Left ventricular (LV) dilation in chronic significant aortic regurgitation (AR) is commonly assessed using LV diameters and volumes, but these metrics are influenced by body surface area, sex, and age. We hypothesized that the left-to-right ventricular end-diastolic volume ratio (LV/RV ratio), which remains close to 1 in healthy individuals, could provide a more individualized assessment of adverse LV remodeling in AR patients.

We investigated the relationship between the LV/RV ratio, conventional LV metrics, and AR severity.

This bi-center study included 258 patients (median age: 55 years, 18% female) with at least chronic moderate AR, assessed using echocardiography (Echo) and cardiac magnetic resonance imaging (CMR). LV and RV volumes were measured from short-axis steady-state free precession cine-CMR images. The relationships between the LV/RV ratio, conventional LV metrics, and AR severity (Significant AR: grade 3-4 [Echo], Regurgitant fraction≥33% [CMR]) were analyzed using area under the curve (AUC) and logistic regression models.

The median LV/RV ratio was 1.54 [1.30; 1.88], with no significant difference by age or sex. A strong association was observed between the LV/RV ratio and significant AR, assessed by Echo (AUC 0.75, 95% CI [0.68–0.82]) and CMR (AUC 0.82, 95% CI [0.76–0.87]), remaining significant after adjustment for age and sex (Echo: OR 3.57, 95% CI [2.12–6.02], P<0.001; CMR: OR 5.55, 95% CI [3.41–9.02], P<0.001). The LV/RV ratio correlated more strongly with CMR AR-RegFrac (r=0.66, P<0.001) than conventional LV metrics and showed superior diagnostic performance, with a threshold of 1.5 identifying significant AR (Figure 1, Figure 2).

In chronic AR patients, the LV/RV ratio showed a stronger association with AR severity assessed by Echo and CMR than conventional LV metrics. These findings suggest its potential as an individualized marker for adverse LV remodeling in chronic AR, warranting further studies on its relationship with clinical outcomes.