First-Degree Heart Block: The Guiding Light to Discovering an Aortic Root Abscess

Minor conduction abnormalities such as first-degree heart blocks are generally overlooked on electrocardiogram (EKG) as their impact on clinical management is usually not substantial. However, they can be an important screening tool for early diagnosis of infective endocarditis (IE) and associated perivalvular complications, especially in patients with surgical valve replacements. This case report describes a 58-year-old male with a past medical history of bicuspid aortic valve status post replacement five years prior to presentation who initially presented with presumed symptoms of a complicated urinary tract infection (UTI) and later developed chest pain and shortness of breath. He showed no initial signs of infection including negative blood and urine cultures. EKG showed new onset prolonged PR interval. He then underwent a transthoracic echocardiogram (TTE) which showed prosthetic valve dysfunction and subsequently underwent transesophageal echocardiogram (TEE) which revealed vegetations on all leaflets and circumferential peri-aortic abscess encompassing both coronary ostia and extending towards the tricuspid and mitral valve leaflets. The patient then underwent redo-sternotomy for dissection of mediastinal adhesions, extraction of the aortic bio-prosthesis, and debridement of the aortic root abscess. The aortic root was replaced with a homograft and the valve cultures were positive for Enterococcus faecium. The patient developed complete heart block afterwards and received a permanent pacemaker; repeat cultures showed no further evidence of infection. This case report is presented to reiterate the importance of early detection of IE-related aortic valve abscess and their rare sequelae. Early screening for conduction abnormalities via EKG and subsequently a TEE can allow prompt identification and management of valvular abnormalities to prevent life-threatening complications and improve patient outcomes.