Coronary heart disease (CHD), also called coronary artery disease, affects about 14 million men and women in the United States. 

Disease develops when a combination of fatty material, calcium, and scar tissue (plaque) builds up in the arteries that supply the heart with blood. Through these arteries, called the coronary arteries, the heart muscle (myocardium) gets the oxygen and other nutrients it needs to pump blood. 

• The plaque often narrows the artery so that the heart does not get enough blood. 
• This slowing of blood flow causes chest pain, or angina. 
• If plaque completely blocks blood flow, it may cause a heart attack (myocardial infarction) or a fatal rhythm disturbance (sudden cardiac arrest). 
• A major cause of death and disability, coronary heart disease claims more lives in the United States than the next 7 leading causes of death combined. 

The heart consists of 4 chambers: an atrium and a ventricle on the right, and an atrium and ventricle on the left. 

• Blood returning to the heart from veins all over the body flows into the right atrium. 
• From there the blood flows into the right ventricle, which pumps it out to the lungs for oxygenation. 
• The oxygen-rich blood returns to the left atrium. 
• From there the blood flows into the left ventricle, which pumps it at high pressure into the arteries. 
• This entire process constitutes one heartbeat. 

The pumping, or contraction, of the left ventricle must be very powerful because that is what keeps the blood flowing throughout the body. 

• The strength of the heart muscle depends on the oxygen and nutrient supply coming via the coronary arteries. 
• These arteries are usually strong, elastic, and quite flexible. 

The heart has 3 major coronary arteries. 

• Two of these arteries arise from a common stem, called the left main coronary artery. 
• The left main coronary artery supplies the left side of the heart. 
• Its left anterior descending (LAD) branch supplies the front part of the heart. 
• The left circumflex (LCX) branch supplies the left lateral and back side of the heart. 
• Finally, the right coronary artery (RCA)  is separate and supplies the right and the bottom parts of the heart. 

As  a child, the inner lining of the coronary arteries is quite smooth, allowing blood to flow easily. As a person ages,  the cholesterol and calcium content  in the walls of the coronary arteries increases, making them thicker and less elastic. 

• Unhealthy habits, such as  a diet high in cholesterol and other fats, smoking, and lack  of exercise accelerate the deposit  of fat and calcium within the inner lining  of coronary arteries. 
• This process is known as atherosclerosis,  or hardening of the arteries. The deposits, or plaques, eventually obstruct  the blood vessel, which begins  to restrict blood flow. 

Plaque is like a firm shell with a soft inner core containing cholesterol. As blood hits it during each heartbeat,  the plaque may crack open and expose its inner cholesterol core, which promotes blood clotting. Clots may further reduce blood flow, causing severe pain (angina), or even block it all together. 

Coronary Heart Disease Causes 

Coronary  heart disease  is caused by any problem with the coronary arteries that keeps the heart from getting enough oxygen- and nutrient-rich blood. The most common cause by far is atherosclerosis. Lack of sufficient blood is  called ischemia, so  coronary heart disease is sometimes called ischemic  heart disease.

The cause of coronary heart disease is related to multiple risk factors. The following are  the most common: 

• Heredity: Coronary heart disease runs  in the family. 
• High cholesterol: Levels of cholesterol in  the blood are above healthy levels. This usually involves high levels of low-density lipoprotein (LDL),  the bad cholesterol,  and low levels of high-density lipoprotein (HDL), the good cholesterol. 
• Tobacco abuse: This includes not only smoking any form of tobacco (cigarettes, cigars, pipes), but also chewing tobacco. 
• Obesity 
• High blood pressure (hypertension) 
• Diabetes 
• Lack of regular exercise 
• High-fat diet 
• Emotional stress 
• Type A personality (impatient, aggressive, competitive) 

Coronary Heart Disease Symptoms 

The most devastating sign of coronary  heart disease is abrupt, unexpected cardiac arrest. 

• Cardiac arrest commonly occurs in people who have had previous heart attacks, but it may occur as the first symptom of heart disease.
• Most people exhibit some symptom or discomfort. 
• Symptoms usually occur during exercise or activity because the heart muscle's increased demand for nutrients and oxygen is not being met by the blocked coronary blood vessel. 

More common symptoms of coronary heart disease include the following. No one person usually has all of these symptoms. 

• Chest pain on exertion (angina pectoris), which may be relieved  by rest 
• Shortness of breath on exertion 
• Jaw pain, back pain, or arm pain, especially on left side, either during exertion or  at rest 
• Palpitations (a sensation of rapid or very strong heart beats in your chest) 
• Dizziness, light-headedness, or fainting 
• Weakness on exertion or at rest 
• Irregular heartbeat 

Silent ischemia is a condition in which no symptoms occur even though an electrocardiogram (ECG, or heart tracing) and/or other tests show evidence of ischemia. Arteries may be blocked 50% or more without causing any symptoms. 

When to Seek Medical Care 

Call  your health care provider if you notice any of the following symptoms, which suggest angina: 

• Chest pain,  pressure or feeling of indigestion after physical exertion, which may or may not be relieved by rest 
• Shoulder or arm pain involving left, right, or both sides during physical or mentally stressful activity 
• Jaw pain, unexplained by another cause, like a sore tooth   
• Shortness of breath after exertion or walking uphill 
• Fainting spell 
• Pain in the upper part of  your abdomen
• Unexplained nausea, vomiting, or sweating 
• Palpitations or dizziness 

Call or have someone take you immediately to a hospital emergency department if you have signs of a heart attack. 

• The most crucial factor is time. Each year, thousands of Americans die because they do not seek medical attention quickly. 
• Err on the side of caution and go to the hospital. 
• This may prove to be the difference between life and death. 

The most common symptoms of heart attack include the following: 

• Unremitting or prolonged chest pain, chest pressure, or a feeling like heartburn 
• Shoulder or arm pains (left or right) or upper abdominal pain that won't go away 
• Shortness of breath after minimal activity or while resting 
• Blackout spells 
• Unexplained profuse sweating with or without nausea or vomiting 
• Frequent chest pain or discomfort at rest 

Notes: Dr. Nelson Crumfield

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EditText of this page (last edited June 27, 2010)