Sunday, September 9, 2001		Keeping fit

IN the previous instalment of this write-up we discussed the various risk factors in the genesis of ischemic heart disease. It is, therefore, obvious that prevention or modification of these factors is the key to prevent this epidemic of heart disease. We, therefore need to be familiar with the evaluation and treatment of this rather common heart disease.

The present-day physicians are lucky to have very powerful and effective diagnostic and therapeutic tools for heart diseases. Even when I was a postgraduate student 40 years ago, there were very limited options to diagnose and treat heart ailments. During the past 40-50 years, the scene has changed for the better with breakthroughs in all fields.

X-ray chest: It is the simplest investigation to see the size and various chambers of the heart. But it has its limitations and has to be supplemented with more recent and sophisticated investigations.

Electrocardiogram (ECG): This is a graphic recording of electrical potentials generated by the heart and amplified through electrodes and machine. It is the oldest, yet very useful investigation. It is available immediately, inexpensive, non-invasive, versatile and can yield a wealth of information. It is often the first investigation which confirms the diagnosis of the heart attack.

Echo-cardiogram: It has made tremendous improvement in the diagnosis of heart diseases and is based on the recording of echoes from the heart chambers, valves and along with Dopplers principles, can give a wealth of information. It can measure the fraction of blood that the heart is pumping out.

Stress test (TMT): If the resting ECG and echo-cardiogram are normal but there is a strong suspicion of ischemic heart disease, both these investigations can be performed while a person is undergoing exercise during which presence of ischemia and other abnormalities can be recorded if there is an underlying disease.

Holter monitoring and continuous blood pressure recording: The devices are now available which when attached to the patient can continuously record the heart beat and blood pressure and thus show a graphic picture of his cardiac activity during the 24 hours or longer. A computer analysis can then show the changes which take place during various activities. It can yield an amazing amount of information regarding the patient’s condition.

Radioactive isotope studies (nuclear medicine): These studies can bring out the conditions of the cardiac muscle and chambers and can supplement the information derived from TMT and echo-cardiogram. The lay public may be familiar with the thalium test which is based on this principle.

Cardiac-catheterisation and angiography: This is the ultimate and final yardstick of diagnosis of ischemic heart disease and is based on putting a catheter in the coronary artery and then injecting the dye. This maps out the various vessels of the heart and gives graphic picture of the vessels of the heart. Interestingly Dr. Werner Forsmann, the first person to perform cardiac-catheterisation in 1929, performed it on himself while standing in front of a mirror. This test is a must before angioplasty or by-pass procedure is undertaken.

Biochemical tests: These tests are performed routinely by the physicians in the diagnosis of acute heart attack in the form of enzymes and other tests to evaluate various risk factors like lipids, blood sugar, kidney functions and hemogram.

I do not intend to cover treatment in details as that is likely to be somewhat technical but will mention the broad categories of tools available to the modern physicians to handle heart problems.

Drug therapy: A broad and very useful group of drugs are now availble to deal with various problems of the heart and the diseases associated or predisposing one to this. There are drugs available now which can dissolve a clot if the patient reaches the hospital within 12 hours or preferably 6 hours. This is known as thrombolytic therapy. Even before the person reaches the hospital, a simple tablet of aspirin can do the job to a limited extent.

Angiography and bypass surgery: When the diagnosis of the ischemic heart disease is made and confirmed with angiography, the availability of angioplasty (ballooning of the artery) and putting a graft to bypass the obstruction are the two great advancements in the treatment of ischemic heart disease.

Heart transplantation: When in spite of these measures the heart is unable to do the required pumping, it is unable to supply the desired amount of blood and oxygen to the body, heart failure developes. There are a number of drugs to help the heart during this stage including the oldest drug, Digitalis, introduced by an Englishman, William Wuthering, as early as 1776. But this condition finally defies all treatments and then a time comes when the heart is unable to perform its duties despite all the drugs. This is the point when the most dramatic treatment for the heart is needed. Dr Christian Bernard from South Africa performed the first cardiac transplant in 1967. In our country, Prof Venugopal from AIIMS is performing such transplants.

Attempts have been made for the last many decades to develop mechanical substitutes for the heart pump. These are physical short term measures and may help those who are waiting for heart transplantation. Only last month, a new breakthrough has been made in this field when a team of surgeons in Loueville Kentucky, USA, put a heart pump in a patient which has no attached tubes from outside and works on a battery giving power to the pump through the skin. The patient is still alive after more than six weeks.

The race to conquer heart disease is going on relentlessly. The American Heart Association selects 10 most important advances in heart research every year. During 2000, it included - (1) Sequencing the human gene, (2) Discovery of the genetic basis of familiar primary pulmonary hypertension, a disease afflicting the arteries taking blood from the heart to the lungs, (3) Use of stem cells to repair the damage heart tissues, (4) Gene therapy to prevent reblocking of vessels after the bypass surgery, (5) Gene therapy to treat atrial fibrillation, a condition in which the rhythm of the heart is totally irregular. (6) Introduction of drugs lowering the blood cholesterol, (7) Diagnostic ability of MRI to detect atherosclerotic plaques, (8) More convincing evidence of linking salt intake and high blood pressure, (9) Demonstrating that low cholesterol diet right in the childhood is beneficial and (10) Improved survival after the cardiac arrest by the use of automatic external defibrillators.

(Concluded)