When the heart stops -- A shock at home can save your life

[Guest guest]

This was in the Red Flags Weekly newsletter this morning at:

http://www.redflagsweekly.com/

which has a link to the original site at:

http://www.health.harvard.edu/article.cfm?id=133

A shock at home can save your life

As you read this page, someone somewhere in the United States is

collapsing from a cardiac arrest. The odds are poor that she or he

will survive this sudden disruption of the heart's normal rhythm. Most

of the 1,000 or so people who go into cardiac arrest each day die

because they don't get the treatment they need - an electric shock to

the heart - fast enough.

Heart-shocking devices were once found only in hospitals and

ambulances. Now they're popping up in airports, movie theaters,

fitness centers, casinos, malls, office buildings, and elsewhere.

These public versions, called automated external defibrillators

(dee-FIB-rih-lay-tors), are so easy to use that sixth graders who have

never seen one before can master their use in a minute or so.

This ease of use, combined with the fact that 3 in 4 cardiac arrests

happen at home, have opened a national debate over whether it's a good

idea to have a defibrillator at home.

When the heart stops

The television image of a heart attack - a man suddenly clutches his

chest and keels over - is actually a picture of cardiac arrest. A

heart attack, as the term is commonly used today, generally means the

blockage of an artery in the heart that kills some heart muscle.

(Medically speaking, this is a myocardial infarction.) A heart attack

usually gives some warning. Its chest pain or other symptoms can

prompt someone to get help before the blockage totally disrupts the

heart's rhythm.

Cardiac arrest, though, strikes suddenly and out of the blue.

Most cardiac arrests occur when the heart's powerful lower chambers,

the ventricles, start beating very fast (ventricular tachycardia

[ta-kih-CAR-dee-uh]) or fast and chaotically (ventricular fibrillation

[fib-rih-LAY-shun]). Either one of these makes it impossible for the

heart to pump blood to the body.

After just five seconds without blood circulation, a person passes

out. In another few seconds, the lack of oxygen in the brain causes

nerves to start firing, making the muscles twitch and the eyes roll

back. Even that activity stops in less than a minute.

The chances of surviving a cardiac arrest fall about 10% for each

minute the heart stays in ventricular fibrillation. Shock the heart

back into a normal rhythm within two minutes, and the victim has an

80% chance of surviving. Deliver that shock after seven minutes - the

average time it takes an emergency medical team to arrive in many

cities - and the odds are less than 30%.

If someone near you goes into cardiac arrest, calling 911 is a must.

That's the first step in what's called the chain of survival (see

Chain of survival below). Even if there's a defibrillator nearby,

you'll need professional help as soon as possible. CPR is also

important because it keeps blood flowing to the brain and other vital

organs. Still, a home defibrillator could let you make the third link

several crucial minutes sooner.

Chain of survival

What the American Heart Association calls the " chain of survival " can

help people live through cardiac arrest.

This chain has four links:

* Recognize an emergency and call 911.

* Start cardiopulmonary resuscitation (CPR).

* Use a defibrillator to restore a healthy heart rhythm.

* Get advanced care from a doctor, paramedic, or emergency

medical technician.

Can home defibrillators help?

With a prescription from a doctor and $2,500 or so, you can buy a

defibrillator for your home, office, or car at many large pharmacies

or medical supply companies. The question is, should you?

Experts in the areas of sudden cardiac arrest, emergency medicine, and

public health don't see eye-to-eye on this issue. Some argue that

people who want to buy defibrillators for their homes should be able

to do so without needing a prescription from a doctor. Others argue

that people won't maintain the devices so they will be ready when

needed, or that most people would be better off spending some of the

money on a health club membership and donating the rest to their local

emergency response team.

Training is a must

If you decide to buy a defibrillator for your home, or if you just

want to be prepared for the chance you'll someday need to use one at

work or in a public venue, make the time now to take a class on using

this device.

Why bother to go through training when these machines have been

designed for virtually mistake-free use? Several reasons. A class can

help you use the defibrillator with confidence and speed. It can help

you deal with unusual situations, such as where to apply the pads on

someone with an implanted pacemaker, a medication patch, or a hairy

chest. It will also teach you how to do CPR, an important part of the

process.

The American Heart Association has developed a 3 1/2-hour course

called " HeartSaver AED for Lay Rescuers and First Responders. " To find

the closest training center that offers this course, call the AHA at

800-242-8721, or visit our Web site, health.harvard.edu/heart

<http://www.health.harvard.edu/heart> .

Researchers have collected relatively little evidence on the benefits

and risks of wider access to defibrillators. A few studies have

examined their use in public places. The most recent showed that 11 of

18 people who collapsed with ventricular fibrillation over a two-year

period in Chicago's three airports were revived, mostly by passers-by

who used highly visible and well-marked defibrillators. (Journal of

the American Medical Association, October 17, 2002, pages 1242-47.)

But their use at home is uncharted territory. A pilot project modeled

after neighborhood Crime Watch programs is putting automated

defibrillators in volunteers' homes in Indianapolis neighborhoods.

When there's a call to 911 about a cardiac arrest in that

neighborhood, it's routed to both the emergency services and the

nearest home with a defibrillator. The Neighborhood Heart Watch is the

brainchild of Indianapolis cardiologist Zipes, a past

president of the American College of Cardiology.

The $18 million Home Automatic External Defibrillator Trial, sponsored

in part by the National Institutes of Health, will take a stab at

mapping the benefits and risks. It will give home defibrillators to

3,500 heart patients and train their partners to use the devices. The

partners of another 3,500 heart patients will get training in CPR, but

no home defibrillator. Recruitment for the trial began last month. If

you're interested in taking part in the study, contact the trial's

organizers at hat@... to find out if a physician in your area is

involved. The results aren't expected until 2007.

Who should have one?

Four years is a long time to wait for a definitive answer. Until then,

what should you do?

A home defibrillator would probably be a good investment for anyone

who has survived a sudden cardiac arrest but who does not have a

pacemaker capable of shocking the heart (an implantable

cardioverter/defibrillator, or ICD). If your heart has veered out of

rhythm once, there's a good chance it will do it again. Most people

who have had this experience end up with an ICD. If for some reason

you didn't, a home defibrillator could be a good insurance policy.

Owning this device might also make sense for someone with severe heart

failure, unstable angina, or other severe forms of heart disease. So

far, though, there's no good evidence that home defibrillators will

save lives in this group of people.

So, if you have survived a cardiac arrest but don't have a pacemaker

capable of rebooting your heart if it slips into ventricular

tachycardia or fibrillation, you might think about investing in a home

defibrillator. This also might be a wise purchase if you've learned

CPR in hopes of resuscitating a loved one with high-risk heart disease

in case he or she suddenly collapses.

Delivering the shock of a lifetime

All automated external defibrillators use the same four steps. Most

also have a gentle but authoritative computerized voice that gives the

user easy-to-follow instructions.

* Turn on the machine. Most have a large, unmistakable ON

button.

* Attach the pads to the victim's chest. The heart-shocking

current comes from two hand-sized pads. You stick one on the upper

part of the person's right chest, just below the shoulder. The other

goes on the left side, near the armpit. Both must go on bare skin.

* Wait while the machine analyzes the heart rhythm. Sensors in

an automatic defibrillator record and analyze the heart rhythm, just

as an electrocardiogram does. If they detect ventricular fibrillation,

the machine tells you to go to the next step. If they don't, the

machine won't deliver a shock, even if you push the " shock " button.

* Deliver the shock. If the victim's heart is in ventricular

fibrillation, you'll be instructed to press the shock or rescue

button. The machine then checks the heart rhythm again before telling

you whether another shock is needed.

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