Medical News Today

High-risk patients with hypertrophic cardiomyopathy appear to have reduced risk of sudden cardiac death with an implantable cardioverter-defibrillator that terminates dangerous heart rhythm disorders, according to a study in the July 25 issue of JAMA.

Hypertrophic cardiomyopathy (HCM) is the most common cause of sudden cardiac death in young people, including trained athletes. HCM is a genetic disease in which the heart muscle thickens abnormally, which can interfere with the heart's electrical system, increasing the risk for life-threatening abnormal heartbeats (arrhythmias). Only in the last few years has the implantable cardioverter-defibrillator (ICD) been systematically used as a potentially life-saving treatment in high-risk patients with HCM, according to background information in the article. An ICD is a device designed to quickly detect a life-threatening, abnormal heart rhythm, and attempt to convert the rhythm back to normal by delivering an electrical shock to the heart. The effectiveness and appropriate selection of HCM patients for this therapy is not certain.

Barry J. Maron, M.D., of the Minneapolis Heart Institute Foundation, Minneapolis, and colleagues examined the clinical risk profile and incidence and effectiveness of ICD intervention in patients with HCM. The researchers analyzed data from a multicenter registry of ICDs implanted between 1986 and 2003 in 506 patients with HCM, average age 42 years. Patients were judged to be at high risk for sudden death. Average follow-up was 3.7 years.

Risk factors analyzed included history of premature HCM-related sudden death in 1 or more first-degree or other relatives younger than 50 years; massive left ventricular hypertrophy (enlargement); a certain type of nonsustained ventricular tachycardia (abnormally rapid heart rhythm); and prior unexplained syncope (temporary loss of consciousness).

Of the 506 patients, 20 percent experienced 1 or more appropriate device interventions, in which the ICD terminated ventricular fibrillation (severely abnormal heart rhythm that results in cardiac arrest) or ventricular tachycardia. Intervention rates were 10.6 percent per year for secondary prevention after cardiac arrest (5-year cumulative probability, 39 percent), and 3.6 percent per year for primary prevention (5-year probability, 17 percent).

Time to first appropriate discharge was up to 10 years, with a 27 percent probability 5 years or more after implantation. For primary prevention, 35 percent of the patients with appropriate ICD interventions had undergone implantation for only a single risk factor; likelihood of appropriate discharge was similar in patients with 1, 2, or 3 or more risk markers.

"The results of this international, multicenter study show the effectiveness and reliability of the ICD in prevention of sudden cardiac death in high-risk patients with HCM," the authors write. "An important proportion of these device interventions occurred in patients who had undergone prophylactic ICD implantation for a single risk factor. Therefore, a single marker of high-risk status may justify consideration for a primary prevention defibrillator in selected patients with HCM."

In an accompanying editorial, Rick A. Nishimura, M.D., and Steve R. Ommen, M.D., of the Mayo Clinic College of Medicine, Rochester, Minn., comment on the findings of the study by Maron and colleagues.

"Patients who have experienced cardiac arrest or documented sustained ventricular tachycardia definitely should be considered for implantation of an ICD. Patients with 2 or more risk factors likely present a high enough risk to warrant implantation of an ICD. However, the decision to implant an ICD in any patient, especially one with a single risk factor, must include a thorough and earnest discussion of the accuracy of the current risk assessment tools, the risks and benefits of ICD therapy, and the individual patient's viewpoints on procedures, devices, and death. Such an approach will allow the patient-physician team to arrive at an individualized decision regarding ICD implantation."

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by Barbara Kram, Editor DOTmed.com

Washington -- The House of Representatives overwhelmingly passed reauthorization of the Prescription Drug User Fee Act (PDUFA), enhancing the FDA's safety programs, by a vote of 403-16. The bill, H.R. 2900, will next go to a conference committee to work out differences with the Senate version (S. 1082), which was passed in May 2007.

The bill revises user-fee programs for prescription drugs and medical devices, and strengthens the role of the FDA with respect to postmarket safety of drugs and devices, and for other purposes.

Regarding devices in particular, the bill appropriates an additional $7,100,000 for fiscal years 2008-2012, plus an inflation adjustment. The resources are aimed at collecting, developing, reviewing, and evaluating postmarket safety information on medical devices.

The FDA's traditional role in safeguarding drugs and devices had focused on approval, with rigorous pre-market regulation to ensure safety and efficacy before products are prescribed and sold in the U.S. However, recent cases have called drug safety into question after approval and marketing, most notably in the case of Merck's VIOXX, pointing to the need for the agency to strengthen its role throughout the product lifecycle. VIOXX was voluntarily withdrawn from the market by Merck in 2004 following safety questions raised about its cardiovascular risk in a study of arthritis drugs.

Industry advocates applaud the PDUFA legislation. "House passage of this important piece of legislation is a victory for American patients as they will continue to have timely access to the latest medical technology advancements. HR 2900 will enhance patient safety by providing FDA's device program with the financial resources it needs to meet its medical technology review commitments, while protecting future FDA appropriations and providing manufacturers with predictability regarding user fee rates," said AdvaMed President and CEO Stephen J. Ubl. "AdvaMed encourages the House and Senate leadership to quickly name members to a conference committee so that differences between the two chambers' versions of the legislation can be reconciled and a final bill sent to the President before the current user fee program expires on September 30, 2007." (AdvaMed, the Advanced Medical Technology Association, is a professional organization of medical device makers.)

A summary of selected provisions follows:
-Food and Drug Administration Amendments Act of 2007 - Prescription Drug User Fee Amendments of 2007 - Amends the Federal Food, Drug, and Cosmetic Act to reauthorize the collection of prescription drug user fees for FY2008-FY2012.
-Requires the Secretary of Health and Human Services to assess and collect fees for advisory review of direct-to-consumer television advertisements of prescription drugs.
-Medical Device User Fee Amendments of 2007: Reauthorizes the collection of medical device user fees for FY2008-FY2012. Sets forth provisions governing the inspection of medical device establishments by accredited persons.
-Pediatric Medical Device Safety and Improvement Act of 2007: Requires a person that submits an application for approval of a medical device to provide information on pediatric subpopulations that suffer from the disease or condition that the device is intended to treat, diagnose, or cure.
-Provides special rules (Section 103) for positron emission (PET) drugs to be exempt from the annual establishment fee for some not-for-profit medical centers.
-Encourages the FDA to reconsider the termination of the Medical Imaging Drugs Advisory Committee (MIDAC).
-Requires the Secretary of HHS, acting through the Director of the National Institutes of Health (NIH), to establish and administer a clinical trial registry database and a clinical trial results database for drugs and devices.
-Authorizes the Secretary to require a responsible person for a drug to conduct a post-approval study on the basis of scientific information.

Read the bill at:
http://thomas.loc.gov/cgi-bin/bdquery/z?d110:HR02900: