Left atrial structure and function and the risk of death or heart failure in atrial fibrillation

Abstract

Aims: The present study aimed to assess the association between left atrial (LA) structure and function and the risk for cardiovascular (CV) death or heart failure (HF) hospitalization in a population with atrial fibrillation (AF).

Methods and results: In a prospective echocardiographic substudy of the Effective Anticoagulation with Factor Xa Next Generation in AF-Thrombolysis in Myocardial Infarction 48 (ENGAGE AF-TIMI 48) study, 971 patients underwent transthoracic echocardiography. The associations between LA structure (LA volume index [LAVi]) and function (LA emptying fraction [LAEF] and LA expansion index [LAEi]) and risk for the composite endpoint of CV death or HF hospitalization, and its components, were assessed. Over a median follow-up of 2.5 years, 142 patients (14.6%) experienced CV death or HF hospitalization. Higher LAVi and lower LAEF and LAEi were each associated with a higher unadjusted risk for the composite outcome and its components. After adjustment for clinical and echocardiographic confounders, only measures of impaired LA function were predictive of the composite outcome (hazard ratio [HR] per 1 standard deviation [SD] decrease in LAEF: 1.35; 95% confidence interval [CI] 1.09-1.67 [P = 0.005]; HR per 1 SD decrease in LAEi: 1.34; 95% CI 1.06-1.69 [P = 0.012]). These findings were similar regardless of left ventricular ejection fraction, history of HF or whether patients were in AF or sinus rhythm at the time of the echocardiographic examination.

Conclusions: In patients with AF, LA dysfunction was significantly associated with an increased risk for CV death or HF hospitalization and was more predictive of these outcomes than LA size. These parameters may help to identify AF patients at greatest risk for the development of HF.

Clinical trial registration: ClinicalTrials.gov, NCT00781391.

Keywords: Atrial fibrillation; Cardiovascular death; Echocardiography; Heart failure; Left atrium.

© 2019 The Authors. European Journal of Heart Failure © 2019 European Society of Cardiology.

Figures

Figure 1

Adjusted association of left atrial emptying fraction (LAEF) and left atrial expansion index (LAEi) for the composite endpoint of cardiovascular (CV) death or hospitalization for heart failure (HF). The gold bars represent the distribution of LAEF and LAEi measures reported as percentages. The solid black lines represent an estimation by Poisson regression of the association between LAEF and LAEi and the outcome after adjusting for age, sex, diabetes, heart rate, history of HF, history of myocardial revascularization, atrial fibrillation pattern, allocated therapy, left ventricular (LV) end-diastolic volume index, LV mass index, LV ejection fraction and E/e′. Dashed lines represent 95% confidence intervals. Incidence rates are displayed on the y-axis. py, person-years.

Figure 2

Adjusted association of measures of left atrial (LA) structure and function and the composite endpoint of cardiovascular (CV) death or hospitalization for heart failure (HF) and its components. Each 1-standard deviation (SD) decrease in LA emptying fraction (LAEF) and LA expansion index (LAEi), but not LA volume index (LAVi), was associated with an increased risk for the composite endpoint of CV death or HF hospitalization and for HF hospitalization alone. Point estimates were similar for CV death alone. The reported adjusted hazard ratio (HR) and 95% confidence interval (CI) are adjusted for age, sex, diabetes, heart rate, history of HF, history of myocardial revascularization, atrial fibrillation pattern, allocated therapy, left ventricular (LV) end-diastolic volume index, LV mass index, LV ejection fraction and E/e′.

Figure 3

Adjusted association between left atrial emptying fraction (LAEF) and left atrial expansion index (LAEi) and the composite endpoint stratified by rhythm at the time of echocardiography (atrial fibrillation [AF] vs. normal sinus rhythm [NSR]). The red and blue lines represent an estimation by Poisson regression of the association between LAEF and LAEi and the outcome stratified by cardiac rhythm at the time of echocardiography after adjusting for age, sex, diabetes, heart rate, history of heart failure (HF), history of myocardial revascularization, AF pattern, allocated therapy, left ventricular (LV) end-diastolic volume index, LV mass index, LV ejection fraction and E/e′. Dashed lines represent 95% confidence intervals. Incidence rates are displayed on the y-axis. P-values refer to interactions between the two groups. CV, cardiovascular; py, person-years.