Ventricular fibrillation causes most of the sudden non-traumatic deaths in Western society—up to 400 000 deaths a year in the United States alone.1 Most deaths occur in people without known heart disease, but many occur in people with known coronary artery disease.1 Defibrillators in aircraft, airports, railway stations, sports stadiums, police patrol cars, gymnasiums, and various public places are designed for the population at large,2 and in these locations their use is regarded as cost effective.3 Like fire extinguishers, they seem to be for use in a rare emergency.

Guidelines for the implantation of defibrillators now include patients of all ages whose left ventricular ejection fraction is less than 30% but who have a prospect of living without major cardiac disability for two years.4 Implantation of a defibrillator is encouraged by manufacturers and by proceduralists, who fear that deviating from guidelines …