Guidelines update for ICD, CRT, pacing therapy reflect recent trials, emphasize core principles

San Francisco, CA - The landscape of device therapy to regulate heart rhythm and rate and to prevent sudden cardiac death has changed a lot since 2002 ^[1], the last time the two largest North American cardiology organizations and the one that would become the Heart Rhythm Society (HRS) issued guidelines on the use of pacemakers and implantable cardioverter defibrillators (ICDs). For example, the evidence base and indications for ICD use in primary prevention have broadened, pacemakers are now an important therapy for heart failure, and a barrage of high-profile generator and lead "recalls" or safety advisories has, many believe, made device therapy a tougher sell for both patients and nonspecialist physicians.

These issues and more are met head-on in the 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities^[2,3] developed by the American College of Cardiology (ACC), American Heart Association (AHA), and HRS and unveiled recently at the Heart Rhythm Society 2008 Scientific Sessions. According to the chair of the document's writing committee, Dr Andrew E Epstein (University of Alabama, Birmingham), the new guidelines go beyond device indications and detailed "level-of-evidence" ratings to emphasize the importance of several broadly applicable patient-management issues. For example, they repeatedly specify the need for optimal medical therapy prior to attempts at device therapy and encourage the participation of patients and their families in assessing its risks, their expectations for improved survival and quality of life, and end-of-life issues

"I think our guidelines are unique, and I know of no others that have been published before that pay attention to human issues in the way we have done," Epstein said during a live session at the HRS meeting that introduced and summarized the new document, which has also been posted on the ACC, AHA, and HRS websites and is slated to run in the three societies' flagship journals.

Evidence-based, not eminence based

"They are as evidence-based as they possibly could be, not eminence based," Epstein said, and are overwhelmingly derived from peer-reviewed, published clinical trials and other studies. "Late-breaking trials were not used as references but could be discussed in tables; abstracts were discouraged."

At a briefing for reporters, Epstein observed that since the new material in the guidelines reflects clinical-trial developments since the previous guidelines in 2002, "there shouldn't be any surprises to physicians who pay attention to the literature." The sections on pacemaker indications, in particular, he said, are much the same as they were before.

But new, he said, is the guidelines' recurring emphasis on the patient's perspective and needs, a sense that the guidelines apply to real people who can participate in treatment decisions, not just numbers of patients with a particular disorder. "We've emphasized not just taking care of rhythm problems or heart failure, but the global cardiovascular needs of patients," Epstein said.

That focus, according to Epstein, is at least partly aimed at strengthening trust between device patients and their physicians, trust that has been shaken in recent years by highly public generator and lead safety issues. The emphasis on considering the needs of patients "has always been implied in the guidelines but I don't think [ever] stated so explicitly," he said.

The strengthened emphasis on optimal medical therapy—which the guidelines frame as, essentially, a prerequisite for ICD implantation or cardiac resynchronization therapy (CRT), Epstein observed—is a recurring theme throughout the document and is among the most important of its innovations and changes compared with the 2002 guidelines, he said. Others include the ascendancy of the so-called MADIT-2 primary-prevention ICD indication (ischemic cardiomyopathy with LVEF an <30%) from a class 2a to a class 1 recommendation (ie, from treatment that is "reasonable to perform" to treatment that "should be performed") and affirmation of LVEF <35% as the threshold for considering a primary-prevention ICD in patients with ischemic or nonischemic heart failure in NYHA functional class 2-3, an indication based on the SCD-HeFT trial.

"Some of the literature published in the past several years has made the cutoff ejection fraction for implantation of devices very murky," Epstein said at the press conference. "We have, I think, clarified the importance of this ejection fraction of 35% as being a turning point, a critical level for considering implantation."

Pacing for heart failure

The new document greatly expands discussion of CRT, which is now well established as a treatment for heart failure, and calls for a trial of optimal medical therapy for at least three months, usually, before the device therapy can be considered. "The idea is that in some cases this will improve both ventricular function and clinical capacity such that CRT may no longer be indicated," said writing committee member Dr Lynne Warner Stevenson (Brigham and Women's Hospital, Boston, MA) at the session that unveiled the guidelines. "A time may also be required to recover from potentially reversible insults, such as acute MI, cardiac surgery, tachycardia, or excess alcohol consumption."

The document says CRT can be provided with or without the ability to defibrillate, Stevenson said. "We thought it very important to include that caveat. First of all, in Europe, [CRT devices] are often used without an ICD. But we [in the US] certainly have patients in whom CRT is appropriate [while] perhaps the ICD is not. There are some patients, particularly older patients, who are seeking to improve their quality of life but want to make sure that they're not going to prolong death, either from heart failure or from other conditions that might arise."

Stevenson acknowledged that the evidence base supporting the addition of defibrillation to CRT is thin but said that "there's clearly a role for it," for example, in patients who don't necessarily have an ICD indication when they receive a CRT device but whose disease might progress such that they qualify later on.

Conventional pacing

Among the new recommendations for pacemaker therapy, Epstein said, are "new and expanded indications" in a number of inherited disorders, such as long-QT syndrome, Brugada syndrome, hypertrophic cardiomyopathy, and arrhythmogenic right ventricular dysplasia, and in some recently identified disorders, such as the short-QT syndrome.

Dr Roger Freedman (University of Utah, Salt Lake City), the most important differentiating feature to consider is the programming's capacity to minimize right-ventricular pacing. "It is incumbent on the implanter to understand what features the various models have to accomplish this, to choose the appropriate model, and no less important, to program the pacemaker appropriately to prevent unnecessary ventricular pacing."

HRS vice president and guidelines writing-committee member Dr Richard L Page (University of Washington, Seattle), reminded clinicians attending the session that the guidelines are "just that—guidelines"—and can be useful even if they are not followed to the letter. "You can't be faulted for not going directly by the guidelines, because every patient is different." Page chaired the meeting's program committee.

"I strongly recommend, though—especially if you are doing something that's a class-3 recommendation [it "should not be performed since it is not helpful and may be harmful"] or not doing a class-1 recommendation—that you acknowledge that you are aware of the guidelines and clearly document [how], in that patient, you used your best judgment to provide the therapy you think was correct," he said. "And in that way, the guidelines can help you, whether you are going directly by the recommendations or not."

Disclosures for all writing committee members are provided in the guidelines document.

 

 

 

 

 

Heartwire from Medscape © 2008 

Cite this: Guidelines update for ICD, CRT, pacing therapy reflect recent trials, emphasize core principles - Medscape - May 28, 2008.