Download Atrial fibrillation Patient Information Leaflet

Atrial fibrillation
Patient Information Leaflet
Atrial fibrillation, often shortened to ‘AF’ is a
very common heart rhythm abnormality. It
affects 1 in 20 middle aged people and around
1 in 10 people over the age of 80.
The right and left ‘atria’ are the two heart
chambers which collect blood from the body
and the lungs respectively. When working
correctly, they push blood into the ‘ventricles’,
the main pumping chambers, from which blood
is then pumped to the lungs to be refreshed
with oxygen or around the rest of the body to
feed the brain, muscles, internal organs and
the heart itself with nutrients and oxygen.
Many patients are not aware that their
heartbeat is no longer regular and in AF, and it
is often only picked up on examination by a
doctor and confirmed on an ECG (tracing of the
electrical activity of the heart). AF may occur
suddenly often due to an acute illness, may
come and go intermittently (termed ‘episodic’
or ‘paroxysmal’) or be chronic and persistent.
The healthy heart’s natural pacemaker and
internal ‘wiring’ ensures that the timing of the
contraction of the atria and ventricles is
properly co-ordinated – this is called sinus
rhythm.
Atrial fibrillation, literally means ‘shaking or
wobbling of the atria’. There is a loss of the
normal contraction of the atria and the
important co-ordination with the ventricles. The
normal regular, steady heart beat becomes fast
and chaotic leading to a reduction in the
efficiency of heart function.
Typical symptoms include:
• Irregular pulse or sensation of fast, irregular
heart beating in the chest – a form of
palpitation
• Shortness of breath and tiredness when
walking or running
• Chest tightness or pain
• Feeling light-headed or dizzy
There are a variety of conditions
which can lead to AF. Common
underlying causes include:
• Undetected or uncontrolled high
blood pressure
• ‘Wear n’ tear’ of the heart’s
internal electric wiring
• Heart attacks due to coronary
artery disease
• Excessive chronic or binge
alcohol drinking
• Chronic lung damage due to
smoking
• Infections especially of the lung
• Disorders of heart muscle cardiomyopathies
• Thyroid gland disorders
• Leaky or narrowed heart valve
• Heart surgery
The main long-term risks or
complications to health related to
AF are:
• Blood clots developing within
the atria causing a blockage in blood vessels
supplying the arms, legs or internal organs
called an embolus or part of the brain called
an embolic stroke.
• Enlargement and weakening of the heart
resulting in heart failure.
© Dr Winston Martin
January 2007 - Information accurate at time of going to print.
Darent Valley Hospital, Darenth Wood Road, Dartford, Kent , DA2 8DA - Telephone: 01322 428100 - www.dvh.nhs.uk 1
The main aims of treatment in AF are:
• Rate control - Slowing the heart rate to
ease
symptoms
and
prevent
heart
enlargement.
• Anticoagulation - Blood thinning to
prevent blood clots.
• Cardioversion - Restoration of normal
heart rhythm if possible.
• Maintaining sinus rhythm – Keeping the
heart beat regular and co-ordinated.
Rate control
Maintaining
SR
Cardioversion
Anticoagulation
The exact treatment of a patient with AF can be
complex and depends on a number of factors:
• How long the heart has been in AF
• The severity of any symptoms
• The presence of any underlying heart
disease
• The presence of other underlying conditions
or illnesses
Rate control
There are a number of different drugs termed
anti-arrhythmic drugs which can reduce fast
heart rate. Common drugs include:
• Beta-blockers such as atenolol, bisoprolol
and sotalol. Possible side-effects are tiredness,
dizziness, breathlessness or wheezing . They
are generally avoided in people with asthma.
• Calcium channel blockers such as
diltiazem and verapamil. Possible side-effects
are flushing, ankle swelling and constipation.
They are generally avoided in people with poor
heart pump function or heart failure.
• Digoxin alone used to be the most common
treatment for AF. In injection form, it can help
to slow the heart rate quickly. Nowadays it is
most often used in combination with either
beta-blockers or calcium channel blockers to
improve heart rate control.
Anticoagulation
The risk of clot formation is high if AF occurs in
association with an acute illness such as a
heart attack or serious infection. In these
circumstances,
blood
thinning
heparin
injections are given into the skin around the
lower abdomen.
If the heart has been in AF for longer than 2
days, warfarin in tablet form is started to
prevent new clots developing and help any clots
already present to dissolve while the heart rate
is being slowed down. The drug blocks the
action of vitamin K which is required by the
liver for making clotting factors. Warfarin takes
several days to become effective and this is
measured by a standardised blood test called
the ‘international normalised ratio’ or ‘INR’.
The normal level in a well person not on
warfarin is 1. The aim is to achieve an INR
between 2 and 3. The correct dose varies from
person to person, over time and can be affected
by different foods and alcohol. Therefore regular
blood
checks
are
necessary
and
are
generally performed in a
special anticoagulation or
warfarin clinic with the
result and recommended
daily dose recorded in a
yellow booklet.
If the INR is too low, the risk of clots and stroke
remain high. If the INR is too high, then there is
a much higher risk of internal bleeding.
Warfarin is avoided if there is a high risk of
bleeding due to stomach ulcers, chronic liver
disease, unexplained anaemia or a high risk of
falls or confusion. After a stroke, starting
warfarin is best delayed for at least 2 weeks.
Patients with AF who have had a previous
stroke or mini-stroke, underlying heart disease
(especially heart failure or valve disease),
diabetes or over 65 years of age are at
increased risk of clots and strokes. Warfarin is
often continued lifelong in these patients even if
normal regular sinus rhythm is restored
because there is a high likelihood of AF
occurring
again
without
warning
(see
cardioversion below).
Aspirin is another drug which blocks the action
of platelets in the blood. It can be used to
reduce the development of clots but is much
less effective than warfarin, especially in high
clot and stroke risk patients. Whereas warfarin
© Dr Winston Martin
January 2007 - Information accurate at time of going to print.
Darent Valley Hospital, Darenth Wood Road, Dartford, Kent , DA2 8DA - Telephone: 01322 428100 - www.dvh.nhs.uk 2
reduces the yearly risk of stroke by 2/3rds,
aspirin reduces the risk by less than 1/3rd.
Aspirin is suitable for patients aged 60-65 years
without high risk features. It is often given with
a stomach protecting agent e.g. omeprazole or
lansoprazole to reduce the risk of stomach
ulcers.
Clopidogrel, is another antiplatelet agent.
Studies however have shown that it is not an
effective alternative used on its own or in
combination with aspirin and is associated with
an increased risk of internal bleeding.
The decision regarding the choice of blood
thinning
medication
requires
careful
assessment of the clot and stroke risk and
discussion between the patient and specialist
doctor regarding the risks and benefits of
treatment. Any decision may also need to be
reviewed from time to time if circumstances
change and as the patient gets older.
Cardioversion
If the AF is of sudden onset, then normal heart
rhythm may return by itself within several
hours especially if any underlying acute illness
is treated.
Where this does not occur
spontaneously, restoration of normal sinus
rhythm by other means is desirable, if possible.
This is normally achieved by the use of drugs,
electric shock treatment or a combination of
both of these.
Helpful
drugs
include
beta-blockers,
flecainide, propafenone and amiodarone. In
AF of sudden
onset,
these
drugs may be
given
by
injection or by
mouth
to
restore
sinus
rhythm quickly.
cardioversion
Electrical
cardioversion
performed
under a shortacting
general
anaesthetic
is
used
in
two
circumstances:
• As an emergency treatment where the
patient has very low blood pressure as a
result of AF
• As a planned daycase procedure where
normal sinus rhythm has not been restored
by drugs.
If treatment with blood thinning injections is
started within 48 hours of AF onset, then
cardioversion can be performed before leaving
hospital. Otherwise, it is best delayed for at
least 4 weeks to ensure that any possible clots
in the heart have dissolved.
Although cardioversion is generally effective, it
does not work in some patients, especially
those who have been in AF a long time, are very
overweight, have underlying heart disease or
the very elderly. Unfortunately even in those
that do convert initially, there is a fairly high
risk of AF occurring again – 40-50% in the first
year. It is for this reason that warfarin is often
continued for at least a few months after a
successful cardioversion.
Where cardioversion is not successful, a repeat
attempt with prior loading with amiodarone or
sotalol is sometimes tried if restoring sinus
rhythm is very desirable as in severe heart
failure. There is however no benefit in many
repeated attempts; treatment should then focus
on achieving good rate control.
Maintenance of sinus rhythm
For patients who suffer with episodic or
paroxysmal AF or in patients after a successful
cardioversion, it is often helpful to use drugs to
improve the chances of the heart staying in
sinus rhythm. Agents such as beta-blockers,
calcium
channel
blockers,
flecainide,
propafenone and amiodarone are used alone or
sometimes in careful combination.
Amiodarone is the most effective drug for
maintaining sinus rhythm but can cause a
number of side-effects in the long term
especially if used at high dose. These sideeffects include: thyroid function abnormalities,
liver inflammation, numbness or ‘pins &
needles’, lung scarring, glaring of vision in
bright light and increased skin sensitivity to
sunlight. Use of high factor sunscreen lotion,
sunglasses
and
hat
are
recommended
especially during the summer months. Regular
yearly blood checks on thyroid and liver
function
are
recommended.
Importantly,
amiodarone affects the action of warfarin and
digoxin and the doses of these often need to be
reduced to prevent side-effects.
Drug therapy unfortunately rarely provides a
complete ‘cure’ and at best reduces the
frequency, severity and duration of palpitations
helping the patient to continue or return to
normal activities as quickly as possible.
© Dr Winston Martin
January 2007 - Information accurate at time of going to print.
Darent Valley Hospital, Darenth Wood Road, Dartford, Kent , DA2 8DA - Telephone: 01322 428100 - www.dvh.nhs.uk 3
Invasive therapies
Over recent years, newer more invasive
techniques termed ablation have been
developed which offer the prospect of ‘curing’
AF palpitations. These involve introducing long
electrodes via the veins at the top of the legs
into the heart and cauterising or burning
specific spots or foci of abnormal electrical
activity or creating tracks to isolate or block
them. Because of the risk of heart injury with
ablation treatments, they are generally only
considered if drug therapy has failed to control
symptoms effectively, and are better suited to
treating episodic or paroxysmal AF rather than
persistent or permanent AF. Anti-arrhythmic
drugs can hopefully be stopped after a
successful procedure, however aspirin or
warfarin are generally continued longterm as
the risk of clots and stroke still persists.
Summary
AF is common and can present with a variety of
symptoms or be identified on medical
examination or on an ECG. There are various
types and causes of AF. Most patients with AF
are treated successfully with a combination of
drugs which are used to reduce symptoms and
reduce the risks of clot formation, stroke and
heart failure. Newer minimally invasive ablation
techniques are being used increasingly to
prevent symptomatic palpitations.
© Dr Winston Martin
January 2007 - Information accurate at time of going to print.
Darent Valley Hospital, Darenth Wood Road, Dartford, Kent , DA2 8DA - Telephone: 01322 428100 - www.dvh.nhs.uk 4