[The left atrial reservoir strain in ischemic stroke]

The search for a potential cardiac source is a fundamental step in the urgent evaluation of an ischaemic stroke (IS) or Transient ischemic attack (TIA). The most common cardioembolic cause of IS is atrial fibrillation (AF). Analysis of the left atrial function is superior to left atrial (LA) dimensions measurements as predictor of paroxysmal AF, especially with the study of deformation anomalies using 2D Speckle-Tracking. Alteration of the reservoir strain (RS) of the LA is associated with the incidence of IS.

Retrospective observational study in patients hospitalised in the neurology departement from January 2022 to April 2023, for IS or TIA, with no history of AF nor anticoagulation treatment. The objectives of the study were to investigate 1) an association between RS and the embolic origin (cardio-embolic and ESUS) of IS, identifying factors associated with IS; 2) an association between RS and the occurrence of atrial fibrillation, identifying factors associated with impaired RS < 20%.

The study included 79 patients (56% men, median age 72 years), 39% of ischemic strokes were cryptogenic (of which 26% were transient), 23% were cardioembolic, and 14% were embolic of undetermined origin (ESUS). Among the cardioembolic causes (18 patients), 33% were secondary to atrial fibrillation, 39% to a patent foramen ovale (PFO). The median RS was 27%, and the RS was < 39% in 86% of cases, whether the left atrium was dilated or not. With a threshold of 20% and a P value of 0.01, the RS was associated with the embolic origin of the ischemic stroke (PFO group excluded). An RS < 20% was associated with the occurrence of atrial fibrillation during follow-up (P= 0.04).

Our study suggests that a reservoir strain of the left atrium < 20% during the acute phase of an ischemic stroke/transient ischemic attack, in patients without a history of atrial fibrillation or anticoagulant treatment, may be associated with an embolic origin of the ischemic stroke and the occurrence of atrial fibrillation during follow-up.