the precordial thump is a medical procedure that may be used by healthcare professionals, to respond to ventricular fibrillation or ventricular tachycardia under certain conditions. the procedure is outside the scope of first-aid treatment and requires, at minimum, training in advanced cardiac life support (acls). the precordial thump may be considered in those with witnessed, monitored, unstable ventricular tachycardia (including pulseless vt) if a defibrillator is not immediately ready for use, but it should not delay cpr and shock delivery or be used in those with unwitnessed out of hospital arrest. ==procedure== in a precordial thump, a provider strikes with a single blow of the fist to the middle of a person's sternum. the intent is to interrupt a potentially life-threatening rhythm. the thump is thought to produce an electrical depolarization of 2 to 5 joules. however, it is effective only if used near 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 attempted only once during the onset of cardiac arrest. while the odds of success are poor, if the procedure is performed properly then little time is lost. the provider will immediately continue with other acls skills, including cpr, acls drugs, and defibrillation, as appropriate. ==adverse effects== there are concerns that the precordial thump can result in worsening of a person's heart rhythm more often than it improves it. 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. if applied incorrectly it may cause further injury, for instance inducing commotio cordis (cardiac arrest caused by blunt trauma) or breaking the tip of the sternum. at o
Cardiac_procedures