Short episodes of atrial tachycardia or fibrillation are not associated with increased risk of clinical events, compared with absence of these episodes, according to a study published October 18 in Circulation. The Registry of Atrial Tachycardia and Atrial Fibrillation Episodes enrolled 5,379 patients with pacemakers or implantable cardioverter defibrillators. There were 478 hospitalizations among 342 patients for clinical events. Study authors adjudicated 37,531 electrograms. Patients with clinical events were more likely than those without them to have long atrial tachycardia or fibrillation. Only short episodes of atrial tachycardia or fibrillation were documented in 9% of patients with pacemakers and in 16% of patients with implantable cardioverter defibrillators. Patients with clinical events were no more likely than those without them to have short atrial tachycardia or fibrillation.
A brain signature identifies patients with fibromyalgia with 93% accuracy, according to a study published online ahead of print August 31 in Pain. Researchers examined 37 patients with fibromyalgia and 35 matched healthy controls. They analyzed participants' functional MRI responses to painful pressure and nonpainful multisensory stimulation. Investigators used machine-learning techniques to identify a brain-based fibromyalgia signature. When exposed to the same painful stimuli, patients with fibromyalgia had greater Neurologic Pain Signature responses. Furthermore, a new pain-related classifier revealed augmented responses in sensory integration and self-referential regions in fibromyalgia, and reduced responses in the lateral frontal cortex. Combined activity in the Neurologic Pain Signature, fibromyalgia pain, and multisensory patterns classified patients vs. controls with 92% sensitivity and 94% specificity in individuals who were not part of the study sample.
Children have measurable brain changes after a single season of youth football, even when they do not sustain a concussion, according to a study published online ahead of print October 24 in Radiology. Head impact data were recorded using the Head Impact Telemetry system and quantified as the combined-probability risk-weighted cumulative exposure. Twenty-five male participants were evaluated for seasonal fractional anisotropy changes in the inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, and superior longitudinal fasciculus. There were statistically significant linear relationships between risk-weighted cumulative exposure and decreased fractional anisotropy in the whole, core, and terminals of the left inferior fronto-occipital fasciculus. A trend toward statistical significance in the right superior longitudinal fasciculus was observed. Decrease in fractional anisotropy of the right superior longitudinal fasciculus terminal was significantly correlated with risk-weighted cumulative exposure.
Zika virus contributes to the development of Guillain-Barré syndrome, according to a study published online ahead of print October 5 in the New England Journal of Medicine. From November 2015 through March 2016, clusters of cases of Guillain-Barré syndrome were observed during an outbreak of Zika virus in Colombia. Researchers characterized the clinical features of 68 patients with Guillain-Barré syndrome during the outbreak and investigated their relationship with Zika virus infection. In all, 97% of patients had symptoms compatible with Zika virus infection before the onset of Guillain-Barré syndrome. Among the 42 patients who had samples tested for Zika virus infection, the results were positive in 40%. Most of the positive results were in urine samples, although three samples of CSF were also positive.