Progressive Familial Heart Block Type I in a Korean Patient

A 29-year-old man was referred to the emergency department with a complaint of abdominal pain and dizziness. He had experienced two previous syncopal episodes. His family history revealed that his mother and his two uncles had received permanent pacemaker implantation. His initial heart rate was 49 beats per minute. The electrocardiography (ECG) showed atrial flutter and right bundle branch block (RBBB) with left anterior fascicular block (LAFB). On admission, 24-hour Holter showed ventricular pause up to 16 seconds during syncope. Radio frequency catheter ablation (RFCA) of atrial flutter was performed. The ECG revealed bifascicular block (RBBB and LAFB) and first-degree atrioventricular block. He received a permanent pacemaker implantation. His brother's and his sister's ECGs also showed trifascicular block and the pedigree showed autosomal dominant inheritance. This patient was diagnosed with a progressive familial heart block (PFHB) type I. This would be the first report of a PFHB type I case documented in Korea.