Table 1: Causes of tricuspid regurgitation.

Primary tricuspid regurgitation

Secondary tricuspid regurgitation

1. Congenital: Ebstein’s anomaly Dysplasia or hypoplasia of tricuspid valve Double orifice tricuspid valve Tricuspid valve tethering with perimembranous ventricular septal aneurysm or defect Connective tissue disorder (e.g. Ehlers-Danlos syndrome, Marfan syndrome) 2. Acquired: Chest wall trauma Direct valve trauma secondary to right ventricular intramyocardial biopsy, pacemaker/ICD insertion or removal Drug-i nduced: anorectic drugs/ appetite suppressants, pergolide, fenfluramine, and phentermine Carcinoid syndrome: fixation of leaflets in semi-open position due to thickening and retraction of fibrous leaflets and subvalvular apparatus Rheumatic valve disease Infective endocarditis Marantic endocarditis: SLE/RA Tricuspid valve prolapse/ flail associated with myxomatous degeneration (Barlow’s disease)

Left-sided heart disease: valvular (mitral stenosis or regurgitation), left ventricular failure/dysfunction, left-sided ischemic and nonischemic cardiomyopathy Pulmonary arterial hypertension: secondary to chronic pulmonary diseases, pulmonary embolism, left-to-right shunt, cor pulmonale, or isolated idiopathic SPAP >50 mmHg Right-sided heart disease: rightsided ischemic and non-ischemic cardiomyopathy, right ventricular dysfunction, pulmonary valve stenosis or regurgitation Idiopathic: isolated in absence of pulmonary hypertension and ventricular dysfunction; usually associated with hyperthyroidism, atrial fibrillation, diastolic dysfunction, and heart failure with preserved ejection fraction

ICD = implantable cardioverter defibrillator; RA = rheumatoid arthritis; SLE = systemic lupus erythematosus; SPAP = systolic pulmonary artery pressure.