Speckle tracking-derived mechanical dispersion of left atrial myocardial deformation: An essential parameter in atrial fibrillation management?

Left atrial deformation and risk of transient ischemic attack and stroke in patients with paroxysmal atrial fibrillation

Left atrial (LA) remodeling is closely related to the occurrence of cerebral stroke; however, the relationship between early-stage impaired deformability of the left atrium and stroke/transient ischemic attack (TIA) remains unclear. The aim of this study was to evaluate the changes in LA deformability and to assess its relationship with stroke/TIA events using speckle tracking echocardiography. A total of 365 patients with paroxysmal atrial fibrillation (non-stroke/TIA [n = 318]; stroke/TIA [n = 47]) underwent comprehensive echocardiography with speckle tracking imaging to calculate mean LA longitudinal strain and strain rate values from apical 4-chamber, 2-chamber, and 3-chamber views. The stroke/TIA group was older, had a greater proportion of males, and had lower LA strain rate during left ventricular early diastole (SRE), and the difference was statistically significant (P < .05). On univariate linear regression analysis, the following clinical and conventional echocardiographic parameters showed a significant linear correlation (P < .001) with SRE: E/A ratio; LA volume index (VI); body mass index; mean E/e'; left ventricular ejection fraction; age; and hypertension. Multiple linear regression analysis revealed a linear dependence between SRE and E/A ratio, LA VI, and body mass index. The regression equation was y = -1.430-0.394X1 + 0.012X2 + 0.019X3 (P < .001) (y, SRE; X1, E/A ratio; X2, LA VI; X3, body mass index). In multivariate logistic regression analyses, SRE and sex ratio were independent risk factors for stroke/TIA (SRE, odds ratio 2.945 [95% confidence interval 1.092-7.943]; P = .033; sex, odds ratio 0.462 [95% confidence interval 0.230-0.930]; P = .031). Among patients with paroxysmal atrial fibrillation, SRE reflected impaired deformability of the left atrium in the early stages and was associated with the risk of stroke/TIA.

Utility of left atrial strain for predicting atrial fibrillation following ischemic stroke

Twenty-five percent of ischemic strokes (IS) are cryptogenic, but it is estimated that paroxysmal atrial fibrillation (PAF) is the underlying cause in up to a third of cases. We aimed to investigate the predictive value of speckle tracking of the left atrium (LA) in diagnosing PAF in IS patients. We retrospectively studied 186 IS patients with a clinical echocardiographic examination during sinus rhythm. Outcome was PAF defined by at least one reported episode of AF following their IS. Conventional echocardiographic measures were performed. Global longitudinal strain (GLS), LA reservoir-(ε_s), conduit-(ε_e), contraction-strain (ε_a) and LA dyssynchrony (standard deviation of time-to-peak ε_s; LA SD-T2P) were obtained by left ventricular and LA speckle tracking. Of 186 patients, 28 (15%) were diagnosed with PAF. PAF-patients did not differ from non-PAF patients with regards to GLS nor SD-TPS, but atrial strain measures were significantly impaired at baseline (ε_s 27 vs. 35%, ε_e 12 vs. 16%, ε_a 15 vs. 18%, p < 0.02 for all, for PAF and non-PAF, respectively). However, only ε_s remained independently associated with PAF after adjustment for clinical and echocardiographic parameters (OR 1.13 [1.04; 1.22], p = 0.003, per 1% decrease). ε_s also provided the highest area under the receiver operating characteristic curve among all variables (AUC = 0.74). With a cutoff of 29%, ε_s had a specificity of 76% and a negative predictive value of 93%. Atrial reservoir strain is independently associated with PAF and may be used to improve the diagnosis of PAF following IS.