La concentración plasmática de microARN-1-3p se asocia con fibrilación auricular subclínica en los pacientes con ictus criptogénico / Plasma levels of miRNA-1-3p are associated with subclinical atrial fibrillation in patients with cryptogenic stroke

Introducción y objetivos La identificación de biomarcadores de fibrilación auricular (FA) subclínica en los pacientes con ictus criptogénico (ICr) es de gran interés. Con dicho objetivo, se evaluó el perfil de microARN circulante de los pacientes con ICr y FA frente a aquellos en ritmo sinusal. Métodos Se incluyó a 64 pacientes con ICr consecutivos monitorizados mediante Holter subcutáneo. Se seleccionó a 18 pacientes (9 con FA y 9 en ritmo sinusal persistente) para determinación de 754 microARN mediante tecnología de alto rendimiento. Se incluyó a 9 pacientes adicionales con ictus y FA concomitante para guiar la selección de microARN. Los microARN de interés se replicaron en una cohorte independiente (n=46). La asociación de biomarcadores con FA a los 6 y 12 meses se analizó mediante regresión logística. Resultados Ocho microARN mostraron expresión diferencial entre los pacientes con y sin FA. El miR-1-3p, un regulador génico involucrado en la arritmogénesis cardiaca, fue el único que permaneció significativamente más elevado en pacientes con ICr y FA de la cohorte de repetición, y además mostró una discreta asociación con la carga arrítmica. Los valores de miR-1-3p por encima de la mediana y la fracción de eyección de la aurícula izquierda se asociaron de forma independiente con la presencia de FA a los 6 y 12 meses. Conclusiones En nuestra cohorte, los valores plasmáticos de miR-1-3p fueron más altos en los pacientes con ICr y FA en el seguimiento. Nuestros resultados indican que el miR-1-3p podría ser un nuevo biomarcador de FA oculta en los pacientes con ICr (AU)

Introduction and objectives Identifying biomarkers of subclinical atrial fibrillation (AF) is of most interest in patients with cryptogenic stroke (CrS). We sought to evaluate the circulating microRNA (miRNA) profile of patients with CrS and AF compared with those in persistent sinus rhythm. Methods Among 64 consecutive patients with CrS under continuous monitoring by a predischarge insertable monitor, 18 patients (9 with AF and 9 in persistent sinus rhythm) were selected for high-throughput determination of 754 miRNAs. Nine patients with concomitant stroke and AF were also screened to improve the yield of miRNA selection. Differentially expressed miRNAs were replicated in an independent cohort (n=46). Biological markers were stratified by the median and included in logistic regression analyses to evaluate their association with AF at 6 and 12 months. Results Eight miRNAs were differentially expressed between patients with and without AF. In the replication cohort, miR-1-3p, a gene regulator involved in cardiac arrhythmogenesis, was the only miRNA to remain significantly higher in patients with CrS and AF vs those in sinus rhythm and showed a modest association with AF burden. High (= above the median) miR-1-3p plasma values, together with a low left atrial ejection fraction, were independently associated with the presence of AF at 6 and 12 months. Conclusions In this cohort, plasma levels of miR-1-3p were elevated in CrS patients with subsequent AF. Our results preliminarily suggest that miR-1-3p could be a novel biomarker that, together with clinical parameters, could help identify patients with CrS and a high risk of occult AF (AU)

[Adverse effects of dobutamine stress echocardiography]. / Efectos secundarios de la ecocardiografía de estrés con dobutamina.

OBJECTIVES: To study the side effects of dobutamine echocardiography and to define the protocol with less side effects. PATIENTS AND METHODS: Since June 1992 to November 1994 dobutamine echocardiography was performed on two different groups of patients. In the first, the test was preoperatively done to evaluate the surgical risk. The remaining were patients with angina. Dobutamine was started at a dose of 5 micrograms/kg/min and increased up to a total dose of 40 micrograms/kg/min. Since March 1993 atropine was added if the heart rate was under 90 beats/min. RESULTS: One hundred and forty one patients were included (76 for a preoperatory appraisal and 65 with angina). Echocardiography test was not performed on 3 patients (2 with pulmonary disease and 1 with a therapeutic neumothorax). Among the remaining 138 patients, side effects appeared in 53 patients (38%) and test had to be prematurely interrupted in 11 (8%) of them. Side effects presented during the test in 9 (7%) although it could be finished and at the end of the test in 33 (24%). The most frequent side effects were arrhythmias that appeared in 28 patients (20%) and were considered significant in 17: 7 with supraventricular tachycardia, 7 with more than 6 ventricular premature systoles per minute, 2 with ventricular tachycardia and 1 with multifocal supraventricular premature systoles. These arrhythmias were observed when the dose of dobutamine was 20 micrograms/kg/min or more (p < 0.05). Hypotension developed in 11 patients (8%) and noncardiac effects in 13 (9%). The dobutamine test was interrupted for arrhythmias in 4% of cases, noncardiac side effects in 2% and poor image quality in 3%. A steady increment of heart rate 5 minutes after infusion of atropine was detected in 12 patients (maximal: 93 +/- 23 beats per minute; after five minutes: 94 +/- 19) and side effects were encountered in only one of these patients (hypotension). CONCLUSIONS: Intravenous administration of dobutamine during echocardiography can be finished in the majority of patients with good tolerance in spite of its side effects. Arrhythmias with dose over 20 micrograms/kg/min, poor image quality and chronotropic insufficiency are the most frequently encountered limitations.