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Major complications can occur after ICD implantation and are associated with increased mortality risk


Implantable cardioverter-defibrillators (ICDs) can prevent sudden cardiac death in many patients whose hearts have weakened pumping ability, as well as for some who have suffered a past heart attack. However, the frequency and types of complications occurring in patients who receive these devices are not fully known. New research from the Institute for Clinical Evaluative Sciences (ICES) conducted in collaboration with 18 major cardiac centres in Ontario shows that complications occur in approximately 7.5 per cent of ICD patients within 45 days of the operation to implant the defibrillator. While most of these complications are not life-threatening, some, like mechanical problems or serious surgical infections, can be serious. An estimated 2,000 Ontarians undergo this procedure annually.

“The Ontario ICD database, funded by the Ontario Ministry of Health and Long-Term care, is one of the most comprehensive ICD databases in the world. While ICDs can be life-saving devices for many patients, this analysis of the database shows that there is a significant risk of complications occurring after their implantation. Ontario cardiologists are world-leaders in the development of strategies to reduce the frequency of these types of complications, and our study provides insights into further opportunities for reducing the frequency of these adverse events,” says principal author and ICES scientist Dr. Douglas Lee.

“While these findings show complication rates that are in line with published data from leading international centres, the finding that these complications are associated with the risk of death is new,” says Dr. Chris Simpson, a heart rhythm specialist from Kingston General Hospital. “We all need to double our efforts to continue making this procedure safer for our patients.”

The study of 3,340 patients in 18 major cardiac centres in Ontario from February 2007 to May 2009 found that:

  • 4.1 per cent of patients experienced major complications (such as mechanical problems of the leads or the devices, heart failure, fluid in the lungs or serious surgical infections) within 45 days of device implant and they had more than three times the risk of dying within the next 6 months.
  • Women and those with enlarged hearts were approximately 50 per cent more likely to develop major complications than men.
  • Early complications occurred more frequently in the first 1.5 months after discharge from the hospital, than during the first hospital stay when the defibrillator was implanted.
  • The type of ICD implanted was the most significant predictor of increased complications, with the highest risks observed among sicker patients who may need more complex devices. The most complex defibrillators that involved leads to pace the left and right sides of the heart were associated with double the risk of major complications, compared to the simplest devices.
  • However, it was noted that patients who require these complex devices have more severe heart disease, which may predispose them to more complications.

The most complex defibrillators may be used in some patients suffering from fluid build-up in the lungs because of a weakened heart, with the aim of improving quality of life and reducing the need for frequent hospitalizations.

“Although some complications developed immediately after defibrillator implantation, most complications tended to occur after a patient had been discharged from the hospital. The development of major complications was associated with a significantly increased risk of mortality. This highlights the critical importance for patients who have undergone a defibrillator procedure to follow-up with their physicians should they suspect they have developed a device-related complication,” says Lee.

The study “Evaluation of early complications related to de novo cardioverter-defibrillator implantation” is in the February 23, 2010, issue of the Journal of the American College of Cardiology.

The Ontario Implantable Cardioverter Database is funded by the Ontario Ministry of Health and Long-Term (MOHLTC) and involves a collaborative effort between ICES and all 18 hospitals in Ontario involved in the implantation and follow up of patients who receive ICDs in Ontario (http://icd.ices.on.ca). The results and conclusions are those of the authors, and should not be attributed to the MOHLTC.

ICES is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy.


  • Deborah Creatura
  • Acting Media Advisor, ICES
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