<P> Transcutaneous pacing (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 . </P> <P> The most common indication for transcutaneous pacing is an abnormally slow heart rate . By convention, a heart rate of less than 60 beats per minute in the adult patient is called bradycardia . 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 . 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 . </P> <P> Some common causes of hemodynamically significant bradycardia include myocardial infarction, sinus node dysfunction and complete heart block . 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). </P> <P> During transcutaneous pacing, pads are placed on the patient's chest, either in the anterior / lateral position or the anterior / posterior position . The anterior / posterior position is preferred as it minimizes transthoracic electrical impedance by "sandwiching" the heart between the two pads . The pads are then attached to a monitor / defibrillator, a heart rate is selected, and current (measured in milliamps) is increased until electrical capture (characterized by a wide QRS complex with tall, broad T wave on the ECG) is obtained, with a corresponding pulse . Pacing artifact on the ECG and severe muscle twitching may make this determination difficult . It is therefore advisable to use another instrument (e.g. SpO2 monitor or bedside doppler) to confirm mechanical capture . </P>

Electrical capture and generation of a qrs complex ensures return of a pulse