Background: Conservation of the normal atrial size and architecture by preventing structural atrial remodeling due to atrial fibrillation (AF) seems of prime importance for the future management of AF. 2-Dimensional strain is a novel technique that depicts regional deformation via frame-to-frame tracking of unique acoustic grayscale patterns within image. We attempted to assess the relevance of strain echocardiography for quantitative assessment of the left atrial(LA) status in AF. Methods: Tissue Doppler strain and 2-dimensional strain imaging were performed in 15 patients with chronic AF(CAF), 15 paroxysmal AF(PAF) and 15 healthy age-matched controls using a GE vivid 7 dimension. LA diameter, LA volume index and mitral inflow parameters were measured by standard echocardiography. Longitudial peak strain was obtained from 2 different areas of the basal left atrial free wall and inter-atrial septum in the apical 4 chamber view by tissue Doppler strain. Mean peak systolic strain/strain rate (Sm-SR), peak early diastolc (Em-SR) and peak late diastolic(Am-SR) strain rate were measured at the inter-atrial sepum in the apical 4 chamber view by 2-dimensional strain. Results: Peak strain(normal;48.2±17.8%, PAF;19.8±8.9%, CAF;8.3±4.7%), Sm-SR(normal;3.03±0.60s-1, PAF;1.38±0.58s-1, CAF;0.57±0.39s-1), Em-SR(normal;-2.61±0.46s-1, PAF;-1.11±0.53s-1, CAF;-0.82±0.52s-1) and Am-SR(normal;-2.44±0.31s-1, PAF;-1.46±0.71s-1, CAF;-0.62±0.43s-1) were significantly reduced(P<0.0001) in the AF group comparing normal, especially in the chronic AF group(P<0.0001). There were no significant differences in LA size and A wave velocity between PAF and normal groups, however, peak systolic strain/rate, Em-SR, Am-SR were significantly lower(P<0.0001) in paroxysmal AF group than normal. Conclusions: The lower values of atrial Sm-SR, Em-SR and Am-SR revealed that active contraction and passive stretching of LA wall may impair in some patients with PAF even before LA enlargement possibly because of atrial fibrosis and reduced compliance. Our results indicated that strain echocardiography enabled qualitatively precise LA contractile function and provided clinically useful information of LA function and remodeling.
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