Left atrial mechanical function and clinical performance in non-dilated versus dilated cardiomyopathy.

BACKGROUND

Non-dilated left ventricular cardiomyopathy (NDLVC) is a distinct entity characterized by impaired left ventricular ejection fraction despite normal chamber dimensions. While it may represent an earlier or less fibrotic stage of non-ischemic cardiomyopathy compared to dilated-cardiomyopathy (DCM), its clinical and structural characterization remains incomplete.

OBJECTIVES

This study aimed to compare left atrial (LA) phasic strain parameters between patients with NDLVC and those with DCM, all with similarly reduced ejection fractions. Additionally, the relationship between LA function and exercise capacity was assessed using the 6-minute walk test (6MWT).

METHODS

In this prospective, observational study, 83 patients with non-ischemic systolic dysfunction were enrolled(NDLVC:n = 51; DCM:n = 32). All underwent comprehensive transthoracic echocardiography, including LA strain analysis (reservoir, conduit, contractile phases) using speckletracking imaging. Functional capacity was evaluated via 6MWT.

RESULTS

Patients with NDLVC exhibited significantly higher LA reservoir and conduit strain values than those with DCM. Among all echocardiographic parameters, LA conduit strain showed the strongest correlation with 6MWT distance (r = 0.42, p = 0.002) and was the only independent predictor of functional capacity in multivariable analysis.

CONCLUSIONS

LA conduit strain is a promising noninvasive parameter for identifying functional and structural differences between NDLVC and DCM. Its strong association with exercise capacity and ability to differentiate phenotypes may support its integration into clinical assessment and follow up,particularly in clarifying structural and functional differences in non-ischemic remodeling patterns. These findings suggest that preserved LA conduit function in NDLVC may reflect a less hemodynamically burdened atrial profile, which is consistent with better clinical performance and functional capacity.