Evaluación y validación diagnóstica de las variables iQT, razón iQTRR, razón iRTRR para el diagnóstico DEQTc prolongado / Validation of iQT, iQTRR, iRT/RR ratio for estimation of QTc

ANTECEDENTES: El intervalo QT representa la despolarización y repolarización ventricular y su prolongación está asociada a un mayor riesgo de arritmias graves y muerte súbita. Depende de la frecuencia cardíaca y su rápida valoración es difícil de obtener en la práctica clínica. Una forma que facilita este proceso es medir sólo el intervalo QT pero este no siempre se relaciona con un intervalo QTc prolongado. Debido a esto, se postula que una variable compuesta debería tener mejor rendimiento diagnóstico para este objetivo. OBJETIVO: Describir la correlación de 3 variables electrocardiográficas; intervalo QT (iQT), razón del intervalo QT intervalo RR (%iQTRR) y razón del intervalo RT intervalo RR (%iRTRR), en relación a la variable QT corregido (iQTc). Se efectuó una evaluación diagnóstica y validación de las variables mencionadas para establecer el diagnóstico de intervalo QT largo y las propiedades diagnósticas de las mismas para el diagnóstico de iQTc prolongado según la fórmula Bazett. METODOS Y RESULTADOS: Se efectuó un estudio transversal descriptivo-relacional, usando una muestra no probabilística formada por 220 electrocardiogramas registrados en la base de datos del centro cardiovascular. Las mediciones provenían de ECGs registrados en reposo con medición con cáliper de los intervalos QT y RR en derivadas D2 y/o V5, expresadas en milisegundos. Se excluyó la presencia de isquemia, preexcitación y repolarización precoz. Se obtuvo como resultado que la variable razón iQTRR tiene mejor correlación, concordancia, sensibilidad y valor predictivo negativo para el diagnóstico del iQTc prolongado, versus las variables iQT y razón iRTRR, principalmente en mujeres. CONCLUSIONES: La variable razón iQTRR tiene una mejor correlación, concordancia, sensibilidad y valor predictivo negativo (VPN) para el diagnóstico del iQTc prolongado, comparado con las variables iQT y razón iRTRR, principalmente, en mujeres. Utilizando ambas variables este efecto se potencia y permite concluir que si una mujer tiene un iQT observado <470 ms, y una razón QTRR< 47,5%, esto se corresponde con un intervalo QTc normal, con un VPN de 100% .

BACKGROUND: The QT interval (QT) includes depolarization and repolarization phases of cardiac cycle. Its prolongation is associated to an increa sed risk of serious arrhythmia and sudden death. QT depends on heart rate and it is usually corrected using the Bazett formula (QTc). Prolonged QT is not usually well related to QTc. We postulate that a composite formula muy have a greater value for predicting serious arrhythmia. AIM: To correlate the predictive value of a different approach to estimate a corrected QT interval: the ratio of RT to RR intervals (QT/RR, expressed as a percentage METHODS and RESULTS: A non probabilistic sample of 220 ECGs were obtained from our data base. ECGs were recorded at rest and measurements were performed in leads Ds and/or V5 using zetcalipers, the values being expressed in ms. The presence of ischemia, pre excitation and early repolarization were excluded. The QT/RR ratio showed better correlation, concordance, sensitivity, and negative predicted value with the usual QTc interval compared to QT alone or de RT/RR ratio, especially so in women.

Impacto de la Dieta Vegetariana en la Salud Mental de Adolescentes / Impact of the Vegetarian Diet on the Mental Health of Adolescents

El vegetarianismo en adolescentes está aumentando, sin embargo, la evidencia sobre las consecuencias físicas y psíquicas de este patrón dietario es aún escasa. El objetivo de esta revisión es sistematizar la información científica disponible acerca del vegetarianismo adolescente, para guiar a los jóvenes en la búsqueda de un patrón de dieta saludable. Se realiza una revisión en Pubmed. Se encuentran 9 trabajos en relación a consecuencias físicas y déficit nutricionales, y 6 sobre asociaciones con salud mental. Los resultados se sintetizan según la siguiente clasificación: (1) Consecuencias en la salud física y nutricional; (2) Consecuencias en la salud mental y relación con trastornos de la conducta alimentaria. Sobre el primero, se observa que adolescentes vegetarianos tendrían mayor ingesta de frutas y verduras, y menor riesgo de sobrepeso y obesidad. Una dieta vegetariana restrictiva conlleva déficits nutricionales, que son prevenibles. En cuanto a la salud mental, se evidencia mayor riesgo de conductas de control de peso poco saludables, y, además, tener un trastorno de conducta alimentaria aumenta la probabilidad de haber sido o ser vegetariano. A modo de conclusión, ante un adolescente vegetariano es fundamental explorar las motivaciones a tener este patrón dietético, de modo de pesquisar e intervenir en posibles trastornos alimentarios subyacentes. En cambio, a un adolescente con convicción, se le debe proporcionar orientación para convertirse en un vegetariano saludable. Palabras claves: Adolescentes; dietas vegetarianas; impacto nutricional y de salud y consecuencias en salud mental.

Becoming a vegetarian is an increasing trend among adolescents; however, evidence on the physical and mental health consequences of assuming this dietary pattern is still scarce. This review seeks to review the available scientific knowledge about adolescent vegetarianism in order to guide young people in their search for a healthier diet. A Pubmed review was performed, obtaining 9 studies with relation to physical consequences and nutritional deficits, and 6 on associations with mental health. The results are summarized according to the following classification: (1) Consequences in physical and nutritional health; (2) Consequences in mental health and links to eating disorders. The first findings point to vegetarian teenagers having a higher intake of fruits and vegetables, and a lower risk of overweight and obesity. Nonetheless, a restrictive vegetarian diet leads to nutritional deficits, which are preventable. In terms of mental health issues, we observed a greater risk of unhealthy weight control behaviour; moreover, having an eating disorder increases the likelihood of being (or having been) vegetarian. We suggest that for physicians evaluating a vegetarian adolescent, it is fundamental to explore the motivations behind this dietary pattern in order to diagnose and intervene in possible underlying eating disorders. However, a vegetarian teenager with strong personal beliefs should be provided with guidance and support to develop a healthier diet. Keywords: adolescents, vegetarian diet, physical and nutritional impact, mental health consequences

Isolation and characterization of the equine influenza virus causing the 2006 outbreak in Chile.

The equine influenza virus is the causal agent of influenza in horses. In July 2006, horses from various regions of Chile presented fever, serious nasal discharge, dry cough, anorexia and depression. Here we describe the isolation and characterization of the virus responsible for this outbreak. The virus was identified as equine influenza virus H3N8, since haemagglutination was inhibited by an anti-A/equi/1/H3N8 serum, but not by an anti-A/equi/1/H7N7 serum. The isolate was named A/equi/2/Lonquén/06 (H3N8). In addition, we describe the isolation and sequencing of the haemagglutinin, neuraminidase and nucleoprotein genes of this new isolate. Sequence alignments show important differences with the Santiago/85 isolate and a closer relation to North American isolates, especially with the Florida lineage, and to Argentina isolates from 1990s.

Social anxiety disorder in children and adolescents: epidemiology, diagnosis, and treatment.

Social anxiety disorder (SOC) is characterized by marked and persistent fear of one or more social performance situations in which the person is exposed to unfamiliar people or to possible scrutiny. The person fears that she or he might act in a way that will be humiliating or embarrassing. Children and adolescents with this disorder often have great impairment in their academic performance, social skills, peer relationships, and family life. Early diagnosis is vital. Primary care providers are in a unique situation to first diagnose and treat SOC in children and adolescents. There is evidence of successful pharmacologic and psychosocial treatment in pediatric SOC. Serotonin reuptake inhibitors, which are considered first-line medications for SOC, have shown promising results in open-label and double-blind trials. Studies have demonstrated that psychosocial treatments, specifically cognitive-behavioral therapy and group therapy, are efficacious in pediatric SOC. There is some evidence that the use of combination therapy, both pharmacology and psychosocial treatment, is beneficial in the management of pediatric SOC.