Background: DC cardioversion (DCCV) is commonly used to restore sinus rhythm (SR) in patients with persistent atrial fibrillation or flutter (AF). DCCV is not always successful and often AF recurs soon after. Oral amiodarone therapy increases the efficacy of DCCV on the day and increases duration of SR after DCCV.
The NUH elective DCCV service was suspended for 6 months at the start of the COVID-19 pandemic. On its resumption, the NUH Arrhythmia team advised that all eligible patients be commenced on oral amiodarone at the time of referral for DCCV with the aims of achieving chemical cardioversion prior to DCCV, increasing on-the-day DCCV success rates, reducing the volume of repeat DCCVs and reducing the number of patients on the waiting list.
Methods: This was a retrospective analysis of 576 DCCV referrals and outcomes from January 2019 until August 2021; 281 prior to March 2020 and 295 after August 2020. Patient demographics, specialty of consultant in charge of patient care, body mass index, left ventricular function, left atrium size, medications, chemical cardioversion rates and DCCV success rates were collected. Propensity score matching to assess impact of amiodarone use was performed.
Results: Post COVID-19 suspension, 46% of DCCV patients were on amiodarone vs 33% before (p=0.001). Amiodarone use was higher in patients referred by an electrophysiology consultant (OR 1.42; 95% CI 1.01–1.98; p=0.04). Propensity score matching demonstrated that patients on amiodarone were more likely to chemically cardiovert and obviate the need for DCCV (OR 1.75, 95% CI 1.06–2.89; p=0.03). Being on amiodarone made no significant difference to on-the-day DCCV success (on amiodarone 155/170 [91%] vs off amiodarone 267/279 [95.7%]; p=ns).
Conclusion: Amiodarone use increased in DCCV patients post COVID-19, resulting in greater chemical cardioversion success and therefore reduced need for DCCV. Patients looked after by an electrophysiologist were more likely to receive amiodarone. Further follow-up is needed to assess maintenance of SR at first follow-up post DCCV.
