ICDs recommended for patients at risk for SCD
ACC, AHA give recommendation
Updated heart failure guidelines released Aug. 16 by the American College of Cardiology (ACC) and the American Heart Association (AHA) give the highest level of recommendation that patients at risk of sudden cardiac death (SCD) be treated with implantable cardioverter defibrillators (ICDs).
Specifically, the guidelines strongly recommend that eligible heart failure patients, at greater risk for SCD, be treated with ICDs, which are devices implanted under the skin that save lives by automatically shocking chaotic and deadly heart rhythms back into a healthy pattern. The guidelines define eligible heart failure patients as those who have mild or moderate symptoms, left ventricular ejection fraction (LVEF) less than or equal to 30%, and who have reasonable expectations of survival with a good functional status for more than one year.
The revised guidelines expand the indications and number of heart failure patients eligible for ICDs and move this recommendation from category 2b to 1, the highest level of classification, which represents consensus from the scientific community that a given procedure or treatment is beneficial, useful, and effective.
In addition, the revised guidelines move cardiac resynchronization therapy (CRT) systems to a class I recommendation. People with advanced heart failure with LVEF less than or equal to 35% and cardiac dyssynchrony defined as a wide QRS interval on an office electrocardiogram are eligible for CRT therapy systems, which are placed beneath the skin near the collarbone and assist and monitor every heartbeat. CRT therapy systems deliver small electrical impulses that may improve the timing of the heart and its pumping ability.
The device also can be combined with an ICD in eligible patients, which also monitors the heart for potentially fatal heart rhythms. If such a rhythm is detected, the device can deliver a life-saving shock, restoring normal heart rhythm and preventing sudden cardiac death.
"From the time of the last guidelines, about 2001, until recently there have been a number of clinical trials conducted that demonstrated ICDs are beneficial in a broad population of patients with heart failure, regardless of the presence of arrhythmias, based solely on left ventricular function and specifically left ventricular ejection fraction," says John Boehmer, MD, associate professor of medicine at the Penn State Heart and Vascular Institute in Hershey, PA.
Who needs ICDs?
The largest areas of patients that are indicated, Boehmer continues, are those in symptomatic heart failure with low LVEF. "The studies clearly indicated that unless there is a problem with the patient that would limit their survival chances with good functional status to less than one year [ICDs should be recommended]," he says.
"So, it excludes people who are terribly ill, or patients that have other medical conditions or limited ability to function well over the long term.
In other words, you wouldn’t recommend it for patients with metastatic cancer or some other disease process, but in patients for whom we expect a good outcome for greater than a year — hopefully several years." For those patients, he emphasizes, "The ICD should be recommended as primary prevention."
A timing issue
Traditionally, when a patient has had arrhythmias, defibrillators have been used as secondary prevention, Boehmer notes. "But this [new guideline] is really primary prevention; there’s no indication [of danger] in terms of rhythm, but their [ventricular] function is so bad, and there is such a risk of cardiac arrest and sudden death, that it makes sense."
New questions for physicians
For hospitals with heart failure patients, the new guidelines point to a possible change in timing, says Boehmer. "It’s not a question of if, but when," he explains. "The current state of care for heart failure patients who are hospitalized is that patients with some measurement of [impaired] heart function on the chart, usually are implanted within a year. But now, patients with low ejection fraction should be looked at for appropriate referral for an implantable ICD."
This also raises new questions for physicians. "What will you lose if you let the patient go home, heal up, and then come back at some later point?" Boehmer poses.
"Medicare right now requires the patient be 40 days out if they are an MI patient with non-ischemic cardiomyopathy," he says. "Such a patient could perhaps be implanted at any time, though there’s no evidence they have to be implanted emergently. However, many physicians may worry about what would happen if they tell them to come back in a month and the patient dies. So, they may wish to act more urgently."
The bottom line
In any event, he adds, possible negative reactions must be discussed with the patient. "There are always two caveats you need to discuss," he advises.
"One is the probability they will benefit from the ICD. It varies a bit from study to study; as few as one in 11 to as many as one in four will be alive in five years. In addition, besides the risk of the implant — which is under 1% under local anesthesia — the bigger concern is the patient will receive a shock when they do not need one."
This occurs in about 2% of all patients each year, says Boehmer. "It does not generally cause lasting harm, but it is painful," he observes.
But the bottom line, says Boehmer, is that the new guidelines make good sense. "I don’t think they represent anything terribly controversial," he concludes.
Updated heart failure guidelines released Aug. 16 by the American College of Cardiology (ACC) and the American Heart Association (AHA) give the highest level of recommendation that patients at risk of sudden cardiac death (SCD) be treated with implantable cardioverter defibrillators (ICDs).You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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