ICDs should be implanted in heart attack victims whose left-ventricular ejection fraction is 30% or less one month after the event and three months post-revascularization, according to new practice guidelines issued jointly by ACC, AHA and NASPE.

Issued Sept. 24, the recommendation is part of the "American College of Cardiology, American Heart Association, and North American Society for Pacing and Electrophysiology's 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices," to be published in the Oct. 15 issue of Circulation.

Prophylactic ICD implantation in this patient group is supported by results from the 1,232-patient, Guidant-sponsored MADIT II study. The randomized trial compared ICDs to optimal medical management in patients with persistently low LV ejection fraction and heart function post-myocardial infarction, even if the patient had not been tested for ventricular tachycardia.

The ICD group had a 31% lower relative risk of death than the drug cohort, according to the trial results (¹ Also see "Guidant MADIT II Trial Could Support Doubling Of ICD-Eligible Population" - Medtech Insight, 26 November, 2001., p. 30).

LV ejection fraction is the percentage of blood in the ventricle pumped out during each heartbeat. An ejection fraction of 50-75% is considered normal, while an ejection fraction of below 40% is indicative of heart failure.

ACC/AHA classifies the prophylactic ICD indication as a Class IIa recommendation, meaning that the "weight of evidence/opinion is in favor of the usefulness/efficacy" of the therapy, even though "there is conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of the procedure."

The divergence of opinion on prophylactic use remains because some trials have suggested that the benefit of the procedure is limited to a narrower subset of patients than those indicated in the guidelines.

For example, in the German CAT study conducted by Dietmar Bansch, MD, et al., prophylactic ICD implantation was evaluated in non-ischemic patients with idiopathic dilated cardiomyopathy (DCM) and impaired LV ejection fraction. Investigators in the 104-patient study concluded that there was no difference in all-cause mortality between the treatment and control groups.

Furthermore, in comments available on the AHA, NASPE and ACC websites, an ACC/AHA task force cites several sub-studies derived from MADIT II data stratifying the patients' relative risk of death based on noninvasive ECG criteria.

A study by Wojciech Zareba, MD/PhD, University of Rochester, presented at the NASPE annual meeting in May, showed that QRS-wave measures taken from standard ECGs can help prioritize those patients that would benefit most from ICD therapy. Atrial fibrillation as the baseline rhythm also was an independent predictor of ICD benefit (² Also see "Cardiologist Groups Guard Medicare ICD Payments From Physician Fee Cuts" - Medtech Insight, 20 May, 2002., p. 6).

However, the task force elected to support the MADIT-II indication while awaiting "additional risk stratification studies...to better define which patient subgroups will benefit more or less from ICD therapy than that demonstrated" in MADIT. "Whether the recommendation to implant ICDs in post-myocardial infarction patients...should be limited to individuals with these high-risk variables awaits further clarification," the task force explains.

Representatives from the task force met with CMS officials on Sept. 20 to discuss how the MADIT II results and new practice guidelines support a request by Guidant and Medtronic for a national coverage decision mandating Medicare reimbursement for the prophylactic indication (³ 'The Gray Sheet' Sept. 23, 2002, In Brief).

The Centers for Medicare & Medicaid Services is expected to issue a decision soon. The agency had originally set Sept. 27 as the expected completion date.

The prophylactic indication for ICDs could double the size of the ICD-eligible population in the U.S. from 300,000 to 600,000 annually over the next few years, potentially creating a $2.8 bil. market.

During the NASPE meeting, several electrophysiologists expressed concern that CMS would be forced to cut Medicare payments to physicians in order to meet the increased demand for ICDs. However, based on a cost analysis of several ICD trials, the ACC/AHA task force believes ICD implantation is cost effective.

"The cost-effectiveness of the ICD [in the trials] was $31,500 per life-year added, comparable to widely accepted, non-cardiac therapies such as renal dialysis, ($30,000 to $50,000 per year of life saved)," the task force notes.

ICD Guidelines From ACC/AHA/NASPE Embrace MADIT-II Prophylactic Use

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