MRSA endocarditis with coronary sinus abscess causing transient complete atrioventricular block: A rare case

Infective endocarditis complicated by a coronary sinus abscess is extremely rare and can lead to conduction issues. We report a 63-year-old hemodialysis patient with Methicillin-resistant Staphylococcus aureus infective endocarditis who developed complete atrioventricular block. Transesophageal echocardiography and cardiac computed tomography showed vegetations on the posterior mitral annulus, severe mitral regurgitation, and a coronary sinus abscess. Atrioventricular conduction recovered spontaneously, probably due to abscess drainage into the left atrium. Despite surgery, the patient died from cardiogenic shock. This case highlights the diagnostic and therapeutic challenges of periannular complications.