Diagnostic utility of the left atrioventricular coupling index in heart failure and its subtypes

Background

The Left Atrioventricular Coupling Index (LACI), defined as the ratio of left atrial to left ventricular end-diastolic volume, reflects the mechanical interplay between the atrium and ventricle. It has been proposed as a novel marker of atrioventricular remodeling and is associated with diastolic dysfunction severity and is an independent predictor of outcomes in patients with HF. This study aimed to assess the utility of LACI in detecting HF and differentiating among its subtypes based on left ventricular ejection fraction (LVEF).

Methods

A total of 144 patients were evaluated and stratified into two major groups based on clinical and echocardiographic findings: patients with heart failure (HF+, n=79) and those without heart failure (HF–, n=65). The HF+ group was further categorized as HFrEF (n=30), HFmrEF (n=20), and HFpEF (n=29). Demographic, clinical, and echocardiographic parameters including LA volume, LVEF, LAEF, and LACI were compared across groups.

Results

LACI was significantly higher in the HF+ group compared to HF– (0.23 ± 0.15 vs 0.14 ± 0.08, p < 0.001). Among HF subtypes, LACI was highest in HFpEF patients (HFpEF: 0.32 ± 0.18 vs HFrEF: 0.17 ± 0.10, HFmrEF: 0.17 ± 0.09, p < 0.001). LA volume, LAVI, and LAEF showed significant differences between HF+ and HF–, supporting the presence of atrial remodeling in HF patients. GLS and NT-proBNP levels were also significantly worse in the HF+ group.

A LACI threshold of approximately 0.17 showed high sensitivity (93.5%) with moderate specificity (53%) for the diagnosis of HFpEF. In multivariable logistic regression analysis including LACI, NT-proBNP, and LAVI, both LACI and NT-proBNP remained independently associated with HFpEF (p = 0.021 and p = 0.025, respectively), whereas LAVI did not reach statistical significance (p = 0.159).

Conclusion

LACI is significantly elevated in patients with heart failure and demonstrates the highest values in HFpEF, indicating its potential as a non-invasive marker of left atrioventricular uncoupling. These findings support the role of LACI as a novel parameter to distinguish heart failure subtypes, especially in the evaluation of diastolic dysfunction.For image description, please refer to the figure legend and surrounding text.For image description, please refer to the figure legend and surrounding text.