Circadian Variation in Defibrillation Energy Requirements

摘要: Background Reports have demonstrated a circadian variation in the incidence of acute myocardial infarction, ventricular arrhythmias, and sudden cardiac death. We tested hypothesis that similar exists for defibrillation energy requirements humans. Methods Results reviewed time threshold (DFT) measurements 134 patients with implantable cardioverter-defibrillators (ICDs) who underwent 345 DFT measurements. The was determined 130 at implantation, 121 2 months, 94 6 months. All had nonthoracotomy systems. morning (8 am to 12 noon) 15.1±1.2 J compared 13.1±0.9 midafternoon (12 noon 4 pm) 13.0±0.7 late afternoon (4 8 pm), P <.02. In separate group 930 implanted an ICD system date stamps each therapy, we 1238 episodes tachyarrhythmias treated shock therapy. To corroborate arrhythmia termination vary during course day, plotted failed first frequency all per hour. There significant peak shocks other intervals ( =.02). Conclusions is corresponding frequency. This resembles peaks seen events, specifically These findings important implications appropriate function, particularly marginal DFTs.