MYOKINASE

Heart Attack Overview

If you believe that you are having the symptoms of a heart attack, please rush to hospital immediately.

The heart is a muscle like any other in the body. It needs blood flow to supply oxygen to allow it to do work. When there isn't enough oxygen, the muscle starts to suffer, and when there is no oxygen, the muscle starts to die.

Heart muscle gets its blood supply from arteries that start in the aorta and run on the surface of the heart, known as the coronary arteries. The right coronary artery supplies the right ventricle of the heart and the inferior (lower) portion of the left ventricle. The left anterior descending coronary artery supplies the majority of the left ventricle, while the circumflex artery supplies the back of the left ventricle.

Heart Attack Causes

Over time, cholesterol buildup can occur in these blood vessels in the form of plaque. This narrows the artery and can restrict the amount of blood that can flow through it. If the artery becomes too narrow, it cannot supply enough blood to the heart muscle when it becomes stressed. Just like arm muscles that begin to hurt if you lift too much, or legs that ache when you run too fast; the heart muscle will ache if it doesn't get adequate blood supply. This ache is called angina.

If the plaque ruptures, a small blood clot can form within the blood vessel and acutely block the blood flow. When that part of the heart loses its blood supply completely, the muscle dies. This is called a heart attack, or an MI - a myocardial infarction (myo=muscle +cardial=heart; infarction=death due to lack of oxygen).

Heart Attack Risk Factors

Heart attack is most often caused by narrowing of the arteries by cholesterol plaque and their subsequent rupture. This is known as atherosclerotic heart disease (AHSD) or coronary artery disease (CAD).

The risk factors for ASHD are the same as those for stroke (cerebrovascular disease) or peripheral vascular disease:

• Family history or heredity
• Smoking
• High blood pressure
• High cholesterol
• Diabetes

While heredity is beyond a patient's control, all other risk factors can be addressed to minimize the risk of developing coronary artery disease or decreasing its progression if already present.

Non-coronary artery disease causes of heart attack may also occur, these include:

• Prinzmetal angina or coronary artery vasospasm. Coronary arteries can go into spasm and cause angina without specific cause known as Prinzmetal angina. There can be EKG changes associated with this situation, and the diagnosis is made by heart catheterization showing normal coronary arteries that go into spasm when challenged with a medication injected in the cath lab. Approximately 2%-3% of patients with heart disease have coronary artery vasospasm.
  
  
• Anomalous coronary artery. In their normal position, the coronary arteries lie on the surface of the heart. On occasion, the course of part the artery can dive into the heart muscle itself. When the heart muscle contracts, it can temporarily kink the artery and cause angina. Again, diagnosis is made by heart catheterization.
  
  
• Inadequate oxygenation. Just like any other muscle, heart muscle requires adequate oxygen supply for it to work. If there isn't adequate oxygen delivery, angina and heart attack can occur. This means that an adequate number of red blood cells and normal lung function are required to deliver oxygen to the cells of the heart. Profound anemia from bleeding or bone marrow failure can lead to lack of red blood cells. Lack of oxygen in the bloodstream can occur due to a variety of causes including respiratory failure or carbon monoxide poisoning.

Heart Attack Symptoms

Classic symptoms of a heart attack may include:

• chest pain associated with shortness of breath,
• profuse sweating, and
• nausea.

The chest pain may be described as tightness, fullness, a pressure, or an ache.

Unfortunately, many people do not have these classic signs. Other presentations of heart attack may include:

• indigestion,
• jaw ache,
• pain only in the shoulders or arms,
• shortness of breath, or
• nausea and vomiting.

This list is not complete, since many times people can experience a heart attack with minimal symptoms. In women and the elderly, heart attack symptoms can be atypical and sometimes so vague as to be easily missed. The only complaint may be extreme weakness or fatigue

When to Seek Medical Care

Chest pain is almost always considered an emergency. Aside from heart attacks, pulmonary embolus (blood clot in the lung) and aortic dissection or tear can be fatal causes of chest pain.

Classic pain from a heart attack is described as chest pressure or tightness with radiation of the pain to the jaw and down the arm, accompanied by shortness of breath or sweating. But it is important to remember that heart problems may not always present as pain or with the classic symptoms. Indigestion, nausea, profound weakness, profuse sweating, or shortness of breath may be the main symptom of a heart attack.

Remember to take an aspirin immediately if you are concerned that you are having a heart attack.

Doctors and nurses in Emergency Departments take chest pain very seriously. You are not wasting anybody's time, and you are not bothering anybody when you seek care for chest pain.

Many people die before they present for medical care because they ignore their symptoms out of fear that something bad is happening. It is much better to seek care if you are unsure whether your symptoms are related to heart disease and find that all is well than to die at home.