Left Atrial Function in Patients in Sinus Rhythm, Normal Left Ventricular Function and Indeterminate Diastolic Function

Background:
Diastolic dysfunction (DDFx) is the major underlying mechanism of heart failure with preserved left ventricular ejection fraction (EF). Yet, guidelines directed echocardiographic diagnosis of DDFx in patients in sinus rhythm is challenging, and up to 25% of studies have undefinable diagnostic features of DDFx. We aimed to assess whether left atrial (LA) function can contribute to the diagnosis of DDFx.

Methods:
We randomly selected from our database 67 patients in sinus rhythm, EF≥45% without wall motion abnormalities, valvular, congenital heart diseases, cardiomyopathies or pulmonary disease. Patients were divided according to their lateral mitral E/E’ ratio and left atrial systolic diameter: normal DFx (LAd<40mm, E/E’<10), DDFx ((LAd≥40mm, E/E’≥10) and indeterminate DFx (conflicting LAd diameter and E/E’ ratio). LV and LA myocardial mechanics were analyzed by speckle-tracking echocardiography to compare subgroups and identify predictors of dyspnea.

Results:
Table shows clinical and echocardiographic characteristics of the 3 groups. The DDFx group (n=21) and IndtDFx (n=19) were significantly different form NDFx (n=27) in most of the demographics, cardiovascular risk factors, presentation and echocardiographic parameters. Left ventricular strain was lower only in the DDFx group. Phasic LA volumes were larger in both groups, overall and passive LA functions were decreased, while active function remained in the normal range.

Septal E/E` and LA strain were found to predict of dyspnea (E/E` 11±5 vs. 15±5 ,p<0.02, and LA strain 47±16 vs. 36±15, p=0.03 for no dyspnea vs. dyspnea respectively). The ROC= 0.7 for LA strain ≤36ml (CI=0.533 to 0.785, p=0.04) for dyspnea. LA maximal volume did not correlate with dyspnea (p=0.45) while LA minimal volume did (p=0.054).

Conclusions:
LA phasic function suggests that IndtDFx is similar to DDFx , helping in re- classification of patients with IndtDFx as DDFx.

LA function and minimal volumes correlated with symptoms.