Your doctor may someday suggest that you get a heart-regulating medical device called an implantable cardioverter defibrillator (ICD) placed in your chest. And you might be tempted to agree right away—but don’t be too hasty. Although ICDs can and do save lives, the risks of these devices can far outweigh the potential benefits in some patients. Such people can wind up with pain, infections, even life-threatening complications—all from a device they didn’t really need. Here’s what you should know to protect yourself…

The job of an ICD is to guard against sudden cardiac arrest, a condition in which the heart abruptly stops beating due to a malfunction of the internal electrical system that controls the heart’s rhythm and rate. Sudden cardiac arrest is not the same as a heart attack (though the two can occur simultaneously). A heart attack happens when a blocked artery prevents oxygen-rich blood from reaching a section of the heart—and though many people fear heart attacks more, sudden cardiac arrest is much likelier to be deadly. A person experiencing sudden cardiac arrest typically passes out within seconds and dies within minutes unless the heart is restarted almost immediately. As many as 95% of sudden cardiac arrest victims die before they can reach a source of emergency help, such as a hospital.

That’s where the ICD comes in. If you are known to be at risk for sudden cardiac arrest, your cardiologist may recommend implanting this small metal device under the skin of your chest or abdomen. It includes a box with a battery, small computer and pulse generator…leads (wires) that run from the box through a vein to your heart…and electrodes that connect to the heart itself. When the ICD computer detects a potentially dangerous arrhythmia (abnormal heart rhythm), the pulse generator sends out an electric shock to reestablish a normal heartbeat.

Sounds reasonable so far, right? Here’s the worrisome part. Among patients who have ICDs, only 7% end up ever getting a needed shock from the device during an episode of arrhythmia. This means that for the other 93%, the ICD was unnecessary…yet these patients still face the risks involved in having the device.

Of course, it’s impossible to know in advance whether you’ll be among that small percentage of patients who actually needs that lifesaving shock. But since ICDs do carry risks, you want to be as certain as possible that the device’s potential benefits—for you personally—will outweigh its risks.


To weigh the balance of an ICD’s risks and benefits, it is essential to have an in-depth and frank discussion with your cardiologist, said John Mandrola, MD, a cardiologist and electrophysiologist (a cardiologist with additional training in the diagnosis and treatment of abnormal heart rhythms) in private practice in Louisville, Kentucky. Here’s what to cover…

Possible complications. For instance…

ICDs sometimes misfire, shocking the heart unnecessarily even when there is no arrhythmia. Inappropriate shocks occur in an estimated 5% to 30% of patients, Dr. Mandrola said. These shocks are not only painful, they might cause damage to the heart or even trigger an irregular and dangerous heartbeat.

Infection is another concern. Staphylococcus and other bacteria can lodge around the ICD and overwhelm the immune system’s defenses. Among patients who develop such infections, 18% die within a year.

The wire leads sometimes become dislodged, in which case repeat surgery—with all its attendant risks—is needed to reposition them. Dislodged leads also can perforate the heart or lungs.

Influence of gender. Women encounter more problems with ICDs than men do. In a recent three-year study involving more than 5,400 ICD patients, women were nearly twice as likely as men to develop severe complications such as heart or lung perforation. Women also were less likely than men to get needed shocks from their ICDs when arrhythmia did develop. This doesn’t mean that women should never get ICDs, Dr. Mandrola said—but women and their doctors should take these factors into account when gauging the risks versus the benefits.

Your overall health. This sounds blunt, but it’s an important factor to consider, Dr. Mandrola said. For a patient with other serious health problems (such as late-stage cancer, severe kidney disease or advanced dementia), getting an ICD may mean “trading” a very quick and nearly painless death from sudden cardiac arrest for a still inevitable, yet much more prolonged and difficult, death from some other illness.


So who is most likely to benefit from an ICD? Dr. Mandrola’s ideal candidate is someone who is sick enough to be at significant risk for sudden cardiac arrest—but not so sick that he or she is likely to succumb fairly soon to some other illness.

  • Those who have survived a life-threatening arrhythmia.
  • Those with inherited disorders of the heart that predispose them to severe arrhythmia (such as hypertrophic cardiomyopathy or long QT syndrome). (For an explanation of long QT syndrome, see our Daily Health News article, “Sickening Finding About Common Anti-Nausea Drug.”
  • Those with persistently weakened heart muscle, such as occurs with congestive heart failure.

Even if you do fall into such a category, if your doctor emphasizes only the benefits of an ICD and glosses over the risks, it’s vital to get a second opinion, Dr. Mandrola advised.

If you do opt for an ICD: Remember that experience matters. Patients whose ICDs are implanted by electrophysiologists have significantly lower rates of complications than patients whose devices are implanted by cardiologists or surgeons who are not electrophysiologists. Currently, only about one in 16 cardiologists in the US is an electrophysiologist. Best: If your cardiologist is not an electrophysiologist, request a referral or find an electrophysiologist near you by visiting the Heart Rhythm Society.

You might also be interested in another Daily Health News article on cardiac implant dangers, “Infection Protection for Cardiac Implant Patients.”