Studies have shown that even moderate drinking can be harmful to your health, but for people with heart rhythm disorders, the dangers of consuming too much alcohol are higher.

A study published in EP Europace, a journal of the European Society of Cardiology (ESC), shows that drinking 14 alcoholic beverages per week is linked to a higher risk of stroke and embolism in patients with atrial fibrillation, an irregular and often rapid heartbeat.

“Our study suggests that atrial fibrillation patients should avoid heavy alcohol consumption to prevent stroke and other complications,” said author Dr. Boyoung Joung of Yonsei University College of Medicine, Seoul, Republic of Korea in a press release.

More than 9,000 patients with atrial fibrillation from 18 tertiary hospitals treating all geographical regions of South Korea were involved in the research. Patients were placed into four categories based on how much alcohol they drank each week: abstainer/rare for less than one drink, light for seven drinks, moderate for seven-14 drinks and heavy for at least 14 drinks.

The majority of patients — 79.2% — were in the abstainer/rare category while 8.7% were heavy drinkers, 8.4% were considered light and 3.7% deemed moderate.

Within an average of 17.4 months, researchers followed up with patients for adverse effects, which included stroke, a blood clot in an organ or limb and hospitalization for heart failure management among them. Researchers tracked how many patients who had these effects and took calculations of their incident rate.

The incident rates were 6.73 for abstainer/rare, 5.77 for light, 6.44 for moderate and 9.65 for heavy drinkers. Adverse effects were tabulated for each category.

“Our study did not find any significant association between light or moderate drinking and complications,” Joung said. “A significant deleterious relationship with heavy drinking was identified, suggesting that heavy alcohol consumption should be avoided.”

In particular, atrial fibrillation patients had a significant risk of harm from drinking heavily.

“The findings indicate that heavy drinking is particularly detrimental for atrial fibrillation patients who are considered less vulnerable to complications. Clinicians should ask patients about their alcohol consumption and take it into account when calculating their stroke risk,” Joung said. “While heavy drinking should be strongly discouraged among atrial fibrillation patients, moderate drinking seems to be safe.”