What is a heart attack?

The heart is a complex pump which operates through a series of precise electrical signals. People often wonder: “what is a heart attack?” Typically problems can arise in any part of the heart, from the muscle walls and valves to the electrical system. One of the most common problems which can arise in the heart is a myocardial infarction, or what’s known in layman’s terms as a “heart attack”.  In fact, the public frequently misuses this term “heart attack” whenever there’s any issue with the heart.

A heart attack can occur when the blood supply to the heart becomes compromised.  The heart is nourished through its own blood supply via the coronary arteries, and if a part of the heart is not getting enough blood flow providing the necessary nutrients and oxygen, then that part of the heart will start to die.

Atherosclerosis of the heart occurs when a buildup of fatty substances, such as cholesterol occurs in the linings of the coronary arteries.  These buildups are called plaques.  Sometimes, these plaques can rupture or “crack”.  When a rupture occurs, irritating compounds float into the bloodstream, and the body tries to stop this by forming a blood clot over the cracked area.  This will then cause limited or even complete blockage of blood flow to the part of the heart nourished by that particular coronary artery.  The lack of blood flow can damage and even kill part of the heart muscle.  This is the most common cause of a heart attack.

A much less common cause of a heart attack can occur if the coronary arteries spasm.  This spasm can result in physical blockage of the artery and limited to no blood flow to the part of the heart nourished by the artery, in the same way plaque rupture and blood clot formation limits blood flow.  Coronary artery spasms are rare and may be caused by certain drugs.

When a heart attack occurs, the victim is conscious and may experience a variety of symptoms, including, chest pain, particularly in the center or left of the chest, shortness of breath, nausea, feeling faint, a cold sweat, and feeling abnormally tired.  The chest pain may radiate to the jaw or down the arm.

Time is of the essence for the heart attack victim.  If the blockage is not relieved within a few hours, the damaged heart muscle can die.  The dead muscle will ultimately be replaced with scar tissue, and long lasting problems may occur.  The heart may not be able to pump as effectively as it once had.

The Electrocardiogram (ECG) can be very helpful in locating exactly which part of the heart is being damaged although sometimes, the ECG can be normal even during a heart attack.  Certain blood tests can also be helpful in diagnosing damage to the heart.

The mainstay of treatment for a heart attack is to get the affected artery open and unblocked as quickly as possible.  This can be done either with medications or physically opening the artery with a balloon.  The medications are known as “clot busters”, and they will help dissolve the clot.  For most victims of heart attack, the preferred method to open the blocked artery is to go to the cardiac catheterization lab.  There a catheter is passed through the femoral artery in the groin up into the heart, and dye is injected into the coronary arteries.  This allows the Cardiologist to see the anatomy of the arteries and find the blockage.  Then, a balloon is passed into the blocked area and inflated, causing the clot to break into pieces opening the artery.  Frequently, a stent is left in the area where the artery was blocked.  The stent will keep the artery open for years to come.

The procedure of injecting dye into the coronary arteries is called a cardiac angiogram.  If more than one artery shows significant blockage, more than one stent may be placed.  If there are many arteries with significant blockage, then the decision may be made to take the patient for coronary bypass surgery.   This is when the Cardiothoracic surgeon removes veins from the patient’s legs and uses them to bypass the areas of blockage in the coronary arteries.

There are risk factors for developing atherosclerosis in the coronary arteries which may then lead to a heart attack.  The more risk factors you have, the more likely you are to develop heart disease.  There are risk factors you can control to help prevent a heart attack, and there are risk factors completely out of your control.  The risk factors out of your control can be called non-modifiable.  They include advancing age and family history of early heart disease.  But, there are several risk factors you can modify.  These include keeping your cholesterol at an optimal level, controlling high blood pressure, controlling blood sugar and treating diabetes, not being overweight or obese, good nutrition, exercising and increasing physical activity, and not smoking.  Lifestyle modification alone can significantly decrease the risk of developing heart disease.

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