New York, Aug 30 : About 1 in 4 women may develop irregular heart rhythms after menopause, with stressful life events and poor sleep being leading factors, finds a new study  Known as atrial fibrillation, it may lead to blood clots, stroke, heart failure or other cardiovascular complications. 'In my general cardiology practice, I see many postmenopausal women with picture perfect physical health who struggle with poor sleep and negative psychological emotional feelings or experience, which we now know may put them at risk for developing atrial fibrillation,' said lead study author Susan X. Zhao, a cardiologist at Santa Clara Valley Medical Center in San Jose, California. 'I strongly believe that in addition to age, genetic and other heart-health related risk factors, psychosocial factors are the missing piece to the puzzle of the genesis of atrial fibrillation,' Zhao said. In the study, published in the Journal of the American Heart Association, researchers reviewed data from more than 83,000 questionnaires by women ages 50-79. During approximately a decade of follow-up, the study found about 25 per cent or 23,954 women developed atrial fibrillation. For each additional point on the insomnia scale, there is a 4 per cent higher likelihood of developing atrial fibrillation. Similarly, for each additional point on the stressful life event scale, there is a 2 per cent higher likelihood of having atrial fibrillation. 'The heart and brain connection has been long established in many conditions,' Zhao said. 'Atrial fibrillation is a disease of the electrical conduction system and is prone to hormonal changes stemming from stress and poor sleep. These common pathways likely underpin the association between stress and insomnia with atrial fibrillation.' Researchers noted that stressful life events, poor sleep and feelings, such as depression, anxiety or feeling overwhelmed by one's circumstances, are often interrelated. It's difficult to know whether these factors accumulate gradually over the years to increase the risk of atrial fibrillation as women age. Chronic stress has not been consistently associated with atrial fibrillation, and the researchers note that a limitation of their study is that it relied on patient questionnaires utilised at the start of the study. Stressful life events, however, though significant and traumatic, may not be long lasting, Zhao noted. Further research is needed to confirm these associations and evaluate whether customised stress-relieving interventions may modify atrial fibrillation risk, the researchers said. /IANS