Measurement of heart rate and Q-T interval in the conscious mouse.
Transgenic mouse models provided a powerful tool to evaluate the physiological significance of altered quantities or characteristics of specific gene products, such as cardiac ion channels. We have developed a system to record and analyze changes in the electrocardiogram in the mouse using an implantable telemetry system. The R-R and Q-T intervals were measured on individual beats and on signal-averaged complexes derived from 1, 2, or 4 s of contiguous data each hour during a 24-h period in three male and three female FVB mice. Duration of averaging had minimal effect on the measured Q-T. The Q-T interval was shown to be related to the square root of the R-R interval, and an appropriate formula for a rate-corrected Q-T interval (Q-Tc) was derived. Ketamine anesthesia was shown to markedly increase duration and variability in R-R, Q-T, and Q-Tc intervals. In conscious animals, variability in Q-T was low across animals and over time, suggesting that this should be a sensitive model for detection of changes in the Q-T interval in transgenic mice with ion channel defects.
Mitchell
G F
GF
Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
Jeron
A
A
Koren
G
G
D000818:Animals; D002940:Circadian Rhythm; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D007649:Ketamine / Q000494:pharmacology; D008133:Long QT Syndrome / Q000175:diagnosis*; D008297:Male; D051379:Mice / Q000502:physiology*; D010641:Phenotype; D012737:Sex Factors; D013686:Telemetry; D013997:Time Factors; D014851:Wakefulness
D007649:Ketamine