Heart attack

A heart attack also known as a myocardial infarction is the death of the heart muscle from the sudden blockage of a coronary artery by a blood clot. Coronary arteries are blood vessels that supply the heart muscle with the blood and oxygen. Blockage of a coronary artery deprives the heart muscle of blood and oxygen causing injury of the heart muscle. Injury of the heart muscle causes chest pain and chest pressure sensation. If blood flow is not restored to the heart muscle within 20 to 40 minutes irreversible death of the heart muscle will begin to occur. Muscle continues to die for 6 to 8 hours at which time the heart attack usually is “complete”. The dead heart muscle is eventually replaced by scar tissue.

Approximately 1 million Americans suffer a heart attack each year. Four hundred thousand of them die as a result of their heart attack.

What causes a heart attack?

Atherosclerosis. It is a gradual process by which plaques (collections) of cholesterol are deposited in the walls of arteries. Cholesterol plaques cause hardening of the arterial walls and narrowing of the inner channel (lumen) of the artery. Arteries that are narrowed by atherosclerosis cannot deliver enough blood to maintain normal function of the parts of the body they supply. For example, atherosclerosis of the arteries in the legs causes reduced blood flow to the legs. Reduced blood flow to the legs can lead to pain in the legs while walking or exercising, leg ulcers, or a delay in the healing of wounds to the legs. Atherosclerosis of the arteries that furnish blood to the brain can lead to vascular dementia (mental deterioration due to gradual death of brain tissue over many years) or stroke (sudden death of brain tissue).

In many people atherosclerosis can remain silent (causing no symptoms or health problems) for years or decades. Atherosclerosis can begin as early as the teenage years but symptoms or health problems usually do not arise until later in adulthood when the arterial narrowing becomes severe. Smoking cigarettes, high blood pressure, elevated cholesterol, and diabetes mellitus can accelerate atherosclerosis and lead to the earlier onset of symptoms and complications particularly in those people who have a family history of early atherosclerosis.

Coronary atherosclerosis (or coronary artery disease) refers to the atherosclerosis that causes hardening or narrowing of the coronary arteries. Diseases caused be the reduced blood supply to the heart muscle from coronary atherosclerosis are called coronary heart diseases (CHD). They include heart attacks, sudden unexpected death, chest pain (angina), abnormal heart rhythms, and heart failure due to weakening of the heart muscle.

Atherosclerosis and angina pectoris. Angina pectoris (also referred to as angina) is chest pain or pressure that occurs when the blood and oxygen supply to the heart muscle cannot keep up with the needs of the muscle. When coronary arteries are narrowed by more than 50 to 70 percent the arteries may not be able to supply of blood to the heart muscle during exercise or other periods of high demand for oxygen. An insufficient supply of oxygen to the heart muscle causes angina. Angina that occurs with exercise or exertion is called exertional angina. In some patients especially diabetics the progressive decrease in blood flow to the heart may occur without any pain or with just shortness of breath or usually early fatigue.

Exertional angina usually feels like a pressure, heaviness, squeezing, or aching across the chest. This pain may travel to the neck, jaw, arms, back, or even the teeth and may be accompanied by shortness of breath, nausea, or a cold sweat. Exertional angina typically lasts from 1 to 15 minutes and is relieved by rest or by taking nitroglycerin by placing a tablet under the tongue. Both resting and nitroglycerin decrease the heart muscle’s demand for oxygen thus relieving angina. Exertional angina may be the first warning sign of advanced coronary artery disease. Chest pains that last a few seconds are rarely due to coronary artery disease.

Angina can also occur at rest. Angina at rest more commonly indicates that a coronary artery has narrowed to such a critical degree that the heart is not receiving enough oxygen even at rest. Angina at rest infrequently may be due to spasm of a coronary artery (a condition called Prinzmetal’s or variant angina). Unlike a heart attack there is no permanent muscle damage with either exertional or rest angina.

Atherosclerosis and heart attack. Occasionally the surface of a cholesterol plaque in a coronary artery may rupture and a blood clot forms on the surface of the plaque. The clot blocks the flow of blood through the artery and results in a heart attack. The cause of rupture that leads to the formation of a clot is largely unknown but contributing factors may include cigarette smoking or other nicotine exposure, elevated LDL cholesterol, elevated levels of blood catecholamines (adrenaline), high blood pressure, and other mechanical and biochemical forces.

Unlike exertional or rest angina heart muscle dies during a heart attack and loss of the muscle is permanent unless blood flow can be promptly restored usually within 1 to 6 hours.

While heart attacks can occur at any time more heart attacks occur between 4.00 A.M. and 10.00 A.M. because of higher blood levels of adrenaline released from the adrenal gland during the morning hours. Increased adrenaline as previously discussed may contribute to rupture of cholesterol plaques.

Approximately 50% of patients who develop heart attacks have warning symptoms such as exertional angina or rest angina prior to their heart attacks but these symptoms may be mild and discounted.

What are the symptoms of a heart attack? Although chest pain or pressure is the most common symptom of a heart attack, heart attack victims may experience a variety of symptoms including pain, fullness, and squeezing sensation of the chest; jaw pain, toothache, headache, shortness of breath, nausea, vomiting, and general epigastric (upper middle abdomen) discomfort; sweating, heartburn, and indigestion; arm pain (more commonly the left arm but may be the either arm), upper back pain, general malaise (vague feeling of illness); no symptoms (approximately one quarter of all heart attacks are silent without chest pain or new symptoms). Silent heart attacks are especially common among patients with diabetes mellitus.

Even though the symptoms of a heart attack at times can be vague and mild, it is important to remember that heart attacks producing no symptoms or only mild symptoms can be just as serious and life-threatening as heart attacks that cause severe chest pain. Too often patients attribute heart attack symptoms to “indigestion” or “stress” and consequently delay seeking prompt medical attention. One cannot overemphasize the importance of seeking prompt medical attention in the presence of symptoms that suggest a heart attack. Early diagnosis and treatment saves lives and delays in reaching medical assistance can be fatal. A delay in treatment can lead to permanently reduced function of the heart due to more extensive damage to the heart muscle. Death may also occur as a result of a sudden onset of arrhythmia such as ventricular fibrillation.

What are the complications of a heart attack?

Heart failure. When a large amount of heart muscle dies the ability of the heart to pump blood to the rest of the body is diminished and this can result in heart failure. The body retains fluid, and organs, for example the kidneys, begin to fail.

Ventricular fibrillation. Injury to heart muscle can also lead to ventricular fibrillation. It occurs when the normal, regular, electrical activation of heart muscle contraction is replaced by chaotic electrical activity that causes the heart to stop beating and pumping blood to the brain and other parts of the body. Permanent brain damage and death can occur unless the flow of blood to the brain is restored within five minutes. Most of the deaths from heart attacks are caused by ventricular fibrillation of the heart that occurs before the victim of the heart attack can reach an emergency room. Those who reach the emergency room have an excellent prognosis; survival from a heart attack with modern treatment should exceed 90%. The 1 to 10% of heart attack victims who later die frequently had suffered major damage to the heart muscle initially or additional damage at a later time.

Death from ventricular fibrillation can be avoided by cardiopulmonary resuscitation (CPR) started within five minutes of the onset of ventricular fibrillation. CPR requires breathing for the victim and applying external compression to the chest to squeeze the heart and force to pump blood. In 2008 The American Heart Association modified the mouth-to mouth instruction of CPR and recommends that chest compressions alone are effective if a bystander is reluctant to do mouth-to-mouth. When paramedics arrive medications and an electrical shock (cardioversion) can be administered to convert ventricular fibrillation back to a normal heart rhythm and allow the heart to pump blood normally. Therefore, prompt CPR and rapid response by paramedics can improve the chances of survival from a heart attack. In addition, many public venues now have automatic external defibrillators (AEDs) that provide the electric shock needed to restore a normal heart rhythm even before the paramedics arrive. This greatly improves the chances for survival.

What are the risk factors for atherosclerosis and heart attack? Factors that increase the risk of developing atherosclerosis and heart attacks include increased blood cholesterol, high blood pressure, use of tobacco, diabetes mellitus, male gender, and a family history of coronary heart disease. While family history and male gender are genetically determined the other risk factors can be modified through changes in lifestyle and medications.

High blood cholesterol (hyperlipidemia). A high level of cholesterol in the blood is associated with an increased risk of heart attack because cholesterol is the major component of plaques deposited in arterial walls. Cholesterol, like oil, cannot dissolve in the blood unless it is combined with special proteins called lipoproteins. Without combining with lipoproteins cholesterol in the blood would turn into a solid substance. Cholesterol in the blood is either combined with lipoproteins as very low-density lipoproteins (VLDL), low-density lipoproteins (LDL), or high-density lipoproteins (HDL).

Cholesterol that is combined with LDL (LDL cholesterol) is the “bad” cholesterol that deposits cholesterol in arterial plaques. Thus, elevated levels of LDL cholesterol are associated with an increased risk of heart attack.

Cholesterol that is combined with HDL (HDL cholesterol) is the “good” cholesterol that removes cholesterol from arterial plaques. Thus, low levels of HDL cholesterol are associated with an increased risk of heart attacks.

Measures that lower LDL cholesterol and increase HDL cholesterol (losing excess weight, diets low in saturated fats, regular exercise, and medications) have been shown to lower the risk of heart attack. One important class of medications for treating elevated cholesterol levels (the statins) have actions in addition to lowering LDL cholesterol which also protect against heart attack. Most patients at high risk for a heart attack should be on a statin no matter what the levels of their cholesterol are.

High blood pressure (hypertension). High blood pressure is a risk factor for developing atherosclerosis and heart attack. Both high systolic pressure (when the heart beats) and high diastolic pressure (when the heart is at rest) increase the risk o heart attack. It has been shown that controlling hypertension with medications can reduce the risk of heart attack.

Tobacco use (smoking). Tobacco and tobacco smoke contain chemicals that cause damage to blood vessel walls, accelerate the development of atherosclerosis, and increase the risk of heart attack.

Diabetes mellitus. Both insulin dependent and non-insulin dependent diabetes mellitus (type 1 and 2 respectively) are associated with accelerated atherosclerosis throughout the body. Therefore, patients with diabetes mellitus are at risk for reduced blood flow to the legs, coronary heart disease, erectile dysfunction, and strokes at an earlier age than non-diabetic subjects. Patients with diabetes can lower their risk through rigorous control of their blood sugar levels, regular exercise, weight control, and proper diets.

Male gender. At all ages men are more likely than women to develop atherosclerosis and coronary heart disease. Some scientists believe that this difference is partly due to the higher blood levels of HDL cholesterol in women than in men. However, this gender difference narrows as men and women grow older.

Family history of heart disease. Individuals with a family history of coronary heart diseases have an increased risk of heart attack. Specifically, the risk is higher if there is a family history of early coronary heart disease including a heart attack or sudden death before the age of 55 in the father or other first-degree male relative or before the age of 65 in the mother or other first-degree female relative.

How is a heart attack diagnosed? When there is a severe chest pain suspicion that a heart attack is occurring is usually high and tests can be performed quickly that will confirm the heart attack. A problem arises, however, when the symptoms of a heart attack may not be suspected and the appropriate tests may not be performed. Therefore, the initial step in diagnosing a heart attack is to be suspicious that one has occurred.

Electrocardiogram. An electrocardiogram (ECG) is a recording of the electrical activity of the heart. Abnormalities in the electrical activity usually occur with heart attacks and can identify the areas of heart muscle that are deprived of oxygen and areas of muscle that have died. In a patient with typical symptoms of heart attack such as crushing chest pain and characteristic changes of heart attack on the ECG a secure diagnosis of heart attack can be made quickly in the emergency room and treatment can be started immediately. If a patient’s symptoms are vague or atypical and if there are pre-existing ECG abnormalities, for example, from old heart attacks or abnormal electrical patterns that make interpretation of the ECG difficult, the diagnosis of a heart attack may be less secure. In these patients the diagnosis can be made only hours later through detection of elevated cardiac enzymes in the blood.

Blood tests. Cardiac enzymes are proteins that are released into the blood by dying heart muscles. These cardiac enzymes are creatine phosphokinase (CPK), special subfractions of CPK and troponin and their levels can be measured in blood. These cardiac enzymes are typically elevated in the blood several hours after the onset of a heart attack. A series of blood tests for enzymes performed over a 24-hour period are useful not only in confirming the diagnosis of heart attack but the changes in their levels over time also correlates with the amount of heart muscle that has died.

The most important factor in diagnosing and treating a heart attack is prompt medical attention. Rapid evaluation allows early treatment of potentially life-threatening abnormal rhythms such as ventricular fibrillation and allows early reperfusion (return of blood flow to the heart muscle) by procedures that unclog the blocked coronary arteries. The more rapidly the blood flow is reestablished, the more heart muscle that is saved.

Large and active medical centers of the have a “chest pain unit” where patients suspected of having heart attacks are rapidly evaluated. If a heart attack is diagnosed prompt therapy is initiated. If the diagnosis of heart attack is initially unclear the patient is placed under continuous monitoring until the results of further testing are available.

ARTHRITIS

We all have mornings when we wake up a bit stiff. We all know the achy feeling that comes from working too hard in the garden, sitting too long at the computer or sleeping in an awkward position, And from time to time we have all suffered pain because we’ve lifted a heavy object in a slightly wrong way. Even a particularly ferocious sneeze can cause a twinge of discomfort. But arthritis goes far beyond these occasional aches or pains.

The condition that we commonly refer to as arthritis includes a number of diseases that result in inflammation, pain and stiffness, primarily in the joints and connective tissues. Connective tissues are the supporting structures for joints, such as muscles, cartilage, ligaments and tendons. In many cases, these diseases affect other parts of the body as well. Arthritic disorders may be able chronic, but some such as gout, are intermittent. The conditions that are truly inflammatory (that is with actual joint inflammation present) cause warmth and swelling, whereas others are degenerative in which cartilage lining the joint wears out and the amount of inflammation is minor.

How the joint works. The ends of bones meet at the joint where they are cushioned by cartilage, a layer of smooth tissue. Around many of the larger joints such as the knee, hip and shoulder there is a pad-like sac or cavity called the bursa which is lined with cells similar to those lining the joint. In addition to acting as a buffer to reduce friction between the muscle, tendon tissue and bone, the inner lining produces a fluid, synovial fluid, that keeps the joints lubricated and provides nutrients. Ligaments connect and support bones to keep them in proper alignment whereas tendons connect muscles to bones. Joints move when a muscle on the one side of a joint contracts and pulls on the tendons that attach to a bone on the other side of the joint.

How arthritis affects the joints. The word arthritis means joint inflammation. Inflammation, a natural part of the body’s response to injury and infection, is a complex process that produces swelling, pain, warmth and redness. But inflammation is not only a response to injury, it may perpetuate injury as well. Significant problems arise when inflammation is persistent, intense or recurrent or spreads to other areas of the body.

Joints and the surrounding areas become inflamed for a number of reasons including trauma, disease, infection or merely wear and tear, which naturally occurs over time. Many forms of arthritis are thought to result from the uncontrolled inflammation of an autoimmune disease in which the body’s defense mechanism malfunctions and attacks its own tissues. At other times the joint area becomes inflamed and tender for no apparent reason.

When joints become arthritic, swelling causes stiffness, rigidity and tissue damage. Pain which is the body’s signal that something is wrong occurs as the joint is moved to the brink of its own limits. As mobility decreases the muscles surrounding the joint also weaken allowing for further injury to the joint. Over time, the cartilage breaks down, the bone erodes, and the joints become misshapen. It is this process regardless of the source, that may develop in the worst forms of arthritis.

There are more than 100 different types of arthritis and each has its own characteristic symptoms and its own course. In addition, the way in which the disease progresses varies from individual to individual. If you suffer from an arthritic condition you will most likely experience pain and limited movement at the involved sites. In chronic forms of arthritis there may be times when the disease is active (flares) and times when it is inactive (remission). Depending on the specific condition and how severe it is arthritis can interfere with even the most ordinary activities such as walking, dressing or bathing. In the most inflammatory types of arthritis such as rheumatoid arthritis pain and stiffness are more severe in the morning or on certain days. Sometimes symptoms disappear completely for considerable stretches of time only to flare up again later.

Diagnosing arthritis. In most cases, arthritis is diagnosed after an individual contacts with his or her health care professional because pain is significant and has begun to interfere with daily life. If you have that kind of pain your physician will ask you to describe the feeling because he severity and quality of the pain is helpful in figuring out the cause. Is it a throbbing, achy, burning or stabbing sensation? Is it constant or occasionally intense? Do certain activities make the pain worse? Is it worse in the morning or at night? In some cases your doctor may ask you to record your daily experiences in a pain diary.

Your health care professional will review your current symptoms as well as your past medical history, family history, and medication use. A thorough medical examination will follow. The doctor may order blood and urine tests and in select cases X-rays and possibly imaging procedures such as a computed tomography (CT) or magnetic resonance imaging (MRI) may be recommended.

Once arthritis has been detected a treatment plan can be developed to suit you and your lifestyle. With early diagnosis most arthritic conditioned can be managed sufficiently to minimize both the pain and the disruption to your daily life. In many instances early diagnosis and treatment can also work to curtail the actual damage that the condition can cause.

The pain associated with arthritis stems from a number of sources. When, for example, the tissue that lines the joints (synovial membrane), tendons or ligaments swells, you may feel aches and discomfort right at the joint. Muscle strain and fatigue frequently follows as well adding to the intensity and duration of pain. If there is joint damage over time, even the most ordinary activities – getting out of bed in the morning, taking a bath, holding a pencil – can cause pain.

At the same time the level of pain and discomfort that people find tolerable varies from person to person, from situation to situation. Each person’s threshold for pain is different. In addition it is not uncommon for an individual who lives with chronic pain or the possibility of intense, intermittent pain, to experience anxiety and reactive depression as a result. Emotional stress and distress can intensify the sensation of pain.

Recognizing the typical types of pain, the location and the accompanying features helps clarify whether arthritis is present. Once diagnosis is established, the type of arthritis may help direct treatment and provide an idea of what to expect. It should be noted, however, that the specific type of arthritis cannot always be diagnosed early in the course of illness. In addition, many types of arthritis are treated similarly so a specific diagnosis is not always as helpful as it might seem.

In many types of arthritis, the course of the disease is unpredictable. Most chronic diseases involve periods when the symptoms are active and troublesome (flares) and periods when symptoms are negligible (remissions). This unpredictable and variable course can complicate both diagnosis and treatment.

Low back pain. What to do when so much is unknown. If you are one of the millions of people unfortunate enough to suffer from low back pain you may have received advice from your primary care doctor, your family, your friends or others experiencing similar symptoms. Few will suggest the same remedy, but remarkably all of their suggestions may be right. Because there is no single approach that will reliably help everyone numerous treatments (including no treatment at all) may provide relief.

How can this be? The answer reveals a well-kept secret about low back pain: for most people the cause is not known. However, there are many things about low back pain that are well known:

Low back pain is common. About 80 percent of the population will have low back pain at least once in the lifetime. Low back pain is not an inevitable result of aging, strenuous work or injury. It often develops for no apparent reason. Most low back pain is not associated with a dangerous or serious cause. There are reliable ways to detect the rarer and more serious causes. Most patients are not helped much by X-rays, computed tomography (CT) or magnetic resonance imaging (MRI). There is no single best treatment for low back pain. The goal of treatment should be to strike an acceptable balance between pain relief and the possible side effects of treatment, that balance is different for different patients.

Causes. Despite decades of research on thousands of people with the condition, despite detailed anatomic pictures with CT scans and MRI, and despite major advances in the scientific understanding of disease mechanisms, the cause of pain in most cases remains uncertain. Moreover, many experts – for example, those at “back clinics” and specialty centers – will disagree about why your back hurts.

For the majority of patients with low back pain the cause is not serious. The pain is variable in its onset, quality, location and course. It may be: acute (sudden in onset) or chronic (lasting many weeks, months or years; centered on one or both sides of the lower back or radiating into one or both legs; sharp or dull, burning or aching; improved or worsened by different positions.

The sudden onset of pain increases the likelihood that the cause is a muscle spasm or bulging (herniated) disk. A patient who has pain on one side spreading into the buttock and back of the leg is often considered to have sciatica because the pain follows the path of the sciatic nerve, a common cause of this problem is a bulging disk.

If low back pain moves into both legs and worsens when you stand, spinal stenosis may be considered. In spinal stenosis the lower part of the spinal cord is compressed by a disk, ligaments, degenerative bone changes or some combination of these. Other common causes include back strain, muscle spasm and osteoarthritis (degenerative joint disease), but the symptoms that are associated with these disorders are much more variable. In older patients slippage of one vertebra on another (spondylolisthesis) and compression fractures (often related to osteoporosis) are important to consider after more serious causes have been excluded.

In many cases even when a common cause is suspected the diagnosis is generally difficult or impossible to prove. Even an abnormal MRI that reveals a bulging disk may not explain low back pain. Many patients perhaps one-third or more of the population have abnormalities on the MRI even when they have no pain and patients thought to have a disk problem based on their history and physical examination often have normal findings or irrelevant abnormalities on MRI. Among older individuals abnormalities on MRI are even more common.

Fortunately, among patients with low back pain dangerous causes are very uncommon representing only 1 percent or fewer of cases. These serious causes include infection, a tumor, vascular disease and fracture.

The red flags that alert your health care provider that one of these may be at play are advances age, weight loss, fever, past cancer, trauma, immune system problems, difficulty with bowel or bladder control, or vascular disease elsewhere in the body. The combination of past and current problems along with the physical examination will generally help guide which people with low back pain should be treated without further tests and which people should be evaluated further.

Treatment. If you or somebody close to you has low back pain what should be done? Common treatments include: rest, pain relievers, anti-inflammatory medicines, muscle relaxants, exercise. Other conservative treatments – those that avoid surgery or other invasive procedures – may include physical therapy, massage, chiropractic treatment and acupuncture.

Only when low back pain persists or worsens or when a doctor suspects a more serious cause should a patient consider elaborate testing and more aggressive treatments such as injections or surgery.

The role of imaging tests. When will a doctor recommend X-rays or MRI? A doctor will suggest imaging tests if he or she believes that the results are likely to lead to a change in your treatment or your outcome (how much pain you have, how good your function is, or even how long you live). Despite the development of guidelines by experts in the evaluation and management of low back pain, the approach continues to vary greatly among health care providers.

For example, one study found that a patient who sees a neurologist, rheumatologist andorthopedic surgeon with the same back complaints would receive dramatically different recommendations regarding which diagnostic tests to order, each specialist would tend to order tests that detect diseases in his or her field of expertise. Even when a disk problem is suspected and confirmed by MRI this test is probably unnecessary if no change in treatment or outcome follows.

Conclusion. Low back pain continues to e a big problem. it is common, its cause is frequently uncertain and the available treatments are not uniformly effective. Until we know more about why only some people have low back and which treatments are reliably effective, the answers you get about your back pain will depend largely on whom you ask. The good news is that most of the time low back pain improves, function returns to normal and the overall outcome is excellent regardless of the diagnosis offered or treatments provided.