Evaluation of left atrial function and left ventricular diastolic function during exercise stress echocardiography in patients with different types of atrial fibrillation

Objective: To determine cut-off values for left atrial function parameters at rest and during physical exercise that are specific to patients with atrial fibrillation (AF). Materials and Methods. The prospective single-center study with screening tests of 300 patients was carried out; 297 of them were included in the final analysis. The main cohort of patients was divided into three groups: patients with sinus rhythm without a history of AF, a group with paroxysmal/persistent AF, and patients with permanent AF. Stress echocardiography was performed in all patients according to the ABCDE protocol with additional assessment of left atrial volume index and left atrial strain (reservoir phase) at rest and peak exercise. Results. The left atrial function assessment was successful in 99% (95% CI 98–100%) of patients. The group with sinus rhythm included 240 patients (Group 1), with paroxysmal/persistent AF (PAF) – 38 patients (Group 2), with permanent AF (PermAF) – 19 patients (Group 3). The threshold values of the parameters were determined: left atrial volume and function and LV diastolic function at rest and during exercise, which reliably distinguished the group of patients with sinus rhythm from patients with paroxysmal/persistent AF (Groups 1 and 2, respectively). The best parameters for classifying belonging to the PAF group were the volume and contractility of the LA. Moreover, the quantitative parameter of LA strain classified these groups of patients significantly better during physical exercise (accuracy – 74%, sensitivity – 89%, specificity – 49%) than at rest (accuracy – 64%, sensitivity – 74%, specificity – 51%), with p < 0.004. Conclusions. The obtained threshold values of the left atrial function and volume, as well as E/e' at rest and during physical exercise, provide more accurate differentiation of patients with dyspnea/chest discomfort into groups with and without paroxysmal/persistent AF. The most accurate parameter is the left atrial strain during the exercise stress test.