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Patients with uncomplicated coronary artery disease have reduced heart rate variability mainly affecting vagal tone
B Wennerblom1, L Lurje, H Tygesen
1Department of Cardiology, Sahlgrenska University Hospital, S-41345 Göteborg, Sweden. maureen.jehler@hjl.gu.se
Insights
Uncomplicated coronary artery disease reduces heart rate variability, particularly high and low frequencies associated with vagal tone. This contrasts with acute myocardial infarction, aligning with the good prognosis observed in stable angina patients.
Area of Science:
- Cardiology
- Autonomic Nervous System Function
Background:
- Coronary artery disease (CAD) can impact autonomic function.
- Heart rate variability (HRV) analysis provides insights into cardiac autonomic regulation.
- Distinguishing HRV patterns in chronic CAD versus acute myocardial infarction (AMI) is clinically relevant.
Purpose of the Study:
- To determine if uncomplicated chronic coronary artery disease alters heart rate variability.
- To compare the HRV pattern in chronic CAD with that observed in patients post-acute myocardial infarction.
Main Methods:
- Sixty-five patients with stable angina and no prior myocardial infarction were studied.
- Heart rate variability was assessed over 24-hour Holter monitoring using time and frequency domain analyses.
- Results were compared to 33 age-matched healthy controls.
Main Results:
- Patients with uncomplicated CAD exhibited significantly reduced global power (GP), high frequency (HF), and low frequency (LF) HRV components.
- Reduced time-domain measures including SD (standard deviation), rMSSD (root mean square of differences), and pNN50 (proportion of adjacent intervals differing >50ms) were observed.
- No significant differences were found in SDNN or SDANN, which reflect ultra-low and very-low frequencies.
Conclusions:
- Uncomplicated coronary artery disease is associated with diminished HRV, reflecting reduced vagal tone.
- The less affected SDNN and SDANN in chronic CAD, compared to AMI, correlate with a favorable prognosis in this patient group.
Aim:
To investigate whether uncomplicated chronic coronary artery disease causes changes in heart rate variability and if so, whether the heart rate variability pattern is different from that described in patients with acute myocardial infarction.
Methods:
Heart rate variability was studied in 65 patients with angina who had no previous myocardial infarcts, no other diseases, and were on no drug that could influence the sinus node. Results were compared with 33 age matched healthy subjects. The diagnosis of coronary artery disease in angina patients was established by coronary angiography in 58, by thallium scintigraphy in six, and by exercise test only in one. Patients and controls were Holter monitored 24 hours outside hospital, and heart rate variability was calculated in the frequency domain as global power (GP: 0.01-1.00 Hz), low frequency peak (LF: 0. 04-0.15 Hz), high frequency peak (HF: 0.15-0.40 Hz), LF/HF in ms(2), and in the time domain as SDNN (SD of normal RR intervals), SDANN (SD of all five minute mean normal RR intervals), SD (mean of all five minute SDs of mean RR intervals), rMSSD (root mean square of differences of successive normal RR intervals) (all in ms), and pNN50 (proportion of adjacent normal RR intervals differing more than 50 ms from the preceding RR interval) as per cent.
Results:
The mean age in patients and controls was 60.4 (range 32-81) and 59.1 (32-77) years, respectively (NS), the male/female ratio, 57/65 and 24/33 (NS), and the mean time of Holter monitoring, 23.0 (18-24) and 22.8 (18-24) hours (NS). Mortality in angina patients was 0% (0/65) at one year, 0% (0/56) at two years, and 3% (1/33) at three years. Compared with healthy subjects angina patients showed a reduction in GP (p = 0.007), HF (p = 0.02), LF (p = 0.02), SD (p = 0.02), rMSSD (p = 0.01), and pNN50 (p = 0.01). No significant difference was found in RR, LF/HF, SDNN, or SDANN.
Conclusions:
Uncomplicated coronary artery disease without previous acute myocardial infarction was associated with reduced high and low frequency heart rate variability, including vagal tone. SDANN and SDNN, expressing ultra low and very low frequencies which are known to reflect prognosis after acute myocardial infarction, were less affected. This is in agreement with the good prognosis in uncomplicated angina in this study.