Table 1.

Pathophysiological classification of tricuspid regurgitation (23).

	Leaflet morphology	Pathophysiology	Etiology	Imaging
Primary	Abnormal	Loss of leaflet coaptation due to intrinsic changes, excessive mobility, or perforation	Myxomatous disease Endocarditis Trauma Carcinoid Rheumatic Iatrogenic (biopsy) Congenital	According to the etiology Description of the etiology, lesions and dysfunction
Secondary: Atrial	Normal	RA enlargement and dysfunction leading to TA dilation, conical remodeling of the RV	Atrial fibrillation	Severe RA remodeling RV basal diameter may be enlarged despite usually normal RV volume Leaflet tethering is absent or limited
Secondary: Ventricular	Considered normal	RV enlargement and/or dysfunction leading to significant leaflet tethering and TA dilation	Pulmonary hypertension RV cardiomyopathy RV infarction	Dominant mechanism is leaflet tethering ± TA dilation
CIED-related: Primary	Abnormal	Leaflet impingement Leaflet/chordal entanglement Leaflet adherence Leaflet laceration/perforation Leaflet avulsion (post lead extraction)	Pacemaker Implantable cardiac defibrillator Cardiac resynchronization therapy	3D echocardiograhy (±color) is mandatory for reliable diagnosis
CIED-related: Secondary	Normal	RV enlargement and/or dyssynchrony/dysfunction due to pace-maker stimulation and leading to significant leaflet tethering and TA dilation	Pacemaker rhythm	Dominant mechanism is leaflet tethering ± TA dilation

RA, right atrial; TA, tricuspid annulus; RV, right ventricle; CIED, cardiac implantable electronic device; 3D, Three dimensional.