| An arrhythmia is a disturbance of the heart's rhythm. An arrhythmia may result in a fast (tachycardia) or slow (bradycardia) heartbeat and produce an even (regular) or uneven (irregular) rhythm. An arrhythmia may occur suddenly (paroxysmal) or be long-standing (chronic). It may arise from the upper chambers (atria) or the lower chambers (ventricles) of the heart.
A common arrhythmia is caused by early (premature) beats that result in a compensatory pause to allow the next beat to occur on time. Because they make it feel like the heart missed a beat, they are widely referred to as "skipped beats."
Premature beats arising from the atria are called premature atrial contractions (PACs), while premature beats arising from the ventricles are called premature ventricular contractions (PVCs). PACs and PVCs do not necessarily indicate heart disease. Many normal, healthy individuals have PACs or PVCs at rest or during sleep, which then vanish when they are awake and active because the faster waking heart rate and activity "suppress" the early beats. Athletes commonly experience PACs and PVCs at rest because they have a slower resting heart rate from being physically fit.
PVCs can, however, attest to the presence of potentially serious underlying heart disease. They may also indicate cardiac dysfunction due to narrowing of the coronary arteries secondary to cholesterol deposits, commonly called hardening of the arteries (atherosclerosis). This condition leads to insufficient oxygen reaching the heart muscle (myocardial ischemia).
PVCs are classified as simple or complex. Simple PVCs are defined as single, early beats that occur amidst normal, regular beats. Complex PVCs are defined as two or more PVCs in a row that arise from more then one site (focus) within the heart (multifocal). Complex PVCs are more likely to be associated with underlying heart disease than simple PVCs. If a number of PVCs occur in a row, the resulting arrhythmia is known as ventricular tachycardia. This can be a life-threatening arrhythmia, especially if it deteriorates into uncoordinated contractions of the ventricles (ventricular fibrillation)
Two common arrhythmias arising from the atria are paroxysmal atrial tachycardia (PAT) and atrial fibrillation (AF). PAT often occurs in young, healthy individuals without heart disease. The heart beats at a rate of 150 to 250 beats per minute (BPM) rather than the normal 60 to 100 BPM. Despite the fast beating, individuals usually feel fine because they are young and healthy.
AF is also known as tachycardia and may occur in otherwise healthy individuals as well as those with significant heart disease. In healthy individuals, excess caffeine or alcohol, fatigue, some street drugs, and diet pills may cause AF. In other individuals, atherosclerosis, an overactive thyroid gland, rheumatic heart disease, lung disease, and inflammation of the surface of the heart (pericarditis) following open-heart surgery can cause AF. In older individuals, rapid AF may alternate with a slow heart rate rhythm; in these individuals, there is a delayed or disconnected rhythm between the atria and ventricles, such that ventricular function becomes totally independent from that of their atria (sick sinus syndrome, sinus node dysfunction, tachycardia-bradycardia syndrome).
The prevalence of atrial and ventricular arrhythmias tends to increase with age, even when there is no clear sign of heart disease. Other factors that may increase the risk of arrhythmias include certain congenital conditions, atherosclerosis, high blood pressure, high or low blood and tissue concentrations of a variety of minerals (such as potassium, magnesium and calcium), alcohol intake, sleeplessness, stress, cigarette smoking, recreational drug use, caffeine intake, various cardiac medications (including drugs used to treat an arrhythmia), coronary heart disease, a heart attack or heart failure, heart valve disease, an inflamed heart muscle or lining (endocarditis), recent heart surgery, lung disease, thyroid disorders, and diabetes.
Arrhythmias can occur in healthy individuals with no consequences, but may also indicate a serious problem and lead to heart disease, stroke, or sudden cardiac death. Individuals should be encouraged to make an appointment with a physician or go to the hospital for an evaluation if they feel something is wrong.Incidence and Prevalence: Arrhythmias are common and occur throughout the population. During a 24-hour period, about one-fifth of healthy adults are likely to have frequent or multiple types of premature ventricular beats and as many as 2.2 million Americans are living with AF ("Arrhythmia"). |
Source: Medical Disability Advisor
| History: Individuals may report chest pain and the sensation of a heavy or irregular heartbeat, dizziness, fainting (syncope), anxiety, or shortness of breath. Symptoms usually begin suddenly. Current use of medications such as prescription or over-the-counter drugs, herbal products, diet pills, or illegal drugs should be noted. Other useful information includes any stress the individual may be under, intake of caffeine-containing food or drink, and smoking history. Physical exam: A rapid, slow, or irregular heart rate can be felt in the pulse or by listening to the heart. Blood pressure may be low. Signs of heart failure such as difficulty breathing (dyspnea), wheezing, cough, pallor or blue tinged skin or nails (cyanosis), abdominal distension, fainting, or swelling of the feet and ankles (edema) may be present. The feet may appear swollen due to circulation complications. The exam may also reveal a heartbeat that does not match the pulse at the wrist (apical radial heartbeat). If the arrhythmia is not present at the time, the physical exam may be completely normal. Tests: An electrocardiogram (ECG) records the heart's electrical activity and is used to diagnose most arrhythmias. If the arrhythmia is not captured on an ECG, some individuals may be required to wear a portable monitor to record heart activity for 24 hours to document an intermittent arrhythmia. Blood chemistry may help find any chemical imbalance that may be causing the arrhythmias. A special (esophageal) ECG is occasionally needed for diagnosis. A stress ECG taken while the individual is performing an exercise such as rapid walking may be done in the evaluation of an arrhythmia.
Arrhythmias can frequently be detected on ECGs that are done while the individual is resting and lying down. However, when the individual is exercising, the early beats often go away. At other times the arrhythmia only occurs with exercise. |
Source: Medical Disability Advisor
| Simple PVCs are usually not treated. Although many antiarrhythmia drugs are available, many complex PVCs are not treated because the drugs may be ineffective, cause significant side effects, or make the arrhythmia worse (pro-arrhythmia effect).
PAT is often treated using the Valsalva maneuver, which involves having the individual hold his or her breath and strain down as if attempting to lift a heavy object. Rubbing on the side of the neck with the index finger (carotid sinus massage) can also stop PAT. Long-term treatments to prevent recurrences include medications such as digitalis and beta-blockers. Long-term therapy is not used as often if an individual's bouts of PAT are infrequent and easily terminated by a Valsalva maneuver or carotid sinus massage.
PAF or chronic AF is more apt to be treated. In the case of PAF, treatment includes avoiding those stimulants that can cause the arrhythmia such as excess caffeine or alcohol and diet pills. Digitalis, quinidine, and other similar drugs may be used if necessary. Chronic AF is treated with digitalis, certain calcium channel blockers, or beta-blockers to keep the ventricles from beating too fast even though the atria continue to beat fast and irregularly (fibrillate). Anticoagulants are often used to decrease the chances of an embolus somewhere in the body.
Bradycardias that are due to a condition in which the ventricles do not beat fast enough (heart block) are often treated with installation of a permanent pacemaker. Although pacemakers have a small incidence of associated technical problems and require that the battery be changed every 5 to 10 years, they are very effective in the treatment of bradycardias. |
Source: Medical Disability Advisor
| The predicted outcome of arrhythmias varies widely depending on the type of arrhythmia. Simple PVCs and PAT usually have a good outcome, and longevity is not affected in the majority of cases. Complex PVCs may result in no significant effect on survival if they are eradicated or well controlled by drugs. However, the underlying heart problem may affect survival.
The survival rates of chronic AF vary widely depending on the presence or absence of underlying heart disease. In individuals without any underlying heart disease (lone AF), longevity is not affected. In individuals with underlying heart disease (such as congestive heart failure), complications increase and survival decreases. |
Source: Medical Disability Advisor
| A rapid arrhythmia can result in chest pain (angina) or a heart attack (myocardial infarction) if there is underlying coronary artery disease. A very slow arrhythmia can result in loss of consciousness and associated injury. AF can lead to blood clot formation in the atria. The clots can break loose (embolize) and cause a stroke or other serious illness. Ventricular arrhythmias may actually cause the heart to beat wildly so that emergency medical intervention is required to save the individual's life.
Medications used to treat arrhythmia may cause more arrhythmias or make them worse. |
Source: Medical Disability Advisor
| If the arrhythmia involves temporary disturbances in consciousness, chest pain, or dizziness, a restriction of hazardous work environments such as operating dangerous machinery or exposed heights may be required. |
Source: Medical Disability Advisor
| If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case. Regarding diagnosis:
- Did individual exhibit symptoms of an arrhythmia such as palpitations, dizziness, shortness of breath, or chest pain?
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Does individual smoke or use prescription or nonprescription medicines?
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Does individual have history of excessive fatigue, caffeine intake, or coronary artery disease?
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Was heart rate rapid, slow, or irregular during examination? Was blood pressure low?
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Did individual show signs of heart failure such as dyspnea, wheezing, cough, cyanosis, edema of the feet and ankles, abdominal distension, or fainting?
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Was the presence and type of arrhythmia confirmed with an ECG or Holter monitoring?
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Did individual feel like his or her heart missed a beat?
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Was the arrhythmia a PAC or PVC?
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What was individual's overall state of health?
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Was individual an athlete?
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Did individual have simple or complex PVCs? Have a number of PVCs occurred in a row, indicating ventricular tachycardia?
Regarding treatment:
- Was there an underlying cause for which individual was treated?
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Were contributory factors such as smoking or alcohol use eliminated?
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Were anti-arrhythmics prescribed? Did individual experience any side effects?
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Were long-term treatment medications (i.e., digitalis and beta-blockers) necessary?
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Was a pacemaker necessary?
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Did individual have a rapid atrial or ventricular arrhythmia that did not respond to medications and so necessitated the use of electrical cardioversion?
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Was surgical ablation performed?
Regarding prognosis:
- Did individual suffer an arrhythmia considered life-threatening?
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Was the arrhythmia associated with a myocardial infarction or cardiac arrest?
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Does individual have any underlying conditions (cardiac disease, pulmonary disease, thyroid disorders, obesity, smoking, alcohol, or substance abuse) that may impact ability to recover?
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Source: Medical Disability Advisor
| "Arrhythmia." American Heart Association. 22 Oct. 2004. American Heart Association, Inc. 22 Oct. 2004 <http://www.americanheart.org/presenter.jhtml?identifier=10845>. |
Source: Medical Disability Advisor
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