ECG changes after experimental head trauma.

ECG changes have been recorded in 11 monkeys following experimental head injury. The principal changes include bradycardia, shortening of the Q-Tc interval, prolongation of the Q-T interval, and alterations of rhythm. The changes last from a few seconds to approximately 2 hours. It is concluded that the changes result from a massive autonomic out-flow from the injured brain and in occasional instances may result in death due to cardiac arrest.