Assessment of left atrioventricular coupling index as a marker of diastolic dysfunction severity in heart failure patients

Abstract Introduction Assessing diastolic dysfunction involves detecting subtle changes in myocardial compliance that are difficult to quantify. During diastole, the left atrium (LA) and left ventricle (LV) are directly connected, and in the absence of valvular disease, their function and filling pressures are tightly coupled. The left atrioventricular coupling index (LACI), defined as the ratio between the minimum LA volume and LV end-diastolic volume, may reflect dysfunctional atrioventricular coupling and correlate with diastolic impairment. Aim To evaluate correlation between LACI and other diastolic functions parameters and to asses the association between LACI and the severity of LV diastolic dysfunction Methods Retrospective study. Patients (pts) with chronic heart failure (HF) from January 2023 to April 2024 with any LV left ventricular ejection fraction (LVEF) and in sinus rhythm were included. Diastolic function was graded using the American Society of Echocardiography/European Association of Cardiovascular Imaging algorithm. Pearson correlation was used to asses correlation between LACI and diastolic parameters. Differences across diastolic grades were compared using one-way ANOVA with Tukey post hoc analysis. Results 109 pts were included. Table 1 summarize baseline characteristics. LACI showed a moderate correlation with both the E/A ratio (r = 0.569; p < 0.001), mean bi-plane indexed left atrial volume (r = 0.548; p < 0.001) and E/E’ ratio (r = 0.168; p = 0.044) but a weak correlation with tricuspid regurgitation maximum velocity (r=0.222; p=0.022). 25 pts with preserved LVEF were included, with a mean LVEF of 55 ± 5% and a mean LACI of 0.34 ± 0.21. 56% were classified as having normal diastolic function, 32% as indeterminate, and 12% as diastolic dysfunction. ANOVA showed a significant difference between groups (p = 0.011). Further analysis revealed that only the groups with normal diastolic function and diastolic dysfunction differed significantly from each other (mean difference (MD)= 0.37, p = 0.010). 84 pts with reduced LVEF were included, with a mean LVEF of 38 ± 8% and a mean LACI of 0.30 ± 0.17. 58% of pts were classified as having normal diastolic function or grade 1 diastolic dysfunction, 32% as grade 2, and 10% as grade 3. ANOVA showed a significant difference between groups (p < 0.001). Further analysis revealed that comparing the normal/grade 1 group with grades 2 and 3 showed significantly lower LACI values (MD = 0.12, p =0.003; MD = 0.32, p < 0.001, respectively). Regarding grade 2 and 3, a mean significant MD of 0.20 (p=0.003) was found. Conclusion Our study shows that LACI correlates with key diastolic function parameters and varies significantly across different grades of diastolic dysfunction in HF population, suggesting that LACI may serve as marker reflecting atrioventricular coupling dysfunction and the severity of diastolic impairment. Further research is needed to validate our findings.Table1