An Overview of Dioxin-Like Compounds,PCB, and Pesticide Exposures Associated with Sexual Differentiation of Neuroendocrine Systems,Fluctuating Asymmetry,and Behavioral Effects in Birds

Dioxin, polychlorinated biphenyls (PCBs), and pesticides impact neural systems in birds due to interference with sexual differentiation. Early endocrine disrupting chemical (EDC) effects may delay maturation and have long-term effects on lifetime reproduction, especially in precocial birds that complete sexual differentiation prior to hatch. Semi-altricial and altricial species appear more resilient to EDC effects and show a gradient in sensitivity, especially in the neuroplastic song system. Embryonic steroid exposure occurs via maternally deposited steroids followed by embryo produced hormones; EDCs potentially affect these developing systems. As such, EDCs can impact lifelong fitness by acting on neural systems that regulate reproduction, metabolism, and behavior.     

Lead aVL P‐Wave Polarity: Insight from Mapping and Ablation of Atrial Arrhythmia Initiated from Superior Vena Cava

We report a case of focal atrial tachycardia (AT) originating from prior superior vena cava isolation line. The P‐wave morphology in lead aVL during the AT differed from that during sinus rhythm although their foci were in close proximity to each other. We discuss the mechanism based on the activation maps of the right atrium. (PACE 2010; 33:e100–e101)     

Reliability and Validity of the Child and Adolescent Trial for Cardiovascular Health (CATCH) Food Checklist: A Self-report Instrument to Measure Fat and Sodium Intake by Middle School Students

OBJECTIVE: To develop a scoring algorithm and evaluate the reliability and validity of scores from the Child and Adolescent Trial for Cardiovascular Health (CATCH) Food Checklist (CFC) as measures of total fat, saturated fat, and sodium intake in middle school students. DESIGN: Randomized, controlled trial in which participants were assigned to 1 of 3 study protocols that varied the order of CFC and 24-hour dietary recall administration. Criterion outcomes were percent energy from total fat, percent energy from saturated fat, and sodium intake in milligrams. SUBJECTS/SETTING: A multiethnic sample (33% ethnic and racial minorities) of 365 seventh-grade students from 8 schools in 4 states. STATISTICAL ANALYSES: Multivariable regression models were used to calibrate the effects of individual food checklist items; bootstrap estimates were used for cross-validation; and kappa statistics, Pearson correlations, t tests, and effect sizes were employed to assess reliability and validity. RESULTS: The median same-day test-retest reliability kappa for the 40 individual CFC food items was 0.85. With respect to item validity, the median kappa statistic comparing student choices to those identified by staff dietitians was 0.54. Test-retest reliability coefficients ranged from 0.84 to 0.89 for CFC total nutrient scores. Correlations between CFC scores and 24-hour recall values were 0.36 for total fat, 0.36 for saturated fat, and 0.34 for sodium; CFC scores were consistent with hypothesized gender differences in nutrient intake. APPLICATIONS/CONCLUSIONS: The CFC is a reliable and valid tool for measuring fat, saturated fat, and sodium intake in middle school students. Its brevity and ease of administration make the CFC a cost-effective way to measure middle school students' previous day's intake of selected nutrients in school surveys and intervention studies.     

Malfunction of Subpectorally Implanted Cardiac Resynchronization Therapy Defibrillators Due to Weakened Header Bond

Malfunction of Subpectorally Implanted Cardiac Resynchronization Therapy . Background: Implantable cardioverter defibrillator (ICD) implantation has increased significantly over the last 10 years. Concerns about the safety and reliability of ICD systems have been raised, with premature lead failure and battery malfunctions accounting for the majority of reported adverse events. We describe the unique mode of presentation, diagnosis, and management of cardiac resynchronization therapy defibrillators (CRT‐D) malfunctions that were caused by weakened bonding between the generator and header. Methods and Results: Between June 2008 and December 2009, 22 Teligen? ICDs and 24 Cognis? CRT‐Ds were implanted subpectorally at our institution, until a product advisory was issued. Of 24 Cognis? CRT‐D implants, 3 patients presented with CRT‐D malfunctions. All our cases presented with initially intermittent and then persisting increases in shock lead impedance, associated with nonphysiological noise in the shock electrogram channels. These issues were rectified by generator change. Postexplant laboratory analysis confirmed inadequate bonding between device header and titanium casing in all cases, resulting in loosening and rocking of the header followed by fatigue‐induced fracture of the shock circuitry. Conclusion: Weakened bonding between the header and generator casing of subpectorally implanted CRT‐Ds can result in fractures and malfunction of the HV circuit. Physicians monitoring patients with devices affected by the product advisory should remain vigilant in order to diagnose and manage similar device malfunction expediently. (J Cardiovasc Electrophysiol, Vol. 24, pp. 351‐355, March 2013)     

AV Node Reentry Tachycardia in Infants

The purpose of this study was to determine the frequency of atrioventricular (AV) node reentry tachycardia in infants undergoing transesophageal electrophysiological study for paroxysmal tachycardia. The records of all 52 infants < 1-year-old with structurally normal hearts who underwent transesophageal study for paroxysmal tachycardia over a 3-year period were reviewed. Those with a diagnosis of AV node reentry tachycardia underwent complete data review, and follow-up of > 12 months was obtained. Six of 52 infants had a diagnosis of the common type of AV node reentry tachycardia. Tachycardia was diagnosed at a mean age of 2.1 months (range 1 day to 10 months), and 3 of 6 underwent transesophageal study within the first month. Although no patient had structural heart disease, three patients had significant noncardiac disease. Follow-up of 15–38 months (mean 24 ± 7.8) revealed recurrences in 2 of 6 patients. The mean tachycardia cycle length was 240 ms (range 200–310 ms), and the transesophageal ventriculoatrial intervals ranged from < 30 to 55 ms. All patients had an inducible reentrant tachycardia with a ventriculoatrial interval that remained constant even when tachycardia cycle length increased following verapamil or adenosine administration, or decreased following isoproterenol infusion. Five of 6 had evidence for discontinuous AV node conduction curves. In our patients the substrate for AV node reentry tachycardia was present early in life, and AV node reentry tachycardia can be a clinical problem even in the newborn period.