List seven causes of tricuspid regurgitation.

1. Rheumatic fever
2. Tricuspid valve prolapse (may be associated with mitral valve prolapse)
3. Endocarditis (especially in intravenous drug users)
4. Blunt trauma
5. Carcinoid (paraneoplastic syndrome)
6. Annular dilation (caused by dilation of the right ventricle)
7. Pulmonary hypertension