Chicago, IL - Should all implantable devices in left ventricular dysfunction patients have defibrillation capability? That was the question put forth during a debate today here at the American Heart Association (AHA) 2006 Scientific Sessions, with experts arguing for and against the necessity of defibrillation capabilities in these already-expensive devices.

According to Dr William Abraham (Ohio State University, Columbus), the decision is a no-brainer, as the evidence from clinical trials, including the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) and the Multicenter Automatic Defibrillator Implantation Trial (MADIT-2), have "absolutely, definitively, and unequivocally" shown that the prophylactic use of a defibrillator saves lives of heart-failure patients.

"The data are really quite clear, the evidence base is quite strong, and there really is no argument here regarding the necessity of including defibrillation capability in heart-failure therapeutic devices," said Abraham.

Taking an opposing stand, Dr Angelo Auricchio (Fondazione Cardiocentro Ticino, Lugano, Switzerland) made several arguments against the reflexive use of cardiac resynchronization devices equipped with defibrillation capabilities, not the least of which was that the evidence available does not match the patients he sees in clinical practice.

"Older patients are much different from [those whom] we have observed in clinical trials," said Auricchio. "The most recent recommendations state that elderly patients should, generally, be treated in the same manner as younger patients, but where is the evidence?" he asked. The average age of patients in defibrillation trials such as MADIT-2, SCD-HeFT, and Dual Chamber and VVI Implantable Defibrillator (DAVID) was approximately 65 years, he said, whereas those he sees in practice are often 10 and 15 years older, making it difficult to justify the addition of defibrillation in these patients.

Dying of sudden death or pump failure

Taking the podium first, Abraham said that while heart-failure devices typically refer to cardiac resynchronization therapy (CRT), he said that it is possible to imagine including defibrillators with implantable hemodynamic monitors, cardiac contractility modulation, and a host of other investigative heart-failure devices coming down the road. The need for defibrillation capability in these devices stems from the risk heart-failure patients are at from progressive heart failure and sudden cardiac death.

"By way of background, it is essential to this debate for you to remember that patients with left ventricular dysfunction usually die as a consequence of progressive heart failure—that is, pump dysfunction—or sudden cardiac death—that is, a cardiac arrhythmia," he said. "For that reason, we need to treat both modes of death. We need to improve pump function, and CRT can do that, and we need to reduce total mortality with a reduction in sudden cardiac death, and defibrillators do that."

Abraham pointed to data from the Metoprolol Randomised Intervention Trial in Heart Failure (MERIT-HF) that showed sudden cardiac death is the cause of about half of all heart-failure deaths, especially in those with NYHA class 2 and 3 heart failure. Even among those in end-stage heart failure, 33% of patients die suddenly from an arrhythmia, said Abraham.

During his presentation, Abraham stressed that CRT saves lives, and in approximately 4000 patients evaluated thus far, has been shown to reduce all-cause mortality and improve quality of life, functional status, and exercise capacity. There is also strong evidence of reverse remodeling of the failing ventricle with CRT, he said. Additional data have suggested that CRT might reduce sudden cardiac death, said Abraham, but he pointed out that the definition of sudden death is "vague or slippery" in clinical trials and event-adjudicated data show this not to be the case.

"I would suggest that CRT has little, if any, effect on reducing mortality related to sudden cardiac death," said Abraham.

Based on the strength of MADIT-2 and SCD-HeFT, the 2005 ACC/AHA heart-failure guidelines strongly endorse defibrillators for the primary prevention of death in HF patients. Abraham said that ICDs are recommended for primary prevention to reduce total mortality, primarily through a reduction in sudden cardiac death, in patients with ischemic heart disease who have a had a remote MI, have reduced ejection fraction, class 2 or 3 heart failure symptoms, and a reasonable expectation of survival. There is a class 1 indication for patients with nonischemic cardiomyopathy and a class 2 indication for patients with ejection fractions between 30% and 35%, he noted.

Age needs to be a consideration

Making his case before the AHA audience, Auricchio, an electrophysiologist, said he had the unenviable task of seemingly to argue against a treatment that prevents sudden cardiac death, something he has spent years in training and clinical practice trying to prevent. Presenting two cases, both of whom appeared to be candidates for ICD therapy, Auricchio said their age, 75 years and 78 years, respectively, are factors not in favor of defibrillation treatment.

Speaking to the value of defibrillation, Auricchio agreed with Abraham that CRT with defibrillation is superior to CRT in terms of lowering the number of deaths. He noted, however, that data from a European registry of 1300 patients who underwent CRT and CRT-D implantation showed only a trend toward lower mortality rates in patients with CRT-D. In fact, once investigators analyzed various competing events, the impact of sudden death was even less.

"Heart failure continued to be the leading cause of death for these patients," said Auricchio. "Sudden death might play a role but was substantially smaller than expected."

In addition to the increase in cost per quality-adjusted life-year (QALY) with the addition of defibrillation, Auricchio said the cause of death changes when heart-failure patients get older. While approximately half of those younger than 65 years will die of sudden death, among those older than 80 years, sudden cardiac death is less of a concern, said Auricchio, with more patients dying of pump failure. Putting a defibrillator in these people makes little clinical or economic sense, he said.

"One thing I am actually going to give to Dr Auricchio is that there might be some patients in whom we want to palliate their heart failure but not prolong their life because they have an unreasonable expectation of survival," conceded Abraham. "With them, we might actually forgo the defibrillators, but this is a very small subset of patients with very advanced or end-stage disease."

Both doctors agreed that defining sudden cardiac death can be difficult, but Auricchio noted that in the Optimal Therapy in Myocardial Infarction with the Angiotensin II Antagonist Losartan (OPTIMAAL) study, after adjudicating events on autopsy, only 28 patients died of sudden death, down from 77 patients initially determined to have died of sudden cardiac death. In the end, he said, the decision to implant a defibrillator with CRT for left ventricular dysfunction patients lies with the healthcare practitioner, because most patients do not fit neatly into entry criteria outlined by various clinical trials.

"The ultimate judgment must be made by the healthcare provider taking into account all of the circumstances presented by the patient," said Auricchio.

Abraham, on the other hand, contends that by implanting CRT devices only, clinicians are overlooking another dangerous killer of these patients. In terms of optimizing treatment, a defibrillator should be implanted alongside CRT devices to ensure that the patient is not at risk of sudden cardiac death. "When we combine ICDs and CRT, we have a powerful means to reduce mortality to prolong survival in our heart-failure patients," he said.