title: Left Atrial Function Is Impaired in Some Patients With Stroke of Undetermined Etiology: Potential Implications for Evaluation and Therapy.
abstract: OBJECTIVE
  Stroke etiology remains undetermined in up to 30% of cases. Paroxysmal atrial fibrillation is found in 20% to 28% of patients with stroke initially classified as being of undetermined etiology. The aim of our study was to analyze left atrial function in ischemic stroke patients to identify patterns associated with cardioembolic etiology and to determine whether the patterns identified can be found in individuals initially classified as having a stroke of undetermined etiology.
  
  
  METHODS
  We studied a cohort of in-hospital ischemic stroke patients referred for transthoracic echocardiography. Treating neurologists determined stroke etiology based on the TOAST classification. Left atrial contractile function was assessed using 2-dimensional echocardiography to determine their ejection fraction and speckle tracking to measure left atrial strain rate: a-wave. Left atrial function was compared between stroke etiology subgroups and healthy controls.
  
  
  RESULTS
  Ninety-seven patients (aged 67±15 years) with ischemic stroke (16.5% large-artery atherosclerosis, 15.5% small-vessel occlusion, 11.3% cardioembolic, 5.1% other determined etiology, 51.1% undetermined etiology) and 10 healthy volunteers (aged 63±7 years) were included. Left atrial ejection fraction was significantly decreased only in patients with stroke of cardioembolic and undetermined etiology compared with the control group (31.5±17.2%, 40.2±17.1%, and 59.1±8.4%, respectively; P=.004). The left atrial strain rate was significantly lower in patients with stroke caused by cardioembolic or undetermined etiology, or large-artery atherosclerosis compared with controls (-0.86±0.49, -1.31±0.56, -1.5±0.47, -2.37±1.18, respectively; P<.001).
  
  
  CONCLUSIONS
  Patients with stroke of undetermined etiology with left atrial function (ejection fraction and strain) similar to that of cardioembolic stroke patients may be misclassified and could potentially benefit from prolonged electrocardiography monitoring. Left atrial function analysis (ejection fraction and strain) might help to identify potential cardioembolic sources in patients with stroke of undetermined etiology.
authors.affiliation: Departamento de Cardiología, Hospital Clínic, IDIBAPS, Universidad de Barcelona, Spain. Electronic address: lsanchisruiz@gmail.com.
authors.forename: Laura
authors.initials: L
authors.lastname: Sanchis
authors.affiliation: Departamento de Cardiología, Hospital Clínic, IDIBAPS, Universidad de Barcelona, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Montserrat
authors.affiliation: Departamento de Neurología, Hospital Clínic, Barcelona, Spain.
authors.forename: Víctor
authors.initials: V
authors.lastname: Obach
authors.affiliation: Departamento de Neurología, Hospital Clínic, Barcelona, Spain.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Cervera
authors.affiliation: Departamento de Neurología, Hospital Clínic, Barcelona, Spain.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Chamorro
authors.affiliation: Departamento de Cardiología, Hospital Clínic, IDIBAPS, Universidad de Barcelona, Spain.
authors.forename: Bàrbara
authors.initials: B
authors.lastname: Vidal
authors.affiliation: Departamento de Cardiología, Hospital Clínic, IDIBAPS, Universidad de Barcelona, Spain.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Mas-Stachurska
authors.affiliation: ICREA-Universidad Pompeu Fabra, Barcelona, Spain.
authors.forename: Bart
authors.initials: B
authors.lastname: Bijnens
authors.affiliation: Departamento de Cardiología, Hospital Clínic, IDIBAPS, Universidad de Barcelona, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Sitges
mesh_terms: D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000150:complications* / Q000175:diagnosis / Q000628:therapy; D016279:Atrial Function, Left / Q000502:physiology*; D002545:Brain Ischemia / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D000889:Anti-Arrhythmia Agents
keywords: Cardiogenic stroke; Ictus cardioembólico; Ictus criptogénico; Ictus isquémico; Ischemic stroke; Left atrial strain; Speckle tracking; Strain auricular izquierdo; Undetermined etiology stroke