Right Ventricular Systolic Function

Right Ventricular (Systolic) Function (draft)

1. Subjective Assessment

View: A4C (right ventricle-focused view)

Phase: whole period of systole

In normal functionally RV, you would expect:

Longitudinal motion of base-to-apex contraction
The tricuspid annulus moving towards the apex
Thickening of the RV free wall
Reduction of overall RV area during the systolic phase

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If you remain uncertain, you may refer to the more objective methods outlined below.

2. Tricuspid Annular Plane Systolic Excursion (TAPSE)

View: A4C (right ventricle-focused view) + M mode

Phase: whole period of systole

TAPSE measure the distance of systolic excursion of tricuspid annular along its longitudinal plane. It is inferred that a decline in RV systolic function is associated with a reduction in distance.

Measurement can be done by placing the M-mode cursor through the TA.

Normal value: > 16 mm

IMAGE 1

Although the method is straightforward and reproducible, it also assumes that displacement in a single segment reflects the overall function of the right ventricle, which is not always accurate.

3. Fractional Area Change (FAC)

View: A4C (right ventricle-focused view)

Phase: end diastole (largest RV cavity) and end systole (smallest RV cavity)

FAC = [(RVEDA – RVESA) / RVEDA] x 100%

RVEDA: RV end-diastolic area

RVESA: RV end-systolic area

RVEDA and RVESA values can be obtained by tracing the RV endocardial border (tricuspid annulus – RV free wall – apex – IV septum – tricuspid annulus) in both end diastole and end systole phase.

IMAGE 2

FAC assesses the difference in right ventricular area between the systolic and diastolic phases, specifically measuring the reduction that occurs during systole. As the RV function gets more sluggish, the percentage reduced. While the concept is somewhat similar to LVEF, it’s important to note that LVEF measures volume (3D) instead of area (2D).

Normal value: > 35%

Measures of RV systolic function, such as fractional area change (FAC), can independently predict mortality, stroke or the development of heart failure in patients post MI and PE.

4. Extras

4.1 Tricuspid Annular Peak Systolic Velocity (TAPSV or S')

View: A4C (right ventricle-focused view) + Tissue Doppler mode

Phase: whole period of systole

This is similar to TAPSE, but instead of measuring the TA displacement (distance), S’ (pronounced S-prime) measures the speed (velocity). By using the tissue Doppler mode, the machine is picking up tissue movement (instead of blood flow).

Utilizing the tissue Doppler mode, you will able to generate a graph similar to that depicted in Image 4.

Image 5: measurement of S’ using TDI (tissue Doppler imaging)

Anything above the baseline represents tissue moving towards the probe (aka ventricular contraction aka systolic phase), and vice versa. E’ represents a relaxed ventricle in diastole. A’ represents movement of RV away from the probe due to atrial contraction. S’ represents the peak velocity of RV contraction during systolic phase.

Normal value: > 10 cm/s

As RV function declines, there is a corresponding decrease in velocity.

4.2 RV Index of Myocardial Performance (RIMP)

Some books / articles called this as RV myocardial performance index (RMPI). This is all the same things.

It utilises the same graph as above but looking at another parameter (see image X).

Image X: measurement of RIMP using similar method from Image 5

ICT represents the isovolumetric contraction time, the period between closing of tricuspid valve and opening of pulmonary valve. IRT represents the isovolumetric relaxation time, the period between closing of pulmonary valve and opening of tricuspid valve.

As the name suggested, there is no changes in the volume of the ventricle. This interval refers to the period during which the ventricle spends energy without generating forward blood flow (wasted effort).

ET or ejection time represents the time of effective forward ejection. And TCO refers to the tricuspid valve closure to opening time.

RIMP is looking at the time spent in isovolumetric phase relative to the time spent in effective forward ejection.

RIMP = (ICT + IRT) / ET or to simplify the calculation:

RIMP = (TCO – ET) / ET

Normal value: < 0.54

As RV function becomes globally impaired, the RV remains in the isovolumetric phase for a longer duration, resulting in reduced ET and consequently an increased RIMP ratio.

This method can also be applied to mitral annulus to estimate the LV function (Tei Index).

References:

McLean A, Huang S. Critical Care Ultrasound Manual. Sydney, Australia: Churchill Livingstone; 2012
McLean A et al. Oxford Textbook of Advanced Critical Care Echocardiography. UK: Oxford University Press; 2020
Rudski LG, Lai WW, Afilalo J, Hua L, Handschumacher MD, Chandrasekaran K, et al. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography. J Am Soc Echocardiogr. 2010 Jul;23(7):685-713. Available from: www.onlinejase.com
Lang RM, Badano LP, Mor-Avi V, Afilalo J, Armstrong A, Ernande L, et al. Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2015 Jan;28(1):1-39.e14. Available from: www.asecho.org
Schneider M, Aschauer S, Mascherbauer J, Adelbrecht C, Beitzke D, Binder C, et al. Echocardiographic assessment of right ventricular function: current clinical practice. Int J Cardiovasc Imaging. 2019;35(1):49-56. Available from: www.ncbi.nlm.nih.gov
Pavlicek M, Wahl A, Rutz T, de Marchi SF, Hille R, Wustmann K, et al. Right ventricular systolic function assessment: rank of echocardiographic methods vs. cardiac magnetic resonance imaging. Eur J Echocardiogr. 2011 Nov;12(11):871-80. Available from: academic.oup.com
Zornoff LA, Skali H, Pfeffer MA, St John Sutton M, Rouleau JL, Lamas GA, et al. Right ventricular dysfunction and outcomes in myocardial infarction: the SAVE experience. J Am Coll Cardiol. 2002;39(9):1450-5. Available from: www.jacc.org