Relationship between Left Atrial Function and Size and Level of Left Ventricular Dyssynchrony in Heart Failure Patients

Aim To study whether there is any relation between left atrial (LA) size or function and the level of left ventricular dyssynchrony (LV) in patients with heart failure. Method Fifty-two patients (male 34, mean age = 65.77 ± 8.69 years) with ejection fraction (EF) <35%, who were candidates for cardiac resynchronization therapy (CRT), underwent conventional transthoracic echocardiography and tissue Doppler imaging (TDI). Intra-ventricular dyssynchrony, inter-ventricular mechanical dyssynchrony (IVMD), and related time intervals were measured. The LA size and function were evaluated by transthoracic echocardiography and deformation imaging using LA lateral wall strain (ST) and strain rate (SR), and the septal wall ST. Results The LA volume showed severe dilation in 41 (78.8%) patients. 44 (84.6%) cases had intra-ventricular dyssynchrony and 33 (63.5%) had IVMD. In univariable analysis, the LA lateral wall ST and SR as well as the LA septal wall ST had significant but poor correlation with IVMD. There were also poor to moderate correlation between these parameters and the LV end diastolic diameter and mitral annulus tissue velocity at early and late diastole. However, after adjustment for all the related factors, IVMD remained a significant independent correlate for the LA lateral wall ST and SR. This correlation for the LA septal wall ST was not statistically significant. Conclusion IVMD was a significant independent correlate for the LA lateral wall ST and SR. This correlation for the LA septal wall ST was nonsignificant. Future studies are needed to examine whether the correction of inter-ventricular dyssynchrony by CRT in patients with concomitant LA dysfunction can have an independent role in the improvement of the LA function.