Heart disease can affect any part of the heart or its blood vessels (coronary arteries). Types of heart disease are categorized based on which part of the heart is affected or by the cause of the disease. It is common to have more than one type of heart disease — in fact, some types of heart disease can directly cause another type. For instance, hypertension (high blood pressure) makes the heart work harder and can cause atherosclerosis (fatty plaques that narrow the arteries) and cardiomyopathy (heart muscle disease).
It helps to know a little about the anatomy of the heart and how it works. There are four heart chambers — two atria (left and right) on top and two ventricles (left and right) below them. The right atrium receives oxygen-depleted blood from the body and moves it into the right ventricle, which pumps it into the lungs to receive fresh oxygen. The left atrium receives freshly oxygenated blood from the lungs and moves it into the left ventricle — the largest and most powerful chamber of the heart — which pumps the blood around the body.
There are four heart valves — mitral, aortic, tricuspid and pulmonary — that control the flow between each chamber of the heart. The valves open to allow forward flow and snap shut to prevent backward flow.
The heart’s rhythm is controlled by collections of cells that produce electrical impulses. The most prominent of these is the sinoatrial (SA) node, which is the heart’s natural pacemaker. The electrical impulse originates at the SA node and travels down nerves to the atrioventricular node (AV node), ensuring that each chamber of the heart beats in a regular rhythm that allows for effective blood flow.
The vascular system is made up of arteries — which carry blood away from the heart to all the tissues of the body — and veins, which bring blood back to the heart. The coronary arteries supply the heart itself with oxygen and nutrients.
Diseases of the blood vessels, also called vascular diseases, are very common. Blood vessel disease does not usually cause symptoms until it has caused significant permanent damage. Smoking, a diet high in saturated (animal) fats, lack of exercise, and inherited factors all raise the risk for developing vascular disease.
Hypertension (high blood pressure) silently damages organs and causes resistance that makes the heart work harder. About one-third of adults in the U.S. have hypertension, and only about half of those control it with treatment. Hypertension contributes directly to the development of many other types of heart disease and raises the risk for stroke and myocardial infarction (MI, or heart attack).
In atherosclerosis, fatty plaques develop in the arteries. As the arteries become narrower, blood pressure rises. Plaques can break off and block arteries, causing heart attack or stroke.
Atherosclerosis in the coronary arteries is called coronary artery disease (CAD), the most common cardiovascular disease in the U.S. In CAD, the coronary artery, which supplies the heart, may become narrowed and blocked. Many people with CAD are unaware they have developed the condition until they experience chest pain (angina) or a heart attack.
Peripheral artery disease (PAD) is caused by atherosclerosis in arteries outside the heart, such as the arteries of the legs, arms, stomach, or head. PAD can result in blockages that prevent tissues from receiving blood. PAD can cause intense pain, and blockages can cause tissue death (gangrene). PAD can cause stroke or brain damage, and it can be life-threatening if it develops in the arteries of the head and neck.
An aneurysm is a weak spot in an artery wall that enlarges and bulges out. Aneurysms can occur in any artery. Some aneurysms are congenital (present at birth), while others are caused by hypertension, high cholesterol, and smoking. A ruptured aneurysm is a life-threatening emergency.
Heart valves can become stenotic (too rigid to open fully) or incompetent (too loose to close completely). A stenotic valve causes blood to back up because it cannot let enough blood flow through with each beat. An incompetent valve allows some blood to leak back into the previous chamber with each beat. Both stenosis and incompetence result in ineffective pumping. The mitral and aortic valves are most likely to develop disorders. Some valvular disease is genetic, while other cases are caused by deterioration with age, hypertension, rheumatic fever, or as a late side effect of radiation therapy for cancer.
Heart valve problems can lead to cardiomyopathy, as the heart muscle becomes larger and thicker to compensate. Valvular disorders can also promote infection (endocarditis) and blood clots, which may cause heart attack or stroke.
Valvular heart problems include:
The rhythm of the heart is controlled by electrical impulses. Any change to the heart’s normal rhythm can lead to ineffective heart pumping. Arrhythmia can also lead to a stroke or heart attack. Arrhythmia can be caused by damage to the heart’s natural pacemaker (sinoatrial or SA node), for instance during a heart attack. Arrhythmia may also be due to interruptions to the way electrical impulses are communicated through the heart or abnormal impulses originating from another part of the heart.
Tachycardia refers to a faster-than-normal heartbeat, while bradycardia is a slower-than-normal rhythm. Fibrillation is a rapid, irregular heartbeat. Types of arrhythmia include:
Cardiomyopathy is a disease of the heart muscle that can be caused by hypertension, heart attack, alcoholism, drug abuse, valvular heart disease, or arrhythmia. Cardiomyopathy can also be inherited or caused by alcoholism or as a late side effect of chemotherapy for cancer. Types of cardiomyopathy include:
Inflammatory heart conditions are less common types of heart disease. Heart inflammation can be caused by a viral, bacterial, or fungal infection, by an autoimmune attack on heart tissues, or the cause may be unknown. Inflammatory heart conditions may not be chronic, but they can cause damage to heart tissues that leads to chronic heart problems. Endocarditis is the most common type of heart inflammation. Endocarditis involves inflammation of the inner lining of the heart as well as the valves.
Myocarditis is inflammation of the heart muscle. Pericarditis is inflammation of the pericardium, a sac that surrounds and protects the heart.
In the U.S., approximately 1 percent of people are born with congenital heart defects. About 25 percent of those born with congenital heart defects require surgery within their first year of life; subsequent surgeries and medications may be necessary. Some congenital heart defects are mild and do not produce symptoms until later in childhood or adolescence. As treatments improve, the life expectancy of people born with congenital heart defects continues to increase. It is estimated that between 2 million and 3 million Americans live with a congenital heart defect.
Congenital heart defects can lead to the development of other types of heart disease. Types of congenital heart defects include atrial septal defects, atrioventricular septal defects, atresia, transposition of the great arteries, truncus arteriosus, and the Tetralogy of Fallot, which involves four separate defects.
Myocardial infarction (MI), also called a heart attack, is a life-threatening complication of heart disease. Heart attacks occur when an artery in the heart becomes blocked and heart tissues do not get enough oxygen. Heart attacks kill tissues in the heart, causing permanent damage to the part of the heart where they occur. Damage caused by heart attacks can lead to arrhythmia and other problems.
Strokes can be caused when arteries in the brain become narrowed or blocked (ischemic stroke), or when there is bleeding in the brain (hemorrhagic stroke). Strokes can be caused by uncontrolled hypertension, atherosclerosis, and excessive dosage with heart disease medications such as blood thinners.
Heart failure, also known as congestive heart failure (CHF), is not a specific heart disease, but an advanced state of heart disease when the heart can no longer supply enough blood and oxygen to keep all the tissues of the body healthy. Many types of heart disease can progress to heart failure.
Pulmonary hypertension (PH) is high blood pressure in the lungs. Some forms of PH are progressive and potentially fatal. Pulmonary hypertension can be caused by heart valve problems or left-side heart failure. Since the lungs and heart are interdependent, PH can cause arrhythmia and problems in the right side of the heart.
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