title: Age and anesthetic effects on murine electrocardiography.
abstract: Murine models offer potential insights regarding human cardiac disease, but efficient and reliable methods for phenotype evaluation are necessary. We employed non-invasive electrocardiography (ECG) in mice, investigating statistical reliability of these parameters with respect to anesthetic and animal age. Mice (C57BL/6, 8 or 48 weeks) were anesthetized by ketamine/xylazine (K/X, 80/10 mg/kg ip) or by inhalation anesthetic (halothane, HAL; sevoflurane, SEV) and 6 lead ECGs were recorded. P wave duration and QT interval was significantly prolonged with K/X compared to HAL and SEV, indicating slowed atrial and ventricular conduction. P-R interval (atrio-ventricular conduction) was significantly increased in aged mice under all anesthetics. Heart rate was inversely correlated to QT interval and P wave duration. We also detected significant age effects with respect to optimal approaches for QT interval corrections. Power analysis showed 4-fold higher number of mice/group, were required for K/X, to achieve identical statistical sensitivity. These data demonstrate the importance of anesthetic selection for relevant and reliable ECG analysis in mice and illustrate the selective influences of anesthetics and age on cardiac conductance in this species.
authors.affiliation: Center for Developmental Pharmacology and Toxicology, Columbus Children's Research Institute, The Ohio State University, Columbus, OH, 43210, USA.
authors.forename: Alysia A
authors.initials: AA
authors.lastname: Chaves
authors.forename: Spencer J
authors.initials: SJ
authors.lastname: Dech
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Nakayama
authors.forename: Robert L
authors.initials: RL
authors.lastname: Hamlin
authors.forename: John Anthony
authors.initials: JA
authors.lastname: Bauer
authors.forename: Cynthia A
authors.initials: CA
authors.lastname: Carnes
mesh_terms: D000375:Aging / Q000502:physiology*; D019162:Anesthetics, Combined / Q000494:pharmacology; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D004195:Disease Models, Animal; D004562:Electrocardiography / Q000187:drug effects* / Q000379:methods; D005260:Female; D006221:Halothane / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D007649:Ketamine / Q000494:pharmacology; D008738:Methyl Ethers / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D015203:Reproducibility of Results; D000077149:Sevoflurane; D014991:Xylazine / Q000494:pharmacology
chemical_list: D019162:Anesthetics, Combined; D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D014991:Xylazine; D000077149:Sevoflurane; D007649:Ketamine; D006221:Halothane