Measurement of heart rate and Q-T interval in the conscious mouse

Am J Physiol. 1998 Mar;274(3):H747-51. doi: 10.1152/ajpheart.1998.274.3.H747.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Circadian Rhythm
  • Electrocardiography / methods*
  • Female
  • Heart Rate / drug effects
  • Ketamine / pharmacology
  • Long QT Syndrome / diagnosis*
  • Male
  • Mice / physiology*
  • Phenotype
  • Sex Factors
  • Telemetry
  • Time Factors
  • Wakefulness


  • Ketamine