Reliability of Transesophageal Pacing in the Assessment of Sinus Node Function in Patients with Sick Sinus Syndrome

The purpose of this study was to find out whether transesophageal pacing could be utilized for assessment of sinus node function in patients with sick sinus syndrome (SSS). In 17 patients with SSS (study group) we compared the results of sinus node tests obtained both in the basal state and after pharmacological autonomic blockade by endocavitary stimulation and, 24 hours later, by transesophageal pacing. In another group of 17 patients with SSS (control group), we compared the results obtained by two endocavitary studies. In "study group", sinus cycle length (SCL) and corrected sinus node recovery time (CSRT) did not show significant differences between the two studies both in the basal state and after autonomic blockade, whereas sinoatrial conduction time (SACT) was more prolonged during esophageal pacing (P less than 0.01). In "control group", sinus node measures did not show significant differences between the two studies. In the "study group," the following coefficients of correlation were obtained in the basal state; SCL, r = 0.65, CSRT, r = 0.57, SACT, r = 0.52 and after autonomic blockade: SCL, r = 0.95, CSRT, r = 0.62 and SACT, r = 0.53. In the basal state, the correlation for SCL and CSRT between the two studies was lower in the "study group" than in the "control group" (P less than 0.05), whereas after autonomic blockade the correlation for sinus node measures did not show significant differences between the two groups of patients. These data suggest that transesophageal study influences the autonomic tone regulating the sinus node; however, it is not responsible for important variations in sinus node measures.(ABSTRACT TRUNCATED AT 250 WORDS)     

Neuroimaging in childhood arterial ischaemic stroke: evaluation of imaging modalities and aetiologies

Aim The aim of this study was to describe neuroimaging patterns associated with arterial ischaemic stroke (AIS) in childhood and to differentiate them according to stroke aetiology. Method Clinical and neuroimaging (acute and follow‐up) findings were analysed prospectively in 79 children (48 males, 31 females) aged 2 months to 15 years 8 months (median 5y 3mo) at the time of stroke by the Swiss Neuropaediatric Stroke Registry from 2000 to 2006. Results Stroke was confirmed in the acute period in 36 out of 41 children who underwent computed tomography, in 53 of 57 who underwent T2‐weighted magnetic resonance imaging (MRI) and in all 48 children who underwent diffusion‐weighted MRI. AIS occurred in the anterior cerebral artery (ACA) in 63 participants and in all cases was associated with lesions of the middle cerebral artery (MCA). The lesion was cortical–subcortical in 30 out of 63 children, cortical in 25 out of 63, and subcortical in 8 of 63 children. Among participants with AIS in the posterior circulation territory, the stroke was cortical–subcortical in 8 out of 16, cortical in 5 of 16, and thalamic in 3 out of 16 children. Interpretation AIS mainly involves the anterior circulation territory, with both the ACA and the MCA being affected. The classification of Ganesan is an appropriate population‐based classification for our Swiss cohort, but the neuroimaging pattern alone is insufficient to determine the aetiology of stroke in a paediatric population. The results show a poor correlation between lesion pattern and aetiology.     

Total serum IgE levels in Venezuelan schoolchildren

Seventy-eight disease-free children were evaluated by PRIST for total serum IgE in order to establish the normal range for this immunoglobulin and assess its utility, in tropical climates, such as Venezuela, as a diagnostic tool for clinical allergy. Seventy-eight normals were selected from a group of 1053 children, aged 7-12 years from fourteen schools in Caracas. Exclusion from the normal pool was based on nationality, and on historical, clinical, and/or laboratory evidence of atopic and/or infectious diseases, particularly with parasites. In addition to a routine CBC and differential, the following studies were performed: a search for stool ova and parasites; in vitro (RAST) and in vivo (skin prick) testing for specific IgE to Dermatophagoides pteronyssinus, Aspergillusfumigatus, and ragweed. Measurement of antibodies against influenza A and B, adenovirus A₂: and B, cytomegalovirus, parainflucnza 1 and 3, herpes simplex, respiratory syncytial virus, Coxsackie B₁ to B₆, Mycoptasma pneumoniae and Rolavirus was also carried out. Normal serum IgE levels for disease-free children in the age group studied ranged from 1.7-255 u/ml. The highest average level (± 74 u/ml) occurred at the age of 9 years. These values differed significantly from age-matched control groups of known atopic and helminth-infected children. Thus, once common causes for elevated IgE levels are eliminated, determination of total serum IgE can be utilized as a valuable tool in diagnosis of clinical allergy in countries with tropical climates.