Although nearly half of patients who undergo CABG have new-onset atrial fibrillation (AFib), the burden after surgery is very low, especially after 30 days, according to results of a prospective cohort study presented at the 39th European Association for Cardio-Thoracic Surgery annual meeting and simultaneously published Oct. 9 in JAMA.

Florian E.M. Herrmann, MD, et al., analyzed 198 patients (mean age, 66 years; 13% women; baseline median CHA₂DS₂-VASc score = 3) with three-vessel or left main coronary artery disease and without a history of AFib who had CABG at one of two surgery centers in Germany between 2019 and 2023. All patients were implanted with a cardiac monitor during CABG and had long-term continuous electrocardiographic monitoring for detection of AFib.

Results showed that 95 patients developed AFib within one year after CABG (cumulative incidence, 48%), with a median AFib burden of 0.07% or 370 cumulative minutes spent in AFib.

Findings also revealed that the median AFib burden decreased over time: 4% for days one to seven (368 minutes), 0.04% for days eight to 30 (13 minutes) and 0 for days 31–365. Following discharge, three patients had an AFib episode lasting >24 hours. Notably, 63% of all AFib episodes were asymptomatic and 67% were not detected by standard monitoring.

Importantly, the 2023 ACC/American Heart Association AFib guideline gives a Class 2a moderate-strength recommendation to administer anticoagulation for 60 days with reevaluation for long-term consideration. Herrmann and colleagues write that the low AFib burden in their study "calls into question whether long-term oral anticoagulation is necessary in patients with new-onset AFib after CABG" and suggest that "if oral anticoagulation is initiated, a reevaluation 30 days after surgery is recommended."

In an accompanying editorial, Gregory M. Marcus, MD, FACC, notes that the current study provides strong evidence that AFib can be reversible and that postoperative AFib after CABG is different than other types of surgical procedures. He concludes, "The application of long-term therapies, such as anticoagulation, should be the exception rather than the norm."