Diagnosis of coronary heart disease

ECG-TMT-Echo-Coronary Angiogram

How is coronary heart disease diagnosed?

Coronary heart disease (coronary artery disease, coronary artery heart disease, ischemic heart disease) is usually suspected by the symptoms. Typically it is a central chest pain or discomfort induced by exercise and relieved by rest. But this need not be the case always. Pain of heart attack may appear all of a sudden and does not get relieved by rest. Still it is an important manifestation of coronary heart disease. Other symptoms associated with chest pain could be pain in the jaw or arms, excessive sweating along with pain or sometimes breathlessness or dizziness. First investigation to be done is usually an ECG (electrocardiogram). When a heart attack is suspected, other investigations done in the emergency department are a bedside echocardiogram and a blood test for Troponin, which is released into the blood when heart muscle is damaged. Finally an emergency coronary angiogram may be done if there is evidence of a heart attack. In the outpatient setting, a treadmill exercise ECG (treadmill test) can be done in stable patients resting ECG does not give a diagnosis. Other advanced tests are coronary CT angiogram and nuclear scan of the heart.


Ischemic heart disease

Block in blood vessel of the heart

LMCA: Left main coronary artery; LAD: Left anterior descending coronary artery (blood vessels supplying oxygenated blood to the the heart muscle) – as seen on coronary angiogram (X-ray imaging after injecting iodinated contrast into the vessel)

What is ischemic heart disease?

Ischemia means a decrease in the blood supply. Hence ischemic heart disease means blood flow to the heart muscle is reduced. Ischemic heart disease is also known as coronary artery disease. Usually this occurs due to partial or complete blocks in the coronary arteries which supply oxygenated blood to the heart muscle. It could also occur due to transient contraction of the muscle of the blood vessel, known as ‘coronary vasospasm’. Ischemic heart disease due to partial blockage of the blood vessels usually manifest as chest pain on exertion (effort angina). When the block is near total or total there could be chest pain at rest as well. Then it is called unstable angina or sometimes when there is damage to the heart muscle it results in heart attack (technical term: myocardial infarction).

Does ischemic heart disease always manifest with chest pain?

Ischemic heart disease can have other manifestations like breathlessness on exertion, dizziness, undue sweating on exertion, or pain in the jaw, wrist, neck or back. These are known as anginal equivalents, meaning symptoms of ischemic heart disease other than chest pain. Occasionally there is no symptom at all and it is detected on routine medical evaluation for some other reason. Then it is called silent ischemia or even silent heart attack.

Is there any difference in the significance between silent and manifest ischemic heart disease?

Significance is the same for silent and manifest ischemic heart disease. But the risk is probably more for the silent one because there is no warning symptoms and the individual would not take care and exert beyond what his medical condition permits and may end up with more severe problems.

Heart attack

What is heart attack?

Heart attack (Myocardial Infarction) is damage to a region of the heart muscle, usually due to sudden blockage of a blood vessel supplying oxygenated blood to the region (coronary artery). Though heart attack can occur due to a mismatch between the supply and demand for blood in the region, the usual heart attack which we are familiar with is due to blockage of a blood vessel. Heart attack is different from cardiac arrest. In cardiac arrest, heart stops beating and it is equivalent to death unless the function of the heart is promptly restored either spontaneously or by chest compression and artificial breathing protocol known as cardiopulmonary resuscitation (CPR).

What are the important symptoms of heart attack?

The most familiar symptom of heart attack is severe central chest pain. It is often associated with sweating, fatigue, dizziness and sometimes breathlessness. Rarely there are no symptoms and then it is known as a ‘silent heart attack’. Some unfortunate victims of heart attack develop a cardiac arrest and may die suddenly (sudden death). Sudden death in heart attack is often due to a sudden change in the heart rhythm which makes the heart stand still (ventricular fibrillation). This abnormal rhythm can be treated by CPR and direct current shock using a device known as defibrillator which shocks the heart back into action. An automatic external defibrillator for use of untrained persons, is now available in many public places like airport.

What to do if you think you are having a heart attack?

First and foremost is to take rest and call for emergency support. In regions where an emergency ambulance service is available, it should be called and one should proceed to the nearest hospital. In well equipped ambulances, it is possible to make a diagnosis and start early treatment even before reaching the hospital. After initial assessment by the paramedic, an electrocardiogram (ECG) is recorded. When facility is available, the ECG is transmitted to the receiving hospital where the team is ready for further action even before arrival of the victim.

It is not advisable to travel in a self driven vehicle to the hospital unless you have no other options. This is because occasionally cardiac arrest can occur en route. Moreover arrival in ambulance speeds up management in the emergency department. Traffic worries are also lesser while travelling in an ambulance. This is in addition to the medical support available in the ambulance.