Right Ventricular Fractional Area Change in Echocardiography
RV fractional area change (RV-FAC) is calculated as: [(RV end-diastolic area - RV end-systolic area) / RV end-diastolic area] × 100, and normal values are >35%, with values <35% indicating RV systolic dysfunction. 1
Definition and Calculation
RV-FAC represents the proportion of RV area change during right ventricular systole. The measurement requires:
- Optimal imaging view: RV-focused apical four-chamber view 2
- Measurement technique: Planimetry of RV end-diastolic area (RVEDA) and RV end-systolic area (RVESA) 1
- Important technical point: Include trabeculae within the RV cavity when tracing, and ensure the entire right ventricle (apex and free wall) is contained in the imaging sector during both systole and diastole 2
Normal Values and Thresholds
The key cutoff values are:
Context-Specific Thresholds
For arrhythmogenic cardiomyopathy diagnosis, different criteria apply 3:
- Major criterion: RV-FAC ≤33% (with regional wall motion abnormalities)
- Minor criterion: RV-FAC >33% to ≤40% (with regional wall motion abnormalities)
For advanced heart failure, RV-FAC <27% was independently associated with death or need for heart transplantation 4, and RV-FAC <35% indicates dysfunction 4.
Clinical Utility and Prognostic Value
RV-FAC provides important prognostic information across multiple conditions:
- In heart failure with reduced ejection fraction (HFrEF): RV-FAC <35% was present in 33% of patients and associated with increased mortality 5
- In heart failure with preserved ejection fraction (HFpEF): RV-FAC <35% occurred in 28-33% of patients and predicted worse outcomes 5
- Prognostic accuracy: RV-FAC is more accurate than tricuspid annular S' velocity in predicting cardiac death, though TAPSE shows similar accuracy 6
- Combined assessment: Using both RV-FAC and TAPSE together provides incremental prognostic value beyond either parameter alone 6
Technical Considerations and Limitations
Measurement Reliability
- Reproducibility: RV-FAC demonstrates acceptable reproducibility with intraclass correlation coefficients ranging from 0.69-0.97 depending on the study population 7, 8
- Feasibility: Successfully obtained in approximately 99% of patients 7
Important Caveats
RV-FAC has significant limitations for serial assessment:
- While correlated with cardiac MRI-derived RV ejection fraction (r² = 0.567), RV-FAC showed poor sensitivity (33-56%) for detecting deterioration in RV function during follow-up in pulmonary hypertension patients 9
- Load dependency: RV-FAC is sensitive to both preload and afterload, making interpretation challenging when RV function is borderline 4
- Post-surgical changes: After cardiac surgery, RV-FAC may decrease less than longitudinal parameters like TAPSE, indicating non-uniform changes in RV function measures 10
Optimal Assessment Strategy
For comprehensive RV evaluation, combine RV-FAC with:
- Qualitative visual assessment of RV function 11
- TAPSE (tricuspid annular plane systolic excursion) 6
- RV free wall longitudinal strain when available 3
The combination of FAC <35% plus qualitative RV dysfunction assessment correlates best with severe RV dysfunction on cardiac MRI 11, making this integrated approach superior to relying on any single parameter.