Sudden Death After Heart Attacks (Part I)

From Richard N. Fogoros, M.D.,
Very common, but very preventable
Most of the thousands of deaths are not due to repeat heart attack (that is, to repeat blockage of a coronary artery.) Instead, most are due to the sudden appearance of a lethal heart arrhythmia known as ventricular fibrillation. When ventricular fibrillation occurs, it usually occurs suddenly, without a shred of warning. And unless the heart is defibrillated within a few minutes, death ensues. (Defibrillation is usually accomplished by placing the electrode "paddles" of a heart defibrillator on the chest and administering a high-voltage shock.)
Thankfully, ventricular fibrillation is an extremely rare occurrence in people with normal hearts. But in people who have suffered almost any form of heart muscle damage - heart attacks being by far the most common cause of heart muscle damage - ventricular fibrillation is disturbingly likely. (The heart muscle damage itself makes the heart electrically unstable, and produces the environment necessary for ventricular fibrillation to occur.) Indeed, the more muscle damage one has sustained, the higher the risk of having sudden death from this arrhythmia.
There is a treatment that could prevent many of these sudden deaths - the implantable defibrillator. The implantable defibrillator is a pacemaker-like device that is implanted under the skin near the upper chest. It monitors the heart rhythm continuously, and if ventricular fibrillation occurs it automatically delivers a large shock to the heart, restoring the rhythm to normal. Often, the shock is delivered within a few seconds of the onset of the lethal arrhythmia. Implantable defibrillators have been used in patients for over 20 years, and have proven more than 99% effective in restoring the heart rhythm to normal, and in preventing sudden death.