The TV is the most apical cardiac valve, positioned between the RA and the RV, with the largest orifice among the atrioventricular valves (typically 7–9 cm² in healthy adults, according to echocardiographic assessment). Its septal insertion is usually ≤10 mm more apical than the mitral valve plane, a classic echocardiographic finding that aids in anatomical characterization. The leaflets are asymmetrical and show numerical variability, with approximately 54% of cases presenting three cusps and 46% subdivided into the other types (two, four and five cusps). They are identified as anterior (or anterosuperior), septal, and posterior (or inferior/mural):

Coaptation occurs at the annular plane or slightly below it (with a coaptation height of 5–10 mm), functioning as a reserve mechanism in moderate annular dilation, as emphasized in tricuspid regurgitation assessment guidelines. Three-dimensional echocardiography is recommended to map these dynamics and identify pathological changes – such as tethering or dilation – that impair valvular competence.²

The tricuspid annulus has a non-planar geometry, with an oval saddle-shaped configuration (similar to the letter "D"), and dynamic dimensions that respond to preload and the cardiac cycle: approximately 10–15% shortening in diameters and 15–25% reduction in area during systole in healthy individuals. This annular contractility, which can be assessed by echocardiography, may be characterized in greater detail using three-dimensional (3D) techniques when available, contributing to the understanding of leaflet coaptation and the forces exerted on the subvalvular apparatus. Pathological measurements include a diastolic diameter ≥ 40 mm or ≥ 21 mm/m², preferably obtained in the apical four-chamber (4C) view, with body-surface-area indexing for prognostic purposes and intervention planning.

The subvalvular apparatus consists of chordae tendineae that are less distensible than those of the mitral valve, arranged in a fan-shaped distribution, and three papillary muscle groups: anterior and posterior (well defined and anchored to the RV free wall) and septal. These structures anchor the cusps, preventing prolapse or eversion during systole, and are particularly sensitive to RV dilation, which may lead to tethering and functional regurgitation.

Tricuspid regurgitation (TR) is a relatively common echocardiographic finding in the general population, with higher prevalence in women and in older patients. Mild TR is, in most cases, a benign condition that does not require further investigation. Significant TR is defined when regurgitation is ≥ moderate in severity and has an age- and sex-adjusted estimated prevalence of 0.55%, with a gradual increase associated with aging (4% in individuals ≥ 75 years).² Similar to mitral regurgitation, this condition should be interpreted along a continuous spectrum of severity, in which greater regurgitation correlates with higher risk of death and cardiovascular complications, independent of comorbidities, ventricular function, and pulmonary pressures.

Only 8-10% of patients with TR present clear anatomical abnormalities of the tricuspid valve complex (primary TR). These may result from various conditions such as infectious endocarditis, rheumatic disease, carcinoid syndrome, congenital anomalies (Ebstein anomaly), thoracic radiation, myxomatous disease, as well as trauma or iatrogenic valvular injury (e.g., endomyocardial biopsy). TR related to cardiac implantable electronic devices (CIEDs) represents a distinct entity requiring specific diagnostic and management approaches. In patients with CIEDs, diagnostic efforts should aim to determine whether the lead is the cause of TR (CIED-related TR) or merely incidental (CIED-associated TR).

In patients with secondary TR, the tricuspid valve leaflets are structurally normal, and regurgitation is caused by annular dilation and/or leaflet tethering due to right atrial (RA) dilation and/or right ventricular (RV) dilation and dysfunction. Based on key morphological and hemodynamic characteristics, two phenotypes of secondary TR have been proposed:

In advanced stages of the disease, these two phenotypes may no longer be distinguishable; therefore, early characterization is essential for determining prognosis. Currently, there is no evidence of a direct impact on patient management; thus, current recommendations for intervention primarily consider primary versus secondary TR.

A comprehensive transthoracic echocardiographic examination of the tricuspid valve requires a methodical approach to correctly identify the associated pathology. In two-dimensional echocardiography, it is not possible to visualize all three leaflets simultaneously, and there is considerable variability regarding which leaflets appear in each acquired image.

In the parasternal RV inflow view, the anterior leaflet always appears in the proximal field. In the distal field, the leaflet may be either the septal or the posterior one, depending on the transducer angulation.

In the short-axis view, the leaflet adjacent to the aortic valve generally corresponds to either the septal or the anterior leaflet, whereas the leaflet adjacent to the RV free wall is usually the posterior leaflet.

In the apical four-chamber view, the septal leaflet is positioned along the ventricular septum. The leaflet related to the free wall may be either the anterior or the posterior one, depending on the transducer angulation: when the aorta is visualized, it is the anterior leaflet; when the coronary sinus is seen, it is the posterior leaflet.

Figure 1 illustrates the main echocardiographic windows used in the two-dimensional assessment of the tricuspid valve, with identification of the corresponding leaflets visualized.

Compared with transthoracic echocardiography (TTE), transesophageal echocardiography is generally more limited in obtaining ideal windows for severity quantification due to the acquisition of off-axis imaging planes and the greater distance between the probe and the tricuspid valve.

Three-dimensional echocardiography provides unique views of the TV, allowing simultaneous visualization of all three or more leaflets and the entire annulus. Adding color Doppler to a full-volume acquisition not only makes it possible to analyze the mechanism and locate the TR jet, but also to quantify the size of the effective regurgitant orifice (ERO).⁴

The RV is usually dilated in the presence of hemodynamically significant TR. Septal position produces a D-shaped LV, more evident in diastole (a pattern of RV volume overload). When TR is related to pulmonary hypertension, there is septal flattening throughout the entire cardiac cycle, reflecting both diastolic and systolic RV overload (a pattern of RV pressure overload).

Parameters of RV systolic function are important for monitoring the effects of chronic primary TR and detecting deterioration of RV cardiac function. Assessing RV systolic function is challenging in this context because these parameters are load-dependent. A tricuspid annular plane systolic excursion (TAPSE) <1.7 cm and a right ventricular fractional area change (FAC) <35% are suggestive of RV dysfunction, although tricuspid annular excursion in particular may yield false-positive and false-negative results. In the presence of a valve with normal anatomy, abnormal RV function is more likely to be the cause rather than the consequence of TR. Significant chronic TR also leads to enlargement of the right atrium and the inferior vena cava. Finally, right atrial enlargement in patients with permanent atrial fibrillation and concomitant tricuspid annular dilation (>35 mm) may result in secondary tricuspid regurgitation of atrial etiology.³

The ideal approach to evaluating TR severity is to integrate multiple parameters of tricuspid regurgitation, avoiding reliance on a single measurement. It is also important to distinguish between the regurgitant volume and its hemodynamic consequences, particularly when considering acute versus chronic regurgitation.

If qualitative or semiquantitative parameters fall within the intermediate range between mild and severe, the TR severity is more likely to be moderate. Accurate quantification of TR severity is more challenging than in aortic or mitral valve disease. In cases where TTE provides limited assessment of regurgitation, when there is significant internal inconsistency, or when findings are discordant with the clinical presentation, additional evaluation using other imaging modalities may be necessary to more precisely assess the mechanism and severity of TR.⁴

Although the more recent classification proposed by Hahn et al.¹ in 2017 includes the categories of massive and torrential TR, this article will maintain the classification proposed by the American Society of Echocardiography (ASE) in its latest guideline, which divides severity into mild, moderate, and severe, in order to facilitate identification and reporting in outpatient echocardiography studies. Table 1 describes the main parameters used to grade the severity of TR.

The 2025 ESC/EACTS guideline consolidates the understanding that TR should be approached with the same rigor applied to left-sided valvular disease. This repositioning has direct implications for clinical practice by reinforcing the central role of echocardiography in early disease detection, functional stratification of the right ventricle, and determination of the appropriate timing for intervention.

From an echocardiographic standpoint, assessment remains grounded in systematic two-dimensional analysis and conventional Doppler parameters, which are widely available and essential for the initial characterization of tricuspid regurgitation severity, mechanism, and hemodynamic impact. In this context, integration with additional anatomical and functional measurements allows for progressive refinement of diagnostic reasoning. Three-dimensional (3D) echocardiography, when available, serves as a complementary tool, contributing to a more detailed characterization of tricuspid annular geometry, coaptation patterns, and leaflet tethering.

Functional parameters of the right ventricle – such as TAPSE, tricuspid annular systolic velocity, three-dimensional right ventricular ejection fraction (3D RVEF), and global longitudinal strain – should be interpreted in an integrated manner, considering load-dependent limitations and the clinical context. This combined approach supports a more robust evaluation, particularly in scenarios where therapeutic decision-making requires greater anatomical or functional precision, as illustrated in the central figure of the article.

In clinical practice, this conceptual evolution translates into three main developments.

First, earlier detection of structural and functional abnormalities, in which identification of significant annular dilation or early right ventricular dysfunction justifies more frequent reassessment and timely referral for Heart Team discussion.

Second, a clearer definition of the optimal timing for intervention, particularly in patients with significant tricuspid regurgitation associated with left-sided valve disease, favoring concomitant treatment and reducing progression to advanced stages of right ventricular remodeling. Third, the gradual incorporation of transcatheter therapies, considered in selected scenarios – especially in patients with high surgical risk or with favorable anatomy better characterized by advanced imaging modalities.

In the daily routine of the echocardiography laboratory, this approach implies valuing a well-executed and standardized two-dimensional evaluation, using three-dimensional echocardiography as a complementary tool whenever pertinent, and monitoring right ventricular function parameters with the same regularity applied to left-sided valvular diseases. This set of principles supports a more consistent, accessible practice aligned with contemporary recommendations, enabling individualized decisions grounded in multidisciplinary teams.

Advances in tricuspid valve assessment are expected to focus on the integration of emerging technologies that enhance diagnostic precision and the ability to dynamically characterize cardiac remodeling. The incorporation of artificial intelligence algorithms into echocardiography and tomography routines should enable automatic anatomical segmentation, more stable measurements of the tricuspid annulus, and refined three-dimensional analysis of coaptation, favoring interpretations that are less examiner-dependent and more comparable across institutions.

In the therapeutic context, continuous development of devices for transcatheter repair or replacement of the tricuspid valve is observed, with greater suitability for the anatomical spectrum of primary and secondary regurgitation. As these devices achieve technological maturity and wider availability in specialized centers, decision-making is expected to incorporate more objective metrics of right ventricular function, extent of tethering, and annular geometry, expanding the ability to select interventions with greater physiological precision.

The progressive understanding of tricuspid regurgitation phenotypes, particularly the atrial phenotype, enables more informative categorizations of the hemodynamic behavior of the valvopathy and of the mechanisms of structural progression. This differentiation tends to improve management strategies that consider not only the severity of regurgitation but also the trajectory of right atrial and ventricular remodeling.

Finally, the field is moving toward models that integrate clinical data, biomarkers, two-dimensional and three-dimensional echocardiographic parameters, and machine learning–derived variables, with the potential to generate predictive platforms capable of estimating disease progression and functional impact in the medium and long term. These approaches favor a more anticipatory view of the pathophysiological process, with therapeutic choices based on quantitative projections and individualized risk stratification.