Does an abnormal heart beat in patients with coronary heart disease increase the chance of heart attack?

This study investigated whether atrial fibrillation (an abnormal heart rhythm) increases the risk of heart attack among patients with coronary heart disease.

Atrial fibrillation is an irregular heart beat condition that may cause blood to pool and clot. If a blood clot forms it can be pumped to an artery that supplies the heart muscle with blood, blocking off the blood supply and resulting in a heart attack.  

Many people with coronary heart disease (also called coronary artery disease) develop atrial fibrillation. Coronary heart disease is a condition caused by narrowed blood vessels that supply the heart with blood, oxygen and nutrients. If a blood clot travels to the narrowed blood vessels it can block the artery causing a heart attack. 

This study investigated whether whether having atrial fibrillation increases the occurrence of heart attack among patients with coronary heart disease.

The study included 23,928 people with coronary heart disease. Over a follow up period of around 4 years, 648 cases of heart attack were recorded. Atrial fibrillation was found to double the risk of heart attack among coronary heart disease patients compared to coronary artery disease patients without atrial fibrillation. 

This risk was found to be even higher in women than in men, and in patients who were black compared to caucasian. The study also found that in patients who had atrial fibrillation, no matter what age they were, the risk of heart attack was the same, as the occurrence of heart attack in those aged <75 and those aged >75 years was relatively similar. 

Atrial fibrillation more than doubles the chance of heart attack, especially in women and people who are black, who have coronary heart disease. 

The study found that, in general, patients with atrial fibrillation also had worse kidney function, and were more likely to have diabetes and high blood pressure compared to people without atrial fibrillation. This may mean that patients in this study without atrial fibrillation were generally healthier and thus may partly account for their lower rate of heart attack. 

If you or someone you know have atrial fibrillation and coronary heart disease, talk to a doctor about current treatments to help reduce your risk of having a heart attack.