The most common cause of tricuspid regurgitation is secondary to -

Tricuspid regurgitation Primary Rheumatic Endocarditis Myxomatous (TVP) Carcinoid Radiation Congenital (Ebstein's) Trauma Papillary muscle injury (post-MI) Secondary RV and tricuspid annular dilatation Multiple causes of RV enlargement(e.g., long-standing pulmonary HTN)Chronic RV apical pacing ( Harrison&;s principle of internal medicine,18th edition,pg no. 1930 )