When you need a defibrillator for your heart—and when you don't

About 100,000 Americans per year are told they need a sophisticated electronic device implanted in their chest. The device, an implanted cardioverter defibrillator (ICD), delivers a shock when it detects a dan­gerous heart rhythm. For many, it's a lifesaver. But it can cause infections and other compli­cations. And living with an ICD is difficult. It requires frequent monitoring and can trigger unexpected, painful, anxiety-provoking shocks. ICDs can also malfunction; several models have even had to be recalled in recent years. And research suggests that many people who receive an ICD—especially older people—may not need the device.

Duke University researchers looked at almost 112,000 ICD implantations and found that 22 percent of them were done on patients who were not ideal candidates based on expert guidelines. Such patients were "more likely to have worse outcomes," including premature death, the authors wrote.

Why would doctors insert an unnecessary defibrillator? Well, Medicare pays $50,000 for the procedure, making it one of the most expensive devices it covers. Concerns that some hospitals might take advantage of that prompted the Department of Justice to initiate an investigation in 2010. The inquiry is ongoing.

In addition, some doctors may simply not be up to date. The Duke study found that specialists with the most training in ICDs—electrophysiologists—were less likely to use the devices inappropriately. And doctors might decide that a less-­than-­ideal patient could still benefit from the device. "Guidelines don't have to be followed blindly," says Marvin M. Lipman, M.D., Consumer Reports chief medical adviser. "But doctors should have good reasons for not complying with them."

You need an ICD if you have ventricu­lar fibrillation (VF). That's when the heart's lower chambers don't contract hard enough to pump blood throughout the body, triggering cardiac arrest. You also need one if you've already suffered cardiac arrest, from VF or another cause.

If you don't have a history of those problems but are at increased risk of them, because of a heart attack or another form of heart disease, you might need an echocardiogram to measure your heart's pumping capacity, or ejection fraction. You probably need an ICD if the ejec­tion fraction is below 35 or 30 percent, depending on whether you had a prior heart attack. If it's higher, ask why your doctor thinks you need an ICD. If you have doubts, get a second opinion.

ICDs pose unique challenges near the end of life. As the heart fails there may be more and more shocks, which can lead to aggressive treatments at a time when comfort should be the priority. For that reason, frail older people often aren't good candidates for an ICD, and those with an ICD may want to talk with a doc­tor about turning it off. Read more advice about implantable defibrillators at the end of life, from the American Academy of Hospice and Palliative Medicine.

Read more about how to prevent, diagnose, and treat heart disease, plus our reviews of blood pressure monitors.