Carcinoid Heart Disease: The Role of Echocardiography in Raising the First Suspicion

Neuroendocrine tumors (NETs) are rare neoplasms arising from the diffuse neuroendocrine system that can range from indolent to highly aggressive diseases. They usually clinically manifest when reaching a significant size or when hepatic metastases develop, leading to overproduction and impaired hepatic metabolism of vasoactive substances. The clinical course of NETs may be complicated by cardiac involvement, known as carcinoid heart disease (CHD), predominantly affecting the right side of the heart. CHD is characterized by specific echocardiographic features, including thickening, reduced excursion and retraction of valvular leaflets, resulting in valvular stenosis or regurgitation. Despite its clinical relevance, awareness of CHD as a complex hormonal sequela of NETs remains limited among cardiologists, and its echocardiographic findings are not universally recognized. This review aims to (a) provide cardiologists with the main principles for understanding CHD pathophysiology; (b) illustrate the main echocardiographic features of CHD, using a stepwise approach; and (c) refine a diagnostic algorithm for detecting cardiac involvement in NET populations and identifying patients at high risk of developing CHD.