Heart disease encompasses many conditions that affect the cardiovascular system, which includes the heart and blood vessels. The cardiovascular system supplies the entire body with oxygen and nutrient-rich blood.
Types of heart disease include blood vessel diseases such as coronary artery disease, arrhythmias such as atrial fibrillation, heart infections, congenital heart defects, cardiomyopathy, and problems with heart valves. Many types of heart disease can lead to heart failure when the heart can no longer supply enough blood and oxygen to keep all the tissues of the body healthy. Heart disease can cause stroke and myocardial infarction (heart attack). Heart disease is usually chronic and requires lifelong treatment.
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Any disorder that makes the heart pump less effectively or interferes with the passage of blood through the veins and arteries can be considered a type of cardiovascular disease. Most heart disease develops slowly over many years, while other types are congenital (present at birth) or come on suddenly as a result of a blood clot or infection. 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 an enlarged and less effective heart.
Many types of heart disease are caused by the effects of lifestyle factors — poor diet, lack of exercise, smoking — over time. Some people are more likely than others to develop heart disease based on congenital heart defects or the genes they inherited from their parents. Certain diseases raise the risk of developing heart disease. Read more about the causes of heart disease.
Until recently, scientists believed heart disease to be a newer condition — a phenomenon of the modern diet and lifestyle. In 2013, researchers studied the hearts of 137 mummies from four different geographic regions (Egypt, Peru, the American southwest, and the Aleutian Islands) using CT imaging. They discovered evidence of atherosclerosis (clogged arteries) in 34 percent of the mummies studied, leading them to conclude in a study published in The Lancet that heart disease was common in premodern times.
The first description of atherosclerosis was written by artist Leonardo da Vinci in the early 1500s. In addition to producing famous works of art, da Vinci studied anatomy and illustrated medical textbooks. In 1628, English physician William Harvey published the earliest detailed descriptions of the heart’s circulation system and valves in De Motu Cordis. This publication energized the medical community to begin studying the heart in depth.
The invention of new tools enabled a greater understanding of the heart and its diseases. The 19th century brought critical discoveries such as French doctor René Laennec’s invention of the stethoscope in 1819. In the same year, English botanist William Withering introduced the medical use of digitalis, a compound derived from the foxglove plant and still in use as digoxin. The electrocardiogram (EKG or ECG) — a vital tool for monitoring heart rhythm and diagnosing many heart conditions — was developed in the late 1860s soon after the advent of electricity. In 1895, German physicist Wilhelm Röntgen created the first X-ray machine.
The pulmonary arteries could not be examined in a living person until the procedure for cardiac catheterization was developed. In 1929, German physician Werner Theodor Otto Forssmann developed the catheterization process and tested it on himself. Forssmann inserted the first catheter into his own arm and guided it into his heart. Forssmann’s discovery was largely ignored by the scientific community at the time, but in 1956, he received the Nobel Prize for his work on cardiac catheterization. Cardiac catheterization is a vital procedure for diagnosing many types of heart disease and can even be used to place stents.
The visualization of heart disease made a leap with the introduction of coronary arteriography in 1958. Cardiologist Mason Sones developed coronary arteriography imaging by injecting contrast media into the coronary arteries during his work at Cleveland Clinic. Today, doctors use coronary angiography to diagnose and determine treatments for many types of heart disease.
Beginning in the 1960s, cardiologists launched new protocols for people with suspected myocardial infarctions (MIs or heart attacks). The creation of coronary care units (CCUs) in hospitals, the use of continuous EKG monitoring, closed chest cardiac resuscitation, and external defibrillation helped revolutionize the treatment of acute heart disease. CCUs alone reduced in-hospital deaths by half among patients admitted with heart attacks.
In 1963, American doctor Bruno Balke developed the six-minute walk test to classify the severity of symptoms in individuals with cardiovascular or pulmonary conditions. The longer the distance an individual is able to walk in six minutes without symptoms, the milder the disease severity will be. This test is still used today to determine the functional class of some diseases and track treatment efficacy and disease progression.
Surgical and medical treatments for heart disease made significant advances in the second half of the 20th century. The first human heart transplant was performed in 1967 by South African surgeon Christiaan Barnard. In the 1970s, large-scale clinical trials found effective medications to reduce the risk of death from heart disease such as aspirin, cholesterol-lowering drugs, beta-blockers, and angiotensin-converting enzyme (ACE) inhibitor drugs. The first stent was inserted into a human artery in 1986 by French physicians Jacques Puel and Ulrich Sigwart. The stent was approved by the U.S. Food and Drug Administration in 1993 to open collapsed or clogged arteries. The use of stents quickly became popular, and as of 2007, 2 million stents are placed each year.
At its peak in 1960, heart disease was the cause of death in one-third of Americans. Researchers saw a 20 percent drop in heart disease deaths between 1968 and 1978 due to many factors — improved education about smoking, diet, and other risk factors; improvement in medical care, better control of hypertension, the development of coronary care units, the use of stents, and the creation of Medicare and Medicaid. Heart disease deaths have dropped 60 percent since 1960. In recent years, however, doctors have become alarmed that deaths due to heart disease may be rising again due to the increasing rate of obesity, which has risen by 50 percent since 1960.
In the United States, approximately 84 million people, or about 25 percent of the population, have a form of heart disease. Many people with heart disease — especially hypertension — are likely undiagnosed. The risk of heart disease in women begins to rise at age 55 or at menopause. Men often develop heart disease 10 years earlier than women, in their 40s. The risk for both men and women continues to rise with age.
Heart disease is the leading cause of death in the U.S., responsible for about 25 percent of all deaths. Heart disease kills more people than all types of cancer combined. Heart disease is treatable — medications, surgery, and lifestyle changes can help people with heart disease slow the condition’s progress, avoid serious complications, and lower the risk of death.