Coronary Heart Disease (CHD)
also referred to as coronary artery disease (CAD)

On this page: How CHD Develops | Symptoms of a Heart Attack | Reduce Your Risk

Other pages: Anatomy of the Heart | News | Video Tutorials | References

Coronary heart disease is America's No. 1 killer

It's critical to minimize your risk factors, know the warning signs, and know how to respond quickly and appropriately if warning signs occur.(4)

Exertion in the cold weather can be dangerous for the elderlyCold winter weather can be dangerous for those with heart disease,

or even an older person who isn't aware they have heart disease.

People with coronary heart disease often suffer dangerous chest pain or discomfort called angina pectoris when they're in cold weather. Overexertion in cold weather can further stress the heart and possibly lead to a heart attack.

Besides cold temperatures, high winds, snow and rain result in a stressful load on the heart. Cold wind is especially dangerous. For instance, at 30 degrees Fahrenheit in a 20-mile-per-hour wind, the cooling effect is equal to calm air at four degrees. Also, dampness causes the body to lose heat faster than it would at the same temperature in drier conditions.

In cold weather, always wear layers of clothing--this forms a protective insulation. A scarf over your mouth is very helpful and warms the air that you breath. A hood or hat is important as much of your body's heat can be lost through your head. Ears, fingers and toes tend to lose heat quickly and are especially prone to frostbite.

Drinking alcoholic beverages before going outdoors or when outside can be dangerous and lead to hypothermia. Alcohol causes the blood vessels to dilate, which gives an initial feeling of warmth, but then heat is drawn away from the body's vital organs.(5)

About the Heart and Coronary Heart Disease:

Coronary arteries supply blood and oxygen to the heart muscle

The Coronary Arteries: Coronary arteries travel around the surface of the heart and supply oxygenated blood to the heart muscle.

Although the inside chambers of the heart are full of blood, the heart muscle itself is fed from a network of blood vessels, the coronary arteries, traveling on the surface of the heart. As the aorta leaves the heart with oxygenated blood, it immediately sends off branches, referred to as coronary arteries, that surround the hearts surface, and deliver oxygenated blood to the vital heart muscle.

The branches of coronary arteries are first divided into two major coronary arteries, the Left Main and the Right Coronary Artery. The Left Main then divides into the Left Anterior Descending (LAD) and the Circumflex.

See more cardiac anatomy and illustrations of the blood flow through the chambers of the heart

How Coronary Heart Disease Develops

Atherosclerotic plaque and blood clot blocking blood flow through an arteryAtherosclerosis begins in childhood. Throughout life there is a gradual build up of cholesterol and other substances on the inner lining of an artery referred to as paternoster plaques. Over time, these plaques can harden and narrow an artery enough to slow or even block blood flow. 


Arterioscleroses plaques are often unstable and can rupture into the vessel lumen causing a blood clot to form.  This can result in a sudden blockage of an artery.  This is often the process by which people experience heart attacks or strokes.  In some people, the first sign of Atherosclerosis might be a heart attack or even sudden death. 

More individuals may die of sudden death from a 40% blockage of a carotid artery vs. an 80% blockage of an artery as a result of a sudden occlusion due to plaque rupture. Hence, while anthropocentric plaques may only represent a 40% or 50% occlusion of the artery lumen, they pose the greatest risk because of their inherent instability. 

It All Begins With the Build Up of Atherosclerotic Plaques


A gradual build up of cholesterol and other substances on the inner lining of an artery develop into atherosclerotic plaques. Cholesterol is a waxy, fat-like substance made in the liver, but also is found in certain foods.  There are several types of cholesterol, including low-density lipoproteins (LDL) and high-density lipoproteins (HDL). 

Atherosclerotic plaque build-upLDL cholesterol is considered "bad" cholesterol because excessive levels of LDL can lead to a build up of thick, hard deposits called plaque on the inside of the blood vessel wall.  (See yellowish plaque build up in wall of blood vessel in illustration to left, Courtesy of plaques also contain various types of cells often associated with inflammation as the body tries to rid itself of this abnormal buildup. It is desirable to keep LDL levels low, because the more LDL there is in the blood, the greater the risk of heart disease. Saturated fats and transfatty acids in the diet raise the LDL cholesterol levels in the blood.

HDL cholesterol is referred to as "good" cholesterol because it protects your arteries from plaque buildup by acting as a scavenger that removes cholesterol from the arterial walls and carries it back to the liver, which leads to its removal from the body.  The higher the blood level of HDL-cholesterol, the better.  Conversely, low levels of HDL increase the risk of heart disease.  Smoking lowers HDL levels; exercise increases HDL levels.(12)   HDL Blood levels less than 40 mg/dL are a major risk factor for heart disease.  An HDL of 60 mg/dL and above is considered protective against heart disease.(1)

Triglycerides are another type of fat that is also synthesized by the body and found in certain foods as well.  High triglyceride levels have been associated with an increased risk of heart attack.  In addition to genetic predisposition, the following tend to lead to elevated triglyceride levels: excessive carbohydrate intake, excessive alcohol consumption, and lack of exercise.

Read more about controlling your cholesterol levels and reducing your risk of coronary heart disease.

Heart attack

Loss of oxygenated blood supply to the heart muscle can result in permanent damage to the muscle, otherwise known as a heart attack. Coronary arteries during a heart attack

Some heart attacks are sudden and intense — the "movie heart attack," where no one doubts what's happening. But most heart attacks start slowly, with mild pain or discomfort. Often people affected aren't sure what's wrong and wait too long before getting help. Here are signs that can mean a heart attack is happening:

  • Chest discomfort. Most heart attacks involve discomfort in the center of the chest that lasts more than a few minutes, or that goes away and comes back. It can feel like uncomfortable pressure, squeezing, fullness or pain.

  • Discomfort in other areas of the upper body. Symptoms can include pain or discomfort in one or both arms, the back, neck, jaw or stomach.

  • Shortness of breath. May occur with or without chest discomfort.

  • Other signs: These may include breaking out in a cold sweat, nausea/vomiting or lightheadedness

If you or someone you're with has chest discomfort, especially with one or more of the other signs, don't wait longer than a few minutes (no more than 5) before calling for help. Call 9-1-1... Get to a hospital right away. Calling 9-1-1 is almost always the fastest way to get lifesaving treatment. Emergency medical services staff can begin treatment when they arrive -- up to an hour sooner than if someone gets to the hospital by car. The staff are also trained to revive someone whose heart has stopped. Patients with chest pain who arrive by ambulance usually receive faster treatment at the hospital, too. If you can't access the emergency medical services (EMS), have someone drive you to the hospital right away. If you're the one having symptoms, don't drive yourself, unless you have absolutely no other option.(4)

Illustrations courtesy of the National Heart Lung and Blood Institute. Heart Attack Warning Signs from the American Heart Association (4)

Cardiac arrest strikes immediately and without warning. Here are the signs:

  • Sudden loss of responsiveness. No response to gentle shaking.
  • No normal breathing. The victim does not take a normal breath when you check for several seconds.
  • No signs of circulation. No pulse.

    If cardiac arrest occurs, call 9-1-1 and begin CPR immediately. If an automated external defibrillator (AED) is available and someone trained to use it is nearby, involve them.
Chest pain, or angina, is often a symptom of reduced blood flow to the heart muscle. 
Atherosclerosis can occur anywhere in the body. In addition to heart attacks and strokes, occluded arteries can also lead to any vital organ failure, such as kidney failure. Blocked blood flow to a leg can result in pain when walking or even lead to loss of that limb.

Important Steps to Reduce your Risk

  1. Blood work: Get a fasting lipoprotein profile to find out what your total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride numbers are.
  2. Calculate your cardiac risk
  3. Calculate your body mass index (BMI) with the BMI calculator and see how your weight measures up.
  4. Calculate your Waist to Hip Ratio Waist-to-hip ratio is the strongest anthropometrical measure associated with MI risk, and substantially better than BMI in most ethnic groups. Researchers have found that people with the larger waistlines (compared to their hip circumference) were at greater risk of heart disease, than those with smaller waistlines and relatively larger hips. In other words, the pear shape is better than the apple shape. Lancet, 2005
  5. Reduce Cardiac Risk Factors: Discuss your risk for heart disease with your health care provider and take steps to decrease your risk factors.
  6. Increase the good fats and decrease the bad fats in your diet Read food labels and know what you're eating.
  7. Regular exercise: Participate in physical activity of moderate intensity—like brisk walking—for at least 30 minutes on most, and preferably all, days of the week. No time? Break the 30 minutes into three, 10-minute segments during the day.
  8. Don't smoke If you do smoke, read this and contact your healthcare provider to discuss ways in which they can help you quit.(2)


Videos about Heart Disease from Bay Area Medical Information


1) How Does Coronary Artery Disease Develop? from the Cleveland Clinic
2) Who is at risk for coronary heart disease? the National Heart, Lung, and Blood Institute
3) Coronary Artery Disease from Medline Plus, A service of the National Library of Medicine and the National Institute of Health
4) Heart Attack, Stroke and Cardiac Arrest Warning Signs from the American Heart Association
5) Cold Weather and Heart Disease from the American Heart Association
--Written by N Thompson, ARNP; Last Updated June 2012

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