Right Ventricular Function Assessment by Echocardiography: A Multiparametric Approach

Assessing right ventricular (RV) function via echocardiography is uniquely challenging due to the chamber’s complex, crescentic geometry and its position immediately behind the sternum. Because no single two-dimensional geometric model accurately encompasses the entire RV, current guidelines from the American Society of Echocardiography (ASE) mandate a multiparametric approach.

Core Systolic Function Parameters

A comprehensive evaluation requires integrating both longitudinal and global functional metrics.

Parameter	Modality	Normal Cutoff	Reflects
TAPSE	M-Mode	≥ 17 mm	Longitudinal function
S’ Wave	Tissue Doppler	≥ 9.5 cm/s	Longitudinal function
RV FAC	2D Area	≥ 35%	Global systolic function
RIMP (TDI)	Tissue Doppler	< 0.54	Global performance
Free Wall Strain	Speckle Tracking	≤ -20%	Myocardial deformation
3D RVEF	3D Echo	≥ 45%	Global ejection fraction

1. Longitudinal Function (TAPSE & S’ Wave)

Because the superficial myocardial fibers in the RV are arranged longitudinally, base-to-apex shortening accounts for the vast majority of normal RV stroke volume.

• TAPSE (Tricuspid Annular Plane Systolic Excursion): Measured using M-mode aligned through the lateral tricuspid annulus in an RV-focused apical 4-chamber view. It records the total distance of systolic excursion.
• S’ Wave Velocity: Measured using Tissue Doppler Imaging (TDI) at the exact same location. It records the peak systolic velocity of the annulus moving toward the apex.
• Clinical Pitfall: Both parameters are heavily angle-dependent and only reflect regional longitudinal motion. They can overestimate global function in the presence of severe tricuspid regurgitation (volume overload) and underestimate global function in post-cardiotomy patients (where pericardial adhesions tether longitudinal motion despite preserved overall ejection).

2. Fractional Area Change (FAC)

FAC provides a 2D estimate of global RV systolic function. It is calculated by tracing the RV endocardium in both diastole and systole within the RV-focused apical 4-chamber view:

FAC = [(RVEDA – RVESA)/RVEDA] x 100

Care must be taken to exclude trabeculations from the cavity area when tracing. Including the trabeculae artificially reduces the end-diastolic area, which falsely underestimates the FAC.

3. Right Ventricular Index of Myocardial Performance (RIMP)

Also known as the Tei Index, RIMP is a measurement of global RV function that incorporates both systolic and diastolic time intervals. It is calculated as the ratio of isovolumic times to ejection time:

RIMP = (IVCT + IVRT)/ET

A higher RIMP value indicates deteriorating ventricular performance (more time spent in inefficient isovolumic phases relative to active ejection). While independent of heart rate, it is highly load-dependent and cannot be reliably used in patients with atrial fibrillation or other irregular rhythms.

4. RV Strain

Speckle-tracking echocardiography evaluates active myocardial deformation. Right ventricular free-wall longitudinal strain (RV FWS) is the preferred measurement, as it isolates the mechanics of the RV free wall and excludes the interventricular septum, which is heavily influenced by left ventricular contractility. Normal myocardial shortening is typically greater than 20% (reported as more negative than -20%).

Key insight: Recent clinical focus has shifted from isolated RV function toward RV-PA coupling—the relationship between RV contractility and the pulmonary afterload it faces. The simplest non-invasive surrogate for this is the TAPSE/ PASP ratio. A ratio < 0.36 mm/mmHg indicates RV-arterial uncoupling and acts as a powerful prognostic marker in heart failure and pulmonary hypertension.