Clinical Value of NT-proBNP and Performance Myocardial Index as an Echocardiographic Predictor of Early Cardiac Involvement in Patients with Carcinoid Syndrome. acbr. 2022;6(5):732-739. Accessed September 20, 2026. https://www.fortunejournals.org/ojs/index.php/acbr/article/view/14951