Pre-excited RR intervals during atrial fibrillation in the Wolff-Parkinson-White syndrome: Influence of the atrioventricular node refractory period

AbstractThe ventricular rate and percent of pre-excited QRS complexes during atrial fibrillation were compared in two groups of patients with the Wolff-Parkinson-White syndrome. Group A consisted of 22 patients whose anterograde effective refractory period of the accessory pathway was longer than that of the atrioventricular (AV) node. Group B consisted of 23 patients in whom this relation was reversed. No patient had organic heart disease.Both groups had a similar effective refractory period of the accessory pathway (288 ± 37 vs. 280 ± 26 ms), whereas that of the AV node was shorter in group A than group B (242 ± 25 vs. 285 ± 27 ms, p = 0.0001). Patients in group A had a lower percent of pre-excited QRS complexes during atrial fibrillation (39 ± 43% vs. 93 ± 20%, p = 0.0001). In the 21 patients whose refractory period was measured, the difference was plotted against the percent of pre-excited QRS complexes; there was a significant correlation between the two (r = −0.83, p < 0.001).In patients in whom pre-excited RR intervals were present, the pre-excited RR intervals were compared between the two groups. Both groups had similar effective refractory periods of the accessory pathway (265 ± 22 vs. 280 ± 27 ms) and ventricle (200 ± 17 vs. 211 ± 26 ms). The effective refractory period of the AV node was shorter in group A (248 ± 22 vs. 285 ± 28 ms, p = 0.0005). The shortest pre-excited RR interval did not show any difference (244 ± 37 vs. 265 ± 41 ms). However, both the average (328 ± 39 vs. 397 ± 56 ms, p = 0.001) and longest (495 ± 109 vs. 666 ± 205 ms, p = 0.02) pre-excited RR intervals were shorter in group A.These data suggest that interaction between the refractory periods of the AV node and accessory pathway contributes to the percent of pre-excited QRS complexes. The effective refractory period of the AV node also indirectly contributes to the duration of pre-excited RR intervals. This contribution is greatest when RR intervals are long

Community and Programmatic Factors Influencing Effecting Use of System Dynamic Models

Despite knowledge of factors that enable effective system dynamics modeling and organizational change, real-life application of these tools in community settings remains challenging and often produces mixed results. We undertook a two-part evaluation of early community use of the ReThink Health Dynamics Model (RTH model). The RTH model is a realistic, but simplified, portrait of a regional health system that supports multisector planning and strategy design. We assessed the contextual characteristics and implementation processes that promoted or under- mined effective engagement with the model in five pilot sites. These learnings were used to refine a community readiness framework (Elements Affecting Modeling Use) that was then used to select and design a sixth community engagement. We use the evaluation results to assess the value of this organizing framework to identify communities ready for engagement with validated system dynamics models. Enabling better community–model matches will accelerate model adoption and health system transformation

Effect of Two Week L-Arginine Supplementation on Variables Related to Endurance and Strength Performance in Collegiate Football Players

Background: It has been shown that a month-long supplementation period of L-arginine, coupled with exercise training, increases exercise performance more than either supplementation or exercise alone (Hambrecht et al., 2000). Purpose: The purpose of this study was to examine the effects of a shorter 2 wk L-arginine supplementation period on factors related to endurance and strength performance. Methods: Twelve collegiate football players volunteered to participate in this study. The control group (n = 6) and treatment group (n = 6) both participated in the same off-season training program that consisted of strength training 3 d/wk and agility training 2 d/wk. In addition, the treatment group received 1g of L-arginine twice daily, whereas the control group received a placebo twice daily. At the beginning of the study, participants performed a baseline bench press maximum repetitions test at 70% of their most recently recorded bench press 1 RM (MMR). The participants also performed a graded exercise test (GXT) on a cycle ergometer to volitional exhaustion. Following baseline testing, participants immediately began the supplementation period, and were retested in the MMR and the GXT after 2 wk of supplementation. The effect of supplementation on each dependent variable was determined using ANCOVA with pretests serving as the covariates. Results: ANCOVA did not reveal significant effects of L-arginine supplementation on MMR (F(1,9) = 1.71, p = 0.22), VO2max (F(1,9) = 1.08, p = 0.33), time to exhaustion in the GXT (F(1,9) = 0.19, p = 0.67) , or HRmax during the GXT (F(1,9) = 4.79, p = 0.06). Conclusion: A 2 wk supplementation period coupled with training may not be of sufficient length to improve factors related to endurance and strength performance in trained college-aged men

Creation and implementation of an emergency medicine education and training program in Turkey: An effective educational intervention to address the practitioner gap

Background The specialty of Emergency Medicine has enjoyed recognition for nearly 20 years in Turkey. However, the majority of underserved and rural Turkish emergency departments are staffed by general practitioners who lack formal training in the specialty and have few opportunities to increase emergency medicine-specific knowledge and skills. Methods To address this “practitioner gap,” the authors developed a four-phase comprehensive emergency medicine education and training program for general practitioners practicing in government hospitals in Turkey. Results From April 2006 until June 2009, 42 courses were taught by 62 trainers across seven regions in Turkey. A total of 2,262 physicians were trained. The mean course pre-test score for all regions was 42.3 (95% CI 39.8 to 44.7). The mean course post-test score was 70.1 (95% CI 67.2 to 72.9). The difference between the mean scores was 27.8 (95% CI 25.3 to 30.4, P \u3c0.0001), reflecting an improvement of 65.7%. Conclusions A partnership between an academic emergency medicine department and an emergency medicine society to implement country-wide training of physicians practicing in public emergency departments can serve as a successful model for capacity-building global emergency medicine endeavors

Toy articles of manufacture comprising spontaneously wettable fibers

This invention relates to an article of manufacture consisting of a toy having a plurality of synthetic fibers capable of spontaneously transporting water on the surface thereof, said fibers satisfying the following equation wherein .theta..sub.a is the advancing contact angle of water measured on a flat film made from the same material as the fiber and having the same surface treatment, if any, X is a shape factor of the fiber cross-section that satisfies the following equation ##EQU1## wherein P.sub.w is the wetted perimeter of the fiber and r is the radius of the circumscribed circle circumscribing the fiber cross-section and D is the minor axis dimension across the fiber cross-section

Mosaicism of the UDP-Galactose Transporter SLC35A2 Causes a Congenital Disorder of Glycosylation

Biochemical analysis and whole-exome sequencing identified mutations in the Golgi-localized UDP-galactose transporter SLC35A2 that define an undiagnosed X-linked congenital disorder of glycosylation (CDG) in three unrelated families. Each mutation reduced UDP-galactose transport, leading to galactose-deficient glycoproteins. Two affected males were somatic mosaics, suggesting that a wild-type SLC35A2 allele may be required for survival. In infancy, the commonly used biomarker transferrin showed abnormal glycosylation, but its appearance became normal later in childhood, without any corresponding clinical improvement. This may indicate selection against cells carrying the mutant allele. To detect other individuals with such mutations, we suggest transferrin testing in infancy. Here, we report somatic mosaicism in CDG, and our work stresses the importance of combining both genetic and biochemical diagnoses

Common Variation in ISL1 Confers Genetic Susceptibility for Human Congenital Heart Disease

Congenital heart disease (CHD) is the most common birth abnormality and the etiology is unknown in the overwhelming majority of cases. ISLET1 (ISL1) is a transcription factor that marks cardiac progenitor cells and generates diverse multipotent cardiovascular cell lineages. The fundamental role of ISL1 in cardiac morphogenesis makes this an exceptional candidate gene to consider as a cause of complex congenital heart disease. We evaluated whether genetic variation in ISL1 fits the common variant–common disease hypothesis. A 2-stage case-control study examined 27 polymorphisms mapping to the ISL1 locus in 300 patients with complex congenital heart disease and 2,201 healthy pediatric controls. Eight genic and flanking ISL1 SNPs were significantly associated with complex congenital heart disease. A replication study analyzed these candidate SNPs in 1,044 new cases and 3,934 independent controls and confirmed that genetic variation in ISL1 is associated with risk of non-syndromic congenital heart disease. Our results demonstrate that two different ISL1 haplotypes contribute to risk of CHD in white and black/African American populations

Severe acute respiratory syndrome coronavirus 2 environmental contamination in hospital rooms is uncommon using viral culture techniques

We assessed environmental contamination of inpatient rooms housing coronavirus disease 2019 (COVID-19) patients in a dedicated COVID-19 unit. Contamination with severe acute respiratory syndrome coronavirus 2 was found on 5.5% (19/347) of surfaces via reverse transcriptase polymerase chain reaction and 0.3% (1/347) of surfaces via cell culture. Environmental contamination is uncommon in hospitals rooms; RNA presence is not a specific indicator of infectious virus