Patients who develop atrial fibrillation after surgery have an increased risk of subsequently being admitted to hospital with heart failure, according to new research.

The study of over three million patients, which is published in the European Heart Journal, showed that the risk of hospitalisation increased regardless of whether or not the surgery was for a heart condition.

Among 76,536 patients who underwent heart surgery, 14,365 (18.8%) developed post-operative atrial fibrillation and the risk of hospitalisation for heart failure increased by a third compared to patients who did not develop atrial fibrillation.

Among 2,929,854 patients without a history of heart disease who had surgery for non-heart-related conditions, 23,763 (0.8%) developed atrial fibrillation and the risk of hospitalisation for heart failure doubled.

Atrial fibrillation could be important indicator of underlying heart failure

Dr Parag Goyal, Associate Professor of Medicine in the Weill Department of Medicine at Weill Cornell Medicine, New York, USA, said: “Our study, which to our knowledge is the largest study to date, shows that post-operative atrial fibrillation is associated with future heart failure hospitalisations.

"This could mean that atrial fibrillation is an important indicator of underlying but not yet detected heart failure; or it could mean that atrial fibrillation itself contributes to the future development of heart failure. While this study could not specifically address which of these mechanisms are at play, our hope is that this study will inspire future work into exploring the underlying mechanism seen in our important findings."

Post-operative atrial fibrillation occurs in up to 40% of patients undergoing heart surgery and 2% of patients undergoing non-cardiac surgery. Doctors have tended to view it as a benign event, triggered by the stress of the surgery. However, evidence is emerging that post-operative atrial fibrillation is linked to longer term problems such as stroke and death from any cause, although, until now, there has been limited evidence regarding its association with subsequent heart failure.

For the current, retrospective study, the researchers collected data on health claims from 2016 to 2018 for discharges from acute care hospitals across 11 states in the USA. Patients were aged over 18 and they were followed up for an average (median) of 1.7 years. The researchers adjusted their analyses to account for factors that could affect the results such as age, sex, race, insurance status, medical history and body mass index.

In an editorial to accompany the paper, Dr Melissa Middeldorp and Professor Christine Albert, both from the Smidt Heart Institute at Cedars-Sinai, California, USA, added: “These data add to a growing body of literature suggesting that post operative atrial fibrillation is not just a transient response to surgery but may be reflective of underlying atrial and myocardial structural changes that not only predispose to the acute atrial fibrillation event but to other potentially related adverse cardiovascular events, such as heart failure hospitalisation.”