More of this Feature • Part 1: You've survived  1 day - Now what? • Part 2: What's supposed to happen? • Part 3:Preventing another heart attack • Part 4: Preventing heart failure • Part 5: Delaying CAD • Part 7: Summary

Related Resources • Chest pain • Coronary artery disease • Heart attacks • Risk factors

Of all the measures that can be taken to improve the prognosis of patients after a heart attack, this is the one most frequently neglected.  Nearly 300,000 people die suddenly from ventricular arrhythmias in the U.S. alone each year, and a large majority of the victims of sudden death are survivors of myocardial infarctions.  (This is a huge number, and may be difficult to believe at first.  But most individuals in the U.S. over the age of 25 will be able to think of at least one close family member or friend who has died suddenly.  Sudden arrhythmic death is a problem that touches the lives of almost everyone sooner or later.)

The scar that forms on the ventricular muscle after a heart attack tends to create significant electrical instability. This electrical instability often leads to the sudden, unexpected development of ventricular tachycardia or ventricular fibrillation – arrhythmias that often produce instantaneous loss of consciousness, and death within a few minutes.  These arrhythmias most often occur without any warning, in people who seem to be in their usual state of health. 

The sudden deaths that result from these arrhythmias are most often mislabeled “a massive heart attack” by the attending physician.  In fact, less than 20% of these 300,000 yearly sudden deaths are related to acute myocardial infarctions.  The remainder are due to ventricular arrhythmias (though the arrhythmias themselves are ultimately related to a heart attack that occurred in the past.)

While sudden death is an all-too-common (and an always devastating) occurrence in patients who have survived heart attacks, assessing the risk of sudden death is seldom brought up by the attending physician, and doing something about that risk is done even less often.  This is because assessing the risk is not particularly easy, straightforward, or cheap, and doing something about a high risk of sudden death is very expensive.  There almost seems to be a tacit agreement among many doctors to simply ignore the issue altogether as being so impractical as not to warrant consideration.

However, the data from randomized trials are compelling – heart attack survivors with a high risk of sudden death can be identified, and once identified, their risk of dying from ventricular arrhythmias can be virtually eliminated. And in most large university centers these measures are being followed routinely.  There is no reason to expect less to be done in your own case.

How high risk is identified:  It has now been shown that patients whose left ventricular ejection fractions are 30% or lower after a heart attack have a high risk of sudden death.  Further, the survival of these patients is significantly prolonged by insertion of an implantable defibrillator.

In addition, patients whose ejection fractions are between 31% and 40% may be at increased risk, and need further evaluation.  These patients should have Holter monitoring performed, and if they have nonsustained ventricular tachycardia should be referred for electrophysiologic testing.  If the electrophysiology test shows ventricular tachycardia, their risk of sudden death is high.

How high risk patients should be treated:  The data is now definitive.  Patients who are identified as having a high risk for sudden death will have that risk virtually eliminated – and their overall chances for long-term survival significantly increased – by insertion of an implantable defibrillator.  (These are pacemaker-like devices that monitor the heart rhythm continuously, and if a potentially fatal arrhythmia occurs, automatically administer a defibrillating shock to the heart to restore the rhythm to normal.)

There are many reasons doctors seem to be reluctant to identify and treat patients at high risk for sudden death.  Generally these reasons boil down to this: the implantable defibrillator is fairly expensive, and usually needs to be inserted by an electrophysiologist.  Regular cardiologists often worry (not unreasonably) that the electrophysiologist will "steal" their patient forever.  And subtle pressure by managed care organizations makes it very difficult for doctors to embark on potentially expensive undertakings unless they are compelled (by law, by peer pressure, or by their patients’ expectations) to do so.  Here, none of these compelling forces are in play.

As it now stands, most of the patients who receive the necessary assessment and treatment are either being cared for in major university centers, or themselves push for it.  So the major message here is: Push for it.  Insist on it.  Sudden death after heart attacks is very common, and it can be prevented.