Left Atria Strain Is a Surrogate Marker for Detection of Atrial Fibrillation in Cryptogenic Strokes

After complete diagnostic workup, a quarter of ischemic strokes are regarded as undetermined pathogenesis at discharge with a substantial rate of mortality in some cases.1 Paroxysmal atrial fibrillation (PAF) is the most frequent occult cause resulting in significant morbidity and costs when is under diagnosed.2 Recent studies have shown that extending the cardiac monitoring duration with subcutaneous implantable monitors and selecting patients for prolonged monitoring significantly increased the PAF detection in ischemic strokes.3 The left atria volume (LAv) has been used to assess the left atrial function. Nevertheless, the left atria dimension is predictive of stroke but become nonsignificant after adjustment for the older age.4 The left atria function can be also obtained by the analysis of the left atria walls deformation, also called strain of the left atria. The speckle tracking is an echocardiographic technique that uses standard B-mode images for the analysis of the acoustic backscatter generated by the ultrasound beam. The changes between speckles are assumed to represent the strain.5 The published intraobserver and interobserver variability of left atria strain (LAS) is 7.8%, and 8.9%, respectively.6 The LAS profile has been previously described in patients with PAF and in correlation with CHADS2 score (hypertension >140/90 mm Hg, age ≥75, diabetes, prior stroke),7 but it has never been studied in cryptogenic ischemic strokes.We aimed to describe the left atria functionality assessed by LAS parameter in cryptogenic strokes to improve the detection of occult PAF. With the purpose to obtain the best LAS cutoff point to differentiate patients with and without PAF, we planned the comparison as a case–control study. Accordingly, the selection of patients without PAF (non-PAF group) was made considering consecutive patients with cryptogenic stroke after complete workup evaluation with no PAF episodes in 3-year cardiac monitoring with Holter …