Fibrilación auricular en el ictus criptogénico: ¿son necesarias nuevas herramientas para su diagnóstico?

Left Atrial Function Is Impaired in Some Patients With Stroke of Undetermined Etiology: Potential Implications for Evaluation and Therapy

INTRODUCTION AND OBJECTIVES

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.

The CHADS2 Score to Predict Stroke Risk in the Absence of Atrial Fibrillation in Hypertensive Patients Aged 65 Years or Older

INTRODUCTION AND OBJECTIVES

The CHADS2 score is a proven, essential tool for estimating cardioembolic risk (mainly stroke) in patients with nonvalvular atrial fibrillation, with the purpose of determining the indication for anticoagulant therapy. In this study we analyzed the use of CHADS2 in hypertensive patients without known atrial fibrillation in a Mediterranean population.

METHODS

The study included 887 hypertensive patients aged 65 years or older without atrial fibrillation or anticoagulant therapy, who attended a medical consultation. Data on the patients' main risk factors, cardiovascular history, and medication were collected, basic laboratory analyses and electrocardiography were performed, and the CHADS2 score (heart failure, hypertension, age ≥ 75 years, diabetes mellitus, and previous stroke or transient ischemic attack) was calculated. A clinical follow-up was carried out, recording hospital admissions for a stroke or transient ischemic attack. The median duration of follow-up was 804 days.

RESULTS

Mean age was 72.5 (SD,5.7) years, 46.6% were men, 27.8% had diabetes, and 8.6% were smokers. During follow-up, 40 patients were hospitalized for a stroke or transient ischemic attack (4.5%). The event-free survival analysis showed significant differences according to the CHADS2 score (log rank test, P < .001). On multivariate analysis, smoking and CHADS2 ≥3 were independent predictors of stroke or transient ischemic attack.

CONCLUSIONS

The CHADS2 may be useful for estimating the risk of stroke or transient ischemic attack in hypertensive patients without known atrial fibrillation.