Carcinoid Heart Disease Revealing the Burden of a Neuroendocrine Tumour: A Case Report.

Carcinoid heart disease (CHD) is a rare but serious complication of carcinoid syndrome (CS), typically arising in patients with metastatic neuroendocrine tumours (NETs). Prolonged exposure of the right side of the heart to vasoactive substances such as serotonin leads to progressive valvular fibrosis, predominantly affecting the tricuspid and pulmonary valves, and often culminates in right-sided heart failure. We report the case of a 67-year-old woman with a metastatic small bowel NET who developed CS and later presented with worsening exertional dyspnoea and peripheral oedema. Echocardiography demonstrated severe tricuspid regurgitation and moderate pulmonary regurgitation with preserved left ventricular systolic function. Despite aggressive diuretic therapy, her condition deteriorated, and she developed refractory right-sided heart failure with generalised anasarca. She was not a candidate for valve replacement or further disease-directed therapy due to advanced metastatic disease and frailty and was therefore managed palliatively until she passed away. This case highlights the severe burden of CHD in patients with serotonin-secreting NETs and emphasises the importance of early recognition and regular echocardiographic surveillance to facilitate timely intervention and potentially improve outcomes.