Prognostic value of left atrial reservoir strain for incident heart failure and cardiovascular death in an elderly population

Background Left atrial (LA) speckle-tracking echocardiography provides valuable information on atrial function. However, its association with incident heart failure (HF) and cardiovascular (CV) death remains to be fully elucidated. Purpose To investigate the association between low LA reservoir strain (LASr) and the risk of incident HF, as well as a composite of HF or CV death, in a cohort of elderly patients with multiple stroke risk factors, undergoing echocardiographic evaluation. Methods This study analyzed data from the LOOP study, including elderly participants with multiple stroke risk factors. Patients were eligible if they were without known atrial fibrilliation (AF), >70 years of age and with at least 1 additional stroke risk factor from the CHADS2 score: hypertension, diabetes, or prior stroke. Patients with heart failure were excluded from this analysis. The participants were randomized to either an implantable loop recorder monitoring or usual care. An echocardiographic substudy provided data on LA reservoir, conduit strain, and contraction strain. Using data from this substudy, we evaluated the association between low LA reservoir strain (<33%) and incident HF as well as CV death. Univariable and multivariable Cox proportional hazards regression models were used to adjust for potential confounders. Results A total of 1311 participants were included in this analysis. The median age was 72.8 years (IQR: 71.41-76.36), and 52.6% were male. The median LASr was 33.45% (IQR: 27.9-38.8%). The median follow-up period was 5.5 years (IQR: 4.7-5.8), during which 41 (3.1%) were diagnosed with HF and 28 (2.1%) died of CV disease. In univariable cox regression, participants with low LASr (<33%) showed a significantly higher risk of incident HF compared to the high LASr (≥33%) reference group (unadjusted HR: 5.49, 95% CI: 2.44-12.4, p<0.001), consistent with the separation of event curves observed in Kaplan-Meier analysis (log rank χ²=21.3, p<0.001; Figure 1). A similar univariable association was observed for the composite endpoint of HF or CV death (unadjusted HR: 3.26, 95% CI: 1.88-5.66, p<0.001), consistent with the Kaplan-Meier estimates (log rank χ²=19.8, p<0.001; Figure 2). In the multivariable Cox regression analysis adjusting for age, sex, GLS, hypertension, diabetes, and randomization group, low LASr remained associated with incident HF (adjusted HR: 2.99, 95% CI: 1.27-7.073, p=0.013). The association between low LASr and the composite endpoint of HF or CV death was attenuated and no longer statistically significant (adjusted HR: 1.78, 95% CI: 0.98-3.23, p=0.058). Conclusions Impaired left atrial reservoir strain was associated with incident HF in elderly patients with multiple stroke risk factors. In this analysis, LA strain provided prognostic value independent from GLS. Assessment of LASr may provide valuable prognostic information to help identify patients at increased risk of incident HF.Figure 1.KM estimates on HF based on LASrFigure 2.KM estimates on HF/CV from LASr