Disturbed left atrial mechanical function in paroxysmal atrial fibrillation: a speckle tracking study

We aimed to assess left atrial (LA) intrinsic myocardial function and its relationship to left ventricular (LV) filling pattern in a group of paroxysmal atrial fibrillation (PAF) patients.

Twenty-three PAF patients (age 68 ± 7 year, 10 males) were studied using speckle tracking echocardiography and compared with 18 age and sex matched controls. LA segmental longitudinal strain (S), strain rate (SR) and myocardial velocities during atrial systole were measured as were LA diameters. E/A and E/Em were also measured.

LA longitudinal diameter was larger in patients (5.5 ± 0.6 vs. 4.8 ± 0.6 cm, p<0.01) and global LA S (-9.2 ± 4.3 vs. -12.9 ± 4.6%, p=0.01) and SR (-1.1 ± 0.5 vs. -1.6 ± 0.7 1/s, p<0.01) were reduced and correlated with E/A (r=0.52, p=0.01 and r=0.43, p<0.05, respectively). LA lateral S and SR were uniformly reduced compared with controls (p<0.05 for all). Both septal and lateral wall SR correlated with E/A (p<0.05 for all), only septal S correlated with E/A (p<0.05). LA myocardial velocities were highest at the annular level and lowest at the rear in both patients and controls (p<0.01 for all).

In PAF patients, LA systolic function is suppressed and is directly related to the pattern of LV filling which itself may suggest raised pressures. While intrinsic global and segmental function can reproducibly be studied by S and SR, myocardial velocities reflect only regional motion, thus less sensitive in demonstrating localize dysfunction.