frequency, and high-frequency peaks) compared to controls.
- One and six months post-PTCA, a majority of patients were angina-free.
- Significant recovery of vagal modulation was observed 6 months post-PTCA during controlled respiration, though 24-hour HRV parameters showed only nonsignificant trends.
Conclusions:
- Patients with uncomplicated angina display reduced HRV, predominantly affecting vagal activity, but maintain normal low-frequency variability linked to mortality.
- Complete revascularization leads to partial normalization of vagal modulation in these patients.
- These findings indicate that ischemia is a significant, but not the sole, contributor to HRV reduction in uncomplicated chronic coronary artery disease.
Background:
Reduced heart rate variability (HRV) after acute myocardial infarction (AMI) indicates poor prognosis. HRV in patients with uncomplicated coronary artery disease is reduced, and an association with poor prognosis has been suggested. The mechanism of the HRV reduction is not known, but ischemia is a possibility.
Aim:
To evaluate, in angina patients with no prior AMI, no other disease and drug-free, if complete revascularization and thus important reduction of ischemia by means of PTCA influences HRV.
Patients And Methods:
Twenty-four-hour Holter recordings were performed at baseline prior to PTCA in 48 patients with angina and in 41 age-matched healthy control subjects. The recording was repeated 1 and 6 months after complete revascularization. In addition, HRV was registered during controlled respiration in the supine and standing positions and during cold pressure test at baseline in all angina patients and controls and in 17 consecutive angina patients 6 months after PTCA.
Results:
Compared to controls, angina patients had a significantly reduced mean RR interval (p = 0.02), SD (p = 0.003), rMSSD (p = 0.03), pNN50 (p = 0.03), total power (p = 0.003), low- (p = 0.004) and high-frequency peak (p = 0.04), but normal SDNN, SDANN and LF/HF. One and 6 months after PTCA, 42/46 and 32/40 follow-up patients, respectively, were free of angina. Six months after PTCA, there was a significant recovery of vagal modulation seen in the frequency domain during controlled respiration, but only nonsignificant trends in HRV parameters analyzed over 24 h.
Conclusion:
Patients with uncomplicated angina had reduced HRV, mainly affecting vagal activity, but normal low frequency variability associated with mortality. Complete revascularization caused a partial normalization of vagal modulation indicating that ischemia may be one of but not the only mechanism of the HRV reduction in uncomplicated chronic coronary artery disease.