Coronary Artery Disease... Heart Attack

Coronary artery disease is the process that leads to almost all heart attacks or episodes of angina.  The arteries that overly the heart muscle and supply it with blood become plugged or blocked by the process known as  “coronary artery disease”.  The process of coronary artery disease begins early in life.  In North American males it starts in the teens or early twenties and in women about 10 years later.  The disease usually gets slowly worse until there is enough blockage to causes symptoms or an acute event like a heart attack.

The coronary arteries can be imagined like the trunk of  a maple tree (upside down)  with the thickest portion of the trunk at the top and the thinnest  branches or tributaries at the bottom.  If a blockage occurs close to the top, or trunk,  of the artery then there will be a lot of heart muscle that does not get enough blood supply.  Likewise, if a heart attack occurs based on a blockage near the base of the trunk, then there will  likely be a lot of damage to the heart muscle.

      What Is a Heart Attack?

A heart attack in medical terms is a ‘myocardial infarction’ (MI) or ‘coronary thrombosis’ or ‘coronary.’ It is the result of severe narrowing or obstruction in the coronary arteries, which blocks the blood supply to a particular area of the heart and causes permanent damage to that area.

The amount of muscle damage determines the size of the heart attack.

The most common type of heart attack is caused by coronary thrombosis, which occurs when a clot (thrombus) blocks one or more of the coronary arteries. Coronary thrombosis is one of the manifestations of coronary artery disease.

Heart attacks sometimes occur in people with little or no coronary artery disease. Spasm, or sudden constriction of the coronary artery, may also cause a heart attack, but is relatively rare.  Much more common is the situation where there is already some degree of blockage that is suddenly made worse by formation on a blood clot.

Symptoms of a Heart Attack

A heart attack can come on gradually, preceded by several attacks of angina over days, weeks, months, or even years. But a heart attack may also occur without any apparent warning and in people who have never previously experienced any chest pain.

Typically you may experience any or all of the following when having a heart attack:

       – discomfort or band-like pressure, heaviness, tightness, burning or squeezing

– indigestion, fullness or choking sensation across the chest or anywhere in the upper body

       – it may commonly spread to the back, jaw, arms (especially the left arm)

– it may vary in intensity from tightness to one of agonizing crushing or bursting

       – it may be continuous, or it may last a few minutes, fade, and then recur

       – it may be associated with

                        – sweating

                        – nausea and/or vomiting

                        – dizziness

                        – palpitations

                        – loss of consciousness

                        – severe weakness

                        – shortness of breath

Heart attack pain is usually stronger than angina pain and does not go away when you rest or take medication.

Reducing the Risk of Having a Heart Attack

  A variety of different approaches may be taken to deal with the underlying coronary artery disease and to reduce the possibility of a heart attack:

  A) Increased awareness of risk factors and their correction play an important role in preventing or slowing down the progression of heart disease.

       Risk Factors over which You Have No Control

                        – being male

                        – your age

                        – your family history

       Risk Factors that Can Be Altered

                        – cigarette smoking

                        – high blood pressure

                        – high blood cholesterol (LDL, or ‘bad’ C) & low HDL (‘good’ C)

                        – obesity

                        – diabetes

                        – lack of exercise

                        – stress

B) Drug Treatment. The use of drugs depends upon the nature of the heart attack and underlying coronary disease. Antihypertensive drugs may be prescribed to lower the blood pressure. Other drugs may be given to improve heart function, prevent angina, or lower the level of blood cholesterol.

C) Other Treatment. Other forms of treatment are also available. Two (invasive) ones are

                        – coronary artery bypass graft

                        – coronary angioplasty

       Their use depends on individual needs.




This drawing illustrates a blockage of the left anterior descending coronary artery on the front wall of the heart.  The area of damaged muscle, shown as a darkened area would be identified on the ECG as an anterior or front wall heart attack.