This is the most common test, which virtually every patient
who sees a doctor for a heart complaint will have. The electrical
activity of the heart is recorded from various points on the
chest and printed on what is termed a twelve lead ECG. A variety
of changes may be seen reflecting a wide range of cardiac
disorders however the trace may be completely normal even
if there is significant underlying heart disease.
Exercise Electrocardiography
This test is most commonly used to find if patients have significant
coronary artery disease. The twelve lead ECG is applied and
there is graded exercise until either the patient has symptoms,
feels exhausted or the doctor notes changes on the ECG. The
test can also be used to assess risk of further trouble after
patients have had a heart attack and to assess any degree
of heart failure or breathlessness. While the test cannot
absolutely rule out heart disease, a normal exercise test
means it is unlikely patients have serious underlying coronary
artery disease.
These are investigations that use ultrasound to look at the
structure and function of the heart. The standard echo (trans-thoracic
echocardiogram) takes about twenty minutes and is performed
on an outpatient basis. It is painless and safe. A small handheld
ultrasound probe is moved over the front of the chest wall
to produce images of the beating heart on an adjacent monitor.
The size and shape of the various heart chambers can be seen,
together with the movement of the heart valves. A vast amount
of information can be produced, which helps greatly with the
diagnosis and management of a wide variety of heart conditions.
For example, the effects of a heart attack on the heart muscle
can be accurately assessed and many different causes of breathlessness
can be sought.
In a proportion of patients the pictures are not of an adequate
quality, either due to the shape and size of the chest wall,
due to overlying fat or underlying lung. Furthermore, there
are some conditions where even more detailed ultrasound images
of the heart are required. In both these scenarios, a TOE
(Transoesophageal Echo) is undertaken. A TOE involves passing
a fine flexible tube through the mouth into the oesophagus
(gullet) usually under sedation. From a miniaturised ultrasound
probe, highly detailed pictures of the heart can be obtained,
using soundwaves passed from the probe positioned in the gullet
directly behind the heart. The image quality is excellent
because there is no interference from overlying lung, ribs
or fat that is encountered with the standard transthoracic
echo. The TOE probe looks fairly similar to the endoscopy
probe used to examine patients with indigestion and stomach
ulcers.
Patients undergoing TOE should not eat or
drink for 4 hours before the procedure. The throat is anaesthetised
with an anaesthetic spray. Sedation is given if the patient
so requests, but some patients prefer to be fully awake for
the procedure. The probe is then passed into the oesophagus
so that pictures of the heart can then be taken. This takes
about 15 minutes. The anaesthetic spray wears off after about
1 hour. If sedation has been given the patient stays in the
department for approximately one hour, but should then be
driven home by a family member or friend.
In addition to resting echo pictures images can be obtained
during either exercise or more commonly after a drug to stimulate
the heart (Stress Echocardiography). This shows up areas of
the heart that are under strain in a similar but more precise
fashion to an exercise ECG.
Also called coronary angiography (angiogram), this is a test
to look at the coronary arteries and heart muscle. It is the
gold standard by which all other tests looking at the blood
supply to the heart are judged. Developed and refined over
many decades, cardiac catheterisation involves passing a fine,
flexible hollow tube from an artery in the groin, elbow crease
or wrist up to the heart. It only requires a local anaesthetic
to numb the skin overlying the artery at the point of insertion.
The tube is passed up to the heart where a dye is injected
to show up the coronary arteries and the heart muscle. Pictures
(angiograms) are taken using X-ray equipment which enables
your
Left ventriculogram with normal
LV function
Cardiologist to determine whether or not the coronary arteries
are furred up and to what extent. This knowledge is important
for planning the best treatment for patients with coronary
artery disease (atherosclerosis), which ranges from regular
medication to angioplasty +/- stent insertion to coronary
artery bypass surgery. Ina addition pressure measurements
and valve disease can be assessed
The procedure only takes 10 to 20 minutes in most cases. However,
because we are dealing with the heart, patients are kept in
hospital for a few hours after the procedure before being
allowed home. Patients are told not to eat or drink for 2-4
hours before the procedure. You should take your usual medication
with a sip of water, but generally speaking you will be advised
to omit water tablets (diuretics) on that day. Diabetics are
given special advice, particularly those taking metformin
or insulin as are patients on warfarin.
Permanent pacemakers are highly sophisticated devices that
are implanted to treat various disorders of heart rhythm.
Originally they were only capable of treating slow heart rhythms
but modern generation pacemakers help to regulate the heart
beat and prevent irregular rhythms too. Pacemakers have also
been developed to help weakened heart muscle to beat more
effectively.
The pacemaker consists of a metal box (generator) which contains
the battery and circuitry to interpret changes in the heart
rhythm. The pacemaker is implanted under local anaesthetic
under the skin of the anterior chest wall (just below the
collar bone). It is connected to one or more leads that are
passed under X-ray guidance through the vein in the chest
to the heart so that the tip of the lead(s) sits within a
particular heart chamber. The pacemaker detects the electrical
rhythm of the heart and will generate electrical impulses
that pass along the lead(s) to the heart to make it beat regularly
if the heart tries to slow inappropriately.
Pacemakers are highly effective treatments for blackouts and
certain other abnormalities of heart rhythm. The aim is to
restore the patient to a normal life.
This procedure is similar to a cardiac catheter in that tubes
are placed in and around the heart but they measure the electrical
activity rather than inject dye. Once an abnormal electrical
pathway has been identified it is possible to remove it by
a small dose of radiofrequency energy or cryotherapy
