Left atrial reservoir strain, cardiac dysfunction and outcomes in acute heart failure

Background/Introduction The clinical relevance of left atrial (LA) dysfunction in acute heart failure (AHF) is unclear. Whether LA strain reflects disease mechanisms and predicts adverse outcomes in this heterogeneous population remains insufficiently investigated. Purpose The aim was to examine the relationships between LA reservoir strain and echocardiographic markers of cardiac dysfunction in AHF, and to evaluate its association with 90-day outcomes. Methods We conducted an analysis of a prospective dual-centre cohort, including adults hospitalised with AHF between 2022 and 2024. All patients underwent bedside transthoracic echocardiography and lung ultrasound shortly following admission. Associations between LA reservoir strain and markers of cardiac dysfunction and congestion were evaluated using restricted cubic splines; where nonlinearity was not evident, linear regression was used. The main outcome was a composite of 90-day all-cause mortality or heart failure (HF) readmission, assessed by Cox proportional hazards models with uni- and multivariable models. Effect modification by LA volume was assessed by including a multiplicative interaction term between LA reservoir strain and LA volume index (≥34 ml/m²). Stratified hazard ratios (HR) were derived from the interaction model. Results This analysis consisted of 334 patients with a median age of 80 years (IQR, 73-86 years), of whom 139 (42%) were female and 107 (32%) had a left ventricular ejection fraction (LVEF) above 40%. The median LA reservoir strain was 10.1%. LA reservoir strain demonstrated a positive linear association with LVEF and negative linear associations with early mitral inflow velocity to early diastolic mitral annular velocity ratio, total B-lines, and LA volume index (Figure 1). Nonlinear associations were observed with global longitudinal strain (positive) and ln-transformed N-terminal pro–B-type natriuretic peptide (negative). Overall, 87 patients (26%) reached the composite endpoint. In univariable Cox regression analysis, lower LA reservoir strain was associated with an increased risk of the composite endpoint (HR: 1.05 [95% CI 1.01, 1.09) per 1% decrease, p=0.007), however, the association was not statistically significant in multivariable analysis (Table 1). LA volume index significantly modified the association between LA reservoir strain and the composite endpoint (p for interaction = 0.016), such that LA reservoir strain was only associated with the endpoint in patients with enlarged LA volume (LA volume index ≥ 34 ml/m2). After multivariable adjustment the association remained significant in patients with abnormal LA volume index (HR: 1.18 [95% CI 1.06, 1.31) per 1% decrease, p=0.002). Conclusions Lower LA reservoir strain was associated with worse systolic function and higher filling pressures. Overall, LA reservoir strain was associated with higher 90-day all-cause mortality or HF readmission rates in patients with enlarged LA volume.