Chapter 2: Preventing Cardiovascular Disease Cardiovascular disease is the leading cause of death in the U.S.— 38.5% of all deaths Approximately 25% of Americans have one or more forms of heart or blood vessel disease. Approximately 340,000 people die annually of coronary heart disease (CHD). Many deaths can be prevented with proper treatment.

Circulation The left side of the heart (systemic pump) receives the oxygenated blood from the lungs and pumps it to all the tissues in the body The right side of the heart (pulmonary pump) receives deoxygenated blood from the body and pumps it to the lungs

Circulation The primary function of circulation is to provide a constant supply of blood and nutrients to cells while removing their waste products The heart has its own conduction system The beating rate and rhythm are established by the sinoatrial (SA) node (pacemaker) Average heart rate is between 60-100 beats per minute (bpm). Elite athletes can have heart rates as low as 30-40 bpm as a result of adaptation from training. Overweight and sedentary persons may have heart rates above 100 bpm.

Circulation The electrical contraction pauses at the atrioventricular (AV) node, allowing the ventricles to fill with blood The heart is supplied with blood from coronary circulation after it has been ejected from the heart Blood is so important to the heart that every muscle fiber is supplied by at least one capillary The blood in the heart does not nourish the cardiac muscle. The heart itself is nourished by coronary arteries. The blood is made up of 55% plasma and 45% solids (red blood cells, white blood cells, and platelets)

Anatomy of the Heart The heart: Consists of cardiac muscle Weighs 8 to 10 ounces Has two halves (pumps) divided by the septum Halves are divided into upper chambers (atria) and lower chambers (ventricles) The pumps work simultaneously. Carbon dioxide in the blood is exchanged for a fresh supply of oxygen.

Cardiovascular Disease (1) Coronary heart disease (coronary artery disease; CAD) is diagnosed when any artery is narrowed by 60% or more A myocardial infarction (heart attack; death of the heart muscle) occurs when blood flow to the heart muscle is disrupted Most heart attacks occur after age 65, but the process begins as early as adolescence The amount of damage is affected by: a. location of obstruction b. how soon medical intervention begins All hearts attacks result in irreversible injury and death of myocardial tissue.

Myocardial Infarction The medical term for heart attack is myocardial infarction (MI) Up to one third of all heart attacks are silent—without obvious signs or symptoms Silent ischemia, reduced blood flow, can initiate heart attacks without warning Most heart attacks are obvious Those having a silent heart attack will not experience chest, arm, neck, or jaw pain. This more than doubles the risk of death because people wait longer before seeking medical treatment.

Cardiovascular Disease (2) Heart disease is an acquired disease that is preventable Americans as young as 18 have obstructions in their coronary arteries caused by atherosclerosis Atherosclerosis, characterized by plaque beneath artery linings, is responsible for 80% of CAD deaths in the U.S. Heart disease is not a consequence of aging or bad luck. Prevention should begin in early childhood.

Brain Attack (Stroke) Brain attacks are caused by a thrombus or an embolus (70% to 80%) or a cerebral hemorrhage Brain cells die, causing loss of function of some parts of the body Brain attacks have the same risk factors and prevention factors as heart disease Thrombus- a clot that forms in and occludes an artery to the brain Embolus- a clot that forms elsewhere and travels to a cerebral artery Cerebral hemorrhage- a blood vessel in the brain that bursts Aneurysm- a weak spot in the blood vessel that forms a pouch that is subject to rupturing

Unchangeable Risk Factors for Heart Disease (AHA) Age—55% of heart attacks occur after age 65 Male gender—Heart disease is the leading cause of death for both males and females Females have a lower rate than males Rate is increasing among females, particularly those who smoke and use oral contraceptives Heredity and Race—A tendency toward heart disease appears to be hereditary Reasons for increased incidence among males- 1) estrogen protects against atherosclerosis, and 2) females traditionally have higher levels of HDL, which fights against heart disease Certain minority groups, such as African-Americans have a higher incidence of heart disease. Though nothing can be done to change these risk factors, have a heart-healthy lifestyle can reduce the risk.

Changeable Risk Factors Cholesterol (1) A certain amount of cholesterol is necessary for good health The best way to lower serum (blood) cholesterol is to reduce intake of saturated fat Saturated fat increases the liver’s production of cholesterol The liver and intestinal walls synthesize cholesterol even if none is eaten.

Changeable Risk Factors Cholesterol (2) Cholesterol is a steroid that does not dissolve in blood, so it is transported to cells by protein packages Low-density lipoproteins (LDL), the primary transporters of cholesterol, are the most capable of producing atherosclerosis People with low blood levels of LDL (less than 100 mg/dl) rarely have heart attacks

Changeable Risk Factors Blood Pressure (1) Blood pressure is the force exerted against artery walls as blood travels through the circulatory system High blood pressure (hypertension) has no signs or symptoms An estimated 90% to 95% of hypertension is essential (of unknown origin) High BP= 140/90 mmHg Normal blood pressure is around 120/80 mmHg The top number is the systolic pressure (maximum heart contraction) and the bottom number is the diastolic pressure (minimum pressure between beats) Hypertension is known as the “silent disease”

Changeable Risk Factors Blood Pressure (2) Long-term uncontrolled hypertension increases the work of the heart, causes it to hypertrophy, and leads to congestive heart failure Hypertension damages the arteries, accelerates atherosclerosis, and is the most important risk factor for brain attacks Treatment of hypertension includes: weight loss, salt and alcohol restriction, calcium and potassium supplements, use of relaxation techniques, exercise, and medication

Changeable Risk Factors Tobacco Cigarette smoking may be the most harmful of the preventable risk factors for chronic illness and premature death These illnesses include chronic bronchitis, emphysema, strokes, and 87% of all lung cancers Passive smoking, inhaling the smoke of others, causes the deaths of 38,000 to 43,000 nonsmokers annually Two issues must be addressed in order to quit smoking, the nicotine addiction and psychological dependence. One-third of all cigarette smokers try to quit each year, but less than 10% succeed. Cigarette smoking is responsible for one out of ever five deaths in the U.S. annually.

Changeable Risk Factors Physical Inactivity Physical inactivity increases the risk of coronary heart disease by 1.5 to 2.4 times The greatest health benefits are gained when people expend 1500 to 2000 calories (walk 15 to 20 miles) per week Exercise for health does not have to be as strenuous as exercise for physical fitness Physical inactivity is the primary contributor to overweight and obesity in children in the U.S.

Changeable Risk Factors Physical Inactivity Physical activity is any physical movement that results in energy expenditure—walking, mowing the lawn, vacuuming “Every U.S. adult should accumulate 30 minutes or more of moderate intensity physical activity on most, preferably all, days of the week.” (ACSM/CDC statement)

Changeable Risk Factors Obesity Obese people who have no other risk factors are still more likely to develop heart disease or stroke. Fat that accumulates in the upper half of the body (central abdominal obesity) is significantly more likely to contribute to heart disease A 5% to 10% weight loss that is maintained can significantly reduce the risk of heart disease

Changeable Risk Factors Diabetes Mellitus Diabetes is a metabolic disorder in which the body cannot properly use sugar (glucose) as fuel Type II (90% of all diabetes) occurs in older, overweight, sedentary adults Diabetes increases the risk of coronary artery disease 2 to 3 times in men and 3 to 7 times in women

Changeable Risk Factors Stress Stress elevates heart rate, blood pressure, breathing rate, and blood sugar levels, activates the immune response, and causes other physiological changes Chronic (long-term) distress significantly strains the body

Preventing and Reversing Heart Disease Preventing includes: Exercising regularly Maintaining an optimal body weight Practicing sound nutrition Nonuse of tobacco and other drugs Nonuse or moderate use of alcohol Dealing constructively with stress Periodic medical examinations

Preventing and Reversing Heart Disease Reversing includes: Following a low-fat diet Stopping tobacco use Managing stress Attending support group meetings regularly Exercising consistently at a moderately intense level

Other Risk Factors Other factors include: Iron-enriched blood Homocysteine Lipoprotein High Sensitivity C-Reactive Protein Fibrinogin

Diagnostic Techniques Medical examination and patient history Exercise stress tests Thallium treadmill test Echocardiography Cardiac catheterization

Medical Treatment Low-dose aspirin therapy Coronary artery bypass surgery Balloon angioplasty Coronary stent Artificial valves Left ventricular assist devices Heart transplants