ElectricalArrhythmias that originate in thehearts upper chambers, the atria

Atrial Fibrillation (AF or A Fib)

More than 2 million people in theUnited States have atrial fibrillation,making it a very common heart rhythmdisorder. In A Fib, the heartbeat isirregular and rapid, sometimes beatingas often as 300 times a minute, aboutfour times faster than normal. Althoughit isn't life threatening, A Fib can leadto other rhythm problems, chronicfatigue and congestive heart failure.Chances of having a stroke are fivetimes higher for those with A Fib.

Atrial Flutter (AFL)

Atrial flutter is similar to A Fib because it too is characterized by a rapid heartbeat. Instead of many disorganized signals, however,AFL is caused by a single electrical wave that circulates very rapidly in the atrium, about 300 times a minute, leading to a very fast, steady heartbeat.

Sick Sinus Syndrome (SSS)

SSS is not a specific disease, but a group of signs or symptoms that indicate the hearts natural electricalpacemaker, the sinoatrial node, is notfunctioning properly. In SSS, the heartrate can switch back and forth betweena slow rate (bradycardia) and a fastrate (tachycardia). A permanent pace-maker, sometimes in combination withmedication, is the primary treatment.

Sinus Tachycardia

A harmless rhythm, sinus tachycardiais a normal increase in heart rate thathappens with fever, excitement andexercise. It does not require treatmentexcept in rare cases when an under-lying problem, such as anemia orhyperthyroidism, should be treated.

Arrhythmias that originate in thehearts lower chambers, the ventricles

Ventricular Tachycardia (VT)

Characterized by a very fast heartrate, VT usually is seen in the settingof other serious heart disease.Occasionally, it occurs in people withnormal hearts. It usually requiresprompt treatment, sometimes with

DISEASE CATEGORIES

Electrical: Abnormal heartrhythms (arrhythmias) are

caused by problems with the

electrical system that regulates

the steady, rhythmic beat of the

heart. The heartbeat may be too

slow or too fast; it may remain

steady or become chaotic. Some

arrhythmias are dangerous and

cause sudden cardiac death,

while others may be bothersome

but are not life threatening.

Circulatory: High blood pressureand coronary artery disease are

the main culprits in blood vessel

disorders. The results, such as

stroke or heart attack, can be

devastating. Fortunately, many

treatment options exist today.

Structural: Heart muscle disease(cardiomyopathy) and congenital

abnormalities are two problems

that can damage the heart muscle

or valves.

Heart Diseases and Disorders

Millions of people experience irregular heartbeats at

some point in their lives. Most of these episodes, called

arrhythmias, are harmless and happen in healthy people

free of heart disease. Sometimes, however, rhythm distur-

bances can be serious or even fatal. Other heart diseases

can be dangerous in their own right and can increase the

likelihood of arrhythmias.

Heart Diseases and Disorders

over

www.HRSpatients.orgThis information is not intended to cover all aspects of any medical condition. It is generalized and is not intended as specific medical advice.

Those with questions or who need more information should check with their physician. HEART RHYTHM SOCIETY is a service mark of the Heart Rhythm Society. All Rights Reserved. Copyright 2004 Heart Rhythm Society. Funded by a grant from the Guidant Foundation.

lo-res_Diseases_4/6.qxd 4/7/04 2:07 PM Page 1

Heart Diseases and Disorders continuedmedication. Sometimes it is treatedwith radiofrequency ablation or surgery. Often people with VT areprotected by implantation of a defibrillator. Because VT can lead to ventricular fibrillation (next item) it is considered a serious conditionthat warrants aggressive monitoringand treatment.

Ventricular Fibrillation (VF)

Sudden cardiac death, caused byventricular fibrillation, poses thegreatest threat and accounts for halfof all cardiac deaths. In VF, the heartbeat is rapid and chaotic, whichcauses the lower heart chambers, orventricles, to go into a spasm.Sometimes, however, a heart attackcan lead to VF. VF is abrupt and happens without any warning and ithalts all heart functioning. The lackof oxygen throughout the body, andespecially to the brain, is deadly. Also known as cardiac arrest, suddencardiac death is due to an electricalcircuitry problem. It is not a the sameas a heart attack, or myocardialinfarction, which is a circulatoryproblem caused by clogged bloodvessels that cut off the supply ofblood to the heart.

Although CPR can provide some benefit, the only truly effective VFtreatment is defibrillation, whichrelies on paddles or electrodes toshock the heart back to normalrhythm. Without treatment, loss ofconsciousness comes in seconds, and death is inevitable.

Other

Premature Contractions

Extra, early or skipped beats are the most frequent cause of irregularheart rhythms. These can start in theupper or lower chambers of the heart.

Long QT Syndrome (LQTS)

Long QT Syndrome is a disorder of the electrical system. It can beinherited, acquired after taking certain medications, or caused by a combination of heredity and medications. People with LQTS aresusceptible to ventricular fibrillation.

Heart Block

When electrical impulses generatedin the upper chambers of the heartare not properly transmitted to the lower chambers, Heart Blockhappens. The heart then beats tooslowly, reducing the oxygen that gets to the body and brain.

Syncope (Fainting)

Fainting, or feeling as if one mightfaint, can be caused by serious heartrhythm disorders and needs to beevaluated carefully. Sometimes thecause is not heart related, for instancewhen low blood sugar is to blame,but still can be dangerous. No matterwhat the cause, fainting can be dangerous simply because of thepotential for injuries from falling.

CirculatoryHeart Attack (Myocardial Infarction)

When arteries are clogged to thepoint of decreasing or stopping theflow of blood to the heart muscle, a lack of oxygen damages or kills heart muscle causing a heart attack.Recognizing symptoms and gettingprompt emergency treatment caneliminate, prevent or limit theamount of heart muscle damage.

Stroke

Although not true heart disorders,strokes are a related condition. Whilesome strokes occur when a bloodvessel bursts, most strokes happenfor the same reasons as a heart attack,clogged or blocked vessels. Allstrokes pose serious health threats.

StructuralHeart Failure

When the heart muscle is too weak to effectively pump bloodthrough the body, heart failure, or cardiomyopathy, sets in. Early diagnosis and treatment can stop or slow progression of heart failure.

Heart Valve Problems

Heart valve problems can be inherited or can develop and canwreak havoc on the hearts ability to push blood from chamber tochamber. Medication and surgery aretreatment options.

www.HRSpatients.orgThis information is not intended to cover all aspects of any medical condition. It is generalized and is not intended as specific medical advice.

Those with questions or who need more information should check with their physician. HEART RHYTHM SOCIETY is a service mark of the Heart Rhythm Society. All Rights Reserved. Copyright 2004 Heart Rhythm Society. Funded by a grant from the Guidant Foundation.

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