Left atrial strain lower before atrial fibrillation appears after cryptogenic stroke

Patients who go on to have atrial fibrillation detected after a cryptogenic stroke show measurably lower left atrial strain on baseline echocardiography than similar patients in whom the rhythm disorder never appears, according to an updated systematic review and meta-analysis published in Cardiovascular Ultrasound. The review, covering literature from database inception to May 3, 2026, pooled 19 reports representing 17 cohort clusters of adults with cryptogenic ischemic stroke or embolic stroke of undetermined source, all of whom had no known atrial fibrillation at baseline and underwent speckle-tracking echocardiography measuring left atrial phasic strain or left ventricular global longitudinal strain.

The pooled estimates pointed consistently toward the atrium rather than the ventricle. Patients with subsequently detected atrial fibrillation had lower left atrial reservoir strain, with a mean difference of −7.44 percentage points (95% CI, −9.52 to −5.36) and a standardized mean difference of −0.87 (95% CI, −1.11 to −0.62), the largest standardized group separation of any marker examined. Left atrial conduit strain, in the primary analysis excluding one report with unresolved values, showed a mean difference of −3.29 (95% CI, −5.17 to −1.41; SMD −0.45), and left atrial contractile strain a mean difference of −4.31 (95% CI, −5.96 to −2.65; SMD −0.80). By contrast, left ventricular global longitudinal strain did not differ significantly between groups (mean difference −1.15; 95% CI, −2.89 to 0.60).

The authors are careful about what these group-level differences do and do not establish. Prediction intervals crossed the null for every outcome, signaling that in a new study the average difference could plausibly fall on either side of zero, and heterogeneity across the included cohorts was substantial. Most of the pooled data were aggregate and unadjusted, so the analysis cannot determine whether left atrial strain independently predicts atrial fibrillation or how well it would discriminate in an individual patient. An exploratory subgroup analysis of 15 left atrial reservoir strain datasets by monitoring duration found no statistically significant between-category difference (P = 0.9275), offering no clear evidence that shorter or longer rhythm monitoring explains the variation among studies.

The review’s conclusion frames left atrial strain as one candidate component of such multivariable strategies rather than a standalone diagnostic or treatment-decision tool, and calls for prospective evaluation in that role. The meta-analyses used random-effects models with raw mean differences and complementary Hedges g standardized mean differences, restricted maximum-likelihood estimation, Hartung-Knapp confidence intervals, and prediction intervals, with outcome-level deduplication and revision-stage sensitivity analyses for reservoir and conduit strain.

For readers tracking this field, the practical takeaway is modest but concrete: across nearly 3,000 pooled patients for reservoir strain, atrial fibrillation detected during follow-up was associated with atria that deform less during filling and contract less vigorously at baseline, while ventricular strain carried no clear signal. Whether adding strain values to existing risk models improves patient selection for extended monitoring remains an open question that this evidence, by design, cannot answer.

Subject of Research: Association of echocardiographic left atrial strain with subsequent atrial fibrillation detection after cryptogenic stroke

Article Title: Echocardiographic strain markers and subsequent atrial fibrillation detection after cryptogenic stroke: an updated systematic review and meta-analysis

Article References: He, Y., Fan, Z., Li, X., Zhang, H., Zhou, G., Luo, Q., & Li, Z. (2026). Echocardiographic strain markers and subsequent atrial fibrillation detection after cryptogenic stroke: an updated systematic review and meta-analysis. Cardiovascular Ultrasound. https://doi.org/10.1186/s12947-026-00393-3

Image Credits: AI Generated

DOI: 10.1186/s12947-026-00393-3

Keywords: cryptogenic stroke, atrial fibrillation, left atrial strain, speckle-tracking echocardiography, meta-analysis, systematic review, ESUS, left ventricular global longitudinal strain, Cardiovascular Ultrasound, risk prediction, Echocardiographic, strain