Heart disease 101
Why it happens, how to avoid it and how it's treated.
Heart disease refers to any disease that affects the coronary arteries, heart valves, muscles and tissues of the heart, or the heart's electrical system.
Some types of heart disease are present at birth. Others may result from infection or injury, and others develop slowly over decades.
The most common type of heart disease is coronary artery disease (CAD), the gradual narrowing of the arteries by the buildup of fatty plaques on artery walls. CAD can lead to many other types of heart disease and to heart attacks. According to the National Heart, Lung, and Blood Institute, CAD is a leading cause of death for American men and women.
About 48% American adults has some form of cardiovascular disease, according to the American Heart Association (AHA).
Risk factors for heart disease include smoking, high blood pressure, high cholesterol, an inactive lifestyle and a family history of heart disease. Your risk is also greater if you have diabetes or are overweight. Heart disease is more common in men than women and is more likely to occur as people get older. Rates are also higher in certain ethnic groups, such as African Americans.
Cholesterol is a soft, waxy, fatlike substance in the blood. Your body needs cholesterol in order to function properly. But millions of Americans have too much cholesterol in their blood. This excess cholesterol can stick to artery walls, narrowing them and making it more difficult for blood to pass through. Eventually an artery may become completely blocked, causing a heart attack or stroke.
Smoking contributes to the buildup of plaque in blood vessels all over the body, including the arteries that lead to the heart, according to the Centers for Disease Control and Prevention. Cigarette smoking also decreases levels of high-density lipoprotein (HDL), or good cholesterol, and increases levels of low-density lipoprotein (LDL), or bad cholesterol. It also increases blood pressure.
Healthy blood vessels are muscular and elastic and give easily when blood surges through them with each heartbeat. But less healthy vessels become stiff and won't give easily when blood moves through them. As a result the blood puts excess pressure on the artery walls. This is known as high blood pressure, and it means the heart has to work extra hard to move blood through the arteries. High blood pressure is a major risk factor for both heart attack and stroke.
Blood pressure readings include two numbers. The higher number, called systolic pressure, is your blood pressure when your heart beats. The lower number, known as diastolic pressure, is your blood pressure when your heart rests. Both are measured in millimeters of mercury (mm Hg).
You have high blood pressure if you consistently have a systolic pressure of 130 or higher or a diastolic pressure of 80 or higher. The threshold for high blood pressure may be different for people with some chronic diseases.
A heart attack occurs when blood supply to the heart is severely reduced or cut off completely. This means a section of the heart is being starved of the oxygen it needs to survive.
Symptoms of a heart attack can include nausea, vomiting, shortness of breath, and pressure or pain in the chest that may reach into the arm or jaw.
A heart attack can lead to permanent heart muscle damage or to death. The AHA recommends calling 911 immediately if you have heart attack symptoms. Rapid treatment can save heart muscle or your life.
Several tests can be used to diagnose heart disease. Electrocardiograms, also known as ECGs or EKGs, can show if the heart is beating normally. A variety of imaging tests can create pictures that show areas of damage to heart muscle or narrowed arteries.
A long, thin tube called a catheter can also be used to measure blood flow in the heart, take samples of blood from the heart and measure the blood pressure inside the heart. The same catheter can be used to inject a special dye that shows up on x-rays, creating a detailed image of blood flow to and inside the heart.
Exercise stress testing can also be done to see how the heart responds when you walk, jog or ride a stationary bike.
Heart disease may be treated with medicines to reduce risk factors such as high blood pressure and high blood cholesterol or with medicines that make it easier for the heart to pump effectively. In some cases, a procedure or surgery to improve blood flow to the heart may be recommended. A procedure called angioplasty widens narrowed arteries using a catheter with a tiny balloon on the tip. The tube is threaded into the artery to the narrowed section, and the balloon is inflated to widen the artery.
Coronary artery bypass surgery creates a new pathway for blood headed toward the heart. A surgeon uses blood vessels from another part of the body, attaching them above and below the narrowed or blocked artery.
Healthy lifestyle choices such as eating right, not smoking and getting regular physical activity are an important part of any heart disease treatment plan.
You can reduce your risk of heart disease by choosing a heart-healthy lifestyle that includes:
- At least 30 minutes of moderate-intensity activity five or more days per week if you are a healthy adult between the ages of 18 and 65. (Be sure to get your doctor's approval first.)
- A diet rich in fruits, vegetables, grains and low-fat sources of protein. The AHA recommends limiting saturated fat to less than 6% of daily calories, replacing trans fats with monounsaturated or polyunsaturated fats, and limiting sodium to less than 1,500 milligrams each day.
- Not smoking.
- Getting regular screenings for high blood pressure and high cholesterol.