DOI: https://doi.org/10.36347/sjmcr.2026.v14i03.003

Pages: 332-335

Background: Single ventricle (SV) is a rare congenital heart disease in which a single functional ventricular chamber supports both systemic and pulmonary circulations. Arrhythmias are frequent late complications and significantly impact prognosis. Case Presentation: We report a 29-year-old patient with SV physiology admitted for palpitations secondary to atrial flutter with variable conduction. Transthoracic echocardiography revealed a single right ventricle with double inlet, moderate-to-severe atrioventricular valve regurgitation, and pulmonary arterial hypertension. Clinical evolution was favorable under medical therapy, including beta-blockers, digoxin, anticoagulation, and diuretics. Conclusion: This case highlights the complexity of long-term follow-up in adults with SV physiology and emphasizes the importance of early recognition and management of arrhythmias to improve outcomes.