Presumed right atrial myxoma causing mechanical inflow obstruction and a heart-failure-with-preserved-ejection-fraction-mimicking phenotype in a resource-limited setting: A case report.

Right atrial masses are rare and may present with features of right-sided heart failure that can be clinically mistaken for heart failure with preserved ejection fraction (HFpEF) despite preserved left ventricular systolic function. We report a 55-year-old man with a background of hypothyroidism who presented with a one-month history of progressive dyspnea and systemic congestion (NYHA class III). Transthoracic echocardiography demonstrated a large (approximately 5.0 × 3.0 cm), heterogeneous, pedunculated, and highly mobile right atrial mass located near the inferior vena cava, causing mechanical tricuspid inflow obstruction with a ball-valve effect and reduced right ventricular systolic performance (TAPSE 1.1 cm). Left ventricular systolic function and wall thickness were preserved and normal, respectively. In this resource-limited setting, advanced cross-sectional imaging, natriuretic peptide testing, and advanced cardiac histopathological confirmation were not available; the diagnosis of presumed right atrial myxoma was therefore based on echocardiographic morphology and clinical assessment. The patient improved partially with conservative management (diuretics, oxygen); surgical referral was recommended but was not feasible locally or abroad. This case highlights the importance of considering structural, right-heart mimics when a patient with apparent HFpEF has predominant right-sided congestion, and underscores the diagnostic value of echocardiography, including subcostal imaging, in low-resource environments.