Ambulatory electrocardiography (Holter monitoring) in caged monkeys

A swivel-tethering and jacket system was used in conjunction with vinyl patch electrodes and Holter recorders to obtain continuous ECG recordings in 12 rhesus monkeys on a long-term (12 day) study. Animals were custom-fitted with nylon mesh jackets that were connected to a swivel unit by a flexible, stainless steel tether. Lead wires from the chest electrodes passed through the tether to the electrical swivel apparatus located at the top of the cage. Wires from the upper part of the swivel were attached to a reel-to-reel Holter recorder. This technique was used to obtain 24-h continuous ECG recordings, which were later processed using a computer-assisted Holter analysis system.