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

OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Atrial interaction in the form of 'cross talk' in patients with ventricular outflow tract obstruction.

BACKGROUND: The Bernheim 'a' wave in the jugular venous pulse of patients with left ventricular hypertrophy has been shown to reflect accentuated right atrial activity. OBJECTIVE: To study possible atrial interaction in patients with right and left ventricular outflow tract obstruction due to significant pulmonary (PS) and aortic valvular stenosis (AS) respectively. METHODS: We studied 41 PS patients (age 36 ± 10 year) and 41 AS patients (age 35 ± 12 year) and their results were compared with those of 27 controls (age 30 ± 7 year). RV and LV filling were recorded by conventional PW Doppler. Biventricular segmental function was studied using the PW tissue Doppler imaging (TDI) and M-mode techniques. RESULTS: The 2 patient groups had similar degree of ventricular outflow tract obstruction. Long axis function was impaired while global systolic function was preserved in the pressure-overloaded ventricle. Patients had higher peak late filling (A wave) and TDI late diastolic (Aa) velocities recorded in the disease-free ventricles despite having similar peak early filling velocities (E wave), E wave deceleration time and E/Ea ratios were not different from controls (p > 0.05 for all). Such accentuation of atrial activity (A wave) was moderately correlated with the degree of contralateral ventricular outflow tract obstruction (p < 0.001 for both). CONCLUSIONS: Long axis function is more sensitive than global function in revealing myocardial dysfunction in the pressure-overloaded ventricles. The increased contralateral atrial systolic activity suggests an evidence for atrial interaction in the form of 'cross talk'.