Transcutaneous pacing (TCP), also called external pacing, is a temporary means of pacing a patient's heart during a medical emergency. It should not be confused with defibrillation (used in more serious cases, in ventricular fibrillation and other shockable rhythms) using a manual or automatic defibrillator, though some newer defibrillators can do both, and pads and an electrical stimulus to the heart are used in transcutaneous pacing and defibrillation. Transcutaneous pacing is accomplished by delivering pulses of electric current through the patient's chest, which stimulates the heart to contract.[citation needed]
The most common indication for transcutaneous pacing is an abnormally slow heart rate. By convention, a heart rate of fewer than 60 beats per minute in the adult patient is called bradycardia.[1] Not all instances of bradycardia require medical treatment. Normal heart rate varies substantially between individuals, and many athletes in particular have a relatively slow resting heart rate.[2] In addition, the heart rate is known to naturally slow with age. It is only when bradycardia presents with signs and symptoms of shock that it requires emergency treatment with transcutaneous pacing.
Some common causes of hemodynamically significant bradycardia include myocardial infarction, sinus node dysfunction and complete heart block.[citation needed]
Transcutaneous pacing is no longer indicated for the treatment of asystole (cardiac arrest associated with a "flat line" on the ECG), with the possible exception of witnessed asystole (as in the case of bifascicular block that progresses to complete heart block without an escape rhythm).[4]