Prevention is better than cure is an age old idiom which seems to have lost its significance in our country especially amongst the busy ones who believe in crossing the bridge only on reaching it. The unfortunate end result is an increasing incidence of both morbidity and mortality in our country from disease which could have been otherwise prevented.
Of significance is the fact that a large percentage of mortality and morbidity is preventable by a proper general education. Wrong notions and myths are still rampant in our country. Even amongst the educated the knowledge of various heart disease and diagnostic aids is scanty. An apt and clear image of the diagnostic paraphernalia in our armamentarium could clear a lot of misconceptions amongst patients. Addition of high technology gadgets has, although it should not, undermined importance of medical examination. A properly taken history and meticulous physical examination of the patient is still the best diagnostic tool. It can diagnose over 65 per cent of all cardiac ailments.
Given here are the latest diagnostic tests which are undertaken for different symptoms. One should know about them so as to avoid physical and financial strain of going through all of them
With an aim of sharing the information with the people at large about the how and why of often used diagnostic tests instruments in heart patients, an attempt is made to briefly touch upon the various investigations commonly done, the significance of various kits/machines used by doctors and clear the existing doubts/myths about their utility.
You can best treat disease by learning about it yourself and having it detected early when it is still in the formation stage. Only by this way you can attain a positive state of health and happiness which is much more than just absence of disease. We now discuss some of the common diagnostic aids used in detection of heart disease.
TREADMILL STRESS TEST – TMT
Treadmill test also called as stress test or exercise test, is done to evaluate the effort tolerance of an individual. It is the only test which often decides about the need of bypass surgery. Following a heart attack it can safely be done after 3-4 weeks. The test is absolutely safe and carries no risk if done under the supervision of a doctor and after proper patient selection. This test is not done in case of unstable angina or in patients with acute heart attack. Exercise in this test is graded and limited to a particular heart rate or symptoms of the patient. A fasting patient is asked to walk on a moving belt, the speed of which increase gradually. change in the ECG, if any, are recorded on the monitor. Normally if you can do more than 9 minutes of exercise, you are said to have good effort tolerance.
Normally it has been said that if your treadmill test is abnormal in the first three minutes of exercise, results of bypass may be better than medical treatment, if abnormal between 3-6 minutes of exercise, the surgical and medical results are equivocal and if the test is abnormal after 6 minutes of exercise, the medical results are better than the surgical results.
Basically the test is done either to diagnose underlying blockage or to see the response of therapy. Indication of bypass in stable angina is only if three is failure to respond to adequate medical therapy. In such situations TMT should be done in the morning, after 2 hours of morning does of medicines in a fasting state.
This is the blood pressure measuring instrument, the cuff of which is tied on the arm and with a bulb, pressure is raised to inflate the cuff. Using a stethoscope one hears sounds on the patients elbow to measure the blood pressure.
The upper limit of blood pressure is called as systolic and the lower limit as diastolic blood pressure. A blood pressure of over 160/90 mm Hg. is labelled high blood pressure.
BP may differ depending upon the size of the cuff used. An obese person requires a large sized cuff and a small child a smaller cuff for BP measurement. Your BP may be high for years together and yet you may be unaware about it. It sometimes can manifest for the first time as brain haemorrhage or bleeding through nose.
A single elevated reading of BP is a wake-up alarm warranting repeat checkup, as also a single normal reading in an otherwise high suspect patient does not rule out high blood pressure and both warrant a repeat check. A normal blood pressure at rest alone is not enough. Blood pressure should remain within normal limits at all times of the day even during heightened mental and physical activity. BP is usually high in the morning hours and hence it is important to control early morning BP so as to prevent paralysis and heart attacks, common in the early hours of the day. There may be a difference of up to 10-20 mm in blood pressure in the two arms normally. A greater difference could signify a serious disease.
Normally blood pressure is high in the lower limbs by up to 20 mm Hg. A greater difference than that may represent a congenital lesion of the main blood vessel.
Many patients say they have been suffering from low blood pressure for years together; no such condition exists in medicine. Low BP is compatible with long life unless it follows an illness. Nowadays there is a trend of self-checking of blood pressure by electronic automatic gadgets.
A doctors basic instrument, by putting its diaphragm over the chest one can listen to various sounds produced by the heart and lungs and clinically diagnose most heart and lung diseases. Presence of extra sounds and murmurs classifies various cardiac disorders.
PERIPHERAL DOPPLER MACHINE
Using a small Doppler machine the ratio of blood pressure is calculated between legs and arm , called as ankle brachial index. Normally the index is more than 1. An index of less then 1 signifies narrowing in the leg vessels. An individual may have blockage in heart, neck and leg vessels simultaneously. Individuals with index of less than 1 have pain in legs on walking.
Index is also calculated between the shaft of the penis and arms called as penile/brachial index. An abnormal signal signifies diminished blood flow to the penis leading to impotence. Excessive smoking is a common cause of diminished blood flow to the penis. Onset of impotence in a middle aged man may be an indication of underlying coronary artery disease and proneness to heart attack.
COLOUR DOPPLER ECHOCARDIOGRAPHY
A simple and non-invasive test in which we can pick up the morphology of various structures of the heart as well as the functions of the heart at rest and during exercise. It is the ultrasound of the heart and can pick up areas of deficient blood supply: status of various valves as well as enlargement of different chambers of the heart. It can easily pick up presence of a clot in any chamber of the heart which can be a source of paralysis in future. In around 5-10 per cent of cases it can pick up a blockage in the main coronary artery of the heart. Apart from patients with coronary artery disease it is useful in all cases with congenital heart disease as well as rheumatic heart disease having lesions of the heart valves. The flow information in the heart can be quantitated using the Doppler and visualised in colour on the screen using the Colour Dropper flow mapping. Holes in the heart, narrowing/leakage if any can directly be visualised.
COLOUR DROPPER OF THE CAROTIDS
Carotid arteries are the vessel supplying blood to the brain from heart. In 22/1000 high risk individuals one of the carotid artery shows over 50 per cent blockage. This can lead to paralysis in the future. In patients with paralysis, over 50 per cent of them have underlying coronary artery disease and around 10-15 per cent of patients with angina/heart attack have significant blockage in the carotid arteries. Early detection and timely treatment of blockage in these vessels can thus prevent this deadly disease. Using colour Dropper echocardiography, one can see the neck vessels and blockage in them if any. The procedure is safe, simple and should be done as a screening procedure in all individuals at risk.
A sonogram of arteries in the neck might be the best screening tool yet to identify which older people are most at risk for a heart attack or stroke according to a recent study.
Thick carotid artery walls turned out to be a stronger predictor of cardiovascular disease than high blood pressure or any other traditional risk factors.
Those with the thickest walls were almost five times more likely to have a heart attack or strokes than those with the thinnest.
Holter is a small walkman like machine worn by a patient on the waist belt and carried along with him. It provides an accurate 24 hours beat to beat monitoring of the heart. It basically pick up irregularities in the pulse rate and painless or painful episodes of deficient blood supply to the heart. The principle involves the electronic beat to beat graphing of your ECG on an ordinary audio cassette placed inside the recorder. After the end of 24 hours the audio cassette is put into a specialised computerised analyses which then analyses the data in the next 20-30 minutes to give a 30-40 pages laser print out report. Instructions are given to note down the time of daily event and activities and the timings of these events is correlated with the abnormalities seen in the record.
Normal 24 hour record does not rule out a disease. It only tells you the changes occurring in those 24 hours. Sometimes your symptoms may be so infrequent that they may not be picked up in those 24 hours. But usually it gives enough useful relevant data.
It is basically indicated in patients of coronary artery disease where we want to know the response of the heart to routine daily life as against a treadmill where we evaluate the response of the heart to exercise. After heart attack Holter is helping in predicting the future course of action as well as mode of rehabilitation. Holter is often done on the 1st and 7th day of heart attack. If abnormal changes in the Holter are seen on 7th day after an attack it may necessitate further investigations on the patient. Sexual activities after a heart attack lead a sudden death is only a myth. It is often helpful to undertake Holter monitoring of an individual, the day he wants to have his first sexual activity. This test is also termed as SEXERCISE TOLERANCE TEST.
MUGA AND THALLIUM TEST
Nuclear medicine plays an important role in our lives. In nuclear medicine we use radioactive isotopes for diagnosis and treatment. The equipment which is required is a Gamma camera which is linked to sophisticated computer for the purposes of data analyses.
At present we have many diagnostic modalities available. What makes nuclear medicine different from other is the ability to study the functional aspect of the organ, whereas other methods, study only the anatomical aberrations.
The methods used in nuclear medicine are truly non-invasive and the information it provides about the functioning of the heart, brain, lungs, liver, thyroid, kidneys, etc. is mind boggling. The latest in medical technology, the PET scan, also comes under the purview of nuclear medicine. No other discipline in medicine can give so much information without causing any pain to the patient.
MUGA and Thallium gives similar information as a treadmill test. MUGA test is done both at rest and after exercise and like exercise ECG/exercise echocardiography is helpful in detecting areas of deficient blood supply to the heart. The test requires intravenous injection of a radioactive isotope. However, unlike colour Doppler echocardiography the test does not depict the valvular lesions of the heart.
Unlike MUGA, Thallium test requires injection of a radioactive substances having a short half life and hence all the test has to the done within a span of less then 24 hours of availability of the drug at a particular centre. The cardiac centre thus is dependent upon a fix minimum number of patients to be collected on a specified data to be able to gainfully utilise the entire does of this expensive dye. Thallium studies assess the blood reaching various part of the heart and help in the assessment of coronary artery disease and patients having bypass surgery. MUGA studies are also done here which permit evaluation of heart contractility and function.