Transcutaneous pacing (TCP), also called external pacing, is a temporary means of pacing a patient's

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...

during a medical emergency. It should not be confused with

defibrillation Defibrillation is a treatment for life-threatening cardiac arrhythmias, specifically ventricular fibrillation (V-Fib) and non-perfusing ventricular tachycardia (V-Tach). A defibrillator delivers a dose of electric current (often called a ''cou ...

(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

to contract. The most common indication for transcutaneous pacing is an abnormally slow

heart rate Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excr ...

. By convention, a heart rate of less than 60 beats per minute in the adult patient is called

bradycardia Bradycardia (also sinus bradycardia) is a slow resting heart rate, commonly under 60 beats per minute (BPM) as determined by an electrocardiogram. It is considered to be a normal heart rate during sleep, in young and healthy or elderly adults, a ...

. 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 Shock may refer to: Common uses Collective noun *Shock, a historic commercial term for a group of 60, see English numerals#Special names * Stook, or shock of grain, stacked sheaves Healthcare * Shock (circulatory), circulatory medical emergen ...

that it requires emergency treatment with transcutaneous pacing. False-capture

Some common causes of hemodynamically significant bradycardia include

myocardial infarction A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may ...

sinus node dysfunction Sinus node dysfunction (SND), also known as sick sinus syndrome (SSS), is a group of abnormal heart rhythms (arrhythmias) usually caused by a malfunction of the sinus node, the heart's primary pacemaker. Tachycardia-bradycardia syndrome is a varian ...

and

complete heart block Third-degree atrioventricular block (AV block) is a medical condition in which the electrical impulse generated in the sinoatrial node (SA node) in the atrium of the heart can not propagate to the ventricles. Because the impulse is blocked, an a ...

. Transcutaneous pacing is no longer indicated for the treatment of

asystole Asystole (New Latin, from Greek privative a "not, without" + ''systolē'' "contraction") is the absence of ventricular contractions in the context of a lethal heart arrhythmia (in contrast to an induced asystole on a cooled patient on a heart-lun ...

(

cardiac arrest Cardiac arrest is when the heart suddenly and unexpectedly stops beating. It is a medical emergency that, without immediate medical intervention, will result in sudden cardiac death within minutes. Cardiopulmonary resuscitation (CPR) and possib ...

associated with a "flat line" on the

ECG Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording of the heart's electrical activity. It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the hear ...

), with the possible exception of witnessed asystole (as in the case of

bifascicular block Bifascicular block is a conduction abnormality in the heart where two of the three main fascicles of the His/Purkinje system are blocked. Most commonly, it refers to a combination of right bundle branch block (RBBB) and either left anterior fas ...

that progresses to

without an

escape rhythm In cardiology, a ventricular escape beat is a self-generated electrical discharge initiated by, and causing contraction of the ventricles of the heart; normally the heart rhythm is begun in the atria of the heart and is subsequently transmitted ...

). __TOC__

Process

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 In electrical engineering, impedance is the opposition to alternating current presented by the combined effect of resistance and reactance in a circuit. Quantitatively, the impedance of a two-terminal circuit element is the ratio of the comp ...

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 The QRS complex is the combination of three of the graphical deflections seen on a typical electrocardiogram (ECG or EKG). It is usually the central and most visually obvious part of the tracing. It corresponds to the depolarization of the ri ...

with tall, broad T wave on the

) 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. Transcutaneous pacing may be uncomfortable for the patient.

Sedation Sedation is the reduction of irritability or agitation by administration of sedative drugs, generally to facilitate a medical procedure or diagnostic procedure. Examples of drugs which can be used for sedation include isoflurane, diethyl ether, ...

should therefore be considered. Before pacing the patient in a prehospital setting sedation is recommended by administering an analgesic or an anxiolytic. Prolonged transcutaneous pacing may cause burns on the skin. According to the Zoll M Series Operator's Guide," Continuous pacing of neonates can cause skin burns. If it is necessary to pace for more than 30 minutes, periodic inspection of the underlying skin is strongly advised." It is meant to stabilize the patient until a more permanent means of pacing is achieved. Other forms of cardiac pacing are

transvenous pacing Transvenous cardiac pacing (TVP), also called endocardial pacing, is a potentially life-saving intervention used primarily to correct profound bradycardia. It can be used to treat symptomatic bradycardias that do not respond to transcutaneous paci ...

, epicardial pacing, and permanent pacing with an implantable pacemaker. In addition to synchronized transcutaneous pacing offered by newer cardiac monitor/defibrillators, there is also an option for asynchronous pacing. Sometimes in the prehospital setting a situation may arise where ECG electrodes are not available or something interferes with their adhesion to the patient's skin. In these rare situations where the patient must be paced and there are no other alternatives, asynchronous pacing may be used. Again, this setting should only be used as a last resort due to possible adverse cardiac effects it could cause.

References

* Bledsole, B., Porter, R., and Cherry, R. "Paramedic Care: Principles & Practice: Volume 3". Third Edition, Pearson, 2009. * Urden, L., Stacy, K., and Lough, M. ''Thelan's Critical Care Nursing: Diagnosis and Management''. Fourth Edition, Mosby, 1998. * ''Handbook of Emergency Cardiovascular Care for Healthcare Providers''. Editors Hazinski, M., Cummins, R., and Field, J. 2004. {{Cardiac procedures Cardiac electrophysiology Emergency medical procedures

Process

See also

References