The research, led by Duke University heart specialist Sana M. Al-Khatib, M.D., found that patients who received a defibrillator but whose heart condition didn't match recommended criteria were more likely to die or suffer from a complication in the hospital.
What do you do if you've been implanted with a defibrillator? And if you're told you need one, how can you tell whether the advice is solid?
Here are the facts heart patients may want to consider — along with the guidelines that list which heart patients shouldn't get a defibrillator.
If you have an implanted defibrillator already
If it shocks your heart in response to an abnormal rhythm, it's clearly helping you, says Al-Khatib. In the absence of such evidence, ultrasound and nuclear medicine tests can evaluate heart function and your current risk of cardiac arrest. When the implantable cardioverter defibrillator (ICD) battery runs down (roughly every five to seven years), there's an opportunity to discuss whether or not to replace the device.
If your doctor recommends a defibrillator
According to this study, you may want to pay close attention to who is giving the advice. The study found electrophysiologists, who are specially trained in using the devices, were more likely than other heart doctors to stick to the guidelines.
"It makes sense for patients to ask their physician, 'Is this based on guidelines, is it based on your best judgment, and how much experience have you had with this?' " says Alan Kadish, M.D., a cardiologist at Touro University in New York. The question of experience is especially important if the doctor recommending and implanting the device is not an electrophysiologist.
Guidelines say you shouldn't get a defibrillator if you:
- have experienced a heart attack within 40 days.
- have undergone bypass surgery within three months.
- have been recently diagnosed with congestive heart failure.
- have suffered very severe heart failure symptoms.
In the first three cases, the issue is timing, says Kadish, who coauthored an editorial that accompanied the study in the Jan. 5 Journal of the American Medical Association. Patients in the early stages of recovery or diagnosis may need time to stabilize before undergoing an invasive procedure. Or they may regain enough heart function with medication and other therapies to make an ICD unnecessary. On the other hand, those with the most severe symptoms are considered too sick to benefit from the device.
The new findings suggest that the device is used inconsistently by doctors.
While some patients who don't need defibrillators are having them implanted, earlier research also suggests that half of the men and women who really would benefit from the devices are not getting one.
"Our first group focused on people who do meet the guidelines for an ICD, and found a significant degree of under-use," says Al-Khatib. Women and African Americans, she says, were especially unlikely to get a device when indicated.
In the new study, the rate of ICD implantations that didn't meet the established criteria varied widely by institution, with potentially inappropriate procedures making up less than 10 percent of all implantations at some sites, more than half at others. "Some sites did much worse than others," says Al-Khatib. "It's hard to say why."
The researchers examined records of more than 110,000 people who received an ICD from January 2006 through June 2009. The national guidelines for ICD implantation are not mandates, and a certain number of implantations in the study that were performed outside the guidelines may well represent valid decision-making by doctors and patients, says Douglas Packer, M.D., a cardiac specialist at Mayo Clinic Rochester and president of the Heart Rhythm Society, which draws up the guidelines.
Kadish agrees that not every doctor who implanted a device without following the guidelines made the wrong decision.
The big picture? "We need to do a better job educating all physicians about the guidelines," says Kadish, including, it appears, some doctors who are responsible for the implants.
Katharine Greider lives in New York and writes about health and medicine.