Atrial fibrillation-induced severe left ventricular dysfunction postmitral valve replacement in an adolescent with rheumatic mitral regurgitation

An adolescent boy with a history of chronic rheumatic heart disease (RHD) and severe mitral regurgitation presented with progressive exertional dyspnoea and palpitations. Echocardiography revealed preserved left ventricular function preoperatively, and the patient underwent mechanical mitral valve replacement (MVR). Postoperative management included anticoagulation and RHD prophylaxis. 4 months later, he developed acute heart failure (New York Heart Association class IV) secondary to atrial fibrillation (AF) with rapid ventricular rate despite a normally functioning prosthetic mitral valve. Echocardiography showed significant left atrium and ventricle dilatation, with severe left ventricle dysfunction (left ventricle ejection fraction (LVEF) ~14%), severe tricuspid regurgitation and pulmonary hypertension. The patient was stabilised with rate control, diuretics, inotropes, digoxin, anticoagulation and intravenous amiodarone. Notably, the LVEF improved to 30%, and he was discharged in stable condition. This case highlights the challenges in managing a paediatric patient with AF and severe LV dysfunction following MVR.