Heart Diseases (General)

Heart disease is the leading cause of death and disability worldwide. Approximately 16.7 million people die from heart disease each year, with coronary heart disease killing more than 7 million people. Heart disease can affect any component of the cardiovascular system, which includes the heart muscle, valves, conduction system, coronary arteries and veins, as well as systemic arteries and veins. Coronary artery heart disease, alone, accounts for roughly 2.3 million cases of heart disease annually. There are a variety of types of heart disease that affect a wide range of age groups and ultimately may lead to heart failure. Congenital heart disease, valvular heart disease, cardiomyopathies, and coronary artery disease are examples of heart disease. The severity of these diseases is dependant upon the degree to which they affect the ability of the heart to adequately pump blood throughout the body to meet nutritional demands.

Coronary artery disease (CAD) is the most common form of heart disease. CAD is the number one killer worldwide for those older than 60 years of age, and is the second leading cause of death, behind HIV/AIDS, for those 15 to 59 years old. Each year, 3.8 million men and 3.4 million women worldwide die from CAD. Currently, in the United States it is estimated that one out of every 2,000 people are affected by CAD. Although genetics play a role in the development of CAD, 80 to 90 percent of people who die of CAD have one or more risk factors influenced by an unhealthy lifestyle. CAD occurs when the arteries that supply blood to the heart muscle become hardened and narrowed.

This process is due to a buildup consisting mostly of fat, cholesterol, and calcium that circulate in the blood. The buildup of material is referred to as a plaque and leads to a condition known as atherosclerosis. As the plaque grows in size, the amount of blood passing through the vessels decreases and heart muscle does not receive adequate oxygen needed to survive. The development of atherosclerosis is a process that develops over time, often beginning in childhood and gradually increasing with age. CAD varies in severity and its presentation can range from asymptomatic to chest pain associated with exertion (angina), heart attack, and sudden cardiac death. Acute coronary syndrome refers to the symptoms associated with acute myocardial ischemia due to CAD. Of all people who die within the first month of experiencing CAD symptoms, approximately two-thirds of these people die before reaching the hospital. This highlights the importance of prevention and early recognition of CAD symptoms.

Risk factors for CAD in developed countries are divided into two groups: modifiable and nonmodifiable. Modifiable risk factors include high blood pressure, high cholesterol, smoking, diabetes, excess weight, and sedentary lifestyle. Nonmodifiable risk factors include family history, increased age, and male gender. Approximately 75 percent of heart disease can be attributed to conventional risk factors. Some less recognized risk factors include low socioeconomic status, mental illness, stress, alcohol, excess blood homocysteine, and inflammation. Those in developing countries face an even greater burden of risk factors in the fact that they also have to contend with low birth weight and folate [Page 814]deficiency due to malnutrition and communicable diseases, as well as the other risk factors.

...