Left atrial strain in non-ischemic dilated cardiomyopathy in sinus rhythm: Prognostic implications and interrelationship with left ventricular deformation.

Background: Left atrial deformation analysis may identify patients at higher risk of adverse events in the setting of non-ischemic dilated cardiomyopathy (NIDCM). The purpose was to determine the association between peak longitudinal (PALS) and contraction (PACS) LA strain in NIDCM, accounting for left ventricular global longitudinal strain (LV-GLS).

Methods: Consecutive patients with NIDCM, sinus rhythm and LV ejection fraction (LVEF)<50 % were included. PALS, PACS and LV-GLS were obtained from echocardiography images. The composite outcome was a combination of hospitalization for heart failure, cardiovascular death, or ventricular arrhythmia. The association with the composite outcome was assessed using Cox regression and a classification and regression tree (CART) analysis was performed.

Results: Among 347 patients included (median age 66 years old, median LVEF 35 %), median PALS and PACS values of 16 % and 9 %. After a median follow-up of 3.6 years, the composite outcome occurred in 70 (20.2 %) patients. PACS ≤8 % was associated with the composite outcome (adjusted HR = 2.73, 95 %CI 1.33-5.60), mostly by increasing the risk of heart failure admission. LV-GLS increased the risk of the composite outcome among patients with PACS>8 % (HR = 1.20, 95 %CI 1.07-1.35). PALS more strongly correlated with LV-GLS (Spearmans' rho = -0.71) than PACS (rho = -0.5). A decreased PALS/LV-GLS ratio was associated with higher rates of the composite outcome.

Conclusion: LA dysfunction is a major determinant of the composite outcome in NIDCM with LVEF <50 % and should be routinely assessed. PACS may perform better than PALS when combined with LV-GLS, probably due to lesser dependency from mitral annular motion.