Electrical,device. For selected patients with arrhythmias, particularly heart block- electrical, and slow rhythms, pacing can be life saving. Wires are passed, usually transvenous, to the inner - endocardium surface of the heart, tested for stimulus threshold, and connected to the battery-pacer device. All this is implanted under the skin. The new devices are multi-programmable transcutaneous , and can be checked.
Used when own is bad. The heart has its own internal pacer. When it malfunctions a permanant pace can be placed to take over for the hearts own pacer when it fails.