Cardiac Arrest
Cardiac arrest, also known as cardiopulmonary or circulatory arrest, sudden cardiac arrest, and sudden cardiac death, is a condition in which the heart abruptly stops beating. Cardiac arrest differs from heart attack in that the disruption of blood flow is caused not by a physical blockage, but rather by an electrical disturbance that impairs the heart’s ability to pump blood to the rest of the body. And while the heart may continue to beat during a heart attack, it stops completely in cardiac arrest. As a result, blood ceases to flow, preventing oxygen from being delivered to the body and brain. Cardiac arrest is a very serious medical emergency. Each year, an estimated 295,000 Americans suffer cardiac arrest; only 8 percent will survive when the incident occurs out of hospital. The majority of cases that are not treated within ten minutes end in death; patients who survive are likely to suffer brain damage due to the loss of blood flow and needed oxygen to the brain.
The immediate cause of cardiac arrest is usually a severe arrhythmia such as ventricular fibrillation (see page 11), in which the heartbeat cycle is electrically disrupted to the point of stopping altogether. But this life-threatening arrhythmia is itself the result of an underlying heart condition, usually coronary artery disease, although occasionally an enlarged and weakened heart (cardiomyopathy), heart valve disease, or congenital heart defect is to blame. Cardiac arrest can also be caused by noncardiovascular sources, including trauma, gastrointestinal bleeding, or hemorrhaging inside the cranium. Other factors that compound the increase the risk of cardiac arrest include age (the risk increases in men over forty-five and women over fifty-five), smoking, high blood pressure, being overweight or obese, lack of exercise, diabetes, excessive alcohol consumption, drug use, and a previous history of heart disease. Men are two to three times more at risk for cardiac arrest than women, and blacks are about one-third as likely as other groups to survive.
Symptoms of cardiac arrest appear suddenly and must be treated immediately. A victim of cardiac arrest will collapse, unconscious, unable to breathe, and with no pulse. Sometimes cardiac arrest will be preceded by a period of faintness or dizziness, chest pains, shortness of breath, nausea, or vomiting. It is essential that these symptoms be taken seriously.
Due to the catastrophic nature of cardiac arrest, immediate treatment is essential for survival. A patient is more likely to die with every moment that passes without medical treatment. If you or someone near you appears to be suffering a cardiac arrest, call 911 immediately. Until emergency medical treatment is available, perform cardiopulmonary resuscitation (CPR). If you have not been trained in basic CPR, now is the time to learn—you never know when you could be called on to save a life. Contact your local American Heart Association office for more information. Even if you don’t know CPR, you can still assist the patient until help arrives by pushing firmly and steadily on the patient’s chest at a rate of around 100 pushes per minute. Allow the chest to fully rise between each push. Continue until help arrives or until the patient regains consciousness and is able to breathe unaided.
As soon as possible, an automated external defibrillator (AED) should be used to deliver electrical shocks to the patient’s heart in an effort to get it beating normally again. Many public spaces—including shopping malls, hotels, convention centers, airports, and sports stadiums—have AEDs for general use. If one is not immediately available, the police or emergency medical staff will provide one when they arrive at the scene. When the patient gets to the emergency room, drugs will be administered in order to treat a heart attack (if one has occurred), stabilize heart rhythm, and rectify an electrolyte imbalance.
The cause of cardiac arrest is diagnosed after the event. Patients who survive cardiac arrest need to be tested in order to identify the underlying factors that triggered the episode, which, if left unaddressed, could trigger future episodes. Testing methods include electrocardiogram (EKG), echocardiogram, chest X-ray, and angiogram. Blood and hormone testing are also commonly ordered. Other tests include computed tomography (CT) scan, magnetic resonance imaging (MRI), ejection fraction testing, nuclear heart scans, and electrophysiology (EP) studies.
Treatment may include medications, including angiotensin-converting enzyme (ACE) inhibitors, which widen and relax the blood vessels; beta blockers; and calcium channel blockers. Surgery may also be recommended in order to prevent future recurrence of cardiac arrest. Surgical methods can range from the implantation of an implantable cardioverter defibrillator (ICD) device to monitor heart rhythm and reset it, if necessary; coronary angioplasty stenting or bypass surgery; or corrective heart surgery to repair faulty heart valves, diseased heart muscle tissue, or congenital heart deformities. A procedure called radiofrequency catheter ablation can also be used in order to destroy (ablate) the area or areas of the heart that are causing the arrhythmia.
Because cardiac arrest is frequently fatal, prevention is often the best cure. If you are at risk, your doctor may advise you to make lifestyle changes in order to lower your chance of cardiac arrest. Don’t smoke, drink moderately or not at all, eat a balanced diet, and get plenty of exercise; these choices will improve your health and help lower your vulnerability to cardiac arrest.
Congestive Heart Failure
Congestive heart failure (CHF) is a condition in which the heart is unable to pump a sufficient supply of blood to the rest of the body. CHF can be either chronic and ongoing or sudden and acute. Most cases of CHF initially develop in the heart’s main blood pumping chamber, the left ventricle. CHF gets its name because when it occurs, blood backs up into, or congests, the liver, abdomen, lungs, and/or legs, ankles, and feet. Left untreated, CHF can cause heart valve problems, heart attack, stroke, and damage to the liver and kidneys.
CHF can be caused by a variety of conditions that weaken or damage the heart, including coronary heart disease, heart attack, high blood pressure, congenital heart defects (heart abnormalities that are present from birth), damaged heart muscle or valves, inflammation of the heart, arrhythmia, and atherosclerosis. Risk for CHF can be increased by various noncardiovascular diseases, including severe anemia, diabetes and certain diabetes medications, hyperthyroidism and hypothyroidism, emphysema, lupus, infections, kidney disease, blood clots in the lungs, smoking, and excessive alcohol consumption.
There are many symptoms of CHF, ranging from chest pain and shortness of breath (after exertion or when lying down), fatigue, weakness, edema (swelling in ankles, feet, or legs), rapid or irregular heartbeat, swelling in the abdomen, sudden weight gain due to fluid retention, and nausea. All of these symptoms are typically more severe in cases of sudden CHF.
Diagnosis of CHF begins with a thorough medical history intake and physical exam. Often, your doctor will order a blood test to screen for a chemical known as brain natriuretic peptide, or BNP, high levels of which can indicate CHF. Other diagnostic methods include chest X-ray, electrocardiogram (EKG), echocardiogram, computed tomography (CT) scan, magnetic resonance imaging (MRI), and stress testing. An ejection fraction test can also be used, usually in conjunction with an echocardiogram. An ejection fraction measures how well your heart pumps blood. In a healthy heart, the ejection fraction is above 55 percent, meaning that more than half of all the blood that fills the ventricle is pumped out with each heartbeat; a reading lower than 50 percent can confirm heart failure. Lung function will likely also be checked through the use of a stethoscope to listen for signs of lung congestion.
Chronic CHF requires lifelong management. With proper treatment, CHF symptoms can improve; in some cases the heart itself can even become stronger over time. Conventional medications used to treat CHF include angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers, both of which widen blood vessels, reduce blood pressure, and improve blood flow; digoxin (digitalis), which increases heart muscle contractions and slows the heartbeat; beta blockers, which slow heart rate and reduce blood pressure; and diuretics, to decrease fluid buildup.
Surgical procedures to t
reat CHF include coronary bypass surgery, heart valve repair or replacement, placement of an implantable cardioverter defibrillator, the implantation of a mechanical heart pump, and the insertion of a pacemaker. In severe cases of CHF, a heart transplant may be warranted.
Patients with CHF are often advised to weigh themselves each morning and to notify their doctors if they experience a weight gain of three pounds or more over a 24-hour period. Such weight gain is usually a sign of fluid retention, indicating the need for adjusted treatment. CHF patients are also advised to achieve and maintain a healthy weight; follow a low-fat, low-salt diet; and limit their intake of alcohol and, in more severe cases, other fluids.
Coronary Heart Disease
Coronary heart disease (CHD), also called coronary artery disease, is a type of atherosclerosis that occurs specifically in the arteries of the heart. Once the inner wall of a coronary artery becomes diseased or damaged, fatty deposits composed of cholesterol and other cellular waste products—plaque—accumulate in the coronary artery walls, hardening and narrowing these vessels and restricting blood flow. Because the coronary arteries are already narrower than your other arteries, the effects of this particular type of atherosclerosis can be serious: Deprived of blood, your heart can simply stop working. According to the CDC, an estimated 6 percent of all American adults suffer from CHD, many of them unknowingly.
As with atherosclerosis, CHD can be caused by a variety of factors, including poor diet and lack of exercise, high blood pressure, smoking, chronic stress, high levels of LDL (“bad”) cholesterol and low levels of HDL (“good”) cholesterol, and other health conditions, including diabetes, sleep apnea, and obesity. Radiation therapy, especially when used to treat certain cancers, can also cause CHD.
Initially, symptoms of CHD may not be apparent, but as the condition worsens, so, too, do the symptoms. As the artery blockages grow, CHD can manifest as angina (chest pain), and shortness of breath. Left untreated, CHD can result in arrhythmia, heart muscle failure, heart attack, or sudden death.
Because CHD is a “silent” killer—meaning you can suffer from the disease without experiencing any of its symptoms—regular medical checkups are important for everyone, but especially for those who are considered to have a higher risk for developing this serious disease. A physical exam and a blood test will provide general screening for CHD. Your doctor may also order additional diagnostic tests, such as an electrocardiogram (EKG), echocardiogram, and a stress test. In cases of CHD where significant blockages are suspected, other tests may be prescribed, such as a computed tomography (CT) scan, angiogram, or magnetic resonance angiogram (MRA), during which magnetic resonance imaging (MRI) is used to track the progress of an injected contrast dye in order to check for areas of the arteries that may be narrowed or blocked.
Treatment for CHD usually involves a combination of drugs and lifestyle changes, including adopting a heart-healthy diet, regular exercise, stress management, the cessation of smoking, and often weight loss. The most commonly used drugs to treat CHD are aspirin, statins, beta blockers, calcium channel blockers, and ACE inhibitors. In some cases, nitroglycerin tablets, patches, or sprays may also be used to control chest pain related to CHD, and to help widen arteries. If a nonpharmacological approach is warranted, the most common procedures are angioplasty and coronary bypass surgery (see pages 10 and 11).
Enlarged Heart
Enlarged heart, or cardiomegaly, is not a disease, but rather a manifestation of another heart condition, such as coronary artery disease, high blood pressure, heart valve disease, arrhythmia, or a weakened or damaged heart muscle. While an enlarged heart is usually a chronic condition, there are also more temporary situations in which the heart becomes enlarged for a short period of time due to pregnancy, excessive exertion, or stress being placed on the body. The risk of developing an enlarged heart increases for anyone born with a condition that affects the structure of the heart (congenital heart disease), and for people with high blood pressure or a family history of enlarged heart.
An enlarged heart can go unnoticed, with no signs that anything is wrong; alternatively, it can present with symptoms such as arrhythmia, chest pain, coughing, edema, difficulty exercising, and shortness of breath. Left untreated, an enlarged heart can result in blood clots within the heart chambers, heart failure, cardiac arrest, and sudden death.
Physicians use a variety of diagnostic methods to screen for an enlarged heart. These include electrocardiogram (EKG), echocardiogram, chest X-ray, computed tomography (CT) scan, magnetic resonance imaging (MRI), and stress testing. In addition, blood tests will usually be ordered to screen for signs of other possible heart problems.
If detected early, an enlarged heart can be treated and even reversed. Treatment options include medications such as angiotensin-converting enzyme (ACE) inhibitors, anticoagulants (blood thinners), beta blockers, diuretics, and digoxin (digitalis). Surgery may also be necessary. Surgical options include the placement of an implantable cardioverter device (ICD) or ventricular assist device (VAD), heart valve surgery, and coronary bypass.
Heart Attack (Acute Myocardial Infarction)
A heart attack, or acute myocardial infarction (AMI), occurs when blood flow to the heart is interrupted, causing heart muscle cells to die. Lack of blood flow to the heart is most often due to a blockage of a coronary artery caused by a substance called vulnerable plaque. Vulnerable plaque is an unstable combination of cholesterol, fatty acids, and white blood cells that can form on the arterial wall in response to inflammation. When vulnerable plaque ruptures, blood clots can form, blocking the artery and diminishing blood flow, thus reducing oxygen supply to the heart and causing damage or death to heart muscle cells and tissues. The result is often fatal.
A wide range of factors can increase the risk of heart attack, including age, poor diet, lack of exercise, smoking, diabetes, being overweight or obese, chronic stress, high levels of physical exertion, high blood pressure, excessive alcohol consumption, the overuse of pharmaceutical or illegal drugs, kidney disease, and a personal or family history of heart disease. Risk can also be increased by various psychosocial factors, including low income or poverty, social isolation, depression, and stress. All of these factors impair survival outcomes following a heart attack.
In both men and women, symptoms of AMI may be “silent,” meaning they may occur without being noticed; an estimated 25 percent or more of all cases of AMI in the United States fall into this category. When symptoms are apparent, they occur gradually, over the course of several minutes. The most common symptoms of AMI are chest pain (which can spread down the left arm and/or the left side of the neck), shortness of breath, nausea, vomiting, excessive sweating, and chest palpitations. In women, symptoms may not be as intense or as varied, and most commonly manifest as shortness of breath, fatigue, weakness, and sensations similar to indigestion. In the most serious cases, loss of consciousness or sudden death can also occur.
Because they can be fatal, heart attacks require prompt medical attention. Diagnostic tests include the electrocardiogram (EKG), which can detect abnormalities in the electrical activity of the heart that usually occur during an AMI and also identifies the areas of heart muscle that are deprived of oxygen. Various blood tests may also be used after the incident to screen for blood markers that indicate AMI has occurred.
Once a diagnosis of AMI has been confirmed, immediate treatment can include the use of oxygen, aspirin and other blood thinners (to reduce clotting), and sometimes nitroglycerin tablets (to widen narrowed blood vessels). More invasive procedures, including surgery, may also be necessary in order to unclog blocked arteries and restore the flow of blood and oxygen to the heart as quickly as possible. The more rapidly blood flow can be reestablished, the more heart muscle can be saved.
The restoration of blood flow to the heart is known as reperfusion. Methods of reperfusion include angioplasty and/or the placement of one or more stents inside the coronary arteries. These procedures are the preferred metho
ds for preserving heart muscle, particularly if they can be performed within ninety minutes after AMI patients reach the hospital. If there is a delay past this time or if catheterization is not available, thrombolytics, or clot-busting drugs, may also be used. Patients with multiple blockages in their arteries may also have coronary bypass surgery in order to redirect and improve blood flow.
Following immediate care, with or without surgery, AMI patients will usually be prescribed various heart medications, which can include the continued use of aspirin, ACE inhibitors, beta blockers, blood-thinning drugs such as heparin, and/or statin drugs to control cholesterol levels and prevent a recurrence of heart attack. In addition, doctors will typically provide guidance about necessary dietary and lifestyle changes; stress management can be the key to a successful recovery.
Heart Murmur
A heart murmur is characterized by abnormal sounds heard during the heartbeat cycle. Heart murmur is not a disease, but it can be a sign of an underlying heart condition. There are two types of heart murmur: innocent and abnormal. Innocent murmurs do not require treatment and are common in cases that are present from birth, or congenital. Abnormal murmurs are more serious and can indicate inflammation in the heart, heart valve problems, or a hole in a wall within the heart’s chambers. The severity of the abnormal murmur will determine the kind and intensity of its treatment.
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