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Heart disease is a leading cause of death worldwide, with approximately 16.7 million heart disease-related deaths each year. While the majority of people consider heart disease as a single condition, heart disease should be considered as a group of conditions affecting both the structures and functions of the heart. Moreover, each of these heart conditions has their own distinct causes and symptoms. Understanding the characteristics, causes and symptoms of each of these conditions is the first step in reducing the global burden of heart disease.
The following article provides a detailed and comprehensive description of common heart diseases such as coronary heart disease, angina, rheumatic heart disease, hypertensive heart disease and inflammatory heart disease, as well as, a small discussion of common congenital heart diseases.
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Coronary heart disease
Coronary artery disease (CAD) is the most common form of heart disease. It also has the highest death toll, with approximately 7.2 million deaths worldwide in 2002. It occurs when arteries in the heart are blocked. This can lead to complications such as, angina, chest pain caused by a reduction in the heart’s oxygen availability, or heart attack, complete abolishment of the heart’s oxygen supply causing the death of some of the heart muscles.
The major cause of CAD is atherosclerosis, the build up of sticky, yellow plaque composed of fatty substances such as cholesterol, as well as calcium and waste products from the cells along the wall of blood vessels. This build-up narrows and clogs the arteries, which in turn slows blood flow. This is an ongoing process throughout an individual’s lifetime and it can begin as early as childhood. While all arteries can be affected by this process, it usually affects large and medium-sized arteries. When the plaque grows too big it can completely block the blood flow and cause a heart attack or stroke. Moreover, plaques can also cause arterial ruptures. Following a rupture, the body creates blood clots to repair these vessel wounds. This clot, however, can block the artery and also lead to either a heart attack or stroke.
The early warning signs of CAD include: fatigue, pain and dizziness. However, other symptoms such as angina-associated symptoms (a squeezing, suffocating or burning feeling in of the chest starting in the center of the chest, but it can spread to the arms, neck, back, throat or jaw). If CAD is left untreated, it can lead to more serious problems such as heart attack, stroke or even death.
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Angina (also called angina pectoris) is a condition characterized by a decreased blood flow resulting in reduced oxygen availability due to a blockage of one or more of the coronary arteries. This blockage causes pain in the chest that is commonly described as being squeezing, suffocating or burning. While angina can be mistaken for a heart attack, it is not. It is the heart’s way of telling the body that it is working too hard and it should be considered a warning signal of an elevated risk of a heart attack, cardiac arrest or sudden cardiac death. The pain usually occurs during physical activity, exercise, stress, periods of extreme cold or hot temperatures, after heavy meals, while drinking alcohol or smoking. Usually, this pain goes away with rest and/or medication.
Angina is normally caused by:
- Coronary artery disease stemming from atherosclerosis, a build-up of fatty deposits that block the flow of blood through the coronary arteries
- Coronary artery spasms, one or more of the blood vessels supplying blood to the heart muscle vigorously contracts decreasing or even stopping blood flow
However, in certain cases angina can also be caused by uncontrolled high blood pressure, or other heart conditions such as aortic stenosis, the narrowing of one of the valves in the heart or hypertrophic cardiomyopathy, an enlarged heart.
Angina, itself, is usually a symptom of CAD. However, angina is a group of symptoms that include:
- Pain that starts in the centre of the chest, but can spread to the left arm, neck, back, throat or jaw
- Tightness, pressure, squeezing and/or aching feeling in the chest or arm(s)
- Persistent feeling of moderate to severe indigestion
- Sharp, burning or cramping pain
- An aching pain of the neck, jaw, throat, shoulder, back or arm(s)
- Discomfort of the neck or upper back (particularly between the shoulder blades)
- Loss of feeling (numbness) of the arms, shoulders or wrists
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Rheumatic heart disease
Globally, 300,000 deaths were related to rheumatic heart disease in 2002. While anyone can get acute rheumatic fever, it usually occurs in children between the ages of 5 and 15 years. It is also important to note that about 60% of people with rheumatic fever develop some degree of subsequent heart disease. This condition is described as a group of acute (short-lived) and chronic heart disorders that have rheumatic fever as its primary cause. The most common heart defect associated with rheumatic fever is heart valve damage.
The primary cause of rheumatic heart disease is rheumatic fever, an inflammatory disease that affects the connective tissues of the body such as those of the heart, joints, brain or skin. This condition usually starts from a streptococcal infection or strep throat. Every part of the heart can be damaged by inflammation caused by acute rheumatic fever. However, the most common form of rheumatic heart disease affects the heart valves, particularly the mitral valve, the dual-flap valve that lies between the left atrium and the left ventricle.
The symptoms of rheumatic heart disease-related heart valve problems include: chest pain, excessive fatigue, heart palpitations, a thumping sensation in the chest, shortness of breath and swollen ankles, wrists or stomach. It is important to note that it can take several years after a diagnosis of rheumatic fever before either the development of valve damage to occur or symptoms to appear.
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Hypertensive heart disease
Hypertensive heart disease is the leading cause of illness and death from high blood pressure and was responsible for approximately 900,000 deaths worldwide in 2002. This condition refers to a coronary artery disease, heart failure or enlargement of the heart that is primarily caused by high blood pressure. While high blood pressure can be result of certain conditions or infections such as tumors and/or disease, damage and infection of the kidneys or blood vessels, high blood pressure of unknown origin can also cause hypertensive heart disease. The elevated blood pressure overburdens the heart and blood vessels causing disease.
High blood pressure is the most common risk factor for heart disease and stroke. It can also contribute to the thickening of the blood vessel walls which can also increase the risk of heart attacks and stroke.
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Inflammatory heart disease
Inflammatory heart disease caused approximately 400,000 deaths worldwide in 2002. This condition is caused by the inflammation of the myocarditis (a heart muscle), the pericarditis (the membrane sac surrounding the heart), the endocarditis (the inner lining of the heart) or the myocardium (a heart muscle).
Inflammatory heart disease is primarily caused by toxin or infectious agent induced inflammation of the heart, Moreover, inflammation of an unknown origin can also cause this condition.
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Congenital heart disease
Congenital heart disease occurs at birth, with approximately 1% of live births presenting with a congenital defect. These defects of the heart structures may be caused by genetic factors or by adverse exposures during gestation to factors such as viral infections such as rubella (measles) or drug or alcohol exposure. Examples of these defects include: holes in the heart, abnormal valves, and abnormal heart chambers.
The most common signs and symptoms of congenital heart defects include:
- A heart murmur
- A bluish tint to skin, lips, and fingernails
- Rapid breathing and/or shortness in breath
- Poor feeding and/or weight gain
- Abnormal fatigue during exercise or activity
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Types of congenital heart diseases
There are many types of congenital heart diseases. Listed below are a few commonly occurring congenital conditions.
Stenosis is the narrowing or obstruction of blood vessels resulting in the partial or complete blockage of blood flow. These obstructions can occur in heart valves, arteries or veins.
The child is born with an opening in the septum (the wall that separates the right and left sides of the heart). This allows blood to flow freely between the right and left chambers of the heart instead of its normal flow through the rest of the body. This condition can result in the enlargement of the heart.
Patent ductus arteriosus
The ductus arteriosus, a shunt connecting the pulmonary artery to the aortic arch which allows most of the blood to bypass the fetus' fluid-filled lungs, protecting the lungs from being overworked, is normally closed during birth. In this condition, this shunt fails to close properly, elevating blood flow to the lungs.
In these defects, blood pumped to the body contains less-than-normal amounts of oxygen, causing cyanosis, a blue discoloration of the skin.
Tetralogy of fallot
This condition is characterized by defects that make the level of oxygen in the blood too low. These defects include:
• A large hole in the wall between the two ventricles allowing the mixing of oxygen-poor blood with oxygen-rich blood
• A narrowing of the pulmonary valve, which blocks the flow of blood from the right side of the heart to the lungs
• An increased muscularity of the right ventricle
• An aorta that lies directly over the right ventricle. This allows for oxygen-poor blood to flow directly into the aorta
Transposition of the great arteries
In this condition, the position of the pulmonary artery and the aorta are reversed. Therefore, aorta is connected to the right ventricle. This results in most of the blood returning to the heart from the body being pumped back into the body without first being re-oxygenated by the lungs. Moreover, the pulmonary artery is connected to the left ventricle, so that most of the blood returning from the lungs continuously cycles back to the lungs and not to the rest of the body.
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World Health Organization - http://www.who.int/cardiovascular_diseases/resources/atlas/en/
Heart and Stroke Foundation -http://www.heartandstroke.com/site/c.ikIQLcMWJtE/b.3682421/k.48B/Heart_disease__What_is_heart_disease.htm
National Institute of Health - http://www.nlm.nih.gov/medlineplus/ency/article/000163.htm
World Heart Federation - http://www.world-heart-federation.org/cardiovascular-health/heart-disease/different-heart-diseases/