Wolff-Parkinson-White Syndrome (Arrhythmia)

Arrhythmia An arrhythmia (ah-RITH-me-ah) is a problem with the speed or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm. A heartbeat that is too fast is called tachycardia. A heartbeat that is too slow is called bradycardia.Most arrhythmias are harmless, but some can be serious or even life threatening. When the heart rate is too slow, too fast, or irregular, the heart may not be able to pump enough blood to the body. Lack of blood flow can damage the brain, heart, and other organs.

Understanding the Heart’s Electrical System The heart has an internal electrical system that controls the speed and rhythm of the heartbeat. With each heartbeat, an electrical signal spreads from the top of the heart to the bottom. As it travels, the electrical signal causes the heart to contract and pump blood. The process repeats with each new heartbeat.

Each electrical signal begins in a group of cells called the sinus node, or sinoatrial (SA) node. The SA node is located in the right atrium (AY-tree-um), which is the upper right chamber of the heart. In a healthy adult heart at rest, the SA node fires off an electrical signal to begin a new heartbeat 60 to 100 times a minute.

From the SA node, the electrical signal travels through special pathways to the right and left atria. This causes the atria to contract and pump blood into the heart’s two lower chambers, the ventricles (VEN-trih-kuls). The electrical signal then moves down to a group of cells called the atrioventricular (AV) node, located between the atria and the ventricles. Here, the signal slows down just a little, allowing the ventricles time to finish filling with blood. The electrical signal then leaves the AV node and travels along a pathway called the bundle of His. This pathway divides into a right bundle branch and a left bundle branch. The signal goes down these branches to the ventricles, causing them to contract and pump blood out to the lungs and the rest of the body. The ventricles then relax, and the heartbeat process starts all over again in the SA node.

A problem with any part of this process can cause an arrhythmia. For example, in atrial fibrillation, a common type of arrhythmia, electrical signals travel through the atria in a fast and disorganized way. This causes the atria to quiver instead of contract.

Overview There are many different types of arrhythmia. Most arrhythmias are harmless but some are not. The outlook for a person with an arrhythmia depends on the type and severity of the arrhythmia. Even serious arrhythmias can often be successfully treated. Most people with arrhythmias are able to live normal, healthy lives.

How the Heart Works The heart is a muscle about the size of your fist. The heart works like a pump and beats about 100,000 times a day.

A healthy adult heart generally beats 60 to 100 times a minute, but it can beat faster or slower at times. For example, physical activity, strong emotion, certain medicines, fever, or infection can make the heart beat faster. A person’s heart rate generally slows down during sleep. Some very fit athletes always have heart rates below 60 beats a minute because their hearts work so well.

The heart has two sides, separated by an inner wall called the septum. The right side of the heart pumps blood to the lungs to pick up oxygen. Then, oxygen-rich blood returns from the lungs to the left side of the heart, and the left side pumps it to the body.

The heart has four chambers and four valves and is connected to various blood vessels. Veins are the blood vessels that carry blood from the body to the heart. Arteries are the vessels that carry blood away from the heart to the body.


Heart Chambers The heart has four chambers or “rooms”—two on the left side of the heart and two on the right.

• The atria are the two upper chambers that collect blood as it comes into the heart.
• The ventricles are the two lower chambers that pump blood out of the heart to the lungs or other parts of the body.

Heart Valves Four valves control the flow of blood from the atria to the ventricles and from the ventricles into the two large arteries connected to the heart.

• The tricuspid (tri-CUSS-pid) valve is in the right side of the heart, between the right atrium and the right ventricle.
• The pulmonary (PULL-mun-ary) valve is in the right side of the heart, between the right ventricle and the entrance to the pulmonary artery that carries blood to the lungs.
• The mitral (MI-tral) valve is in the left side of the heart, between the left atrium and the left ventricle.
• The aortic (ay-OR-tik) valve is in the left side of the heart, between the left ventricle and the entrance to the aorta, the artery that carries blood to the body.

Valves are like doors that open and close. They open to allow blood to flow through to the next chamber or to one of the arteries, and then they shut to keep blood from flowing backward.

When the heart’s valves open and close, they make a “lub-DUB” sound that a doctor can hear using a stethoscope.

• The first sound—the “lub”—is made by the mitral and tricuspid valves closing at the beginning of systole (SIS-toe-lee). Systole is when the ventricles contract, or squeeze, and pump blood out of the heart.
• The second sound—the “DUB”—is made by the aortic and pulmonary valves closing at beginning of diastole (di-AS-toe-lee). Diastole is when the ventricles relax and fill with blood pumped into them by the atria.

Arteries

The arteries are major blood vessels connected to your heart.

• The pulmonary artery carries blood pumped from the right side of the heart to the lungs to pick up a fresh supply of oxygen.
• The aorta is the main artery that carries oxygen-rich blood pumped from the left side of the heart out to the body.
• The coronary arteries are the other important arteries attached to the heart. They carry oxygen-rich blood from the aorta to the heart muscle, which must have its own blood supply to function.

Veins

The veins are also major blood vessels connected to your heart.The pulmonary veins carry oxygen-rich blood from the lungs to the left side of the heart so it can be pumped out to the body.The vena cava is a large vein that carries oxygen-poor blood from the body back to the heart.

Types of Arrhythmia There are four main types of arrhythmia: premature (extra) beats, supraventricular arrhythmias, ventricular arrhythmias, and bradyarrhythmias.

Premature (Extra) Beats Premature beats are the most common type of arrhythmia. They are harmless most of the time and often don’t cause any symptoms. When symptoms do occur, they usually feel like a fluttering in the chest or a sensation of a skipped beat. Most of the time, premature beats need no treatment, especially in healthy people.

Premature beats that occur in the atria are called premature atrial contractions, or PACs. Premature beats that occur in the ventricles are called premature ventricular contractions, or PVCs.

In most cases, premature beats occur naturally, not due to any heart disease. But certain heart diseases can cause premature beats. They also can happen because of stress, too much exercise, or too much caffeine or nicotine.

Supraventricular Arrhythmias Supraventricular arrhythmias are tachycardias (fast heart rates) that start in the atria or the atrioventricular node (cells located between the atria and the ventricles). Types of supraventricular arrhythmias include atrial fibrillation (AF), atrial flutter, paroxysmal supraventricular tachycardia (PSVT), and Wolff-Parkinson-White (WPW) syndrome.

Atrial Fibrillation AF is the most common type of serious arrhythmia. It’s a very fast and irregular contraction of the atria. AF occurs when the heart’s electrical signal begins in a different part of the atrium than the sinoatrial (SA) node or when the signal is conducted abnormally. When this happens, the electrical signal doesn’t travel through the normal pathways in the atria, but instead may spread throughout the atria in a fast and disorganized manner. This causes the walls of the atria to quiver very fast (fibrillate) instead of beating normally. As a result, the atria aren’t able to pump blood into the ventricles the way they should.

In AF, electrical signals can travel through the atria at a rate of more than 300 per minute. Some of these abnormal electrical signals can travel to the ventricles, causing them to beat too fast and with an irregular rhythm. AF is not usually life threatening, although it can be dangerous when it causes the ventricles to beat very fast.

The two most serious complications of chronic (long-term) AF are stroke and heart failure. Stroke can happen when a blood clot travels to an artery in the brain, blocking off blood flow. In AF, blood clots can form in the atria because some of the blood “pools” in the fibrillating atria instead of flowing into the ventricles. If a piece of a blood clot in the left atrium breaks off, it can travel to the brain, causing a stroke. People with AF are often treated with blood-thinning medicines to reduce the chances of developing blood clots.

Heart failure is when the heart can’t pump enough blood to meet the needs of the body. AF can cause heart failure when the ventricles beat too fast and don’t have enough time to fill with blood to pump out to the body. Heart failure causes tiredness, leg swelling, and shortness of breath.

AF and other supraventricular arrhythmias can occur for no apparent reason. Most of the time, however, they are caused by an underlying condition that damages the heart muscle and its ability to conduct electrical impulses. These conditions include high blood pressure (hypertension), coronary artery disease, heart failure, or rheumatic heart disease.

Other conditions also can lead to AF, including overactive thyroid gland (too much thyroid hormone produced) and heavy alcohol use. AF also becomes more common as people get older.

Atrial Flutter

Atrial flutter is similar to atrial fibrillation, but instead of the electrical signals spreading through the atria in a fast and irregular rhythm, they travel in a fast and regular rhythm. Atrial flutter is much less common than atrial fibrillation, but has similar symptoms and complications.

Paroxysmal Supraventricular Tachycardia

PSVT is a very fast heart rate that begins and ends suddenly. PSVT occurs due to problems with the electrical connection between the atria and the ventricles. In PSVT, electrical signals that begin in the atria and travel to the ventricles can reenter the atria, causing extra heartbeats. This type of arrhythmia is not usually dangerous and tends to occur in young people. It can happen during vigorous exercise.

A special type of PSVT is called Wolff-Parkinson-White syndrome. WPW syndrome is a condition in which the heart’s electrical signals travel along an extra pathway from the atria to the ventricles. This extra pathway disrupts the timing of the heart’s electrical signals and can cause the ventricles to beat very fast. This type of arrhythmia can be life threatening.

Ventricular Arrhythmias

These are arrhythmias that start in the ventricles. They can be very dangerous and usually need immediate medical attention. Ventricular arrhythmias include ventricular tachycardia and ventricular fibrillation (v-fib). Coronary artery disease, heart attack, weakened heart muscle, and other problems can cause ventricular arrhythmias.

Ventricular Tachycardia

Ventricular tachycardia is a fast, regular beating of the ventricles that may last for only a few seconds or for much longer. A few beats of ventricular tachycardia often don’t cause problems, but ventricular tachycardia episodes that last for more than just a few seconds can be dangerous. Ventricular tachycardia can turn into other, more dangerous arrhythmias, such as v-fib.

Ventricular Fibrillation

V-fib occurs when disorganized electrical signals make the ventricles quiver instead of pump normally. Without the ventricles pumping blood out to the body, a person will lose consciousness within seconds and will die within minutes if not treated. To prevent death, the condition must be treated immediately with defibrillation, an electric shock to the heart. V-fib may happen during or after a heart attack, or in a heart that is already weak because of another condition. Health experts think that most of the sudden cardiac deaths that occur every year (about 335,000) are due to v-fib.

Torsades de pointes (torsades) is a specific form of v-fib with a unique pattern on anEKG (electrocardiogram). Certain medicines and imbalanced amounts of potassium, calcium, or magnesium in the bloodstream can cause this condition. People with a particular finding on an EKG test, called prolonged QT interval, are at increased risk of developing torsades. People with prolonged QT interval need to be careful about taking certain antibiotics, heart medicines, and over-the-counter medicines.

Bradyarrhythmias

Bradyarrhythmias are arrhythmias in which the heart rate is slower than normal. If the heart rate is too slow, not enough blood reaches the brain, and the person can lose consciousness. In adults, a heart rate slower than 60 beats per minute is considered a bradyarrhythmia. Some people normally have slow heart rates, especially people who are very physically fit. For them, a heartbeat slower than 60 beats per minute is not dangerous and doesn’t cause symptoms. But in other people, bradyarrhythmia can be due to a serious disease or other condition.

Bradyarrhythmias can be caused by heart attack, conditions that harm or change the heart’s electrical system (such as underactive thyroid gland or aging), an imbalance of chemicals or other substances (such as potassium) in the blood, or even some medicines (such as beta blockers).

Bradyarrhythmias also can happen as a result of severe bundle branch block. Bundle branch block is a condition in which the electrical signal traveling down either or both of the bundle branches is delayed or blocked. When this happens, the ventricles don’t contract at exactly the same time, as they should, and the heart has to work harder to pump blood to the body. The cause of bundle branch block is often an existing heart condition.

Arrhythmias in Children

Normally, a child’s heart beats between 70 and 100 times a minute. A newborn’s heart beats about 140 times a minute. A baby or child’s heart can beat faster or slower than normal for many reasons. As is true for adults, when children are active, their hearts will beat faster. When they are sleeping, their heart will beats slower. Their heart rates can speed up and slow down as they breathe in and out. All of these changes are normal.

Some children are born with heart defects that cause arrhythmias. In other children, arrhythmias can develop later in childhood. Doctors do the same kinds of tests in children and adults to diagnose arrhythmias.

Treatments for children with arrhythmias include medicines, electric shock (defibrillation), surgically implanted devices that control the heartbeat, and other procedures that fix distorted electrical signals in the heart.

What Causes an Arrhythmia?

An arrhythmia can occur when the electrical signals that control the heartbeat are delayed or blocked. This can happen when the special nerve cells that produce the electrical signal don't work properly or when the electrical signal doesn't travel normally through the heart. An arrhythmia also can occur when another part of the heart starts to produce electrical signals, adding to the signals from the special nerve cells and disrupting the normal heartbeat.

Stress, smoking, heavy alcohol use, heavy exercise, use of certain drugs (such as cocaine or amphetamines), use of certain prescription or over-the-counter medicines, and too much caffeine or nicotine can lead to arrhythmia in some people.

A heart attack or an underlying condition that damages the heart's electrical system also can cause an arrhythmia. These conditions include high blood pressure(hypertension), coronary artery disease, heart failure, overactive or underactive thyroid gland (too much or too little thyroid hormone produced), and rheumatic heart disease.

For some arrhythmias, such as Wolff-Parkinson-White syndrome, the underlying heart defect that causes the arrhythmia is present at birth (congenital). Sometimes, the cause of an arrhythmia can't be found.

What Are the Signs and Symptoms of Arrhythmias?

Many arrhythmias cause no signs or symptoms. When signs or symptoms are present, the most common ones are:

• Palpitations (a feeling that your heart has skipped a beat or is beating too hard)
  
• A slow heartbeat
  
• An irregular heartbeat
  
• Feeling of pauses between heartbeats

More serious signs and symptoms include:

• Anxiety
  
• Weakness
  
• Dizziness and light-headedness
  
• Fainting or nearly fainting
  
• Sweating
  
• Shortness of breath
• Chest pain

How Are Arrhythmias Treated?

Common arrhythmia treatments include medicines, medical procedures, and surgery. Treatment is needed when an arrhythmia causes serious symptoms, such as dizziness, chest pain, or fainting, or when it increases your chances of developing complications, such as heart failure, stroke, or sudden cardiac death.

Medicines

Medicines can be used to speed up a heart that's beating too slow, or slow down a heart that's beating too fast. They also can be used to convert an abnormal heart rhythm to a normal steady rhythm. Medicines can be used to control an underlying medical condition, such as heart disease or a thyroid condition, that might be causing an arrhythmia. Medicines used to convert an abnormal rhythm are called antiarrhythmics.

Some of the medicines used to slow a fast heart rate are beta blockers (such as metoprolol and atenolol), calcium channel blockers (such as diltiazem and verapamil), and digoxin (digitalis). These medicines are often used to slow the heart rate in people with atrial fibrillation.

Some of the medicines used to restore an abnormal heartbeat to a normal rhythm are amiodarone, sotalol, flecainide, propafenone, dofetilide, ibutilide, quinidine, procainamide, and disopyramide. These medicines often have side effects. Some of the side effects can make an arrhythmia worse or even cause a different kind of arrhythmia.

People with atrial fibrillation and some other arrhythmias are often treated with blood-thinning medicines (anticoagulants) to reduce the chances of developing blood clots. Aspirin, warfarin (Coumadin®), and heparin are commonly used blood thinners.

Medical Procedures Some arrhythmias are treated with a device called a pacemaker. The pacemaker is a small device that's surgically placed under the skin at the collarbone; wires lead from it to the atrium and ventricle(s). The pacemaker sends small electric signals through the wires to control the speed of the heartbeat. Most pacemakers contain a sensor that activates the device only when the heartbeat is abnormal.

Some arrhythmias are treated with a jolt of electricity delivered to the heart. This type of treatment is called cardioversion or defibrillation, depending on which type of arrhythmia is being treated.

Some people who are at risk for ventricular fibrillation are treated with a device called an implantable cardioverter defibrillator (ICD). This device is surgically implanted in the chest and connected to the heart with wires. It continuously monitors the heartbeat. If it senses a dangerous ventricular arrhythmia, it sends an electric shock to the heart to restore a normal heartbeat.

A procedure called radiofrequency ablation is sometimes used to treat certain types of arrhythmias when medicines don't work. In this treatment, a special wire is inserted through a vein in the arm or leg and threaded up to the heart. Radiowave energy is sent through the wire to destroy abnormal tissue in the heart that's interrupting the normal flow of electric signals. Radiofrequency ablation is usually done in the hospital as part of an electrophysiologic study.

Surgery Sometimes, surgery is used to treat arrhythmia. Often this is done when surgery is already being performed for another reason, such as repair of a heart valve. One type of surgery for atrial fibrillation is called "maze" surgery. In this operation, the surgeon makes small cuts or burns in the atria, which prevent the spread of disorganized electrical signals.

Coronary artery bypass surgery may be needed for arrhythmias caused by coronary artery disease. The operation improves blood supply to the heart muscle.

Other Treatments Vagal maneuvers are another arrhythmia treatment. These are simple exercises that sometimes can stop or slow down certain types of supraventricular arrhythmias. They stop the arrhythmia by affecting the vagus nerve, which is one factor that controls the heart rate. Some vagal maneuvers include:

• Gagging
• Holding your breath and bearing down (Valsalva maneuver)
• Immersing your face in ice-cold water
• Coughing
• Putting your fingers on your eyelids and pressing down gently

Vagal maneuvers aren't an appropriate treatment for everyone. Discuss with your doctor whether vagal maneuvers are safe and effective for you to try.

Who Is At Risk for an Arrhythmia? Populations Affected Millions of Americans have arrhythmias. They are very common in older adults. About 2.2 million Americans have atrial fibrillation (a common type of arrhythmia that can cause problems).

Most serious arrhythmias happen in adults older than 60. This is because older adults are more likely to have heart disease and other health problems that can lead to arrhythmias. Older adults also tend to be more sensitive to the side effects of medicines, some of which can cause arrhythmias. Some medicines used to treat arrhythmias can cause arrhythmias as a side effect.

Some types of arrhythmia happen more often in children and young adults. Paroxysmal supraventricular tachycardias (a fast heart rate that begins and ends suddenly), including Wolff-Parkinson-White syndrome, are more common in young people.

Major Risk Factors Arrhythmias are more common in people who have a disease or condition that weakens the heart, such as:

• Heart attack
• Heart failure or cardiomyopathy, which weakens the heart and changes the way electrical signals move around the heart
• Heart tissue that is too thick or stiff or that hasn't formed normally
• Leaking or narrowed heart valves, which make the heart work too hard and can lead to heart failure
• Congenital problems (problems that are present at birth) with the heart's structure or function

Other conditions also can increase the chances of arrhythmia, such as:

• High blood pressure
• Infections that damage the heart muscle or the sac around the heart
• Diabetes, which increases the risk of high blood pressure and coronary artery disease
• Sleep apnea (when breathing becomes shallow or stops during sleep), which can stress the heart because it doesn't get enough oxygen
• Overactive or underactive thyroid gland (too much or too little thyroid hormone in the body)

In addition to certain diseases and conditions, several other risk factors increase a person's chance of having an arrhythmia. Heart surgery, certain drugs (such as cocaine or amphetamines), or an imbalance of chemicals or other substances (such as potassium) in the bloodstream can increase a person's chance of having an arrhythmia.

SLEEP APNEA

What is Sleep Apnea?

Obstructive sleep apnea, OSA, is a breathing related sleep disorder which can cause people to snore, as well as pose serious health threats. OSA is a condition that occurs when a person regularly stops breathing (apnea) for 10 seconds or longer during sleep. It is usually caused by either the tongue or the soft palate falling back against the back of the throat when the muscles in the neck and throat relax during sleep.

There are three vital things that you need to know about sleep apnea:

• Not only does sleep apnea result in sleep deprivation, but it can also threaten your life.
• Sleep apnea is a progressive sleep disorder (it gets worse as you age).
• Treatment for sleep apnea is necessary and usually successful

Are Snoring and Sleep Apnea the Same Thing?

Snoring and sleep apnea are not the same thing. Snoring is simply a loud sound that you make during breathing while asleep. Snoring may accompany sleep apnea, but snoring by itself does not mean that breathing has stopped.

Warning signs and symptoms of sleep apnea are:

• Frequent cessation of breathing (apnea) during sleep. Your sleep partner may notice repeated silences from your side of the bed.
• Choking or gasping during sleep to get air into the lungs
• Loud snoring
• Sudden awakenings to restart breathing
• Waking up in a sweat during the night
• Feeling unrefreshed in the morning after a night’s sleep
• Headaches, sore throat, or dry mouth in the mornings after waking up
• Daytime sleepiness, including falling asleep at inappropriate times, such as during driving or at work
• Lethargy
• Rapid weight gain
• Memory loss and learning difficulties
• Short attention span

Diagnosis of Sleep Apnea:

A sleep study is the only way to positively diagnose sleep apnea.. The polysomnography (sleep study) is a standard lab test that measures and records specific body functions during sleep. The test is painless and usually performed overnight in a comfortably appointed suite.

Types of Sleep Apnea

Obstructive Sleep Apnea (OSA)
The most common type of sleep apnea. Caused by a breathing obstruction, which stops the air flow in the nose and mouth.

Central Sleep Apnea (CSA)
A much less common type of sleep apnea. The brain signal that instructs the body to breathe is delayed. This central nervous system disorder can be caused by disease or injury involving the brain stem, such as a stroke, a brain tumor, a viral brain infection, or a chronic respiratory disease.

Mixed sleep apnea
A combination of the two other types of sleep apnea, Obstructive Sleep Apnea and Central Sleep Apnea.

Causes of Sleep Apnea

Sleep apnea is caused by the throat being blocked during sleep. The soft tissues of the upper airway collapse and the tongue falls back, blocking the flow of air during sleep. These periods can last from 10 to 90 seconds during which the body receives no oxygen. While there is no cure for sleep apnea, certain factors can contribute to the disorder. Making some lifestyle changes and seeking medical treatment can alleviate most or all of the symptoms.

Risk Factors

Various risk factors can predispose you to have an obstructed airway and therefore cause sleep apnea. If you have a number of the risk factors below, and you are not sleeping well, you might consult a doctor for a diagnosis of sleep apnea. The risk factors for sleep apnea are:

Obesity or excessive fat in the neck and throat
However, note that almost half of people with sleep apnea are not obese.

Age

Male gender

Irregular sleep hours
An irregular sleep schedule can throw off your sleep cycles. Disruptions include work days vs. non-work days; a snoring bed partner; a new baby; aggravation from the day’s events; not following a natural preference for sleep during unconventional hours; and overuse of caffeinated products. Particularly affected are Stage 1 sleep (when you first fall asleep) and REM sleep (when you dream). The result of disruption can be unstable breathing and sleep apnea during these phases of sleep.

Anatomical anomalies that narrow your airway
For example, a deviated septum, an enlarged tongue, or a receding chin.

Snoring
Snoring itself is not only a result of sleep apnea, but also a cause. The repeated vibrations of the soft palate during snoring can cause the soft palate to lengthen, which can obstruct the airway.

Enlarged tonsils or adenoids
Especially can cause sleep apnea in children.

Use of alcohol and sedatives before bedtime

Smoking or exposure to secondhand smoke

Nasal congestion, nasal blockages, and nasal irritants
For example, household dust and dander can inhibit breathing through the nose and force breathing through the throat, which may also be blocked.

Family history of sleep apnea
No specific genetic marker for sleep apnea has been discovered, but obstructive sleep apnea seems to run in families. This may be a result of facial and neck characteristics or anatomic abnormalities that are passed along to succeeding generations.

Other disorders and syndromes
Hypothyroidism, acromegaly, amyloidosis, vocal cord paralysis, post-polio syndrome, neuromuscular disorders, Marfan's syndrome, and Down Syndrome.

Effects of Sleep Apnea

Periods of not breathing cause an alarming drop in the blood oxygen level and can lead to high blood pressure, cardiovascular disease, and stroke. Sleep apnea episodes can happen from 5 to more than 100 times an hour, and sometimes breathing stops hundreds of times each night. Additionally, from the interrupted loss of sleep, excessive daytime sleepiness can occur. This may put a person experiencing obstructive sleep apnea symptoms at even greater risk by causing them to fall asleep while driving or working.

Treatment of Sleep Apnea

Once diagnosed, there are several types of sleep apnea aids and treatment that can offer patients a clear and open airway during sleep. For some people, developing good sleeping habits, losing weight, and avoiding sleep medications and alcohol may cure the sleep apnea syndrome. Other people may need to use a breathing device called aCPAP machine (Continuous Positive Airway Pressure). Worn while the patient sleeps the CPAP uses air pressure to keep the upper airway from collapsing. For patients that cannot wear a CPAP machine, a dental appliance is the most common prevention & relief for sleep apnea. Dentists use a small appliance much like an orthodontic retainer to prevents the tongue from falling back and blocking the airway.

Classifications

Apnea severity is usually categorized by the frequency of apnea episodes:

mild 5 to 19 episodes per hour
moderate 20 to 39 episodes per hour
severe more than 40 episodes per hour

These episodes can last anywhere between 10 to 90 seconds each, terminating with at least a partial awakening. A severe apnea patient may have more than 300 episodes per night!

Common Blood Test

What Are Blood Tests?

Blood tests help doctors check for certain diseases and conditions. They also help check the function of your organs and show how well treatments are working.

Specifically, blood tests can help doctors:

• Evaluate how well organs, like the kidneys, liver, and heart, are working
• Diagnose diseases like cancer, HIV/AIDS, diabetes, anemia(uh-NEE-me-eh), and heart disease
• Learn whether you have risk factors for heart disease
• Check whether medicines you’re taking are working

Overview

Blood tests are very common. When you have routine checkups, your doctor often orders blood tests to see how your body is working.

Many blood tests don’t require any special preparations. For some, you may need to fast (not eat any food) for 8 to 12 hours before the test. Your doctor will let you know whether this is necessary.

During a blood test, a small amount of blood is taken from your body. It’s usually drawn from a vein in your arm using a thin needle. A finger prick also may be used. The procedure is usually quick and easy, although it may cause some short-term discomfort. Most people don’t have serious reactions to having blood drawn.

Lab workers draw the blood and analyze it. They use either whole blood to count blood cells, or they separate the blood cells from the fluid that contains them. This fluid is called plasma or serum.

The fluid is used to measure different substances in the blood. The results can help detect health problems in early stages, when treatments or lifestyle changes may work best.

However, blood tests alone can’t be used to diagnose or treat many diseases or medical problems. Your doctor may consider other factors, such as your signs and symptoms, your medical history, and results from other tests and procedures, to confirm a diagnosis.

Outlook

Blood tests have few risks. Most complications are minor and go away shortly after the tests are done.

Types of Blood Tests

Some of the most common blood tests that doctors order are:

• Complete blood count (CBC)
• Blood chemistry tests
• Blood enzyme tests
• Blood tests to assess heart disease risk

Complete Blood Count

The CBC is one of the most common types of blood test. It's often done as part of a routine checkup.

A CBC measures many different parts of your blood (as described below). This test can help detect blood diseases and disorders. These include anemia, infection, clotting problems, blood cancers, and immune system disorders.

Red Blood Cells

Red blood cells carry oxygen from your lungs to the rest of your body. Abnormal red blood cell levels may be a sign of anemia, dehydration (too little fluid in the body), bleeding, or another disorder.

White Blood Cells

White blood cells are part of your immune system, which fights infections and disease. Abnormal white blood cell levels may be a sign of infection, blood cancer, or an immune system disorder.

A CBC measures the overall number of white blood cells in your blood. A differential count looks at the amounts of different types of white blood cells in your blood.

Platelets

Platelets (PLATE-lets) are blood cells that help your blood clot. They stick together to seal cuts or breaks and stop bleeding. Abnormal platelet levels may be a sign of a bleeding disorder (not enough clotting) or a thrombotic disorder (too much clotting).

Hemoglobin

Hemoglobin (HEE-muh-glow-bin) is an iron-rich protein in red blood cells that carries oxygen. Abnormal hemoglobin levels may be a sign of anemia, sickle cell anemia,thalassemia (thal-a-SE-me-ah), or other blood disorders.

If you have diabetes, excess glucose in your blood can attach to hemoglobin and raise the level of hemoglobin A1c.

Hematocrit

Hematocrit (hee-MAT-oh-crit) is a measure of how much space red blood cells take up in your blood. A high hematocrit level might mean you're dehydrated. A low hematocrit level might mean you have anemia. Abnormal hematocrit levels also may be a sign of a blood or bone marrow disorder.

Mean Corpuscular Volume

Mean corpuscular (kor-PUS-kyu-lar) volume (MCV) is a measure of the average size of your red blood cells. Abnormal MCV levels may be a sign of anemia or thalassemia.

Blood Chemistry Tests/Basic Metabolic Panel

The basic metabolic panel (BMP) is a group of tests that measure different chemicals in the blood. These tests usually are done on the fluid (plasma) part of blood. The tests can give doctors information about your muscles, including the heart; bones; and organs, such as the kidneys and liver.

The BMP includes blood glucose, calcium, electrolyte, and kidney tests. Some of these tests require you to fast (not eat any food) before the test, and others don't.

Blood Glucose

Glucose is a type of sugar that the body uses for energy. Abnormal glucose levels in your blood may be a sign of diabetes.

For some blood glucose tests, you have to fast before your blood is drawn. Other blood glucose tests are done after a meal or at any time with no preparation.

Calcium

Calcium is one of the most important minerals in the body. Abnormal calcium levels in the blood may be a sign of kidney problems, bone disease, thyroid disease, cancer, malnutrition, or another disorder.

Electrolytes

Electrolytes are minerals that help maintain fluid levels and acid-base balance in the body. They include sodium, potassium, bicarbonate, and chloride.

Abnormal electrolyte levels may be a sign of dehydration, kidney disease, liver disease, heart failure, high blood pressure, or other disorders.

Kidneys

Kidney tests measure levels of blood urea nitrogen (BUN) and creatinine. Both of these are waste products that the kidneys filter out of the body. Abnormal BUN and creatinine levels may be signs of a kidney disease or disorder.

Blood Enzyme Tests

Enzymes are chemicals that help control different reactions in your body. There are many blood enzyme tests. This section focuses on blood enzyme tests used to check for heart attack.

These include creatine kinase (CK) and troponin tests.

Creatine Kinase

When muscle or heart cells are injured, CK (a blood product) leaks out, and its levels in your blood rise. There are different types of CK. CK-MB is released when the heart muscle is damaged.

High CK levels can mean that you've had muscle damage in your body. High levels of CK-MB can mean that you've had a heart attack.

Doctors order CK tests (such as CK-MB) when patients have chest pain or other heart attack signs and symptoms.

Troponin

This is a muscle protein that helps your muscles contract. Blood levels of troponin rise when you have a heart attack. For this reason, doctors often order troponin tests along with CK-MB tests when patients have chest pain or other heart attack signs and symptoms.

Blood Tests To Assess Heart Disease Risk

Abnormal levels of certain chemicals in the blood may mean that you’re at higher risk for heart disease. Your doctor may want to test the levels of these chemicals to assess your risk and to suggest ways to reduce it.

Lipoprotein Panel

This test can help show how high your risk is for coronary heart disease. A lipoprotein panel looks at substances in your blood that carry cholesterol.

The test gives information about your:

• Total cholesterol.
• LDL ("bad") cholesterol. This is the main source of cholesterol buildup and blockages in the arteries.
• HDL ("good") cholesterol. This type of cholesterol helps decrease blockages in the arteries.
• Triglycerides. These are another form of fat in your blood.

A lipoprotein panel measures the levels of HDL and LDL cholesterol and triglycerides in your blood. Abnormal cholesterol and triglyceride levels may be signs of increased risk for coronary heart disease.

Most people will need to fast for 9 to 12 hours before a lipoprotein panel.

High-Sensitivity C-Reactive Protein

This is a fairly new test for heart disease risk. It looks at blood levels of C-reactive protein (CRP). High CRP blood levels can be a sign of inflammation.

Doctors use standard CRP tests to check for inflammation and autoimmune diseases. Your doctor may order an hs-CRP test, along with other tests, to see whether you’re at increased risk for heart disease.

However, CRP tests aren’t routinely done, because it’s still unclear how useful they are for showing heart disease risk.

Homocysteine

High levels of this chemical in the blood can mean that you’re at higher risk for heart attack or stroke. This isn’t a routine test for heart disease risk. But some doctors may use it, a long with other tests, if they think you’re at increased risk.

What To Expect With Blood Tests

What To Expect Before Blood Tests

Many blood tests don’t require any special preparation and take only a few minutes.

Other blood tests require fasting (not eating any food) anywhere from 8 to 12 hours before the test. Your doctor will let you know whether you need to fast for your blood test(s).

What To Expect During Blood Tests

Blood usually is drawn from a vein in your arm or other part of your body using a thin needle. It also can be drawn using a finger prick.

The person who draws your blood might tie a band around the upper part of your arm or ask you to make a fist. These things can make the veins in your arm stick out more. This makes it easier to insert the needle.

The needle that goes into your vein is attached to a small test tube. The person who draws your blood removes the tube when it's full, and the tube seals on its own. The needle is then removed from your vein. If you're getting a few different blood tests, more than one test tube may be attached to the needle before it’s withdrawn.

Some people get nervous about blood tests because they’re afraid of the needle. Others may not want to see blood leaving their bodies.

If you’re nervous or scared, it can help to look away or talk to someone to distract yourself. You might feel a slight sting when the needle goes in or comes out.

Drawing blood usually takes less than 3 minutes.

What To Expect After Blood Tests

Once the needle is withdrawn, you’ll be asked to apply gentle pressure with a piece of gauze or bandage to the place where the needle went in. This helps stop bleeding. It also helps prevent swelling and bruising.

After a minute or two, you can remove the pressure. You may want to keep a bandage on for a few hours.

Usually, you don’t need to do anything else after a blood test, except wait for the results. They can take anywhere from a few minutes to a few weeks to come back. Your doctor should get the results. It’s important that you follow up with your doctor to discuss your test results.

What Do Blood Tests Show?

Blood tests show whether the levels of different substances in your blood fall within a normal range.

For many blood substances, the normal range is the range of levels seen in 95 percent of healthy people in a particular group. For many tests, normal ranges are different depending on your age, gender, race, and other factors.

Many factors can cause your blood test levels to fall outside the normal range. Abnormal levels may be a sign of a disorder or disease. Other factors—such as diet, menstrual cycle, how much physical activity you do, how much alcohol you drink, and the medicines you take (both prescription and over-the-counter)—also can cause abnormal levels.

Your doctor should discuss any unusual or abnormal blood tests results with you. These results may or may not suggest a health problem.

Many diseases or medical problems can’t be diagnosed with blood tests alone. However, they can help you and your doctor learn more about your health. Blood tests also can help find potential problems early, when treatments or lifestyle changes may work best.

Result Ranges for Common Blood Tests

This section presents the result ranges for some of the most common blood tests.

NOTE: All values in this section are for adults only. They don’t apply to children. Talk to your child’s doctor about values on blood tests for children.

Complete Blood Count

The table below shows some normal ranges for different components of the complete blood count (CBC). Some of the normal ranges are different for men and women. Other factors, such as age and race, also may affect normal ranges.

Your doctor should discuss your results with you. He or she will advise you further if your results are outside the normal range for your group.

Test	Normal Range Results*
Red blood cell (varies with altitude)	Male: 5 to 6 million cells/mcL Female: 4 to 5 million cells/mcL
White blood cell	4,500 to 10,000 cells/mcL
Platelets	140,000 to 450,000 cells/mcL
Hemoglobin (varies with altitude)	Male: 14 to 17 gm/dL Female: 12 to 15 gm/dL
Hematocrit (varies with altitude)	Male: 41 to 50% Female: 36 to 44%
Mean corpuscular volume	80 to 95 femtoliter

* Cells/mcL = cells per microliter; gm/dL = grams per deciliter

Blood Glucose

This table shows the ranges for blood glucose levels after 8 to 12 hours of fasting (not eating). It shows the normal range and also the abnormal ranges that are a sign of prediabetes or diabetes.

Plasma Glucose Results (mg/dL)*	Diagnosis
99 and below	Normal
100 to 125	Prediabetes
126 and above	Diabetes†

* mg/dL = milligrams per deciliter.
† The test is repeated on another day to confirm the results.

Lipoprotein Panel

The table below shows ranges for total cholesterol, LDL ("bad") cholesterol, and HDL ("good") cholesterol levels after 9 to 12 hours of fasting. High blood cholesterol is a risk factor for coronary heart disease.

Your doctor should discuss your results with you. He or she will advise you further if your results are outside the desirable range.

Total Cholesterol Level	Total Cholesterol Category
Less than 200 mg/dL	Desirable
200–239 mg/dL	Borderline high
240 mg/dL and above	High

LDL Cholesterol Level	LDL Cholesterol Category
Less than 100 mg/dL	Optimal
100–129 mg/dL	Near optimal/above optimal
130–159 mg/dL	Borderline high
160–189 mg/dL	High
190 mg/dL and above	Very high

HDL Cholesterol Level	HDL Cholesterol Category
Less than 40 mg/dL	A major risk factor for heart disease
40–59 mg/dL	The higher, the better
60 mg/dL and above	Considered protective against heart disease

What Is Pulmonary Embolism?

A pulmonary embolism (PULL-mun-ary EM-bo-lizm), or PE, is a sudden blockage in a lung artery, usually due to a blood clot that traveled to the lung from a vein in the leg. A clot that forms in one part of the body and travels in the bloodstream to another part of the body is called an embolus.

• PE is a serious condition that can cause:
• Permanent damage to part of your lung from lack of blood flow to lung tissue
• Low oxygen levels in your blood
• Damage to other organs in your body from not getting enough oxygen

If the blood clot is large, or if there are many clots, PE can cause death.

Overview

In most cases, PE is a complication of a condition called deep vein thrombosis (DVT). In DVT, blood clots form in the deep veins of the body—most often in the legs. These clots can break free, travel through the bloodstream to the lungs, and block an artery. This is unlike clots in the veins close the skin's surface, which remain in place and do not cause PE.

Outlook

At least 100,000 cases of PE occur each year in the United States. PE is the third most common cause of death in hospitalized patients. If left untreated, about 30 percent of patients with PE will die. Most of those who die do so within the first few hours of the event

Other Names for Pulmonary Embolism

• Venous thromboembolism (VTE). This term is used for both pulmonary embolism and deep vein thrombosis.
  

Who Is At Risk for Pulmonary Embolism?

Populations Affected

Pulmonary embolism (PE) occurs equally in men and women. Risk increases with age: For each 10 years after age 60, the risk of PE doubles. Certain inherited conditions, such as factor V Leiden, increase the risk of blood clotting, and, therefore, the risk of PE.

Major Risk Factors

People at high risk for a blood clot that travels to the lungs are those who:

• Have deep vein thrombosis (DVT, a blood clot in the leg) or a history of DVT
• Have had PE before

Other Risk Factors

People who recently have been treated for cancer or who have a central venous catheter (a tube placed in a vein to allow easy access to the bloodstream for medical treatment) are more likely to develop DVT. The same is true for people who have been bedridden or have had surgery or suffered a broken bone in the past few weeks. Other risk factors for DVT, which can lead to PE, include sitting for long periods of time (such as on long car or airplane rides), pregnancy and the 6-week period after pregnancy, and being overweight or obese. Women who take hormone therapy or birth control pills also are at increased risk for DVT. People with more than one risk factor are at higher risk for blood clots.

What Causes Pulmonary Embolism?

Major Causes

In 9 out of 10 cases, pulmonary embolism (PE) begins as a blood clot in the deep veins of the leg (a condition known as deep vein thrombosis). The clot breaks free from the vein and travels through the bloodstream to the lungs, where it can block an artery.

Other Causes

Rarely, an air bubble, part of a tumor, or other tissue travels to the lungs and causes PE. Also, when a large bone in the body (such as the thigh bone) breaks, fat from the marrow inside the bone can travel through the blood to the lungs and cause PE.

Signs and Symptoms of Pulmonary Embolism?

Major Signs and Symptoms

Signs and symptoms of pulmonary embolism (PE) include unexplained shortness of breath, difficulty breathing, chest pain, coughing, or coughing up blood. An arrhythmia(a rapid or irregular heartbeat) also may indicate PE. In some cases, the only signs and symptoms are related to deep vein thrombosis(DVT). These include swelling of the leg or along the vein in the leg, pain or tenderness in the leg, a feeling of increased warmth in the area of the leg that's swollen or tender, and red or discolored skin on the affected leg. See your doctor at once if you have any symptoms of PE or DVT. It's possible to have a PE and not have any signs or symptoms of PE or DVT.

Other Signs and Symptoms

Sometimes people who have PE experience feelings of anxiety or dread, lightheadedness or fainting, rapid breathing, sweating, or an increased heart rate.

Treatment

Goals of Treatment The main goals of treating pulmonary embolism (PE) are to:

• Stop the blood clot from getting bigger
• Keep new clots from forming

Treatment may include medicines to thin the blood and slow its ability to clot. If your symptoms are life threatening, the doctor may give you medicine to dissolve the clot more quickly. Rarely, the doctor may use surgery or another procedure to remove the clot.

Specific Types of Treatment Medicines

Anticoagulants (AN-te-ko-AG-u-lants), which are blood-thinning medicines, decrease your blood's ability to clot. They're used to stop blood clots from getting bigger and to prevent clots from forming. They don't break up blood clots that have already formed. (The body dissolves most clots with time.)

Anticoagulants can be taken as either a pill, an injection, or through a needle or tube inserted into a vein (called intravenous, or IV, injection). Warfarin is given in a pill form. (Coumadin® is a common brand name for warfarin.) Heparin is given as an injection or through an IV tube.

Your doctor may treat you with both heparin and warfarin at the same time. Heparin acts quickly. Warfarin takes 2 to 3 days before it starts to work. Once warfarin starts to work, usually the heparin will be stopped.

Pregnant women usually are treated with heparin only, because warfarin is dangerous for the pregnancy.

If you have deep vein thrombosis, treatment with anticoagulants usually lasts for 3 to 6 months.

If you have had blood clots before, you may need a longer period of treatment. If you're being treated for another illness, such as cancer, you may need to take anticoagulants as long as risk factors for PE are present.

The most common side effect of anticoagulants is bleeding. This happens if the medicine thins your blood too much. This side effect can be life threatening. Sometimes, the bleeding can be internal. This is why people treated with anticoagulants usually receive regular blood tests. These tests are called PT and PTT tests, and they measure the blood's ability to clot. These tests also help the doctor make sure you're taking the right amount of medicine. Call your doctor right away if you have easy bruising or bleeding.

Thrombin inhibitors are a newer type of anticoagulant medicine. They're used to treat some types of blood clots for patients who can't take heparin.

Emergency Treatment

When PE is life threatening, doctors may use treatments that remove or break up clots in the blood vessels of the lungs. These treatments are given in the emergency room or in the hospital.

Thrombolytics are medicines given to quickly dissolve a blood clot. They're used to treat large clots that cause severe symptoms. Because thrombolytics can cause sudden bleeding, they're used only in life-threatening situations.

In some cases, the doctor may use a catheter to reach the blood clot. A catheter is a flexible tube placed in a vein to allow easy access to the bloodstream for medical treatment. The catheter is inserted into the groin (upper thigh) or arm and threaded through a vein to the clot in the lung. The catheter may be used to extract the clot or deliver medicine to dissolve it.

Rarely, surgery may be needed to remove the blood clot.

Other Types of Treatment

When you can't take medicines to thin your blood, or when you're taking blood thinners but continue to develop clots anyway, the doctor may use a device called a vena cava filter to keep clots from traveling to your lungs. The filter is inserted inside a large vein called the inferior vena cava (the vein that carries blood from the body back to the heart). The filter catches clots before they travel to the lungs. This prevents PE, but it doesn't stop other blood clots from forming.

Graduated compression stockings can reduce the chronic (ongoing) swelling that may occur after a blood clot has developed in a leg. The leg swelling is due to damage to the valves in the leg veins. Graduated compression stockings are worn on the legs from the arch of the foot to just above or below the knee. These stockings are tight at the ankle and become looser as they go up the leg. This causes a gentle compression (or pressure) up the leg. The pressure keeps blood from pooling and clotting.

Prevention

Preventing pulmonary embolism (PE) begins with preventing deep vein thrombosis(DVT). Knowing whether you're at risk for DVT and taking steps to lower your risk are important.

If you've never had a deep vein clot, but are at risk for it, these are steps you can take to decrease your risk.

• Exercise your lower leg muscles during long car trips and airplane rides.
• Get out of bed and move around as soon as you're able after having surgery or being ill. The sooner you move around, the lower your chance of developing a clot.
• Take medicines to prevent clots after some types of surgery (as directed by your doctor).
• Follow up with your doctor.

If you already have had DVT or PE, you can take additional steps to help keep new blood clots from forming:

• Visit your doctor for regular checkups.
• Use compression stockings to prevent chronic swelling in your legs after DVT (as directed by your doctor).

Contact your doctor at once if you have any signs or symptoms of DVT or PE.

Living With Pulmonary Embolism

Treatment for PE usually takes place in the hospital. After leaving the hospital you may need to take medicine at home for 6 months or longer. It's important to:

• Take medicines as prescribed.
• Have blood tests done as directed by your doctor.
• Talk to your doctor before taking anticoagulants with any other medicines, including over-the-counter medicines. Over-the-counter aspirin, for example, can thin your blood. Taking two medicines that thin your blood (even if one is over-the-counter) may increase your risk for bleeding.
• Ask your doctor about your diet. Foods that contain vitamin K can affect how well warfarin (Coumadin®) works. Vitamin K is found in green leafy vegetables and some oils, such as canola and soybean oil. It's best to eat a well-balanced, healthy diet.
• Discuss with your doctor what amount of alcohol is safe for you to drink if you're taking medicine.

Medicines used to treat PE can thin your blood too much. This can cause bleeding in the digestive system or the brain. If you have signs or symptoms of bleeding in the digestive system or the brain, get treatment at once.

Signs and symptoms of bleeding in the digestive system include:

• Bright red vomit or vomit that looks like coffee grounds
• Bright red blood in your stool or black, tarry stools
• Pain in your abdomen

Signs and symptoms of bleeding in the brain include:

• Severe pain in your head
• Sudden changes in your vision
• Sudden loss of movement in your legs or arms
• Memory loss or confusion

Excessive bleeding from a fall or injury also may mean that your PE medicines have thinned your blood too much. Excessive bleeding is bleeding that will not stop after you apply pressure to a wound for 10 minutes. If you have excessive bleeding from a fall or injury, get treatment at once.

Once you have had PE (with or without deep vein thrombosis (DVT)), you have a greater chance of having another one. During treatment and after, continue to:

• Take steps to prevent DVT
• Check your legs for any signs or symptoms of DVT, such as swollen areas, pain or tenderness, increased warmth in swollen or painful areas, or red or discolored skin

If you think that you have DVT or are having symptoms of PE, contact your doctor at once.