Left atrial reservoir strain as a surrogate marker for atrial fibrillation burden in patients with non-valvular atrial fibrillation.

Background: To evaluate the correlation between atrial fibrillation (AF) burden and two-dimensional LA (left atrium) longitudinal reservoir strain (LARS) to explore the potential clinical utility of this novel parameter in patients with AF. Methods: This cross-sectional study was conducted at the cardiac electrophysiology clinic of a tertiary centre by consecutively enrolling patients with non-valvular AF. The AF burden was evaluated using 14-day patch-based electrocardiography and defined as the percentage of time spent in AF during a 14-day monitoring period. High and low AF burdens were defined based on the median 14-day AF burden. Echocardiographic measurements, including the longitudinal strain of the LA, were performed in all patients. Results: Among 267 patients, LARS was successfully performed in 221 (age 63 ± 11 years, male 71%, paroxysmal AF 71%). After adjusting for age, diabetes mellitus, congestive heart failure, estimated glomerular filtration rate, low-density lipoprotein level, left ventricular ejection fraction, LA dimension, and LA volume in multivariable linear regression analysis, low LARS remained a significant predictor of AF burden in addition to N-terminal pro-B-type natriuretic peptide and sex. Receiver operating curve analysis demonstrated that the best cut-off value for LARS to predict high AF burden (above median 10.49%) was 21.5%, with 75% sensitivity and 83% specificity. Conclusions: LARS is associated with the AF burden in patients with AF. Further studies are needed to determine the role of routine LARS measurements in such patients.