High doses of corticosteroids may be linked with an increased risk of atrial fibrillation, which is a heart rhythm disorder featured by irregular heartbeats.

Atrial fibrillation is one of the most common types of irregular heartbeat and affects around 4 percent of people over the age of 60 years.

From News-Medical.Net:

Corticosteroids could affect heart function through several different mechanisms, the authors write. The medication may affect the balance of potassium in heart muscle cells, which in turn causes the muscle to contract irregularly. Corticosteroids also may cause retention of sodium and fluid, which can lead to high blood pressure, congestive heart failure or enlarged atria, all risk factors for atrial fibrillation.

“Our findings suggest that patients receiving high-dose corticosteroid therapy are at increased risk of developing atrial fibrillation,” the authors conclude. “Therefore, careful monitoring of these patients by clinical examination and by performing an electrocardiogram before and after high-dose (pulse) therapy could increase the chance to diagnose and treat this serious arrhythmia as early as possible. Because persons who develop atrial fibrillation are at increased risk of serious cardiovascular complications such as heart failure and ischemic stroke and have a chance to develop chronic atrial fibrillation, early detection of atrial fibrillation is essential.”

It was noted by the authors that corticosteroids that are usually prescribed for asthma and other lung complications are possibly linked with atrial fibrillation.