Left Atrial Function Determined by Cardiac Computed Tomography Predicts Device-Detected Atrial High-Rate Episodes in Patients Treated With Cardiac Resynchronization Therapy

OBJECTIVE: The objective of this study was to examine whether left atrial (LA) volumes and function were associated with atrial high-rate episodes (AHREs) in patients with cardiac resynchronization therapy (CRT). METHODS: Ninety-two consecutive patients without prior atrial fibrillation underwent clinical evaluation, echocardiograms, and cardiac computed tomography (CT) before CRT implantation and after 6 months. Left atrial volumes and LA emptying fraction (LAEF) were derived by CT images reconstructed at 5% phase increments of the cardiac cycle. Cox regression was used to assess associations between AHRE and LA anatomical and functional variables. RESULTS: Twenty-two patients (24%) developed AHRE during 1.9 years (SD, 1 year) At baseline, higher LAEF was associated with a lower risk of AHRE (hazard ratio [HR], 0.94; 95% confidence interval [CI], 0.91-0.98; P = 0.003), and large LA minimal (LAmin) volume was related to higher risk of AHRE (HR, 1.03; 95% CI, 1.00-1.06; P = 0.04). When combining LAEF and LAmin volume, only LAEF remained associated with occurrence of AHRE. Higher passive LAEF was associated with lower risk of AHRE (HR, 0.95; 95% CI, 0.91-0.98; P = 0.003). CONCLUSIONS: In patients with CRT, low preimplant LAEF measured by cardiac CT was independently associated with device-detected AHRE.