Introduction: In patients with heart failure with reduced ejection fraction (HFrEF), right ventricular (RV) size and dysfunction measured by 2-dimensional echocardiography (2DE) were identified as risk factors for increased mortality and morbidity. However, parameters measured by 2DE are prone to errors due to increased variability and geometric assumptions about the complex RV shape. Conversely, 3-dimensional echocardiography (3DE) enabled itself as a more accurate and reproducible method for cardiac volume assessment, closer to measures provided by cardiac magnetic resonance.

Objective: To assess the comparative prognostic value of parameters of RV size and dysfunction measured by 2DE and 3DE, in patients with ischemic and non-ischemic HFrEF, on best clinical care, at long-term follow-up.

Methods: 142 consecutive patients (62 ± 12 years, 104 males), diagnosed with HFrEF, in sinus rhythm, were assessed by 2DE and 3DE, including full-volume multibeat acquisitions of the RV. RV diameter (RVd), RV end-systolic (RV_EDA) and end-diastolic areas (RV_ ESA), RV fractional area change (RV_FAC) and TAPSE were measured from the 2DE datasets, in a dedicated apical four-chamber view. RV end-diastolic (RV_EDV) and end-systolic volumes (RV_ESV), RV ejection fraction (RV_EF) and TAPSE_3D (mean of the entire tricuspid plane excursion), were measured with dedicated 3D software-package. Patients were followed for 37±16 months after the index event. Primary outcome was cardiac death; secondary outcomes were: 1) HF hospitalization (HFH); 2) a composite cardiac events (CE) end-point of cardiac death or hospitalization for heart failure, myocardial infarction, coronary revascularization, arrhythmias, or cardiac resynchronization therapy.

Results: 38 CD, 47 HFH, and 62 CE occurred during follow-up. 2DE and 3DE measurements are in the table. Mean RVd was 34 ± 7 mm, mean RV_EDA was 20 ± 11 cm2, RV_ESA was 12 ± 5.4 cm2, and RV_FAC was 37 ± 13%. Mean RV_EDV was 84 ± 25 ml/m2, mean RV_ESV was 52 ± 22 ml/m2, and RV_EF was 39 10%. Mean TAPSE_2D was 18 ± 4 mm, and mean TAPSE_3D was 16 ± 4 mm. By 2DE, only the RV_ESA and RV_FAC, and not the RV_EDA, correlated with death, HFH, and CE. TAPSE by 2DE correlated with HFH, but not with death or CE. By 3DE, the RV_ESV, and not RV_EDV correlated with death, HFH, and CE. Moreover, RV_EF measured by 3DE had better correlations with death, HFH, and CE than the RV_FAC esti-mated by 2DE (z= 3.8, z= 2.54, and z= 2.45, all p< 0.01). By multivariate linear regression analysis that included RV_ESA,RV_FAC,RV_ESVandRV_EF,andTAPSE_3D, only the RV_EF was an independent predictor for death and HFH (r²= 0.68 and r²= 0.3, both p< 0.001).

Conclusion: In patients with ischemic and non-ischemic HFrEF, 3DE parameters of RV size and dysfunction are better predictors for death and rehospitalization than 2DE parameters. The RV_ EF measured by 3DE was the best predictor for cardiac death in patients with decompensated HFrEF.