Precordial thump

Pronunciation
Other names	Chest thump
Medical specialty
Uses
Complications
Approach
Types
Recovery time
Other options
Frequency

Precordial thump is a medical procedure involving a mechanical blow to the sternum to treat certain types of life-threatening cardiac arrhythmias, specifically ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT). This maneuver is only considered when the onset of the arrhythmia is witnessed, the patient is being continuously monitored, and no immediate access to a defibrillator is available.

Overview

The precordial thump is a rarely used emergency technique in advanced cardiac life support (ACLS). It is intended to deliver a small mechanical energy impulse (approximately 2–5 joules) directly to the heart, potentially depolarizing myocardial tissue and converting a shockable rhythm (VF or pulseless VT) to a perfusing rhythm.

Indications

• Witnessed, monitored onset of VF or pulseless VT
• Immediate unavailability of a defibrillator
• Performed by trained healthcare professionals in a clinical setting

Contraindications

• Unwitnessed cardiac arrest
• Asystole or pulseless electrical activity (PEA)
• Situations where proper placement or delivery of the thump cannot be assured
• Lack of continuous cardiac monitoring

Procedure

The procedure involves:

1. Confirming a shockable rhythm on a monitor.
2. Forming a tight fist with the dominant hand.
3. Delivering a swift, forceful blow using the ulnar aspect of the fist to the lower half of the sternum, near the heart.
4. Immediately resuming cardiopulmonary resuscitation (CPR) or proceeding to defibrillation as appropriate.

Mechanism

The mechanical impact from the thump may stimulate the myocardium in a manner similar to electrical defibrillation. The energy transmitted can cause immediate depolarization of cardiac muscle fibers, potentially interrupting a chaotic arrhythmia and restoring a viable rhythm.

Effectiveness

The success rate of precordial thump is low and is generally considered less effective than electrical defibrillation. When used, it must be applied within seconds of arrhythmia onset. Delayed or inappropriate use has minimal benefit and may worsen outcomes.

Risks and Complications

• Potential induction of more dangerous arrhythmias
• Risk of mechanical injury to the sternum or underlying organs
• Commotio cordis, particularly in untrained attempts
• Liver laceration if force is misapplied
• Rib or xiphoid process fracture

Public Misconceptions

Precordial thump has been frequently dramatized in television and film, often shown as a miraculous life-saving action performed without context. This has led to misuse by untrained individuals, sometimes resulting in additional injury or delay in proper care.

Historical Background

The technique was formally introduced by Bernard Lown and colleagues in the early 1970s. It gained early recognition when a spontaneous rhythm conversion occurred in a patient after a speed bump jolt during an ambulance transport. Research into the procedure led to its temporary inclusion in early CPR protocols, though it was later removed due to inconsistent outcomes and risk of harm when improperly applied.

Fist Pacing

Percussion pacing, also known as fist pacing, involves delivering rhythmic mechanical blows to the chest as a substitute for electrical pacing. There is insufficient clinical evidence to support its use, and it is not recommended in modern resuscitation guidelines.

Current Guidelines

Modern ACLS protocols do not routinely recommend the precordial thump due to its limited efficacy and the availability of rapid defibrillation. However, it remains an option in very specific clinical circumstances, as recognized by the American Heart Association and other resuscitation councils.

See also

• Cardiopulmonary resuscitation
• Defibrillation
• Advanced cardiac life support
• Ventricular fibrillation
• Pulseless ventricular tachycardia
• Commotio cordis