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Higher heart rate variability of smokers after acute myocardial infarction
T Nishiue1, H Tsuji, S Tokunaga
1Cardiovascular Center, Kansai Medical University, Osaka, Japan. nishiuet@takii.kmu.ac.jp
Insights
Smokers with myocardial infarction showed higher heart rate variability (HRV) after quitting smoking compared to non-smokers. This suggests a potential protective effect of smoking cessation on cardiac autonomic function post-heart attack.
Area of Science:
- Cardiology
- Autonomic Nervous System Function
Background:
- Cigarette smoking is a major risk factor for coronary artery disease.
- Current smokers often exhibit a better prognosis post-myocardial infarction (MI) than non-smokers.
- The impact of smoking on heart rate variability (HRV) after MI requires further investigation.
Purpose of the Study:
- To investigate the influence of smoking status on heart rate variability (HRV) in patients following an acute myocardial infarction (MI).
Main Methods:
- Evaluated 52 patients (34 smokers, 18 non-smokers) within 24 hours of a first MI.
- Recorded 24-hour ambulatory ECG 14 days post-MI to assess very low frequency (VLF), low frequency (LF), and high frequency (HF) power.
- Adjusted for clinical factors including age, left ventricular ejection fraction, diabetes, revascularization, and beta-blocker use.
Main Results:
- Smokers tended to be younger (mean age 57 vs. 62 years).
- After adjusting for covariates, smokers demonstrated significantly higher very low frequency (VLF) power (P = 0.0183) compared to non-smokers 14 days post-MI.
- No statistically significant differences in other clinical characteristics were observed between groups.
Conclusions:
- Despite smoking's general negative impact on HRV, smokers exhibited increased HRV post-MI when abstinent.
- Smoking cessation may be associated with improved cardiac autonomic function recovery after acute myocardial infarction.
Abstract:
Although cigarette smoking is known to be a strong risk factor for the development of coronary artery disease, several large clinical studies have demonstrated that current smokers had a favorable prognosis compared to nonsmokers after myocardial infarction. This study sought to evaluate the effect of smoking status on heart rate variability after onset of acute myocardial infarction. We studied 52 patients (34 smokers, 18 nonsmokers) with a first myocardial infarction within 24 h of onset. We recorded 24-h ambulatory ECG to calculate very low frequency power (VLF), low frequency power (LF) and high frequency power (HF) 14 days after onset. Although smokers had a tendency to be younger than nonsmokers (mean age 57 versus 62, P = 0.0812), clinical characteristics were not statistically different between smokers and nonsmokers. After adjustment for age, left ventricular ejection fraction, history of diabetes, acute revascularization and use of beta-blockers, VLF (P = 0.0183) of smokers 14 days after onset was significantly higher than for nonsmokers. In conclusion, although smoking reduces heart rate variability in the general population, higher heart rate variability was observed in smokers than nonsmokers after acute myocardial infarction under the condition of smoking cessation.