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Postoperative atrial fibrillation is the most frequent complication arising after cardiac surgery, occurring in 40% of cases. The treatment of postoperative atrial fibrillation with epicardial amiodarone hydrogel delivery can increase efficacy and reduce side effects. The effective dose of amiodarone and toxicity to local myocytes must be determined. To further evaluate the optimal dose of amiodarone mixture with hydrogel to provide pharmacologic therapy with elevated target tissue levels and minimal local side effects, we performed a randomized prospective study in 150 patients with coronary artery bypass grafting to compare the effectiveness of different doses of amiodarone on postoperative atrial fibrillation.
After institutional review board approval, 150 patients, from January 2012 to July 2015, who had undergone cardiac surgery were randomized to 3 equal groups. Group I received poly-based hydrogel with 1.5mg/kg of amiodarone, and group II received poly-based hydrogel with 2.0mg/kg of amiodarone. Both hydrogels were sprayed diffusely over the biatrial epicardium. The control group underwent the procedure with only hydrogel spray. Continuous telemetry monitored for postoperative atrial fibrillation, and amiodarone levels in the atria, plasma, and tissue were measured postoperatively. Daily electrocardiographic parameters, cardiac biomarker tests and CRP were measured until postoperative day 10.
The incidence of postoperative atrial fibrillation was significantly less in group II, with 2 of 50 patients (4%) incurring atrial fibrillation compared with 9 of 50 patients (18%) in group I and 13 of 50 patients (26%) in the control group (P<.01). The mean amiodarone concentrations in the atria coronary sinus (40.06 ± 5.1) in group II and (20.5 ± 0.9) in Group I respectively. Both groups reached therapeutic level > 20 μg/mL and were significantly greater than those in the extracardiac tissues (1.32 ± 0.9/0.2 ± 0.4; P < .01). The plasma amiodarone levels remained below the detection limit (<8 μg/mL) during the 14 days of follow-up. Troponin I and Troponin T were negative within first postoperative week. Bradycardia was observed less in the control group (93 ± 18) than in study group I (76 ± 29; P < .01).
Epicardial application of amiodarone-releasing adhesive hydrogel is a less-invasive, well-tolerated, quick, and effective therapeutic option for preventing postoperative atrial fibrillation with minimal risk of adverse cardiac effects. A dose of 2mg/kg amiodarone in drug releasing- hydrogel is optimal in preventing postoperative atrial fibrillation.