Evaluation of Electrocardiographic Ventricular Depolarization and Repolarization Variables in Type 1 Diabetes Mellitus / Avaliação de Variáveis Eletrocardiográficas de Despolarização e Repolarização Ventricular em Diabetes Mellitus Tipo 1

Abstract Background: The risk of cardiovascular events and sudden death increases with type 1 diabetes mellitus (T1DM). Objective: To evaluate electrocardiographic markers of arrhythmias in T1DM patients. Methods: Electrocardiographic parameters reflecting ventricular depolarization and repolarization, namely, QT, QTc, QTd, QTdc, Tp-e, JT, and JTc intervals and Tp-e/QT and Tp-e/QTc ratios, of 46 patients diagnosed with T1DM were retrospectively analyzed and compared with 46 healthy age-, sex-, and body mass-matched controls. Correlations between T1DM duration, hemoglobin A1c (HbA1c), and ventricular repolarization variables were analyzed. P values lower than 0.05 were considered statistically significant. Results: Diabetes duration was 16.6 ± 7.1 years, and HbA1c was 10.81% ± 3.27% in the T1DM group. In comparison with the control group, heart rate, QTc, QTd, QTdc, Tp-e and JTc intervals, Tp-e/QT ratio (p < 0.001), and Tp-e/QTc ratio (p = 0.007) were significantly higher in T1DM patients. T1DM duration and HbA1c levels were significantly correlated with QTc, QTd, QTdc, Tp-e, and JTc intervals and Tp-e/QT and Tp-e/QTc ratios. Conclusions: In T1DM patients, potential electrocardiographic repolarization predictors were significantly increased in correlation with disease duration and HbA1c levels. These findings may contribute to the understanding of sudden cardiac death in patients with T1DM.

Resumo Fundamento: O risco de eventos cardiovasculares e morte súbita aumenta com diabetes mellitus tipo 1 (DM1). Objetivo: Avaliar alguns marcadores eletrocardiográficos de arritmias em pacientes com DM1. Métodos: Parâmetros eletrocardiográficos que refletem despolarização e repolarização ventricular, a saber, os intervalos QT, QTc, QTd, QTdc, Tp-e, JT e JTc e as relações Tp-e/QT e Tp-e/QTc, de 46 pacientes diagnosticados com DM1 foram retrospectivamente analisados e comparados com 46 controles saudáveis, pareados por idade, sexo e massa corporal. As correlações entre duração de DM1, HbA1c e variáveis de repolarização ventricular foram analisadas. Foram considerados estatisticamente significativos os valores de p inferiores a 0,05. Resultados: A duração de diabetes foi de 16,6 ± 7,1 anos, e HbA1c foi 10,81% ± 3,27% no grupo DM1. Em comparação com o grupo controle, a frequência cardíaca, os intervalos QTc, QTd, QTdc, Tp-e e JTc, a relação Tp-e/QT (p < 0,001) e a relação Tp-e/QTc (p = 0,007) foram significativamente mais altos em pacientes com DM1. A duração de DM1 e os níveis de HbA1c foram significativamente correlacionados com os intervalos QTc, QTd, QTdc, Tp-e e JTc e com as relações Tp-e/QT e Tp-e/QTc. Conclusões: Em pacientes com DM1, potenciais preditores eletrocardiográficos de repolarização foram significativamente aumentados em correlação com a duração da doença e com os níveis de HbA1c. Estes achados podem contribuir à compreensão da morte súbita cardíaca em pacientes com DM1.

Microscopic aspects of electrosensory system on the partially euryhaline lesser guitarfish

ABSTRACT The electrosensory system on elasmobranchs consists of subcutaneous electroreceptor organs known as ampullae of Lorenzini. The present study investigated the ampullae of Lorenzini morphology of the lesser guitarfish Zapteryx brevirostris, using light microscopy and scanning electron microscopy. The pore number found in the ventral skin surface is much higher than that found in the dorsal portion, characteristic of species that inhabit the euphotic zone. Under light microscopy it was possible to observe that the wall canal consists of a single layer of squamous epithelial cells. The canal features distal expansion, where the ampullae are located with up to six alveoli. The sensory epithelium of ampullae is composed by cubic cells, with oval nucleus, restricted to the interior of the alveoli. With analysis the clusters under scanning electron microscopy, it was possible to observe the structure and the random arrangement of individual ampullae, canals and nerves. The distribution of dorsal and ventral pores and ampullae in Z. brevirostris resembled those of the same family. The number of alveoli per ampullae was similar to that found in euryhaline elasmobranchs species, suggesting that the morphological organization in Z. brevirostris is linked to its possible evolutionary transitory position among batoids.

Acute inflammatory demyelinating polyneuropathy in children; clinical and electrophysiologic findings

The aim of this study was to evaluate the electrophysiologic findings of Guillain Barre Syndrome [GBS] in children and their relation with clinical progress of the disease. Twenty-three children with GBS were evaluated between 2005 and 2007. Electrophysiologic evaluations were performed at admission and one month later. Five patients needed respirator, 15 were bedridden, 1 developed recurrence 6 months later, and 2 experienced chronic GBS. The most common findings included: decreased amplitude of muscle action potential [CMAP] [96%], increased distal latency [74%], increased F wave latency [69%], and decreased nerve conduction velocity [NCV] [61%]. Sensory nerve conduction [evaluating sural nerve] was normal in 78% of the cases. These measures did not significantly change after 1 month. Electrodiagnostic evaluations are helpful at the primary stages of GBS for diagnosis. Fibrillation potentials and positive sharp waves showing denervation and axonal injury are presentative of longer duration of the disease and a worse prognosis