A new study suggests that a common type of irregular heartbeat, known as atrial fibrillation, may be significantly more dangerous in women than it is in men. This results add to a growing body of research suggesting there is a greater divide between male and female heart health than previously believed.

Published online in the British Medical Journal, the current study examined 30 other studies conducted between January 1966 and March 2016 in order to identify whether atrial fibrillation was a stronger risk factor for cardiovascular disease and death in women than in men. In total, the data was based on a 4,371,714 individuals and consisted only of studies that contained at least 50 participants with atrial fibrillation and 50 without.

According to the National Heart, Lung, and Blood Institute, atrial fibrillation is the most common type of arrhythmia, or irregular heartbeat. It occurs when disorganized electrical signals cause the heart’s two upper chambers to beat very fast and irregularly. It's also the leading cause of heart disease and stroke worldwide. People with atrial fibrillation may not feel any symptoms, but when left untreated, the condition can lead to a stroke.

Results of the analysis revealed that atrial fibrillation was indeed a stronger risk factor for cardiovascular disease and death in women than in men. The researchers aren’t quite sure why this discrepancy exists, but the sheer volume of the gender gap suggest it is likely not just a coincidence.

“It may be that the associations we report are not causal, and that women with atrial fibrillation are more likely to have comorbidities [co-existing medical conditions] in addition to atrial fibrillation that cause death and cardiovascular disease," review author Connor Emdin, a doctoral student in cardiovascular epidemiology at the University of Oxford's George Institute for Global Health, told HealthDay .

Atrial fibrillation is not the only heart condition found to affect men and women differently. For example, heart disease affects more young women than men. However, according to Johns Hopkins Medicine, a significant challenge for diagnosing heart disease in women is doctors’ inability to recognize symptoms. Women already have their own list of unique risk factors for heart disease in addition to those factors associated with men, too. What's more, heart symptoms are often more subtle in women. For this reason, a 2015 study published in the Journal of The American College of Cardiology found that a woman’s heart disease risk is vastly underestimated by both her and her doctor.

Atrial fibrillation can be treated. In addition to treatments, experts recommend women with the condition improve their health by exercising, eating right, and managing their stress levels to avoid any serious health consequences.

Source: Edmin CA, Wong CX, Hsiao A, et al. Atrial fibrillation as risk factor for cardiovascular disease and death in women compared with men: systematic review and meta-analysis of cohort studies. British Medical Journal. 2015