L-Carnitine: A New Therapeutic Option for the Prevention of Atrial Fibrillation in Non-Cardiac Surgery—A Single-Group Interventional Pilot Study

Background: L-carnitine is essential in lipid metabolism and reportedly has preventive effects for arrhythmia. Our objective was to examine the incidence of postoperative atrial fibrillation (POAF) and changes in serum biomarker levels following perioperative L-carnitine administration in patients with lung cancer. Methods: Thirteen patients undergoing a lobectomy with preoperative serum brain natriuretic peptide levels >24 pg/mL were perioperatively administered L-carnitine for 5 days (3 g/3×). Accurate 95% confidence intervals (CI) for POAF incidence were calculated. Serum biomarkers for POAF in lung cancer and target proteins for L-carnitine were evaluated by using open-source data from proteomic analysis. Results: The incidence of POAF was 38.5% (95% CI 13.9%–68.4%). Fatty acid-binding protein 4 (FABP4) was selected as a candidate biomarker from 1472, 63, and 26 proteins related to lung cancer, L-carnitine, and AF, respectively. A positive correlation was observed between the predicted POAF incidence rate and preoperative FABP4 levels (Pearson’s r = 0.5183). The mean change in serum FABP4 after L-carnitine administration for 5 days was −2.9 ng/mL (95% CI −4.9 to −0.89 ng/mL). Conclusions: The incidence of POAF after a lobectomy was 38.5% after the perioperative administration of L-carnitine for patients at a high risk of POAF. The serum FABP4 level demonstrates potential as a candidate biomarker for POAF prediction.