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

BACKGROUND

Left atrial (LA) remodeling causing slower and asynchronous conduction is crucial for the maintenance of atrial fibrillation (AF).

OBJECTIVE

We propose a simple and quick method to evaluate the LA asynchrony.

METHODS

One 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.

RESULTS

Both 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.

CONCLUSION

Patients 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.