Alpha-linolenic acid and heart rate variability in women examined for coronary artery disease

Background and aim: Some studies suggest that alpha-linotenic acid (ALA) may protect against coronary artery disease (CAD) and CAD related death (i.e. sudden cardiac death). Thus, some limited data suggest an antiarrhythmic effect of ALA. We therefore investigated the association between ALA and 24-h heart rate variability (HRV), a strong predictor of arrhythmic events and sudden cardiac death, in women. Methods and results: The content of ALA in adipose tissue and HRV was determined in 106 women referred for coronary angiography due to suspected CAD. Mean age was 59.5 years (+/- 7) and the content of ALA in adipose tissue was 0.9% (+/- 0.2). Smokers (n = 33) had significantly lower HRV compared to non-smokers, whereas the two groups were otherwise comparable regarding clinical characteristics. If the patients were divided according to SDNN quartiles (the major HRV parameter), women belonging to the lowest quartile had the lowest ALA level (0.8% vs 0.9%, p < 0.01). Furthermore, a positive correlation was found between ALA and HRV, especially among smokers (r = 0.5, p < 0.001). Linear multiple regression analysis revealed that ALA was independently and positively associated with HRV. Conclusions: A positive and independent association was found between ALA in adipose tissue and HRV in women referred for coronary angiography due to suspected coronary artery disease. This association was even stronger for women who smoked. The results might suggest a possible antiarrhythmic effect of ALA in women, an effect which could explain results from previous studies. However, intervention trials with ALA in humans, not least women are warranted. (c) 2005 Elsevier B.V. All rights reserved.