Published 23 March 2009, doi:10.1136/bmj.b874
Cite this as: BMJ 2009;338:b874

Head to Head

Should doctors recommend automated external defibrillators for use at home after myocardial infarction? Yes

¹ University of New South Wales and St Vincent’s Clinic, 438 Victoria Street, Darlinghurst, NSW 2010, Australia

Should people who risk of reinfarction have defibrillators available at home? Michael F O’Rourke thinks that enthusiasm is an important factor (doi:10.1136/bmj.b874); Mathew Hutchinson and David Callans say at home defibrillators do not save additional lives (doi:10.1136/bmj.b876)

Ventricular fibrillation causes most of the sudden non-traumatic deaths in Western society—up to 400 000 deaths a year in the United States alone.¹ Most deaths occur in people without known heart disease, but many occur in people with known coronary artery disease.¹ Defibrillators in aircraft, airports, railway stations, sports stadiums, police patrol cars, gymnasiums, and various public places are designed for the population at large,² and in these locations their use is regarded as cost effective.³ Like fire extinguishers, they seem to be for use in a rare emergency.

Guidelines for the implantation of defibrillators now include patients of all ages whose left ventricular ejection fraction is less than 30% but who have a prospect of living without major cardiac disability for two years.⁴ Implantation of a defibrillator is encouraged by manufacturers and by proceduralists, who fear that deviating from guidelines may be a cause for legal action. Together with implantation, monitoring, and prior evaluation, they cost about $100 000 in the United States during the first year. Defibrillators were introduced to save lives in patients with hearts "too good to die," but now they are used more often in patients with hearts "too bad to live."

Patients who have had a myocardial infarction have a much higher risk of further coronary events, including ventricular fibrillation, than other people of the same age. Is it reasonable to suggest that such patients have a defibrillator available in their home for use by others in the event of cardiac arrest?¹ Most such events do occur in the home, in the bedroom or adjacent rooms.^{5 6} If such people work in a federal US building or in a casino, airport, or gymnasium or if they travel by air in or towards the United States such a device is available and a programme is in place for its use. But not at home.

Economic argument

Those who argue against home defibrillators quote cost and the HAT (Home Automated External Defibrillator Trial) study.⁷ Defibrillators can be purchased for around $1500, and people pay this much or more for metallic paint or alloy wheels in their new car, or for a better TV or sound system in their home. The cost of purchasing a semiautomatic defibrillator is around 2% that of implanting an internal defibrillator, and in a heart "too good to die" against a heart "too bad to live." The economic arguments do not make sense.

The HAT trial randomised 7001 patients who had survived anterior myocardial infarction a mean of 1.8 years previously and who did not meet the criteria for implantation of an internal defibrillator.⁷ One group was provided with a defibrillator at home and the primary carer was instructed in its use; the other group was not provided with a defibrillator. Both groups had access to community emergency care, which included defibrillation. After average follow-up of 37 months there was no difference in outcome of the two groups, and the primary end point (death) was the same in each, around 2% a year. The defibrillators that were used worked perfectly, and there were no problems with using them. I believe the HAT trial cannot be used to exclude value of home defibrillation: it shows the same problem as noted in an earlier small trial conducted in Seattle.⁸

Participants in HAT (patients, carers, doctors) showed far less enthusiasm than investigators had anticipated. This necessitated heavy promotion worldwide for entry of patients to the trial, liberalisation of criteria to less sick patients, and extension of the time from infarction to entry. Though it was not assessed, carers were not enthusiastic about using the device in elderly patients with cardiac and other comorbidities. Further, there was no organised follow-up to check the device or to check the training of carers or assess their motivation. The device was provided with "once-only" training; from there on, the household was on its own. This approach was justified at a national US meeting by a senior author who referred to a desire to apply a "real world" evaluation. When the trial finished, most devices were returned to the hospital or centre of origin, even when patients were still alive and at risk—resulting in a sudden worldwide glut of second hand but unused defibrillators, and reinforcing the view that people did not wish to have the defibrillator for the family member.

Enthusiasm is important

What, then, of patients about to be discharged from hospital after a small or medium myocardial infarction? I believe that such patients and their spouses should be advised to consider buying a defibrillator for the home, and that there should be follow-up, such as did not occur in HAT, at intervals of 6-12 months. Such a service is arranged in Australia through the St John Ambulance organisation.

Enthusiasm seems to be the key to successful defibrillation. Lack of enthusiasm delayed the development of coronary care wards and led to delay in installing defibrillators in ambulances. Lack of enthusiasm led to withdrawal of defibrillators in some police services. There is no point providing a defibrillator to an unenthusiastic spouse, but there is every reason for suggesting purchase to an intelligent, enthusiastic spouse or carer, provided there is appropriate follow-up.

Cite this as: BMJ 2009;338:b874

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Competing interests: None declared.

Provenance and peer review: Commissioned; not externally peer reviewed.

References

1. Weaver D, Peberdy M. Defibrillators in public places—one step closer to home. N Engl J Med 2002;347:1223-4.[Free Full Text]
2. Caffrey S, Willoughby P, Pepe P, Becker L. Public use of automated external defibrillators. N Engl J Med 2002;347:1242-7.[Abstract/Free Full Text]
3. Whitfield R, Colquohoun M, Chamberlain D, Newcombe R, Davies S, Boyle R. The Department of Health National Defibrillator Program: analysis of downloads from 250 deployments of public access defibrillation. Resuscitation 2005;64:269-77.[CrossRef][Web of Science][Medline]
4. Hayes DL, Zipes DP. Cardiac pacemakers and cardioverter-defibrillator. In: Libby P, Bonow R, Mann D, Zipes D, Braunwald E, eds. Braunwald’s heart disease. In: Philadelphia: Saunders, 2008:831-61.
5. Norris R on behalf of UK Heart Attack Study Collaboration Group. Circumstances of out-of-hospital arrest in patients with ischaemic heart disease. Heart 2005;91:1537-40.[Abstract/Free Full Text]
6. O’Rourke MF. Reality of out of hospital cardiac arrest. Heart 2005;91:1505-6.[Abstract/Free Full Text]
7. Bardy GH, Lee KL, Mark DB, Poole JE, Toff WD, Tonkin AM, et al. Home use of automated external defibrillators for sudden cardiac arrest. N Engl J Med 2008;358:1793-804.[Abstract/Free Full Text]
8. Eisenberg M, Moore J, Cummins R, Andresen E, Litwin PE, Hallstrom AP, et al. Use of the automatic external defibrillator in homes of survivors of out-of-hospital ventricular fibrillation. Am J Cardiol 1989;63:443-6.[CrossRef][Web of Science][Medline]

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