Arrhythmias are abnormalities of the heartbeat. There are many types of arrhythmias, and they are classified by some researchers and doctors by where they begin in the heart (the atria, AV node, or the ventricles). Others classify arrhythmias as one of four types -- premature beats, supraventricular, ventricular, and bradyarrhythmias. Generally speaking, those that do not originate from the ventricles are called supraventricular arrhythmias while those that come from the ventricles are called ventricular arrhythmias. The arrhythmias that can often lead to death in minutes are ventricular fibrillation and ventricular tachycardia. Although others may also cause death, these two arrhythmias can quickly and severely alter the heart's ability to effectively pump blood. Immediate electrocardioversion to put the heart back into a more effective rhythm that allows the heart to pump blood effectively can be life-saving.
The following are some of the more commonly encountered arrhythmias, starting with the supraventricular arrhythmias.
Arrhythmias arising in the ventricle (ventricular arrhythmias) are more likely to be found in people with more serious heart disease but may also be found in healthy individuals.
Bradyarrhythmias produce heart rates that are too slow to allow enough blood to be pumped during either time of demand (stress or increased activity) or even during normal activity. Bradyarrhythmias are usually slower than 60 beats per minute. For example, the person may become dizzy and pass out when they try to stand up because not enough blood is pumped into the brain.
Arrhythmias can be frightening, but in many cases, especially in younger people with normal underlying arrhythmias, they are not life-threatening and can be effectively treated with medications.
The purpose of this article is to give the reader an introduction to arrhythmias. Each disorder or arrhythmia has been studied in great detail by many investigators so there are books and articles devoted to each type of arrhythmia. The reader is advised to click onto the references for more detail on each type of arrhythmia for more in depth details about diagnosis, treatments, and outcomes. Specific details for each type and subtype of disorder are far beyond the scope of this introductory article.
Many arrhythmias cause no or minimal symptoms. Other people, however, can actually feel the arrhythmia when it happens.
Common symptoms include the following:
In addition, some can experience symptoms that are more generalized, including the following:
On the other hand, people may feel many of the sensations described above and have no arrhythmias whatsoever. These symptoms may be due to anxiety, stress, or other causes besides an abnormal heartbeat.
Among individuals without known heart disease, arrhythmias are generally random, isolated occurrences that do not carry any significance. However, an evaluation by a physician is advised if a person notices any unusual or abnormal heart beats, especially if they reoccur or are sustained.
A variety of heart diseases cause arrhythmias. Heart disease can refer to patients with coronary artery disease, heart valve problems, heart failure, or disorders with heart conduction, or high blood pressure. Remember, however, that having an arrhythmia does not necessarily mean that a person has heart disease. Arrhythmias have many causes; sometimes the cause of an arrhythmia is never determined, other times the cause may be easy to determine and treat.
Sometimes, conditions other than heart disease may cause or aggravate arrhythmias. These conditions include the following:
Most people have noticed their heart racing, a fluttering in the chest, or a sensation that the heart skipped a beat. If this happens once, or very infrequently, with no other symptoms, it is usually not serious and medical care is usually not needed. However, any questions or concerns should be discussed with a health care professional. If the person is prescribed a medication, the health care professional should also be notified if a recommended treatment does not alleviate the symptoms.
More serious symptoms should be evaluated immediately at the nearest hospital emergency department. These symptoms include:
People experiencing these symptoms should not drive to the emergency department. They should call 9-1-1 for emergency medical transport.
Evaluation of rhythm disorders usually requires a detailed discussion of symptoms and a physical exam with a health care professional.
In addition, an electrocardiogram (ECG or EKG) is mandatory to establish the exact type of arrhythmia. If the rhythm disturbance is present while the ECG is being recorded, the problem may be identified immediately. Otherwise, more specialized testing may be required. A 24-hour (or longer) recording of the heartbeat is often necessary to detect any rhythm problem that occurs daily but not constantly. (For examples of EKGs of various arrhythmias, the reader is urged to see the references provided in this introductory article.)
However, if the arrhythmia is even more infrequent, an event recorder may be used. These recorders can be hand-held machines that are activated by the patient whenever he or she feels symptoms. These event recorders can be worn for variable amounts of time from days to weeks in order to detect changes in the heart's rhythm. Some recorders are placed surgically under the skin and left there for up to 1 year.
An ultrasound of the heart, called an echocardiogram, is often used for an evaluation of the structure and function of the heart that may help identify underlying causes that lead to arrhythmias.
In general, arrhythmias in children are diagnosed with most of the same tests that are used in adults.
The treatment of arrhythmias varies depending on the presence or absence of symptoms, how frequent the arrhythmia occurs, and the seriousness of any underlying heart condition. The majority of arrhythmias are either not treated or are treated with medications taken by mouth. Some arrhythmias must be treated emergently with electrocardioversion or the patient will die. For others, the treatment may range from vagal maneuvers (for example, the Valsalva, a maneuver of breath holding and bearing down) to medication to more advanced surgical procedures, such as an internal implanted pacemaker or cardiac defibrillator (ICD). Sometimes, no treatment is necessary because the arrhythmia resolves.
Except in life-threatening emergencies, a person should have a detailed discussion of the tests and treatment options with the health care professional to be clear about the tests and potential treatment options before any tests or surgery is done. This discussion should include the risks and benefits the patient may have if they choose to have or not have specific treatments or surgical procedures done.
The choice and use of medications depends on the specific type of arrhythmia present. Although detailed discussion about this is beyond the scope of this article, the reader is encouraged to click onto the links to the predominant arrhythmias to determine the common medications and common surgical methods used to treat these heart beat disorders.
Although some arrhythmias may require some special uses of medications (for example, IV adenosine for PSVT), most utilize various beta-blockers and calcium channel blockers to control fast rates. Although atropine may be used for a short time to speed up heart rates, usually the treatment will be a pacemaker.
The most common electrical and surgical treatments are listed as follows:
Electrical cardioversion is most often used in emergencies, although patients with certain arrhythmias who are stable may have electrical cardioversion done non-emergently. Most of the surgical procedures (implants) are done in patients whose arrhythmias are under medical control (temporarily or longer-term).
Follow-up is usually done with the primary care professional and often with a heart specialist (cardiologist). The patient is monitored for effectiveness of treatment, recurrence of symptoms or arrhythmia, side effects of medication, additional routine testing, and overall condition. For those requiring pacemakers, follow-up on a regular basis is mandatory. Patients are advised to make all follow-up appointments and should not attempt to change their medications without first consulting their doctor(s).
The detection and management of heart rhythm disorders are undergoing constant improvement. The past years have seen an unprecedented explosion of information about these conditions. Detection and management of heart rhythm disorders has improved the quality and quantity of life. However, patients need to keep follow-up appointments and maintain their medications because not doing this can severely reduce a person's outcome. Untreated, ignored, or "undertreated" serious arrhythmias can result in syncope, strokes, heart failure, and sudden death.
Atrial fibrillation is a type of arrhythmia, and may cause no symptoms in some people. A number of people have no symptoms. When signs and symptoms do occur they may include:
