THURSDAY, May 5, 2005 (HealthDayNews) -- Conventional medical wisdom has held that pounding a heart attack victim's chest with your fist -- called a precordial thump -- might restore normal heart function, but new research appears to rule it out as an optimal solution.
"The precordial thump is something which has found its way into our lore," said Dr. Harlan M. Krumholz, a professor of cardiology at Yale University School of Medicine who was not involved in the study. "It has become something which people think about as a magical invention and really it's not clear if it can provide the benefit we've long thought it does."
To reach their conclusion, researchers led by Dr. Mark S. Link of Tufts-New England Medical Center in Boston threw baseballs at 30 or 40 miles per hour at the chests of pigs. In about 30 percent to 50 percent of the cases, the pigs went into ventricular fibrillation, a type of cardiac arrest that is usually fatal if not treated immediately.
Ventricular fibrillation (sometimes called ventricular fibulation) occurs when the lower chambers of the heart contract in a random fashion, preventing blood from circulating. This is what can happen to a child who has been hit in the chest with a baseball, for example. Ventricular fibrillation is one type of cardiac arrest and is usually fatal if not treated immediately.
Among the 29 animals, the researchers were able to induce 31 cases of cardiac arrest, according to the report, which was to be presented Thursday at the Heart Rhythm Society's annual meeting in New Orleans.
In each case, the research team attempted unsuccessfully to revive the pigs using a precordial thump. However, when the pigs were treated with an external defibrillator -- a machine that produces an electric shock, jolting the heart back into a regular rhythm -- they all regained normal heart rhythm.
"In our swine model of ventricular fibulation produced by chest wall impact, precordial thump was not successful in the termination of ventricular fibulation. Based on our data, we cannot recommend precordial thump to cardiac arrest victims, if external defibrillation is readily available," the researchers concluded.
According to Krumholz, the American Heart Association believes the precordial thump should be an optional treatment.
"This study raises questions about whether it's providing any benefit," he said.
Should a person go into ventricular fibrillation, Krumholz said, "People should clear their mind and get an external defibrillator on the person and shock them right away. If that's not available then they should do basic life support -- CPR."
Dr. Roger J. Lewis, an emergency department expert at Harbor-UCLA Medical Center in Torrance, Calif., said, "Physicians used to be taught [in cardiac arrest] that the first thing you do is you try giving a thump to the chest. In fact, what you're taught is that you thump the chest while someone is running to get the defibrillator."
Lewis agreed with Krumholz on the steps to take should a person go into cardiac arrest. When a child is in cardiac arrest from a sports accident, the highest priorities are contacting emergency medical service personnel and beginning CPR, Lewis said. The key to the child's survival is external defibrillation to restore normal heart rhythm, he noted.
"Be aware of this risk," Lewis said. "If a child falls down, you immediately call 911, and if there happens to be an automatic defibrillator, you send someone to get it while someone else begins CPR."
The American Heart Association can tell you more about sudden cardiac death.