Delayed reversibility of complete atrioventricular block: cardio-biliary reflex after alcohol septal ablation in a patient with hypertrophic obstructive cardiomyopathy

Background Complete atrioventricular block (AVB) is a life-threatening condition that usually occurs in elderly people with organic heart disease. We herein describe a rare case of complete AVB in a young man with hypertrophic obstructive cardiomyopathy (HOCM) complicated by cholecystitis and cholangitis. Both cardio-biliary reflex and alcohol septal ablation (ASA) can cause conduction block, but the latter is often irreversible. However, their simultaneous occurrence in a patient has not been reported. Case presentation A 31-year-old man presented with acute cholecystitis and cholangitis and complete AVB, which had been diagnosed at a local hospital on the third day after onset. On the fourth day, he was transferred to the emergency department of our hospital because of persistent complete AVB, although his abdominal pain had been partially relieved. An echocardiogram showed a remarkably elevated left ventricular outflow tract (LVOT) gradient (105.2 mmHg) despite the performance of ASA 9 years previously. The abdominal pain gradually disappeared, and normal sinus rhythm was completely recovered 11 days after onset. We determined that cardio-biliary reflex was the cause of the AVB because of the absence of other common causes. Finally, the patient underwent implantation of a permanent pacemaker to reduce the LVOT obstruction and avoid the risk of AVB recurrence. Conclusions Cholecystitis is a rare cause of complete AVB, which is a difficult differential diagnosis when complicated by HOCM after ASA. Clinicians should be alert to the possibility of cholecystitis in patients with abdominal pain and an unknown cause of bradycardia, complete AVB, or even sinus arrest.