Circulation
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Sinoatrial node (SAN) dysfunction is frequently associated with atrial tachyarrhythmias (ATs). Abnormalities in SAN pacemaker function after termination of ATs can cause syncope and require pacemaker implantation, but underlying mechanisms remain poorly understood. This study examined the hypothesis that ATs impair SAN function by altering ion channel expression. ⋯ AT downregulates SAN HCN2/4 and minK subunit expression, along with the corresponding currents I(f) and I(Ks). Tachycardia-induced remodeling of SAN ion channel expression, particularly for the "pacemaker" subunit I(f), may contribute to the clinically significant association between SAN dysfunction and supraventricular tachyarrhythmias.
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Population-based data for pediatric cardiac arrest are scant and largely from urban areas. The Resuscitation Outcomes Consortium (ROC) Epistry-Cardiac Arrest is a population-based emergency medical services registry of out-of-hospital nontraumatic cardiac arrest (OHCA). This study examined age-stratified incidence and outcomes of pediatric OHCA. We hypothesized that survival to hospital discharge is less frequent from pediatric OHCA than adult OHCA. ⋯ This study demonstrates that the incidence of OHCA in infants approaches that observed in adults but is lower among children and adolescents. Survival to discharge was more common among children and adolescents than infants or adults.
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Hypothermia therapy improves mortality and functional outcome after cardiac arrest and birth asphyxia in adults and newborns. The effect of hypothermia therapy in infants and children with cardiac arrest is unknown. ⋯ Hypothermia therapy was used in resuscitation scenarios that are associated with greater risk of poor outcome. In an adjusted analysis, the effectiveness of hypothermia therapy was neither supported nor refuted. A randomized controlled trial is needed to rigorously evaluate the benefits and harms of hypothermia therapy after pediatric cardiac arrest.