Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
A precordial thump is a medical procedure used in the initial response to a witnessed cardiac arrest when no defibrillator is immediately available. It can be used as a small part of the provision of advanced cardiac life support (ACLS). About 25% of patients in cardiac arrest who received a thump on the precordium regain cardiac function (Scherf and Bornemann:, 1960)
To perform a precordial thump, a highly trained provider such as a paramedic or physician strikes a single very carefully aimed blow with the fist to the center of the patient's sternum. The intent is to possibly interrupt a life threatening rhythm. The precordial thump is thought to produce an electrical depolarization of 2 to 5 joules. However, the thump is effective only if used at the onset of ventricular fibrillation or pulseless ventricular tachycardia and so should be used only when the arrest is witnessed or monitored. There is no evidence that the precordial thump improves recovery in unwitnessed cardiac arrest.
A precordial thump may be given just once. While the odds of success are poor, if a precordial thump is done properly, little time is lost. The provider will immediately continue with other ACLS skills, or CPR if the needed ACLS drugs and equipment (such as a defibrillator) are unavailable.
The performance of a precordial thump is outside the scope of first aid and requires at minimum training in advanced cardiac life support. ACLS is performed primarily by physicians, paramedics and nurses with advanced training in emergency care.
Natural History, Complications and Prognosis
Doctors Jack Pennington and Bernard Lown's cardiology group at Harvard University are credited with formalizing this technique in the medical literature. They published their report in the New England Journal of Medicine in the early 1970s. Doctors. Richard S. Crampton and George Craddock, cardiologists at the University of Virginia helped to promote the paramedic use of chest thump through a curious accident. In 1970, the Charlottesville-Albemarle Rescue Squad (VA) was transporting a patient with an unstable cardiac rhythm in what was then called a Mobile Coronary Care Unit. When the vehicle inadvertently hit a speed bump in a shopping center parking lot, the patient's normal heart rhythm was restored. Further research confirmed that chest thumping patients with life-threatening arrhythmias could save lives.
The use of the precordial thump technique has sometimes been shown in movies and television, usually in passing without any explanation. Untrained laypersons have been known to attempt it and sometimes cause additional injury to the patient as the blow must be carefully aimed. Commotio cordis, cardiac arrest caused by blunt trauma to the heart, may ensue if a precordial thump is applied with a wrong timing.
- Scherf D, and Bornemann C: Thumping of the precordium in ventricular standstill. American Journal of Cardiology 1960; 1 (1): 30-40
- Kloeck W. et al. The Universal Advanced Life Support Algorithm. An Advisory Statement From the Advanced Life Support Working Group of the International Liaison Committee on Resuscitation . Circulation. 1997;95:2180-2182. Full paper.
- Caldwell G, Millar G, Quinn E, Vincent R, Chamberlain DA. Simple mechanical methods for cardioversion: defence of the precordial thump and cough version. Br Med J 1985; 291:627-30.
- Miller J, Tresch D, Horwitz L, Thompson BM, Aprahamian C, Darin JC. The Precordial Thump. Ann Emerg Med 1984; 13:791-4.