Progression of Atrioventricular Conduction Disorder Induced by Radiofrequency Ablation for Hepatocellular Carcinoma

Radiofrequency ablation (RFA) is generally considered a safe treatment for hepatocellular carcinoma. Although cardiovascular complications have been occasionally reported, they are primarily attributed to sedatives and analgesics or the vasovagal reflex. However, a unique case is presented where RFA itself was suspected of inducing a progressive atrioventricular disorder. An 80-year-old male underwent RFA for hepatocellular carcinoma. His electrocardiogram showed a first-degree atrioventricular block on admission. Prior to ablation, fentanyl and propofol were administered. Severe bradycardia developed immediately after initiation of ablation. RFA and propofol infusion were terminated, leading to prompt heart rate recovery. After approximately five minutes, ablation was resumed without propofol, but severe bradycardia recurred. The electrocardiogram during RFA revealed a complete atrioventricular block. Therefore, the procedure was terminated. A 12-lead electrocardiogram performed after the aborted procedure revealed progression to a second-degree AV block (Mobitz type II) requiring pacemaker implantation. The exact mechanism of this effect remains unclear, though progression of the atrioventricular conduction disorder was considered to be induced by RFA. Careful intraoperative patient management is crucial during RFA.