- Types of Heart Disease
- Risk Factors
Facts you should know about heart health and heart attack prevention
- Coronary atherosclerosis is the hardening and narrowing of the arteries that supply blood to the heart muscle.
- Coronary atherosclerosis is the major cause of a heart attack (myocardial infarction). Heart attacks are the major cause of sudden unexpected death among otherwise healthy adults in the prime of their lives.
- Heart attacks are also a significant cause of heart failure (due to weakened heart muscle) in the U.S.
- Heart failure considerably decreases a person's longevity and quality of life. In dollar terms, coronary heart disease is costly.
- The total cost of coronary artery bypass surgery, coronary angioplasty and stenting, medications, and hospitalizations exceeds 50 billion dollars annually.
- Coronary atherosclerosis, and hence heart attacks, are preventable.
- A person can significantly lower his or her risk of heart attack by:
- In recent years, other risk factors for coronary atherosclerosis have been identified. These include patients with a high serum homocysteine level and certain subtypes of LDL cholesterol.
- Cardiovascular disease can be diagnosed and treated by doctors.
- The following is an article review of the signs, symptoms, risks, and causes of atherosclerosis and heart attacks, and the means for their prevention.
What is atherosclerosis, and how does it cause a heart attack?
- Atherosclerosis is a gradual process whereby hard cholesterol substances (plaques) are deposited in the walls of the arteries.
- Cholesterol plaques cause hardening of the artery walls and narrowing of the inner channel (lumen) of the artery.
- Arteries carry blood enriched with oxygen and nutrients to the vital organs such as the brain, heart, kidneys, and liver.
- Arteries also transport blood to other tissues such as the fingers, toes, nerves, bones, skin, and muscles.
- Healthy arteries can deliver an ample supply of blood to the organs and tissues.
- In contrast, arteries narrowed by atherosclerosis have difficulty delivering blood to the parts of the body they supply. For example, atherosclerosis of the arteries in the legs causes poor circulation in the lower extremities. Poor circulation in the lower extremities can lead to symptoms of pain while walking or exercising, slow wound healing, and leg ulcers.
- Atherosclerosis also can cause the complete blockage of an artery from a blood clot. This complete blockage interrupts oxygen supply and results in tissue injury or death. Thus, the blockage of an artery that furnishes blood to the brain can lead to a stroke (death of brain tissue). Likewise, the blockage of the arteries to the heart can result in a heart attack (death of heart muscle), also called myocardial infarction (MI).
How early in life does the coronary atherosclerosis heart disease process begin?
- Although the coronary arteries are wide open at birth, the atherosclerosis process begins early in life. Between the ages of 10 and 20, "fatty streaks" are already being deposited on the inner lining of the coronary arteries. Over the years, some of these fatty streaks grow into larger cholesterol plaques that can protrude into the artery interior space (lumen) and harden the artery walls. Many men and women between the ages of 20 and 30 typically are unaware their coronary arteries are gradually accumulating cholesterol plaques. By ages 40 to 50, many people have developed enough damage to put them at risk for coronary heart disease.
When should you start making changes to prevent a heart attack?
Atherosclerosis prevention should start early, preferably during childhood and adolescence. Most scientists believe preventing atherosclerosis is more effective than trying to reverse established blockages or getting rid of plaques in the arteries. Children and adolescents should be taught heart healthy lifetime habits of regular exercise, quitting smoking, and good nutrition. Many men and women do not take adequate steps to prevent atherosclerosis. Reasons for this failure include:
- Lack of awareness that they already have coronary atherosclerosis heart disease, and ignorance that coronary atherosclerosis and heart attacks are preventable
- Lack of awareness of their blood cholesterol levels and profiles
- Unwillingness or inability to quit cigarette smoking
- High blood pressure or type 2 diabetes that are either undiagnosed or inadequately controlled
- Lack of exercise, an excess of fat and cholesterol in their diet, and an inability or unwillingness to lose excess weight
- Failure to take full advantage of medications that improve cholesterol levels, often out of fear of potential side effects.
What are the types of coronary heart disease (CHD)?
Atherosclerosis is a condition that refers to the hardening and narrowing of the coronary arteries. The coronary arteries supply the blood that carries oxygen and nutrients to the heart muscle. When coronary arteries are narrowed or blocked by atherosclerosis, they cannot deliver an adequate amount of blood to the heart muscle. Disease caused by the lack of blood supply to heart muscle is called coronary heart disease (CHD). Coronary heart diseases include:
- Heart attack (myocardial infarction)
- Sudden unexpected death
- Chest pain (angina)
- Abnormal heart rhythms
- Heart failure due to weakening of the heart muscle.
- Angina pectoris is chest pain or pressure that occurs when the oxygen supply to the heart muscle cannot keep up with oxygen consumption by the heart muscle. (Oxygen consumption by the heart muscle increases with physical exertion or excitement and decreases with rest and relaxation.) Most commonly, the inadequate supply of oxygen is due to narrowing of the coronary arteries by atherosclerosis heart disease. When coronary arteries are narrowed by more than 50% to 70%, the arteries cannot increase the supply of blood to the heart muscle during exertion or other periods of high oxygen demand. An insufficient supply of oxygen to the heart muscle cause chest pain as a symptom. Chest pain is a symptom that occurs with exercise or exertion is called exertional angina. Patients with angina and its symptoms and signs require medical treatment by a doctor.
- A heart attack (myocardial infarction) is the death of heart muscle due to the sudden and complete blockage of a coronary artery by a blood clot. A coronary artery blockage usually occurs in arteries that contain cholesterol plaques. A plaque can rupture and initiate the formation of a blood clot next to it. A blood clot can completely block blood flow through a coronary artery and deprive the heart muscle of needed nutrients and oxygen. Sections of the heart muscle then die, which produces a heart attack. If a person suffering from heart attack and its symptoms and signs require medical treatment by a doctor.
- A heart attack can trigger the sudden onset of ventricular fibrillation. Ventricular fibrillation is a chaotic electrical rhythm of the heart that causes cardiac arrest (the heart stands still and ceases to pump blood). Ventricular fibrillation causes permanent brain damage and death unless a normal heartbeat can be restored within five minutes of its onset. Of the one million Americans who suffer heart attacks annually, an estimated 326,000 Americans experience sudden cardiac arrest, including ventricular fibrillation, each year before the victims can reach any medical assistance. For 90% of these people, the first sign of coronary heart disease is sudden, unexpected death. Patients with ventricular fibrillation and its symptoms and signs require medical treatment by a doctor.
- Unlike angina, a heart attack results in permanent damage of the heart muscle. After a heart attack, the damaged portion of the heart is left with a scar. If the amount of heart muscle damage and the area of scarring are small, the performance of the heart as a pump will not be significantly impaired. However, repeated heart attacks or a heart attack with extensive heart muscle damage can weaken the heart and cause heart failure. People with heart failure experience signs and symptoms of shortness of breath, poor exercise tolerance, and lack of energy because their weakened heart muscle cannot pump enough blood to keep their bodies healthy and active. Patients with heart failure and its signs and symptoms require medical treatment by a doctor.
What is cerebral vascular disease?
Cerebral vascular disease is caused by the reduced supply of blood to the brain. Examples of cerebral vascular disease include conditions such as ischemic strokes, hemorrhagic strokes, and transient ischemic attacks and are provided.
- An ischemic stroke is the sudden and permanent death of brain cells that occurs when the flow of blood to a part of the brain is blocked and oxygen cannot be delivered to the brain. Depending on the part of the brain that is affected, strokes can result in signs and symptoms of weakness or paralysis of the arms, legs, and/or facial muscles, loss of vision or speech, and difficulty walking.
- Ischemic strokes most commonly occur when clots form in small arteries within the brain (known as thrombosis of the artery) that have been previously narrowed by atherosclerosis. The resulting strokes are called lacunar strokes because they look like small lakes. In some cases, blood clots can obstruct a larger artery going to the brain, such as the carotid artery in the neck, causing more extensive brain damage than lacunar strokes.
- A second less common type of ischemic stroke occurs when a piece of a clot breaks loose, for example, from the carotid artery or heart, travels through the arteries, and lodges in an artery within the brain. This type of stroke is referred to as an embolic stroke and occurs commonly as a result of an irregular heart rhythm such as atrial fibrillation, that causes blood clots to form within the heart. Patients with ischemic stroke and its signs and symptoms require medical treatment by a doctor.
- A hemorrhagic stroke occurs when a blood vessel in the brain ruptures, and blood leaks into the surrounding brain tissue. A hemorrhagic stroke, like an ischemic stroke, causes the death of tissue by depriving the brain of blood and oxygen. The accumulation of blood from the hemorrhage also can put pressure on adjacent parts of the brain and damage them as well.
- A subarachnoid hemorrhage is a rupture of a blood vessel that is located between the outer surface of the brain and the inside of the skull. The blood vessel at the point of rupture often has been weakened by the development of an aneurysm (an abnormal ballooning of the wall of the blood vessel). Subarachnoid hemorrhages usually cause a sudden, severe headache and often are complicated by additional neurological problems, such as paralysis, coma, and even death. If a person is having a hemorrhagic stroke and its signs and symptoms require medical treatment by a doctor.
Transient ischemic attack (TIA, mini-stroke)
- A transient ischemic attack (TIA) often is referred to as a mini-stroke. TIAs are caused by the temporary reduction in flow of blood (ischemia) to the brain and is most often caused by a clot that spontaneously forms in a carotid artery. Patients with TIA's often have narrowed (or, less often, ulcerated) carotid arteries due to atherosclerosis. TIAs typically last 2 to 30 minutes, although signs and symptoms sometimes can last 24 hours and can produce problems with vision, dizziness, weakness of the arms or legs, and trouble speaking.
- A TIA is different condition from a stroke in that it does not cause permanent death of brain tissue. Without treatment, however, patients with TIAs are at high risk for having a stroke with permanent damage to the brain. If a person is having a transient ischemic attacks and its signs and symptoms it require medical treatment by a doctor.
What are the risk factors for heart attack?
Well-known risk factors for coronary atherosclerosis and heart attacks include:
- Elevated levels of LDL cholesterol (the "bad" cholesterol) in the blood
- Family history of early coronary heart disease, including a heart attack or sudden death before age 55 in the father or other male first-degree relative, or before age 65 in the mother or other female first-degree relative
- Cigarette smoking
- Diabetes mellitus
- High blood pressure
- Low levels of HDL (the "good" cholesterol) in the blood
- Sedentary lifestyle
Less recognized but just as important risk factors for coronary atherosclerosis are:
- A large number of small LDL cholesterol particles in the blood. LDL cholesterol particles come in different sizes. The size of a person's LDL cholesterol particles is predominantly genetically inherited. The smaller LDL cholesterol particles are far more dangerous in causing atherosclerosis than the larger particles. The smaller LDL particles can penetrate the walls of the arteries more easily than the larger LDL particles. A person with an abundance of small LDL cholesterol particles in the blood has a significantly higher risk of heart attack and coronary atherosclerosis than someone with larger LDL cholesterol particles in their blood.
- Abnormally elevated blood levels of lipoprotein A, (Lp[a]). Lp(a) is an LDL cholesterol particle that is linked chemically to a protein called apo(a). The level of Lp(a) in the blood is als genetically inherited. Men and women with elevated blood levels of Lp(a) have significantly higher rates of coronary atherosclerosis and heart attacks.
- Elevated homocysteine levels in the blood. Homocysteine is a metabolic by-product of animal protein. Tests are now available to measure homocysteine levels in the blood, which helps in diagnosing heart health problems. Higher homocysteine levels in the blood are associated with atherosclerosis in coronary arteries and carotid arteries (arteries that supply blood to the brain).
Is it possible to prevent coronary atherosclerosis and heart attacks?
Atherosclerosis and the risk of heart attacks can be prevented in these ways:
- Control high blood pressure and diabetes mellitus
- Don't smoke or quitting cigarette smoking
- Get regular exercise regularly
- Lose excess weight
- Lower blood levels of LDL cholesterol (the "bad" cholesterol)
- Increase blood levels of HDL cholesterol (the "good" cholesterol)
- Take anti-platelet medications (such as low dose aspirin) to prevent blood clots
Many of the measures that prevent coronary atherosclerosis also benefit other arteries such as carotid arteries and cerebral arteries (arteries that supply blood to the brain). Therefore, these measures also prevent strokes.
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