Assessment of left atrial function in dilated cardiomyopathy patients using speckle-tracking echocardiography

Background: The available methods to assess left atrial function (LAF) have some limitations as angle dependence and opposite distortion. The objective of the current study was to evaluate LAF in dilated cardiomyopathy (DCM) of ischemic (IDCM) and non-ischemic etiologies (NIDCM) using speckle tracking echocardiography (STE). Methods: 52 patients with systolic heart failure were included in our study; 27 with IDCM and 25 with NIDCM along with 15 healthy controls. All patients underwent conventional echocardiography, tissue doppler imaging, and speckle tracking echocardiography. The later modality was used to compare left atrial function in IDCM and NIDCM groups. Results: We found the left atrial maximum volume and the left atrial total emptying volume to be higher in patients with dilated cardiomyopathy compared to healthy patients (52.19 ± 6.01 vs.  21.87 ± 1.69 cm3/m2; p <0.001 and 28.67 ± 4.34 vs. 15.67 ± 2.02 cm3/m2, respectively). Conversely, left atrial emptying index and left atrial active ejection fraction were lower in patients with DCM compared to healthy controls (9.60 ± 2.29 vs. 8.27 ± 3.01 cm3/m2; p< 0.001 and 23 ± 2.56 vs. 37.47 ± 3.54 %; p<0.001, respectively). When comparing the IDCM group with NIDCM patients, we found no significant difference in left atrial maximum volume and left atrial active emptying volume. However, the NIDCM patients had significantly lower left atrial total emptying volume, and left atrial active ejection fraction (8.93 ± 1.86 vs. 9.60 ± 2.29 cm3/m2 and 23 ± 2.56 vs. 31.19 ± 1.66 %; p<0.001). on comparing strain function, DCM patients had lower systolic (28.22 ± 3.84 vs. 60.87 ± 3.07 %, p<0.001), and left atrial systolic strain rate (-2.66 ± 0.45 vs. -3.81 ± 0.35; p = 0.003) compared to healthy controls. All strains and strain rates were significantly lower in NIDCM patients compared to IDCM patients.   Conclusion: STE is a promising method for evaluating LAF in DCM patients. Patients with DCM had significantly lower left atrial systolic and late diastolic strains and strain rates compared to healthy patients. Moreover, NIDCM could be differentiated from IDCM by having more impairment in the LA dynamic reservoir and booster pump function