Left Atrial Reservoir Strain As a Predictor of Cardiac Dysfunction in a Murine Model of Pressure Overload

Aim: Left atrial (LA) strain is emerging as a valuable metric for evaluating cardiac function, particularly under pathological conditions such as pressure overload. This preclinical study investigates the predictive utility of LA strain on cardiac function in a murine model subjected to pressure overload, mimicking pathologies such as hypertension and aortic stenosis.

Methods: High-resolution ultrasound was performed in a cohort of mice (n = 16) to evaluate left atrial and left ventricular function at baseline and 2 and 4 weeks after transverse aortic constriction (TAC). Acute adaptations in cardiac function were assessed in a subgroup of mice (n = 10) with 3 days post-TAC imaging.

Results: We report an increase in LA max volume from 11.0 ± 4.3 μL at baseline to 26.7 ± 16.7 μL at 4 weeks (p = 0.002) and a decrease in LA reservoir strain from 20.8 ± 5.4% at baseline to 10.2 ± 6.9% at 4 weeks (p = 0.001). In the acute phase, LA strain dysfunction was present at 3 days (p < 0.001), prior to alterations in LA volume (p = 0.856) or left ventricular (LV) ejection fraction (p = 0.120). LA reservoir strain correlated with key indicators of cardiac performance including left ventricular (LV) ejection fraction (r = 0.541, p < 0.001), longitudinal strain (r = -0.637, p < 0.001), and strain rate (r = 0.378, p = 0.007). Furthermore, markers of atrial structure and function including LA max volume (AUC = 0.813, p = 0.003), ejection fraction (AUC = 0.853, p = 0.001), and strain (AUC = 0.884, p < 0.001) all predicted LV dysfunction.

Conclusion: LA strain and function assessments provide a reliable, non-invasive method for the early detection and prediction of cardiac dysfunction in a model of pressure overload.