HEART ATTACK AND STROKES

A heart attack occurs when the supply of blood and oxygen to an area of heart muscle is blocked, usually by a clot in a coronary artery. Often, this blockage leads to arrhythmias (irregular heartbeat or rhythm) that cause a severe decrease in the pumping function of the heart and may bring about sudden death. If the blockage is not treated within a few hours, the affected heart muscle will die and be replaced by scar tissue.

How does an arterial-blockage occur?

It occurs as a result of a combination of things.

• Over time, the wall of our artery becomes diseased or "corroded"
• As our blood passes through this corroded section, it dumps some of the fat which it is carrying, and this fat forms a bulge in the wall of the artery. Result? In the same way that double-parking narrows a road and causes a slow down in the flow of traffic, this fatty bulge narrows the width of the artery and slows down the flow of blood as it passes around it.
• If the blood flow gets too slow, and if tiny bits break off the bulge in the wall "clogging up the blood even more" the blood will form a spontaneous clot, completely blocking the artery.
  

Heart attack outcomes

The outcome of a heart attack depends on several factors:

• Where the coronary blockage happens. Blockages on the left side of your heart are usually more dangerous.
• Whether rhythm is disturbed. If the blockage also causes an irregular heartbeat called an arrhythmia, it may cause sudden death. Either fast beating called tachycardia or rapid, uncoordinated contractions called ventricular fibrillation may happen. Ventricular fibrillation prevents blood flow, which must be quickly restored through cardiopulmonary resuscitation (CPR) or electrical therapy (defibrillation).
• Whether your heart is supplied by another blood source. Sometimes a person's body responds to a gradual blocking of an artery by widening another vessel that supplies blood to that same part of the heart. This makes what is called a collateral blood source. If this is the case, you will have less severe damage from the major blockage.
• How soon you got help. In most cases, getting medical attention within an hour of the start of your attack reduces the amount of heart muscle you lose.
  

Left Ventricular Aneurysms

Sometimes after a heart attack, an aneurysm forms in the heart's main pumping chamber, called the left ventricle. If a section of the heart wall becomes damaged after a heart attack, it causes scarring and the heart wall grows thinner and weaker. This may cause a ventricular aneurysm to form. The weakened area of aneurysm does not work well, which makes your heart work harder to pump blood to the rest of your body. Ventricular aneurysms may cause shortness of breath, chest pain, or an irregular heart beat (arrhythmia). If a ventricular aneurysm leads to congestive heart failure, left ventricular heart failure, or arrhythmia, your doctor may want you to have surgery.