The Heart and Major Structures

The Coronary Arteries The movement of blood through the heart is dependent in part on its four valves (tricuspid, mitral, pulmonary, aortic) (see figure 1). They are located between the atria (blood receiving chambers) and the ventricles (major pumping chambers); and between the ventricles and the blood vessels leaving the heart (on the right side this is the pulmonary artery; on the left, the aorta). To coordinate the heart's pumping, it has a built in electrical conduction system. The heart is a muscle and, like other muscles, it contracts (shortens) when stimulated. The heart is unlike other muscles in that it can self generate impulses to stimulate itself along with surrounding muscle cells. The electrical system of the heart keeps its chambers beating in rhythmic sequence so blood is continually pumped through it to all parts of the body.

The coronary arteries stem from the aorta and then branch into three main arteries (figure 2). These arteries, in turn, branch off into smaller vessels, so the oxygen can reach the heart tissues. The three main coronary arteries are the right coronary artery, the left anterior descending artery., and the circumflex artery. Each of the coronary arteries delivers blood to a specific part of the heart. The right coronary artery delivers blood to the back and bottom part of the heart. The left anterior descending artery gives blood to the front part of the heart and the left circumflex furnishes the left side portion of the heart.

Figure 3. Graphic illustration of a longitudinal section of a coronary artery illustrating plaque build-up and narrowing of the lumen

Risk Factors for Coronary Artery Disease

Certain factors increase one's risk of heart attack. The good news is that many of these factors can be changed. The bad news is that there are risk factors that, as yet, are unknown. Of the known risk factors, there are two types, modifiable and non modifiable . Modifiable risk factors can be changed (modified) and the non modifiable cannot. As you read the risk factors below, mark "yes" if they apply to you, and "no" if they do not.  (http://www.uihealthcare.com/)

Answer the following classification of non-modifiable/modifiable risk factors and score with 1/0 depending if "Yes/No":

Non Modifiable Risk Factors : Answer: Yes/No:

Advancing Age - The older you are the more likely it is that plaque has built up. If you are a woman over 44 or a man over 38, check "yes".

Male Gender - Check "yes" if you are a man.

Post Menopausal Female - After menopause women's rate of heart attacks "catch up" to that of men's. If you are a postmenopausal female check "yes".

Heredity - Do you have family members (father, mother, grandparents, aunts, uncles, children) with heart disease or stroke?

Modifiable Risk Factors : Answer: Yes/NO:

High Cholesterol

If your total cholesterol level is above 200 mg/dl, check "yes".

If your LDL (low density lipoproteins) is above 100 or your triglycerides are greater than 180 mg/dl, you have an increased risk of developing plaques in your coronary arteries. Following a low fat, low cholesterol diet will help change this problem. In addition, your doctor may recommend medication to improve your lipid profile [statins].

Low HDL

If your HDL (high density lipoproteins) is less than 35, check "yes".

Exercise and smoking y cessation will both help increase this level. Alcohol also increases HDL, but because alcohol is related to other health problems (high triglycerides, hypertension, liver problems), we do not recommend you start drinking alcohol if you actually do not drink. If your drinking limit is in the amount to two drinks per day, providing your triglycerides are normal, you're not hypertensive, and you do not have other conditions that alcohol would aggravate. 1 goal is to have the HDL as high as possible [over 35]. Your physician may recommend medication to improve your lipid profile [statins].

High Blood Pressure

Increased blood pressure causes the heart to pump against increased resistance, eventually leading to an overgrowth of the heart muscle.

If you have high blood pressure, reducing your sodium intake, losing weight, exercising, decreasing alcohol intake and seeing your doctor about prescribing medication will help control it. Check "yes" if your blood pressure is above 139/89. If your blood pressure is 130/85 or higher, it is on the high end of normal and you are advised to keep a close watch on it.

Cigarette Smoking - The nicotine in cigarette smoke causes your coronary arteries to constrict. Cigarettes also cause the blood to clot and the carbon monoxide decreases the amount of oxygen the blood can carry. The only way to reduce this risk and to stop this damage to your heart is to stop and stay away from others who smoke.

Obesity - This is defined as being 20% or more over your ideal body weight. Obesity causes an additional strain on the heart since there is more body mass requiring blood. Obesity is linked with high cholesterol, high blood pressure, and an increased heart size. To reduce this risk follow a low fat diet and maintain a reasonable body weight.

Lack of Exercise - The heart, like any other muscle, neds to be exercised to function properly. Exercise will favorably affect all the other risk factors. Numerous studies have found that lack of exercise not only increases the risk of cardiovascular disease, but also cancer, osteoporosis and others. Follow the exercise program your "HAMPS"team has developed for you. Exercise can reduce your blood pressure, decrease the urge to eat and smoke, facilitate a positive outlook on life, reduce stress, and make your heart and other muscles work more effectively and efficiently.

Stress - When you are exposed to stressful situations,your body by preparing for a "flight or fight" response. This increases your blood pressure and heart rate. Both of these increase the workload placed on your heart, which increases the oxygen demands of the heart. Over time, chronic stress can, for some people, contribute to the development of coronary artery disease.

Diabetes - The increased blood sugar levels in a diabetic cause an increase in triglycerides and LDL and a decrease in HDL. A diabetic who controls his or her blood sugar level will minimize adverse changes in the lipid profile.

Risk Factor Assessment: See "Risk Factors Assessment" on next topic