<prompt> Carcinoid of heart involves?Valvular endocardium of right atriumValvular endocardium of left atriumMural endocardiumMyocardium  <response>: Ans. a Valvular endocardium of right atriumRef: Robbins 9thpg 562; Heart 2004; 90:1224-1228 doi: 10.1136hrt.2004.040329Carcinoid heart disease Q typically causes abnormalities of the right side of the heart. QPreferential right heart involvement Q is most likely related to inactivation of the vasoactive substances by the lungs QThe two key investigations for the diagnosis of carcinoid heart disease are 24 hour urinary excretion of 5-hydroxyindole acetic acid 5-HIAA and transthoracic echocardiography. 