Samikshka Heart Care

Samikshka Heart Care Heart and Diabetic Centre
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Heart and Diabetic Centre

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Risk stratification using myocardial perfusion scans
A normal perfusion scan is associated with a good prognosis. The annual rate of myocardial
infarction of cardiac death is < 1%, at least for some years.
Stress echocardiography
Ischaemic areas of myocardium are known to have reduced contraction compared with normal
areas. This can be demonstrated by high-quality echocardiograms. A number of standard views
of the heart are obtained and the wall is divided into regions that are assessed for reduced
motion. The echo equipment must be designed to store rest images and to present them next
to stress images on a split screen so that direct comparison can be made.
The stress can be provided by exercise or dobutamine infusion. Exercise echocardiography
is difficult to perform because of movement problems and there is quite high inter-reporter
variability, but both techniques can approach the accuracy of sestamibi testing in experienced
hands. It is not possible to obtain images of adequate quality in all patients.
Coronary angiography (cardiac catheterisation)
This procedure enables the cardiologist to visualise the coronary arteries . It is the
standard against which other less-invasive investigations are assessed. Selective catheterisation
of the right and left coronary ostia is performed. Contrast is then injected into the vessels and
digital tape or disc storage of the images obtained. In most hospitals the patient is admitted on
the morning of the test and allowed to go home that afternoon.
The procedure is most often performed through the femoral artery (Judkins technique)
This artery can be punctured through the skin under local anaesthetic. A fine softtipped
guide wire is then advanced into the artery and the needle withdrawn (Seldinger method).
A short guiding sheath can then be placed over the wire and long cardiac catheters advanced
through this sheath along a long guide wire into the femoral artery and up via the aorta to the
aortic arch. The catheter and wire are advanced under X-ray control. Usually one catheter with
a curved tip (pig-tail catheter; is advanced across the aortic valve into the left ventricle
where left ventricular pressures are measured via a pressure transducer connected to the other
end of the catheter.
Measurement of the left ventricular end-diastolic pressure gives an indication of left ventricular
function. Raised end-diastolic pressure (over 15 mmHg) suggests left ventricular dysfunction

The catheter is then connected to a pressure injector. This enables injection of a large
volume of contrast over a few seconds; for example, 35 mL at 15 mL/second. X-ray recording
during injection produces a left ventriculogram . Here left ventricular
contraction can be assessed and the ejection fraction (percentage of end-diastolic volume
ejected with each systole) estimated. The normal is 60% or more. The figure obtained by this
method tends to be higher than that produced by the nuclear imaging method—gated blood
pool scanning.
The guide wire is reintroduced and the catheter withdrawn to be replaced by one shaped to
fit into the right or left coronary orifice. Hand injections of 5–10 mL of contrast are then made.
Modern equipment enables numerous views of the coronaries to be obtained in both right and

   Over a month ago

Investigations of possible or probable
stable angina
A standard 12-lead ECG should be obtained in all patients. This is likely to be normal in almost
half of patients with subsequently proven coronary artery disease. Nevertheless, an abnormal
trace lends weight to the symptoms and favours further investigation.
Chest X-ray
Routine radiology is not essential but may reveal important co-morbidities. It should always
be performed in those with clinical evidence of hypertension, pericarditis , heart
failure or valvular disease, if only as a baseline. It is similarly indicated for patients with
suspected or known pulmonary or systemic disease such as rheumatoid arthritis, COPD or
Routine blood tests
All patients with suspected angina should have the following routine investigations at presentation
(NHF grade A recommendation):
n fasting lipids, including total cholesterol, LDLs, HDLs and triglycerides—risk factors
n fasting blood sugar—risk factor
n full blood count—anaemia exacerbates angina
n serum creatinine—impaired renal function is a risk factor and can be worsened by some
cardiac investigations.
If indicated clinically, thyroid function tests should be ordered.
Outpatient investigations: exercise stress test
The usual investigation for a patient with a clinical diagnosis of stable angina or atypical chest
pain is an exercise stress test. Even a very typical history of angina does not quite make the
diagnosis, and it is unfair to apply a label with many future repercussions without some objective
evidence. An exercise test will also give important information about the likely severity of
the condition and even about the prognosis.
Exercise testing for patients without significant resting ECG changes but with a history
suggesting angina is a grade A recommendation for risk stratification.
For the diagnosis of ischaemic heart disease, the usual approach is to exercise the patient on
a treadmill using the Bruce protocol. This consists of up to seven 3-minute stages of increasing
speed and elevation. The test is symptom limited; that is, the patient continues until
prevented from going on by symptoms that may be chest pain (typical or atypical), exhaustion,
dyspnoea, or something else (e.g. claudication). Occasionally the supervising clinician will stop

   Over a month ago

heart specialists

   Over a month ago