The VIRTUE Index: A Novel Echocardiographic Marker Integrating Right–Left Ventricular Hemodynamics in Acute Heart Failure

<b>Background/Objectives:</b> Acute heart failure (AHF) is a heterogeneous syndrome with phenotype-dependent prognosis. NT-proBNP is the reference biomarker, but standard echocardiographic measures (TAPSE, RV-RA gradient, LVOT VTI) offer only partial prognostic insight. The Virtue Index, defined as (RV-RA gradient)/(TAPSE × LVOT VTI), was introduced to integrate right-left ventricular interaction. This study evaluated its clinical and prognostic performance in AHF and its behavior across ejection-fraction phenotypes. <b>Methods:</b> We retrospectively analyzed 222 patients with AHF; complete data for Virtue calculation were available in 168 (99 HFrEF, 69 HFpEF) patients. HFmrEF patients were excluded from subgroup prognostic analyses. Correlation with NT-proBNP was assessed using Spearman testing with bootstrap intervals, and in-hospital mortality prediction was evaluated using ROC analysis with DeLong comparisons. <b>Results:</b> In HFpEF, the Virtue Index correlated moderately with NT-proBNP (ρ = 0.38, <i>p</i> = 0.002) and showed fair prognostic discrimination (AUC 0.704), similar to the RV-RA gradient (0.724) and higher than TAPSE or LVOT VTI. In HFrEF, correlation was weak (ρ = 0.19, <i>p</i> = 0.06) and predictive accuracy was modest (AUC 0.584), while LVOT VTI performed best (AUC 0.700). NT-proBNP outperformed all echocardiographic parameters in both groups. <b>Conclusions:</b> The Virtue Index reflects integrated hemodynamics and shows phenotype-dependent prognostic value in AHF, being more informative in HFpEF than in HFrEF. Although NT-proBNP remained superior, Virtue may complement biomarker-based risk assessment by offering a rapid, bedside estimate of short-term mortality risk.