Frequency of Alleles Including Structural Variants in the United States.

The gene encodes an enzyme important in the metabolism of many commonly used medications. Variation in is associated with inter-individual differences in medication response, and genetic testing is used to optimize medication therapy. This report describes a retrospective study of allele frequencies in a large population of 104,509 de-identified patient samples across all regions of the United States (US).

Mechanism of loss of consciousness during vascular neck restraint.

Vascular neck restraint (VNR) is a technique that police officers may employ to control combative individuals. As the mechanism of unconsciousness is not completely understood, we tested the hypothesis that VNR simply compresses the carotid arteries, thereby decreasing middle cerebral artery blood flow. Twenty-four healthy police officers (age 35 ± 4 yr) were studied.

Randomized controlled trial of fixed rate versus rate responsive pacing after radiofrequency atrioventricular junction ablation: quality of life, ventricular refractoriness, and paced QT dispersion.

Introduction: Ablation of the AV junction is a widely accepted treatment of drug-refractory atrial fibrillation. Long-term pacing of the right ventricular (RV) apex following AV junction ablation can result in adverse cardiac remodeling. However, anecdotal studies report that pacing too slowly following AV junction ablation was associated with propensity to sudden cardiac death.

Selective knockout of mouse ERG1 B potassium channel eliminates I(Kr) in adult ventricular myocytes and elicits episodes of abrupt sinus bradycardia.

The ERG1 gene encodes a family of potassium channels. Mutations in human ERG1 lead to defects in cardiac repolarization, referred to as the long QT syndrome. Through homologous recombination in mouse embryonic stem cells the ERG1 B potassium channel transcript was eliminated while the ERG1 A transcript was maintained.

Overexpression of calcineurin in mouse causes sudden cardiac death associated with decreased density of K+ channels.

Background: Overexpression of calcineurin in transgenic (TG) mice results in cardiac hypertrophy and unexpected deaths.

Methods And Results: None of the TG survived beyond 24 weeks (n=38) whereas all of the wildtype (WT, n=47) survived. Prolongation of repolarization preceded the development of sustained pleomorphic ventricular tachycardia and high degree atrioventricular block, which occurred during spontaneous sudden deaths.