Patterns of left atrial activation and evaluation of atrial dyssynchrony in patients with atrial fibrillation and normal controls: Factors beyond the left atrial dimensions

BackgroundLeft atrial (LA) remodeling causing slower and asynchronous conduction is crucial for the maintenance of atrial fibrillation (AF).ObjectiveWe propose a simple and quick method to evaluate the LA asynchrony.MethodsOne hundred thirty patients with AF (AF group) and 70 patients without a history of AF (controls) were examined prospectively using pulsed-wave tissue Doppler imaging. The time intervals from the onset of the P wave to the onset of the A′ wave (P-A′ intervals) were measured at 4 sites at the mitral annulus: septal, lateral, anterior, and posterior. To assess the LA asynchrony, the differences between the longest and the shortest P-A′ interval as well as the standard deviation of all 4 P-A′ intervals were calculated.ResultsBoth groups were matched for the baseline characteristics. The AF group had longer differences between the longest and the shortest P-A′ than did controls (37 ± 16 ms vs 28 ± 13 ms; P = .0001). The standard deviation of all 4 P-A′ intervals was also higher in the AF group (17 ± 7 ms vs 13 ± 5 ms; P = .0001). Furthermore, distinct patterns of LA activation were observed with most patients with AF showing upward LA activation (86.5%) whereas normal controls were showing downward LA activation (65.5%). Receiver operating characteristic analysis revealed that P-A′ anterior successfully discriminated patients with AF from controls (area under the curve 0.85; P < .0001). Furthermore, P-A′ anterior > 55 ms discriminated between patients with AF and controls with a sensitivity of 85% a specificity of 81%, a positive predictive value of 0.898, and a negative predictive value of 0.707.ConclusionPatients with AF showed greater LA asynchrony in pulsed-wave tissue Doppler imaging, upward LA activation, and a prolonged activation time at the anterior mitral annulus. Prolongation of P-A′ anterior discriminated between patients with AF and controls with high sensitivity and specificity.