Efficacy of Intraoperative Low Dose Intravenous Amiodarone in Pharmacologic Cardioversion in Patients with Preoperative Atrial Fibrillation Presenting for Mitral Valve Replacement Surgery Randomized Control Trial

Abstract

Background: Atrial fibrillation (AF) is the most common form of dysrhythmia observed in the clinical field, causing multiple morbidities, such as thromboembolic complications. Hence, the maintenance of sinus rhythm is superior to rate control. This study tests the efficacy of single- and low-dose amiodarone on the persistence of AF after surgery before transfer to the intensive care unit. Methods: A double-blinded, randomized controlled trial assessed 113 patients who underwent mitral valve surgery with preoperative chronic AF. Patients were divided into two groups: the control group (N = 55) who received 50 mL of 5% dextrose over 10 min after general anesthesia induction, and the amiodarone group (N = 58) who received 1 mg/kg of amiodarone diluted in 50 mL of 5% dextrose over 10 min shortly after anesthesia induction. Results: The amiodarone group had a statistically significant successful conversion of preoperative AF to normal sinus rhythm in 40 patients (72.73%). The control group demonstrated spontaneous conversion from AF to a normal sinus rhythm in seven patients (12.73%). The sinus rhythm was maintained in 60% of patients (36), as four patients reverted to AF during the hospital stay despite the initial normal sinus rhythm after the operation. In contrast, 53 (96.36%) patients in the control group were discharged from the hospital with a controlled rate of AF. In addition, low-dose amiodarone caused a statistically significant reduction in heart rates at 10, 30, and 60 min after declamping, extended throughout the first 24 h with mean heart rates of 97.233±7.311, 99.509±8.482, and 97.940±7.715 bpm, respectively. In comparison, the control group had heart rates of 115.382±7.547, 115.055±13.919, and 113.618±8.765 bpm at these times. The mean postoperative heart rate at the end of the first 24 h was 97.793±7.189 bpm in the amiodarone group and 113.036±9.737 bpm in the control group. No mortality or need for mechanical support was recorded in either group. Conclusions: Single and low-dose intraoperative intravenous amiodarone during mitral valve surgery may be practical to aid in pharmacological cardioversion of patients with preoperative chronic AF presenting for mitral valve surgery.