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Ventricular fibrillation
(VFib)
Overview
Ventricular fibrillation is a type of irregular heart rhythm
(arrhythmia). During ventricular fibrillation, the lower heart
chambers contract in a very rapid and uncoordinated manner. As a
result, the heart doesn't pump blood to the rest of the body.
Ventricular fibrillation is an emergency that requires immediate
medical attention. It's the most frequent cause of sudden
cardiac death.
Emergency treatment for ventricular fibrillation includes
cardiopulmonary resuscitation (CPR) and shocks to the heart with
a device called an automated external defibrillator (AED).
Medications, implanted devices or surgery may be recommended to
prevent episodes of ventricular fibrillation. Ventricular fibrillation may also be called VFib, V-fib or VF.
Symptoms
Collapse and loss of consciousness are the most common
symptoms of ventricular fibrillation.
Before a ventricular fibrillation episode, you may have
symptoms of an irregularly fast or erratic heartbeat
(arrhythmia). You may have:
- Chest pain
- Very fast heartbeat (tachycardia)
- Dizziness
- Nausea
- Shortness of breath
When to see a doctor
Make an appointment with a heart doctor (cardiologist)
if you have an unexplained fast or pounding heartbeat.
If you see someone collapse, seek emergency medical help
immediately. Follow these steps:
- Call 911 or your local emergency number.
- If the person is unconscious, check for a pulse.
- If no pulse, begin cardiopulmonary resuscitation
(CPR) to help keep blood flowing through the body
until an automated external defibrillator (AED) is
available. The American Heart Association recommends
hands-only CPR.
Push hard and fast on the person's chest — about 100
to 120 times a minute. It's not necessary to check
the person's airway or deliver rescue breaths.
Continue until emergency medical help arrives.
- Use an automated external defibrillator (AED) as
soon as it's available. Deliver a shock following
the prompts on the device.
Causes
Ventricular fibrillation is caused by either:
- A problem in the heart's electrical properties
- A disruption of the blood supply to the heart muscle
Ventricular fibrillation
In a typical heart rhythm, electrical
signals travel from the heart's upper
chambers (atria) to the heart's lower
chambers (ventricles), causing the
ventricles to contract and pump blood.
In ventricular fibrillation, rapid,
irregular electrical signals cause the
ventricles to quiver uselessly instead
of pumping blood.
Sometimes, the cause of ventricular fibrillation is
unknown.
To understand more about how ventricular fibrillation
occurs, it may be helpful to know how the heart
typically beats.
The heartbeat
The typical heart has four chambers — two upper chambers
(atria) and two lower chambers (ventricles). Within the
upper right chamber of the heart (right atrium) is a
group of cells called the sinus node. The sinus node is
the heart's natural pacemaker. It produces the signals
that start each heartbeat.
These electrical signals move across the atria, causing
the heart muscles to squeeze (contract) and pump blood
into the ventricles.
Next, the signals arrive at a cluster of cells called
the atrioventricular (AV) node, where they slow down.
This slight delay allows the ventricles to fill with
blood. When the signals reach the ventricles, the lower
heart chambers contract and pump blood to the lungs or
to the rest of the body.
In a typical heart, this heart signaling process usually
goes smoothly, resulting in a typical resting heart rate
of 60 to 100 beats a minute. But in ventricular
fibrillation, rapid, irregular electrical signals cause
the lower heart chambers to quiver uselessly instead of
pumping blood.
Risk factors
Things that may increase the risk of ventricular
fibrillation include:
- A previous episode of ventricular fibrillation
- A previous heart attack
- A heart problem present at birth (congenital heart
defect)
- Heart muscle disease (cardiomyopathy)
- Injuries that cause damage to the heart muscle, such
as being struck by lightning
- Drug misuse, especially with cocaine or
methamphetamine
- A severe imbalance of potassium or magnesium
Complications
Without immediate treatment, ventricular fibrillation
can cause death within minutes. The condition's rapid,
erratic heartbeats cause the heart to abruptly stop
pumping blood to the body. Blood pressure drops suddenly
and significantly. The longer the body lacks blood, the
greater the risk of damage to the brain and other
organs.
Ventricular fibrillation is the most frequent cause of
sudden cardiac death. The risk of other long-term
complications depends on how fast treatment is received.
Diagnosis
Ventricular fibrillation is always diagnosed in
an emergency situation. If sudden cardiac death
has occurred, a pulse check will reveal no
pulse.
Tests to diagnose and determine the cause of
ventricular fibrillation include:
-
Electrocardiogram (ECG or EKG). This
quick and painless test measures the
electrical activity of the heart. Sticky
patches (electrodes) are placed on the chest
and sometimes the arms and legs. Wires
connect the electrodes to a computer, which
displays the test results. An
electrocardiogram (ECG) can show if the
heart is beating too fast or too slowly. If
you're having an episode of ventricular
fibrillation, the ECG usually
shows a heartbeat of about 300 to 400 beats
a minute.
-
Blood tests. Blood tests can be done to
check for proteins (enzymes) that leak into
the bloodstream when the heart is damaged by
a heart attack.
-
Chest X-ray. An X-ray image of the chest
can show the size and shape of the heart and
its blood vessels.
-
Echocardiogram. This noninvasive test
uses sound waves to create images of the
heart in motion. It can show the heart's
size and structure.
-
Coronary catheterization (angiogram). This
test helps health care providers see
blockages in the heart arteries. A long,
thin flexible tube (catheter) is inserted in
a blood vessel, usually in the groin or
wrist, and guided to the heart. Dye flows
through the catheter to arteries in the
heart. The dye helps the arteries show up
more clearly on X-ray images and video.
-
Cardiac computerized tomography (CT). A
computed tomography (CT) scan uses X-rays to
create cross-sectional images of specific
parts of your body.
-
Cardiac magnetic resonance imaging (MRI). This
test uses a magnetic field and
computer-generated radio waves to create
detailed images of blood flow in the heart.
Treatment
Ventricular fibrillation requires emergency
medical treatment to prevent sudden cardiac
death. The goal of emergency treatment is to
restore blood flow as quickly as possible to
prevent organ and brain damage.
Emergency treatment for ventricular fibrillation
includes:
- Cardiopulmonary resuscitation (CPR). cardiopulmonary
resuscitation (CPR) mimics the pumping
motion of the heart. It keeps blood flowing
through the body. First call 911 or your
local emergency number. Then start CPR by
pushing hard and fast on the person's chest
— about 100 to 120 compressions a minute.
Let the chest rise completely between
compressions. Continue CPR until
an automated external defibrillator (AED) is
available or emergency medical help arrives.
-
Defibrillation. This treatment is also
called cardioversion. An automated external
defibrillator (AED) delivers shocks through
the chest wall to the heart. It can help
restore a regular heart rhythm. As soon as
an automated external defibrillator (AED) is
available, apply it and follow the prompts.
If you're not trained to use an AED,
a 911 operator or another emergency medical
operator may be able to give you
instructions. Public-use automated external
defibrillators (AEDs) are programmed to
recognize ventricular fibrillation and send
a shock only when needed.
Other treatments for ventricular fibrillation
are given to prevent future episodes and reduce
the risk of arrhythmia-related symptoms.
Treatment for ventricular fibrillation includes
medications, medical devices and surgery.
Medications
Drugs to control the heart rhythm (anti-arrhythmics)
are used for emergency or long-term treatment of
ventricular fibrillation. If you're at risk of
ventricular fibrillation or sudden cardiac
death, your provider may prescribe medications
to slow and control your heartbeat.
Surgery or other procedures
Surgery or medical procedures to treat
ventricular fibrillation include:
-
Implantable cardioverter-defibrillator (ICD). An
implantable cardioverter-defibrillator (ICD)
is a battery-powered unit that's implanted
under the skin near the collarbone — similar
to a pacemaker. The ICD continuously
monitors the heart rhythm. If the device
detects an episode of ventricular
fibrillation, it sends shocks to stop it and
reset the heart's rhythm.
-
Cardiac ablation. This procedure uses
heat or cold energy to create tiny scars in
the heart to block the irregular heart
signals that cause ventricular fibrillation.
It's most often done using thin, flexible
tubes called catheters inserted through the
veins or arteries. It may also be done
during heart surgery.
-
Coronary angioplasty and stent placement. If
ventricular fibrillation is caused by a
heart attack, this procedure may reduce the
risk of future episodes of ventricular
fibrillation.
The health care provider inserts a long,
thin tube (catheter) through an artery,
usually in the groin, to a blocked artery in
the heart. A balloon on the tip of the
catheter briefly inflates to widen the
artery. This restores blood flow to the
heart. A metal mesh stent may be placed into
the artery to help it stay open.
-
Coronary bypass surgery. This open-heart
surgery redirects blood around a section of
a blocked or partially blocked artery in the
heart. It may be done if ventricular
fibrillation is caused by coronary artery
disease. During bypass surgery, the surgeon
takes a healthy blood vessel from the leg,
arm or chest. It's connected below and above
the blocked artery or arteries in the heart.
This creates a new pathway for blood flow.
Self care
Lifestyle changes that help keep the heart as
healthy as possible include the following:
-
Eat a healthy diet. Heart-healthy foods
include fruits, vegetables and whole grains,
as well as lean protein sources such as soy,
beans, nuts, fish, skinless poultry and
low-fat dairy products. Avoid added salt
(sodium), added sugars and saturated fats.
-
Exercise. Physical activity helps you
achieve and maintain a healthy weight.
Regular exercise helps control diabetes,
high cholesterol and high blood pressure —
all risk factors for heart disease. With
your provider's OK, aim for 30 to 60 minutes
of physical activity most days of the week.
Talk to your health care provider about the
amount and type of exercise that's best for
you.
-
Manage weight. Being overweight
increases the risk of heart disease. Talk
with your care provider to set realistic
goals for body mass index (BMI) and weight.
-
Don't smoke. Smoking is a major risk
factor for heart disease, especially
atherosclerosis. Quitting is the best way to
reduce the risk of heart disease and its
complications. If you need help quitting,
talk to your provider.
-
Manage blood pressure and cholesterol. Get
regular health checkups to monitor blood
pressure and cholesterol. Take medications
as prescribed to manage high blood pressure
or high cholesterol.
-
Limit alcohol. Too much alcohol can
damage the heart. If you choose to drink
alcohol, do so in moderation. For healthy
adults, that means up to one drink a day for
women and up to two drinks a day for men.
-
Get regular checkups. Take your
medications as prescribed. Have regular
follow-up appointments with your health care
provider. Tell your provider if your
symptoms worsen.
-
Practice good sleep habits. Poor sleep
may increase the risk of heart disease and
other chronic conditions. Adults should aim
to get 7 to 9 hours of sleep daily. Kids
often need more. Go to bed and wake at the
same time every day, including on weekends.
If you have trouble sleeping, talk to your
provider about strategies that might help.
Coping and support
Some irregular heart rhythms (arrhythmias) can
be triggered by emotional stress. Taking steps
to ease stress and anxiety can help keep the
heart healthy. Getting more exercise, practicing
mindfulness and connecting with others in
support groups are some ways to reduce and
manage stress. If you have anxiety or
depression, talk to your provider about
strategies to help.
Some types of complementary and alternative
therapies may help reduce stress, such as:
- Yoga
- Meditation
- Relaxation or mindfulness techniques
Getting support from loved ones may also be
helpful.
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