You & Your Heart

Cardiac Anatomy & Heart Disease

The Heart is a pump, consisting of four chambers. The top two are called the Atriums, their function is to receive un-oxygenated blood from the body (right atrium) or move oxygenated blood from the lungs to another chamber called the ventricle (left atrium). The two bottom chambers or ventricles are the true pumping chambers of the heart. Their function is to pump un-oxygenated blood from the body (via the right atrium) to lungs for oxygenation. The left ventricle pumps oxygenated blood from the lungs (via the left atrium) to heart and body.

There are a series of four valves between each of the chambers of the heart. Their function is to control the flow of blood in and out of the chambers. These four valves are the: tricuspid, pulmonary, mitral, and aortic.

The coronary arteries originate near the top of the heart off a major blood vessel called the aorta. The major blood vessels supplying blood to the heart are: right coronary artery, which feeds the right side of the heart. Left coronary artery, which feeds the left side of the heart and the bottom. Circumflex, which feeds the back of the left side of the heart. Collateral circulation is extra out growths of the above coronary arteries supplying heart muscle tissue that has been compromised from blockages in the main arteries of that area.

Coronary Artery Disease (CAD) is the progressive obstruction of blood flow through one or more of the coronary arteries ultimately depriving the heart muscle of adequate blood and oxygen. In atherosclerosis, these deposits gradually build up in the lining of the arteries, as this plaque accumulates blood flow decreases. This plaque build-up increases the risk of heart attack, stroke, and other serious vascular problems.

Besides plaque build-up, there is another reason why an artery can stop supplying blood to the heart muscle, namely, coronary artery spasm. The spasms cause tightening or contraction of the blood vessels thus preventing blood flow.

Both of these restrictive processes can cause a heart attack or myocardial infarction (MI). A heart attack is the necrosis or death of myocardial (heart muscle) tissue due to a lack of blood supply (thus no oxygen) to a specific area of the heart.

So how do you know if you have heart disease?
1) Signs and symptoms: a pressure, burning, discomfort, tightness or pain in the chest, arm, jaw, neck, shoulder or upper back associated with or without nausea, sweating or weakness, shortness of breath, lightheadedness.

2) EKG and cardiac enzymes: EKG records the electrical activity of your heart. Electrodes convey impulses of your heart to a device that produces a graphic representation of your hearts activity. EKG changes from normal patterns occur with the MI. Cardiac enzyme (blood lab test) elevation also occurs with the MI. Enzymes are released from damaged cells in the heart muscle, these levels rise and return to normal over a period of 0-72 hrs after the MI.

3) Echocardiogram: sound waves are reflected off the heart leaving an image of shadows allowing detection of wall motion, visualization of valves, and blood flow through the heart. Ejection fraction can be evaluated with this test. Ejection fraction is a measure of the left ventricular function and represents the amount of blood being pumped with each heart beat.

4) Stress test: this test can evaluate the heart for blockages by viewing the EKG response to exercise. If the exercising EKG changes from the resting EKG then there is a possibility of blood flow problems from blockages. A cardiolite stress test or nuclear stress test is a treadmill test done with the injection of a radioisotope at peak exercise. The cardiolite stress test involves two different studies, a resting study and an exercising study, and looks for reversible ischemia (blockages) vs. fixed deficits (heart attacks), and determines the extent and severity of coronary artery disease.

5) Coronary angiogram: names for this test include: coronary catheterization, coronary angiography, angiogram, and cardiac cath. The purpose of this test is to view the blood flow to the heart from the coronary arteries. A catheter is inserted into the right or left femoral or brachial artery then threaded into the heart by way of the aorta, and dye is injected into the coronary circulation, then viewed by x-ray as it travels through the arteries allowing any narrowing to be detected.

Treatment for heart disease:
Medication: Beta-blocker: decreases heart rate which leads to a decreased demand on the heart. Calcium channel blocker and Ace Inbibitors: dilates blood vessels and decreases blood pressure. Aspirin: thins the blood to make blood flow easier and decreases the workload of pumping the blood, reduces blood clot formation. Nitrates: dilates arteries therefore increasing blood supply and decreasing workload.

Angioplasty/Stent or PTCA (Percutaneous Transluminal Coronary Angioplasty). A catheter is inserted in the groin or arm area like an angiogram, when it reaches the narrowed area an inflated balloon opens up the narrowed artery by splitting and compressing the plaque and slightly stretching the artery wall. A stent may be placed in this area which helps keeps the artery open. PTCA can be used in conjunction with a stent, a metal mesh tube that is inserted and holds the coronary artery open.

Atherectomy or "Roto Rotor" : inflated balloon holds a device in place then the plaque is sheared off and sucked back into the catheter.

Coronary Artery Bypass Graft (CABG): blood flow is re-routed around blocked coronary arteries, by implanting veins taken from other areas or attaching one end of an internal mammary artery to the coronary artery, improving blood flow to the heart muscle. Vessels are obtained from other areas of the body and bypass the blocked flow. These new vessels can block too, thus it is very important to lead a healthier lifestyle!

Coronary Artery Disease Risk Factors

Coronary artery disease (CAD) is the major disease of the cardiovascular system; in the United states it is responsible for nearly 600,000 deaths each year. Although the percentage of deaths due to CAD has been declining in recent years, it is still the leading cause of death in this country.

Atherosclerosis, the build-up of plaque inside the arteries which leads to CAD, is a gradual process which begins in childhood, but usually does not become evident until later in life. Most heart attacks are the result of severe atherosclerosis. Over the past 25 years much evidence has been collected to help identify those risk factors which contribute to atherosclerosis and CAD. The major risk factors for CAD are cigarette smoking, abnormal cholesterol levels, hypertension (high blood pressure), and a sedentary lifestyle, diabetes, obesity, stress, a family history of CAD, gender, and age. The only risk factors which are not controllable through changes in lifestyle are family history, gender, and age. The development of atherosclerosis can be slowed down or stopped by controlling or modifying CAD risk factors.

Cigarette Smoking: Cigarette smoking affects the heart and blood vessels in a number of ways and is a major contributor to CAD. Certain substances in cigarette smoke damage the walls of the arteries which can lead to an increased rate of plaque build up. When cigarette smoke is inhaled, nicotine causes an increase in heart rate and blood pressure. Also, cigarette smoking lowers HDL cholesterol levels and increases the chances of developing blood clots. Although the number of smokers in the U.S. has decreased significantly since 1965, approximately 25% of the adult population still smokes and smoking rates are on the rise again, especially amongst youger adults and teens.

Cigarette smoking is responsible for 20%-30% of all deaths due to heart disease in the U.S. and 50% of all heart attacks in women under the age of 55. The degree of CAD risk from smoking is related to the number of cigarettes smoked daily and the number of years someone smokes. On average, smoking more than doubles one's risk of developing CAD.

Cigarette smoking is still the number one preventable cause of death in the United States. Within five years of quitting, an ex-smoker will have a 50%-70% lower CAD risk than current smokers.

High Cholesterol Levels: in atherosclerosis, the plaque that develops in the walls of the arteries is made up partially of fats and cholesterol. Therefore, high levels of blood lipids (triglycerides and cholesterol) are associated with increased levels of plaque formation. Cholesterol is carreid in the bloodstream in large molecules of fat and protein called lipoproteins. cholesterol carried in low density lipoproteins is called LDL-cholesterol. Cholesterol carried in high density lipoproteins is called HDL-cholesterol. LDL-cholesterol and HDL-cholesterol act differently in the body. A high level of LDL-cholesterol in the blood increases the risk of plaque forming in the arteries, which increases the risk of a heart attack. On the other hand, high levels of HDL-cholesterol protect against plaque formation. The following table lists the ideal values for triglycerides and cholesterol in the blood:

• Total cholesterol - Less than 200 mg/dl
• LDL-cholesterol - Less than 130 mg/dl, less than 70 mg/dl with heart disease, diabetes or mutiple risk factors
• HDL-cholesterol - Greater than 40 mg/dl
• Triglycerides - Less than 150 mg/dl

It is important to know that the liver produces all the cholesterol the body needs. Therefore, cholesterol is not needed in the diet. Since cholesterol is produced in the liver, it is found only in animal products. However, eating foods high in saturatedfat raises the level of cholesterol in the blood even more than eatingfoods high in cholesterol. Foods with a high saturated fat content include, but are not limited to, red meat, whole milk products, cheese, palm oil and coconut oil.

For each 1% decrease in blood cholesterol levels, the risk of developing CAD decreases by 2% - 3%. For each 1% increase in HDL-cholesterol levels, CAD risk decreases by 3%. In order to lower the amount of cholesterol in the blood and raise HDL-cholesterol, one needs to lirnit the amount of fat in the diet (especially saturated fat), get regular cardiovascular exercise, maintain an ideal body weight, and avoid cigarette smoking.

Hypertension: approximately 50-60 million adults in the U.S. have high blood pressure, which is defined as a resting blood pressure greater than 140/90. High blood pressure is not only a major risk factor for CAD, but it is also the leading cause of strokes. High blood pressure has been called the "silent killer", because there are no signs or symptoms associated with it. With untreated hypertension the constant high forces exerted on the walls of the arteries causes darnage, and this can lead to an increased rate of plaque atherosclerosis.

People with hypertension can usually lower their blood pressure by making some lifestyle changes. Since obesity is a major contributor of hypertension, losing weight is extremely important. As a general rule, one pound of weight loss results in a one point drop in blood pressure. Other steps to take to lower blood pressure are getting regular aerobic exercise, avoiding cigarette smoking, and limiting the amount of sodium in the diet.

A one point drop in diastolic blood pressure results in a 2%-3% lower risk of having a heart attack. 

Sedentary Lifestyle: a sedentary lifestyle is now considered the most cornmon preventable risk factor for CAD. Based on recent studies it doubles one's risk of having a heart attack. Current research indicates that 40% of the adult U.S. population is completely sedentary and another 40% is not active enough to significantly improve physical fitness.

Physical activity protects against atherosclerosis primarily by modifying other risk factors for CAD. Regular physical activity can lower total cholesterol levels and raise HDL­cholesterol levels. Exercise also contributes to lower resting blood pressure values decreases in body fat, and improved control of blood glucose levels. In addition, exercise is an effective stress management technique and can improve one's self-esteem.

In order to attain all the benefits of exercise, the American College of Sports Medicine recommends that aerobic exercise (walking, biking, swimming, etc.) be performed for 20-60 minutes, at least three days per week, at 55%-90% of one's maximal heart rate. However, results of recent studies suggest that physical activity of even low to moderate intensity, when performed for more than 30 minutes a day, at a total energy expenditure of 1,500 to 2,000 calories per week can bring about sirnilar benefits.

The best available evidence indicates that regular, moderate activity is beneficial in the prevention of CAD. People who maintain an active lifestyle have a 45% lower heart attack risk than those who maintain a sedentary lifestyle.

Obesity: is the leading cause of Type II diabetes and also increases one's risk of developing high blood pressure and elevated cholesterol levels. As a result of these changes, the risk of developing CAD is twice as high for obese individuals as it is for adults who are not overweight. Unfortunately, the number of overweight adults in the U.S. has increased  steadily during the past several decades. It is estimated that one out of every five adults in the U.S. is obese.

The keys to losing weight are moderately reducing the amount of calories in the iiet and getting regular aerobic exercise. People who reduce the amount of calories in their diet but do not exercise have a more difficult time losing weight than those who make both lifestyle changes. One can expect to lose one to two pounds per week on a well designed weight loss program.

Individuals who lose weight and maintain an ideal body weight have a 45% lower rislc of having a heart attack than obese individuals.

Diabetes: accelerates the rate of plaque build-up in the arteries and increases the risk of heart attack, especially in women. The rate of CAD is three to seven times higher in diabetic women than in women without diabetes. Male diabetics double their risk of developing CAD. Many diabetics also have hypertension and abnorrnal cholesterol levels, and this contributes to the increased risk of developing CAD.

Non-insulin-dependent diabetes (Type II diabetes) is the most common fonn of the disease, accounting for 90% of all cases. Type II diabetes usually occurs in adulthood, and is frequently the result of excessive weight gain. In fact, 80% of all Type II diabetics are obese.

Type I diabetes usually occurs in childhood, and is due to the inability of the pancreas to produce insulin. All Type I diabetics must take insulin in order to control the disease, whereas only 20% of Type II diabetics are required to take insulin.

The primary goal for.diabetics is to keep blood sugar (glucose) levels within normal limits. This is done through proper nutrition, exercise, weight control, and medications. For most Type II diabetics, losing weight is essential. A 10 pound weight loss is usually needed in order to improve blood glucose levels.

Stress: the effects of chronic stress on the cardiovascular system are numerous: Increase in LDL-cholesterol levels, decrease in HDL-cholesterol levels, increase in blood pressure, increased clotting of the blood, coronary artery wall damage to name a few.

It is not known how much chronic stress increases one's risk of developing CAD, but it does contribute to an increased rate of atherosclerosis. Therefore, stress management techniques should be used in order to decrease the negative effects of chronic stress. Effective stress management techniques include exercise, progressive relaxation, yoga and meditation. One or more of these techniques should be perforrned on a daily basis.

Angina, Chest Pain/Pressure

What is/causes angina? Angina occurs when the heart needs more oxygen than it is receiving. The heart is a muscle that requires a constant supply of oxygen so that it can continue beating. Oxygen is carried in the blood stream and goes to the heart through blood vessels called coronary arteries. Angina occurs when the amount of oxygenated blood supplied to the heart is in-adequate to meet its needs. Symptoms may occur at rest but is more often triggered by exertion, emotions, eating, or exposure to cold.

Your body will usually provide warning signals that a problem is occuring. It is important to learn your heart's signals for action. Be informed and recognize these signals. Become an active partner in taking care of your heart. Signs and symptoms of angina can be a pressure, burning, discomfort, tightness or pain in the chest, arm, jaw, neck, shoulder or upper back and may be associated with or without nausea, sweating or weakness, shortness of breath, lightheadedness.

If you begin to have these symptoms:

• STOP and REST.
• Nitroglycerin, taken under the tongue, or spray, will sometimes relieve angina. You may take up to three (3) nitroglycerin tablets or sprays, one (1) every 5 minutes until the pain is completely relieved.
• If the pain is not completely relieved after 3 tablets/sprays, CALL FOR EMERGENCY CARE or have someone take you to the hospital. YOU MAY BE HAVING A HEART ATTACK.

Chest pain or discomfort may be angina or the first signs of a heart attack. The signals of a heart attack differ from person to person and may vary with more than one heart attack. It is very important for you and your family to recognize these signals and to know how to take action.

The symptoms that may warn of a heart attack are:

• Chest pain and discomfort (an uncomfortable squeezing, fullness, or pressure) usually beginning in the center of the chest. The pain may move into, or sometimes start in, the shoulder, arm, jaw, neck, or back. This feeling continues even when you rest or take nitroglycerin, and may be accompanied by:
• sudden sweating,
• shortness of breath,
• a feeling of weakness,
• nausea and/or vomiting

It is not required to have all of these symptoms. Also, be aware that these feelings may go away for several hours and then return.

If you think you are having a heart attack, STOP WHAT YOU ARE DOING and sit or lie down. Take your nitroglycerin as described, chew an aspirin and call for emergency care immediately. DO NOT WAIT. Minutes count!

Now would also be a good time for your family (and you) to learn CPR (Cardio-Pulmonary Resuscitation). In the event of a heart attack, this technique of rescue breathing and chest compressions may make the difference. Be prepared to make the difference!