Elderly benefit from using implantable defibrillators

The elderly may benefit from implantable cardioverter defibrillators as much as younger people, according to new research done by scientists at the Institute for Clinical Evaluative Sciences (ICES) and the University of Ottawa Heart Institute in Ontario, Canada.

An implantable cardioverter defibrillator (ICD) is placed in the chest, delivering one or more electrical shocks to restore a normal heartbeat when it detects a dangerous cardiac rhythm.

Overall health — not age alone — should determine how well patients will do after getting an ICD and help guide decisions about who should receive one, researchers said.

“Whether elderly patients benefit from the devices has been controversial and research on the topic is lacking,” said Douglas S. Lee, a scientist at the Institute for Clinical Evaluative Sciences and cardiologist at the Peter Munk Cardiac Centre in Toronto. “The issue is important as the population ages and the number of elderly people living with heart disease grows.”

Researchers studied 5,399 patients who had ICDs implanted because of poor heart function due to a prior heart attack or heart failure, or after being resuscitated from cardiac arrest.

“Older patients were just as likely as younger people to experience an appropriate electrical shock from the device to treat a life-threatening heart rhythm. However, older patients experienced more non-cardiac and cardiovascular hospitalizations, and higher associated rates of death overall,” said Dr. Lee, who is also an associate professor of medicine at the University of Toronto.

Other study findings include:

• Among those who received an ICD with heart failure or after heart attack, 38.5 per cent were 70 years or older and 7 per cent were 80 years or older.
• Among those who received an ICD after surviving a cardiac arrest, 42.5 per cent were 70 years or older and 10.9 per cent were in their 80s.
• Older age correlated with increased risk of death after ICD implantation in both groups. For example, among those undergoing ICD implantation for prevention of cardiac arrest, 2.1 in every 100 patients ages 18-49 died whereas 10.2 in 100 died among those 80 years and older.
• Use of the devices was equally effective among younger and older patients in restoring heart rhythm after the occurrence of a serious life-threatening rhythm disorder. Across all age groups, ICDs more often delivered appropriate electrical shocks when implanted after cardiac arrest than when used to prevent the first cardiac arrest episode.

The Ontario Ministry of Health and Long-Term Care and the Canadian Institutes of Health Research funded the study.

The study “Survival After Implantable Cardioverter Defibrillator Implantation In the Elderly” was published online ahead of publication in the journal Circulation.

Author block: Yung D, Birnie D, Dorian P, Healey JS, Simpson CS, Crystal E, Krahn AD, Khaykin Y, Cameron D, Chen Z, Lee D.

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.

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