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Pacemaker and ICD Generator Malfunctions: Rates, Trends, and Implications - Questions and Answers

1. Did you prepare this report as a result of the recent ICD recalls?

No, this analysis was initiated in 2003, and was performed as an independent research effort separate from the recent issues with ICDs. This was a huge undertaking that involved the retrospective review of 366 PMA annual reports, covering hundreds of pacemaker and ICD models.

2. So why did you do the report?

Pacemakers and ICDs have unique reporting requirements in the post-approval period that are far more stringent than what is required of other medical devices. This is because they are life-sustaining products whose failure could be fatal. This information that manufacturers are required to report provides opportunities like this, to look across vast amounts of data and glean medical findings that can help inform clinical practice. To provide the best possible information to patients and doctors on how these devices are performing, we believe it is important to continue to take opportunities to look across this data in order to glean trends and findings that could help better inform individual medical choices.

3. What information did you use in preparing the report?

FDA analyzed PMA annual reports for pacemakers and ICDs between 1990 and 2002. These reports contain information that manufacturers of pacemakers and ICDs must report to FDA each year, including:

1. The number of ICDs and pacemakers domestically implanted and the number of reported explants and deaths.
2. A breakdown of the reported deaths into ICD and pacemaker related and non –ICD or pacemaker related.
3. A breakdown of the reported explants by reason.
4. The number of ICD and pacemaker returned to the applicant for cause from domestic sources with a breakdown into the numbers currently in analysis, operating properly, at normal battery depletion and failed, with the failure mechanisms described.
5. A cumulative survival table.
6. The number shipped and the number returned with a breakdown on which devices are currently in analysis, operating properly and failed, with the failure mechanisms described.

4. Why does the analysis stop at 2002?

Typically there is some delay in reporting in order for the manufacturer to accurately compile the appropriate data. For example, a report covering the dates November 2003 through October 2004 may not be submitted until 2005. In this case, 2002 was the most recent year for which complete data was available.

5. Did the report assess each manufacturer’s performance separately?

No, this would not have been valid because not all manufacturers were in business during the entire study period. The report combines results for all manufacturers.

6. Who performed the assessment?

William H. Maisel, MD, MPH+; Megan Moynahan, MS; Bram D. Zuckerman, MD; Thomas P. Gross, MD, MPH; Oscar H. Tovar-Calderon, MD; Donna-Bea Tillman, Ph.D., MPA; Daniel B. Schultz, MD

+ Cardiovascular Division, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (WHM)

Dr. Maisel was employed as a special government employee (SGE) during the time he participated in the assessment.

7. What were the conclusions of the study?

It recognized that pacemakers and ICDs are generally safe and effective devices, and pointed out that the number of PM and ICD implants have increased substantially. The study also contains two findings that are a source of concern to FDA: first, the malfunction replacement rate for ICDs is significantly higher than the malfunction replacement rate for pacemakers, and, of perhaps greater concern, that the ICD malfunction replacement rate appears to be increasing.

The study concluded that careful monitoring of device performance is still required, that the clinical community must continue to report adverse events in a timely manner, and that strategies should be developed to increase the proportion of explanted devices that are returned for manufacturer analysis.

8. Why has the rate of ICD malfunction replacements gone up while pacemaker malfunction replacements have gone down?

The reasons are not clear. The increase may be partially attributable to the fact that ICDs are a rapidly changing technology. Over the past 10 years, ICDs have shrunk in size, maintained their high energy output, provided more therapeutic features (such as the addition of dual chamber pacing) and increased their memory. The decrease in size, in particular, has necessitated modifications to battery, capacitor, and circuitry design that may account for some of the observed malfunctions.

9. Are some of these events preventable?

We are unsure at this time. We are going to be listening carefully to the advice given from experts in the field at the HRS meeting on Sept. 16th, 2005. In addition, we are evaluating the type of our post market data we currently receive to determine if we need to request more robust information from manufacturers both before the devices are approved for marketing and while the products are in use by the clinical community. (See 15 below for other things we are doing.)

10. Do any of malfunctions fall into certain categories?

Yes, hardware problems, battery/capacitor abnormalities and electrical issues accounted for a significant amount of the total device failures. It is important to note that the vast majority of reported malfunctions did not lead to death or serious injury and were detected in time to ensure that the patients would continue to receive therapy when it was needed.

11. Why did it take this long for FDA to realize that the rate and number of ICD malfunctions are increasing?

Until now we only had individual pieces of information which indicated that there was a possible increase in the rate of malfunction. In order for us to carefully connect all of the dots that we have it has taken some time. To prepare this report, we reviewed 366 PMA annual reports, covering hundreds of pacemaker and ICD models.

12. In hindsight, what could FDA have done to detect these increased rates sooner?

FDA is considering doing analyses like this for ICDs and pacemakers on a periodic basis. In this way, FDA would be more frequently informed of the malfunction rates to determine if they are trending upwards.

13. How are you going to disseminate this information?

We will present some of the data from the report at an open medical meeting on September 16, and make the presentation available on an FDA web site. Following that, we plan on submitting the report to a medical journal for publication. We are also considering the possibility of continuing this type of analysis periodically for pacemakers and ICDs.

14. You mentioned using manufacturer annual reports to prepare your study. Why aren’t these reports issued to the public?

PMA annual reports contain a wide variety of information including labeling changes, device modifications, and changes to packaging or sterilization procedures. Some of the information contained in these reports is proprietary information, such as specific manufacturing methods, certain distribution/market share information, and supplier information.

15. You said FDA is concerned about some of the information in the report. What are you doing to address those concerns?

We believe there is a public health signal in this report regarding the pacemaker and ICD technology, and it points out the need for FDA to improve the way it regulates these products.

• We have already begun to better coordinate our pre and post-market regulation of these devices—that is, to strengthen the link between how these products are approved and how they are monitored after they are in clinical use.
• We are also considering whether we need to require more comprehensive data from manufacturers in their annual reports
• We are exploring ways to communicate more effectively with physicians and patients when these devices malfunction.
• Today’s meeting, sponsored by the Heart Rhythm Society and FDA, is a good step toward addressing all of these issues bringing together clinicians, patients, industry representatives and regulators to help us address these complex issues.

16. Is there anything in the report that should specifically concern patients?

No. The report, which analyzes data across many companies over several years, alerts FDA that there may be a trend that needs to be addressed, but the report does not single out any specific product or model. It is important for patients to understand that pacemakers and ICDs continue to be important life-sustaining devices that have saved many lives, and that the benefits of the devices clearly still outweigh the any small potential risks. There is no action that patients need to take as a result of this report.

17. What steps has FDA taken or plan to take to ensure that physicians and patients are aware of these device malfunctions?

We have organized a defibrillator working group which is exploring the best way that FDA can make information about defibrillator recalls available to physicians and patients. In addition, the objective of the Policy Conference on Sept. 16, 2005 is “to provide a productive forum among physicians, other healthcare providers, the medical device industry, government agencies and the public to discuss the current process for ICD and pacemaker recalls and communication of device performance”. FDA will be listening carefully to the discussion at the conference and will consider all recommendations made.

18. Will FDA perform more of these types of analyses on other products and make the results public?

Manufacturers of other types of medical devices are not required to submit the detailed and comprehensive data listed in question 3 above, and so the agency does not have the raw material with which to prepare such reports. If it is determined that this type of assessment would be useful in other product areas, FDA will need to request this data.

19. There are 30 and 31 deaths reported in this study.

We’re talking about thousands of devices implanted—the number of deaths is not surprisingly high, given the large numbers of people who receive this device. These rates are actually quite low, not only considering the number of devices and patients in the study, but also when counterbalanced by the tens of thousands of lives that were saved by these same devices during this reporting period.

20. Would these malfunctions lead to a recall?

Not necessarily. A recall is a correction or removal of a violative product that is subject to legal action. In other words, it is possible that some corrections and removals are not recalls due to lack of a violation. For example, a malfunction may not require a recall if the malfunction was determined to be an isolated event and the failure investigation by the firm does not reveal any recurring component or manufacturing problems.

FACTS AND FIGURES

• How many pacemakers and ICDs were involved in the analysis?
  From 1990 to 2002, there were 2.25 million pacemakers and 415,780 ICDs implanted in the United States.
   
• How many pacemakers and ICDs are implanted annually?
  The annual number of pacemakers implanted during the study period increased from 94,755 in 1990 to 267, 278 in 2002. The annual number of ICDs implanted during the study period increased from fewer than 10,000 implants in 1990 to close to 100,000 in 2002.
   
• How many patients were affected by pacemaker and ICD malfunctions?
  During the study period, there were 17,323 devices (8834 pacemakers and 8489 ICDs) that were explanted due to confirmed malfunction.
   
• What is the replacement rate for pacemakers as compared to the replacement rate for ICDs?
  The annual device malfunction replacement rate ranged from 1.4 to 9.0 replacements per 1000 implants for pacemakers and 7.9 to 38.6 per 1000 implants for ICDs.

Updated September 16, 2005

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