记录并比较了180头不同年龄比格犬的Ⅰ、Ⅱ、Ⅲ、aVR、aVL和aVF六个导联的心电图。结果发现，随着年龄的增大，心率减缓，P-R间期和Q-T间期延长，但QRS时间差异不显著。

"Electrocardiogram of six leads including I , H , I .aVL.aVR and aVF was recorded and analysed in 180 Beagle canines at different ages. It was found that there was definite difference in heart rate ,P —R interval and Q —T interval for different age. Heart rate was slower,P — R and Q —T intervals were longer in older canines than those in younger canines, but there wasn’t obvious difference in QRS interval. "