Preventive steps to take plus what to do in an
emergency
September 25, 2017
You may think the most common single cause of
death in the United States is heart attack. Or cancer. Or stroke.
But it’s actually sudden cardiac arrest (SCA).
SCA is a runaway problem with the heart’s electrical system (usually called
ventricular tachycardia or ventricular fibrillation).
Most SCA victims survive if they get help very
quickly. But SCA is fatal 95 percent of the time.
“Only about 5 percent of those who have a
sudden cardiac arrest survive long enough to get to — and then be discharged
from — the hospital alive,” notes cardiologist Bruce Wilkoff, MD, an expert in heart rhythm disorders.
“They might have been alone or with someone
who didn’t know CPR, or no one called 911. Or the ER squad couldn’t get there
within the 10 minutes required to prevent brain death.”
What happens inside
the heart
In sudden cardiac arrest, the heart typically races away
in a confused, disorganized manner.
Circulation halts. Blood doesn’t reach the
lungs or brain. People abruptly pass out, don’t respond, stop breathing, have
no pulse.
“No one can endure this for more than about 4
to 5 seconds without passing out,” says Dr. Wilkoff.
A deadly public health
crisis
About 365,000 people per year experience SCA
at home or out in public. That’s roughly equivalent to the combined annual deaths from:
- Firearms
- Car
accidents
- Breast,
cervical, colorectal and prostate cancers
- House
fires
- Diabetes
- Alzheimer’s
disease
- HIV
- Suicides
SCA is one of the most frequent causes of
sudden death. Others include myocardial infarction (heart attack), heart muscle
rupture and stroke.
5 things that increase
your risk
The heart rhythm disturbances leading to SCA
can result from:
- Scarring. Rhythm
problems can often be traced to scarred heart muscle. “Scarring causes the
heart’s electrical signals to become confused and fragmented,” explains
Dr. Wilkoff. The most common causes are coronary artery disease and
cardiomyopathy. Heart attacks starve the heart muscle, causing tissue
death and scarring. Viral infections, hereditary or autoimmune conditions
and chemical toxicity can also damage and scar the heart muscle.
- A low ejection fraction. If you have heart failure with an ejection fraction of 35
percent or less, your heart can’t pump out enough blood with each beat.
This disrupts your heart rhythm and increases the risk of sudden cardiac
death. “Putting in an implantable cardiac
defibrillator (ICD) will rescue you from these rapid and
irregular heart rhythm episodes, extend your life and allow you to return
to normal living,” says Dr. Wilkoff. “ICDs increase survival from sudden
cardiac arrest to 98 percent because they respond within seconds, not
minutes.”
- A family history. If
a first-degree relative — one of your parents or siblings — died young for
unknown reasons, then your risk of early, sudden death is higher too. (SCA
is often the cause in these cases.)
- Smoking. Smoking dramatically increases your risks of
both heart attack and sudden cardiac death. “When we put ICDs in smokers,
we find they need more shocks from their devices, which means they’re
having more cardiac events,” says Dr. Wilkoff.
- Poorly managed heart
failure. “If you have heart failure
symptoms (shortness of breath and exercise intolerance) with or without a
low ejection fraction, you need medicine,” he says. Drugs such as ACE
inhibitors and beta blockers will keep your heart from working too hard,
improve its function and lower your risk of SCA.
What to do in an
emergency
If someone nearby falls over and is
unresponsive, with no signs of breathing or a pulse, call 911. If you know how
to use an automatic external defibrillator (AED), find one and
use it, says Dr. Wilkoff. If not, do CPR until the ambulance arrives.
“Defibrillation is the No. 1 thing that
improves survival in sudden cardiac arrest. CPR keeps people alive long enough
to be defibrillated,” he explains.
Learning both skills can save a life.
The American Heart Association offers
training, as do many fire departments, schools and libraries.
A word to the wise
“Most people who die suddenly either didn’t
know they were going to die suddenly or didn’t pay attention to the warning
signs,” says Dr. Wilkoff.
Briefly passing out is usually nothing more
than a fainting spell. But it’s also possible to experience a more serious but
temporary irregular heart rhythm that indicates more serious heart disease.
If you or someone you love passes out,
consider whether they might be at risk of SCA and see a physician, he advises.
“If you have heart scarring or symptoms of
heart failure, or a history of heart attack, or a low injection fraction and
continue to smoke, you likely need an ICD,” notes Dr. Wilkoff.
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