Left Atrial Strain and Left Atrio‐Ventricular Coupling in Heart Failure Patients with Left Ventricular Hypertrophy and Wild‐Type Transthyretin Cardiac Amyloidosis

Background Wild‐type transthyretin cardiac amyloidosis (ATTRwt‐CA) is a cardiomyopathy characterized by myocardial and atrial stiffening. Objective We aimed to assess left atrial (LA) function and left atrio‐ventricular coupling index (LACI) in heart failure (HF) patients with left ventricular hypertrophy (LVH) and evaluate their ability to discriminate ATTRwt‐CA from non‐amyloid LVH. Methods We conducted a case‐control study including 50 patients with ATTRwt‐CA and 50 HF patients with hypertensive heart disease. LA reservoir strain (LARS), LA contraction strain (PACS), LA stiffness index (LASI), LA reservoir work (LAWr) and LACI have been measured. Propensity score matching (PSM) was performed for interventricular septal thickness (IVS), relative wall thickness (RWT), age, sex, coronary heart disease (CAD) to mitigate confounding. Results Before matching, significant differences in IVS, RWT, age, sex, and CAD rates were observed between cases and controls. After PSM, LA functional indices remained significantly impaired in CA patients compared to controls. In the multivariate analysis, only LARS and LASI were independently associated with ATTRwt‐CA. A LASI > 1.57 (AUC 0.87) and a PACS 6.0% (AUC 0.79) demonstrated the highest diagnostic accuracy for identifying ATTRwt‐CA, with reduced LARS ( 14.0%) also providing significant discrimination. Incorporating LASI into the AMYLI (AUC 0.91) and IWT scores (AUC 0.89) significantly enhances overall diagnostic accuracy for ATTRwt‐CA detection. Conclusion LA function and the atrio‐ventricular coupling are more impaired in ATTRwt‐CA patients compared to patients with HF alone; especially LARS and LASI are independent predictor for ATTRwt‐CA and should be assessed in HF patients with LVH to detect CA.