Background Sudden cardiac death is a prominent feature of the natural history of heart disease. The efficacy of antiarrhythmic drugs and devices in preventing sudden death and reducing total mortality is uncertain. Methods We reviewed randomized trials and quantitative overviews of type I and type III antiarrhythmic drugs. We also reviewed the randomized trials of implantable cardioverter defibrillators and combined these outcomes in a quantitative overview. Results Randomized trials of type I antiarrhythmic agents used as secondary prevention after myocardial infarction show an overall 21% increase in mortality rate. Randomized trials of amiodarone suggest a 13% to 19% decrease in mortality rate, and sotalol has been effective in several small trials. Trials of pure type III agents, however, have shown no mortality benefit. An overview of implantable defibrillator trials shows a 24% reduction in mortality rate (CI 15%-33%) compared with alternative therapy, most often amiodarone. Conclusion Amiodarone is effective in reducing the total mortality rate by 13% to 19%, and the implantable defibrillator reduces the mortality rate by a further 24%. (Am Heart J 2002;144:422-30.)