Effect of intravenous infusion of blood on the electrocardiogram of anaesthetised dogs.

About 250 to 450 ml of blood was infused within 3 to 5 minutes to study the effect of rapid intravenous infusion of blood on electrocardiogram of 21 anaesthetised dogs. In 16 dogs with initial heart rate above 136/min, i.v. infusion resulted in bradycardia, decrease in P wave amplitude, increase in R wave amplitude and increase in PR, QT and ST intervals. In 3 dogs with initial heart rates above 136/min there was no change in the heart rate, while in 2 dogs with heart rate below 136/min there was tachycardia after the infusion.