Grading Right Ventricular Dysfunction on 2D Echocardiography
Right ventricular dysfunction should be graded using a comprehensive multiparametric approach that includes RV fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), and tissue Doppler-derived tricuspid annular systolic velocity (S') as the primary parameters for assessment. 1, 2
Primary Parameters for RV Function Assessment
1. RV Fractional Area Change (FAC)
- Obtain RV-focused apical four-chamber view
- Trace RV endocardial border at end-diastole and end-systole
- Calculate: FAC (%) = [(RVEDA - RVESA)/RVEDA] × 100
- Normal value: 49 ± 7%
- Abnormal: <35%
- Has established prognostic value and correlates well with RV ejection fraction by CMR 1, 2, 3
2. Tricuspid Annular Plane Systolic Excursion (TAPSE)
- Measure M-mode displacement of tricuspid annulus in systole
- Normal value: >17 mm
- Abnormal: <17 mm
- Easy to perform with high reproducibility but less suitable for serial assessment 1, 2
3. Tissue Doppler S' Velocity
- Measure peak systolic velocity at tricuspid annulus
- Normal value: >9.5 cm/sec (pulsed Doppler)
- Abnormal: <9.5 cm/sec
- Reflects longitudinal RV function 2
Secondary Parameters
4. Myocardial Performance Index (MPI/Tei Index)
- Calculate using: MPI = (TCO - ET)/ET (pulsed Doppler) or MPI = (IVCT + IVRT)/ET (tissue Doppler)
- Normal value: 0.26 ± 0.085 (pulsed Doppler); 0.38 ± 0.08 (tissue Doppler)
- Abnormal: >0.43 (pulsed Doppler); >0.54 (tissue Doppler)
- Advantage: Less affected by heart rate
- Limitation: Unreliable when RA pressure is elevated 2
5. RV Free Wall Longitudinal Strain
- Measure peak systolic strain of RV free wall segments
- Normal value: >-20%
- Abnormal: >-20% (less negative)
- Shows highest specificity (92%) for detecting RV dysfunction compared to 3D-derived RVEF 4
- Can detect RV dysfunction when other parameters are normal 1
RV Size Assessment (Required for Complete Evaluation)
- Measure in RV-focused apical four-chamber view:
- RV basal diameter: normal 25-41 mm
- RV mid diameter: normal 19-35 mm
- RV longitudinal diameter: normal 59-83 mm 1
Grading Algorithm
Normal RV function:
- FAC ≥35%
- TAPSE ≥17 mm
- S' ≥9.5 cm/sec
- Normal RV size
Mild RV dysfunction:
- One abnormal parameter (FAC, TAPSE, or S')
- Normal or mildly increased RV size
Moderate RV dysfunction:
- Two abnormal parameters
- Moderate RV enlargement
Severe RV dysfunction:
- All three primary parameters abnormal
- Severe RV enlargement
- Additional findings: moderate/severe tricuspid regurgitation, increased RA pressure 5
Clinical Pearls and Pitfalls
- When all three parameters (FAC, TAPSE, S') are abnormal, sensitivity for detecting significant RV dysfunction is 91% with negative predictive value of 96% 6
- TAPSE and S' may be misleading in patients with severe tricuspid regurgitation 1
- FAC correlates best with MRI-derived RVEF (r = 0.80) compared to other 2D measures 3
- Subjective visual assessment alone is insufficient and should be avoided 7
- RV free wall strain shows the closest association with 3D-derived RVEF cutoffs 4
- 3D echocardiography for RV volume and EF assessment should be considered when available and expertise exists, but is not required for routine grading 1
By systematically applying these parameters, clinicians can effectively grade RV dysfunction, which has significant implications for patient morbidity and mortality across various cardiovascular conditions.