Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Atrial Fibrillation


Medical Codes

ICD-9-CM:
427.31 - Atrial Fibrillation
427.32 - Atrial flutter

Related Terms

  • AF
  • Atrial Flutter
  • Atrial Tachycardia
  • Heart Palpitations
  • Paroxysmal Atrial Fibrillation

Overview

© Reed Group
Atrial fibrillation (AF) is an abnormal heart rhythm (arrhythmia) in which the upper chambers of the heart (atria) beat irregularly, ineffectively, and very rapidly (up to 400 to 600 beats per minute) (Davis). Only a portion of the electrical impulses generated by these atrial beats will pass through the specialized heart tissue (atrioventricular [AVI] node) that normally acts as the impulse carrier to the lower chambers of the heart (ventricles). Although the resulting ventricular beat also is rapid and irregular (110 to 180 beats per minute), the ventricles beat at a slower rate than the atria. This irregular beat occurs because the atrial impulses are passed irregularly to the ventricle (through the AV node). This results in inefficient pumping action of the heart and reduced output of blood into the circulation.

Atrial fibrillation can be intermittent (paroxysmal), with abnormal atrial rhythm lasting from seconds to days; constant (persistent), but being medically returned to a normal heart beat pattern; or permanent, in which the rhythm cannot be converted back to normal. If the arrhythmia cannot be eliminated, heart rate is controlled by medications.

One common problem with atrial fibrillation is the formation of blood clots (thrombi) in the atria that can enter the bloodstream and become lodged in an artery (embolism). An embolism is particularly serious if it cuts off the blood supply leading to the brain, resulting in a stroke. For this reason, patients with persisting atrial fibrillation are traditionally treated with anticoagulant medication to decrease the incidence of embolism.

Incidence and Prevalence: An analysis of the National Hospital Discharge Survey, which collects data on discharges from nonfederal hospitals in the United States, reported over 2 million admissions for AF between 1996 and 2001. Of these admissions, 44.8% were men, 71.5% were white. The mean age was 71.1, but men were significantly younger compared to women, 67 years old vs. 75 years old, respectively (Khairallah). Although women experienced higher numbers of hospitalizations and deaths, the rates for both were higher among men (2003). The rate of AF increases with age, from <1% among persons aged <60 years to approximately 10% among persons aged >80 years (Ryder).

Current estimates of the prevalence of AF in the United States range from about 2.7 to 6.1 million in 2010. AF prevalence is projected to rise between 5.6 and 12 million by 2050 (Roger).

Source: Medical Disability Advisor



Diagnosis

History: Individuals with new onset atrial fibrillation who have the usual rapid ventricular response (heart rate 140-180 while at rest) may complain of fast or irregular heartbeats, skipped beats (palpitations), or occasional strong beats (palpitations). Anxiety, fatigue, weakness, shortness of breath (dyspnea), lightheadedness, or chest pain (angina pectoris) may also be reported. The arrhythmic symptoms may occur as sudden and temporary episodes (paroxysmally) before becoming the established (persistent) rhythm. In some individuals, atrial fibrillation may cause no symptoms if the heart rate is near normal, and it may be found incidentally.

Physical exam: Physical findings may include an irregular pulse, irregular heart sounds, and low blood pressure (hypotension). The pulse rate that is felt in the individual's wrist may be slower than the heart rate heard with auscultation of the chest (pulse deficit). This disparity occurs when the pulse fails to reach the wrist because the heart, which is only partly filled, contracts prematurely.

Individuals with chronic atrial fibrillation may be treated with enough heart medication to slow the heart rate to normal while at rest, but with the consequence that the individual is not able to adequately raise heart rate during strenuous exercise, resulting in dyspnea and fatigue during attempts at heavy exercise.

Tests: Diagnosis is confirmed by recording the electrical activity of the heart (electrocardiogram, or ECG). If the heart rhythm disturbance is intermittent, a portable electrocardiograph machine (Holter monitor) or event recorder may be used to monitor the individual's heart rate over a 24- to multi-day period. Other tests that may be performed in more seriously ill hospitalized patients include blood tests to determine if oxygen is low in the blood (hypoxia), if the pH is normal (acid-base balance), if certain dissolved substances in the blood are at abnormal levels (electrolyte imbalance), or if there are enzymes present that reveal recent heart damage (heart attack). High-frequency sound waves (ultrasound) may be used to visualize the heart (echocardiogram) to rule out heart valve problems and the presence of blood clots. Blood vessels in the heart may be visualized after injecting a contrast dye into the coronary arteries and then taking a series of x-rays (angiocardiography).

Source: Medical Disability Advisor



Treatment

Treatment involves restoration of the normal heart rate (or at least enough intervention to slow the ventricular response) and prevention of blood clots that may cause a stroke. The heart rate can usually be normalized (slowed) by administering anti-arrhythmic drugs. If atrial fibrillation persists, a short electrical shock applied to the heart (emergency defibrillation) may be necessary to restore the normal heartbeat pattern. If the atrial fibrillation is of recent onset, treatment is usually directed at remedying the underlying disorder. Anticoagulant drug therapy may be given to reduce the risk of blood clot formation and dislodgement (thromboembolism). If the individual has had atrial fibrillation for longer than a day, either testing to prove a clot (that could be embolized by defibrillation) has not already formed in the left atrium, or anticoagulation is usually performed.

If the underlying cause of the atrial fibrillation is not apparent, treatment usually consists of drugs (sedatives; digitalis, beta-blockers, calcium channel blockers) that keep the individual calm and that allow the heart to beat more slowly and strongly. Contributing factors, such as caffeine, alcohol, nicotine, or prescription drugs that may precipitate the atrial fibrillation, should be identified and avoided. The long-term use of anticoagulants in chronic atrial fibrillation may prevent blood clot formation and stroke.

If the fibrillation is persistent, chronic, or combined with severe heart disease, anti-arrhythmic drug therapy should be continued to control the heart rate. A technique called radiofrequency ablation, in which the abnormal conduction pathways between the atria and ventricles are destroyed, may be used to restore normal heart rhythms. Surgery may be necessary if the cause of the fibrillation is found to be a narrowing of the valve between the left atrium and ventricle (mitral stenosis). In some cases, a pacemaker may be inserted to override permanent atrial fibrillation. There remains ongoing discussion in the literature of the benefits of rate vs. rhythm control and whether early ablation therapy may be of benefit (Chinitz, Nielsen).

Source: Medical Disability Advisor



Prognosis

Up to 50% of individuals newly diagnosed with atrial fibrillation will revert back to normal heart rhythm spontaneously within 48 hours (Davis), although many times, the arrhythmia returns. Most individuals who experience atrial fibrillation as a one-time or intermittent event, or in conjunction with a heart attack, have successful outcomes when treated using anticoagulant drugs and/or anti-arrhythmic drugs. The individual may require several weeks of follow-up drug therapy because it often takes 4 to 6 weeks before atrial function returns to normal.

Radiofrequency ablation for atrial fibrillation has a 60% to 88% success rate (Shapira 2009; Terasawa, Balk et al. 2009). For those individuals who require emergency defibrillation, more than 90% will convert to normal heart rhythm (Davis), but there is the likelihood that they will have a recurrence of atrial fibrillation within a year. Nevertheless, most individuals (50% to 70%) with chronic or persistent fibrillation do well with drug therapy, although their need for it may be lifelong (Davis).

The likelihood of eliminating atrial fibrillation is small if it is persistent, chronic, or combined with severe heart disease. Individuals who require surgery to replace the valve between the left atrium and ventricle (mitral valve) may expect generally good results, although complications such as infection, bleeding, stroke, and heart attack may occur. Among patients with atrial fibrillation, the rate of stroke is 5% per year, from 2 to 7 times the rate of stroke in patients without atrial fibrillation (Rosenthal). Prediction of stroke risk is aided by using the CHADS2 scoring (presence of congestive heart failure, hypertension, age, diabetes, prior stroke (Rietbrock).

Source: Medical Disability Advisor



Differential Diagnosis

  • Abnormal functioning of the mitral valve (Wolff-Parkinson-White syndrome)
  • Atrial flutter with heart block
  • Paroxysmal atrial tachycardia
  • Shifting pacemaker associated with multifocal atrial ectopic beats
  • Toxic thyroid gland (thyrotoxicosis)

Source: Medical Disability Advisor



Specialists

  • Cardiologist, Cardiovascular Physician

Source: Medical Disability Advisor



Rehabilitation

If the individual required heart valve replacement surgery, please refer to the Rehabilitation section of that topic. If the atrial fibrillation developed after a pulmonary embolism, or an episode of hyperthyroidism, please refer to the Rehabilitation section of one of those topics.

Source: Medical Disability Advisor



Comorbid Conditions

  • Alcoholism
  • Cardiac surgery
  • Cardiovascular disease
  • Endocrine disorders, especially hyperthyroidism
  • Hyperthyroidism
  • Pneumonia

Source: Medical Disability Advisor



Complications

Possible complications of atrial fibrillation include formation and dislodging of a blood clot (thromboembolism) that can block blood flow to the brain, which results in a stroke. Other complications may include chest pain (angina pectoris), failure of the heart to pump blood adequately (heart failure), and life-threatening organ dysfunction (shock).

Source: Medical Disability Advisor



Factors Influencing Duration

Length of disability may be influenced by whether the condition was sudden or ongoing (chronic), the presence of underlying conditions, the method and extent of treatment, the individual's response to treatment, and the existence of complications.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

A leave of absence may be needed if surgery or prolonged drug treatment is required. Temporary transfer to sedentary activity may be needed for individuals treated with anticoagulant drugs prior to treatment with defibrillation, those who have received radiofrequency ablation, and individuals whose jobs involve strenuous physical activity or high levels of stress. Restrictions from dangerous machinery, work at dangerous heights, or hazardous work may be necessary, especially if chronic anticoagulation therapy is prescribed.

For more information regarding arrythmias, please refer to "Work Ability and Return to Work," pages 276-277.

Risk: Risk of atrial fibrillation recurrence would be due to the presence of structural heart disease, precipitating risk factors including cigarettes, alcohol, hyperthyroidism. Job risk would be of a concern if there were extreme stress at the worksite, heavy pollution or carbon monoxide exposure. Individuals with unpredictable recurrence that become syncopal with onset would not be able to participate in safety sensitive positions.

Capacity: Cardiovascular testing will be a mainstay of determining capacity. Stress testing and monitoring-either a 24-hour Holter or an event monitor may be needed.

Tolerance: Patient reporting of palpitations can be inaccurate and lead to tolerance concerns. Objective testing will help in this situation.

Source: Medical Disability Advisor



Failure to Recover

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:

  • Has individual experienced this condition previously?
  • Does individual have intermittent, constant, or permanent atrial fibrillation? If the individual is back in normal (sinus) heart rhythm, has a Holter monitor or event recorder study been done to see if episodes of recurring atrial fibrillation are occurring?
  • Does individual have anxiety, fatigue, weakness, dyspnea, or light-headedness? Has a cardiac workup established the reason for the symptom(s)?
  • Have an echocardiogram and/or cardiac catheterization been performed?
  • Has an exercise stress test been performed measure the individual's residual exercise capacity?
  • Does individual have mitral valve insufficiency? Is surgery to correct it indicated and scheduled?
  • Is unrecognized alcoholism present, that is the real, issue?

Regarding treatment:

  • Is individual compliant with anticoagulant medication? Anti-arrhythmic drugs?
  • Has individual responded to anti-arrhythmic drugs? Is the heart rate at rest adequately controlled (< 90)?
  • Is radiofrequency ablation an option? Has it been scheduled?

Regarding prognosis:

  • Does individual have any other conditions that may affect ability to recover?
  • Has individual had any complications such as a stroke, angina pectoris, or heart failure?

Source: Medical Disability Advisor



References

Cited

"Atrial fibrillation as a contributing cause of death and Medicare hospitalization--United States, 1999." MMWR - Mortality and Morbidity Weekly Report. 21 Feb. 2003. Centers for Disease Control and Prevention. 17 Jan. 2013 <http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5207a2.htm#top>.

Alonso, A., et al. "Incidence of Atrial Fibrillation in Whites and African-Americans: The Atherosclerosis Risk in Communities (ARIC) Study." American Heart Journal 158 1 (2009): 111-117. PubMed. <PMID: 19540400>.

Chinitz, J. S. , et al. "Rate or rhythm control for atrial fibrillation:update and controversies." American Journal of Medicine 125 (2012): 1049-1056.

Davis, Charles. "Atrial Fibrillation (A Fib)." eMedicine Health. Ed. Melissa Conrad Stöppler. 2 Mar. 2012. WebMD, LLC. 28 Mar. 2013 <http://www.emedicinehealth.com/atrial_fibrillation/article_em.htm>.

Go, A. S. , et al. "Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the AnTicoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study." The Journal of the American Medical Association 258 (18) (2001): 2370-2375.

Khairallah, F. , et al. "Epidemiology and determinants of outcome of admissions for atrial fibrillation in the United States from 1996 to 2001." American Journal of Cardiology 94 (4) (2004): 500-504.

Kodama, S. , et al. "Alcohol consumption and risk of atrial fibrillation: a meta-analysis." Journal of the American College of Cardiology 57 4 (2011): 427-436.

Miyasaka, Y. , et al. "Secular trends in incidence of atrial fibrillation in Olmsted County, Minnesota, 1980 to 2000, and implications on the projections for future prevalence." Circulation 114 (2) (2006): 119-125.

Nielsen, J. C. , et al. "Radiofrequenct ablation as initial therapy in paroxysmal atrial fibrillation." New England Journal of Medicine 367 (17) (2012): 1587-1595.

Rich, D. Q. , et al. "Increased risk of paroxysmal atrial fibrillation episodes associated with acute increases in ambient air pollution." Environmental Health Perspectives 114 1 (2006): 120-123.

Rietbrock, S. E. , et al. "Chronic atrial fibrillation." American Heart Journal 156 (1) (2008): 57-64.

Roger, V. L. , et al. "Atrial Fibrillation." American Heart Association. 18 Oct. 2012. American Heart Association, Inc. 17 Jan. 2013 <http://www.americanheart.org/presenter.jhtml?identifier=4451>.

Roger, V. L. , et al. "Executive summary: heart disease and stroke statistics--2012 update: a report from the American Heart Association." Circulation 125 (1) (2012): 188-197.

Roger, V. L. , et al. "Heart disease and stroke statistics--2012 update: a report from the American Heart Association." Circulation 125 (1) (2012): e2-e220.

Rosenthal, Lawrence. "Atrial Fibrillation." eMedicine. Ed. J. N. Rottman. 10 Jan. 2013. Medscape. 17 Jan. 2013 <http://emedicine.medscape.com/article/151066-overview>.

Ryder, K. M. , and E. M. Benjamin. "Epidemiology and significance of atrial fibrillation." The American journal of cardiology." American Journal of Cardiology 89 (9A) (1999): 131R-138R.

Schoonderwoerd, B. A. , et al. "New risk factors for atrial fibrillation: causes of 'not-so-lone atrial fibrillation." Europace 10 (6) (2008): 668-673.

Shapira, A. R. "Catheter ablation of supraventricular arrhythmias and atrial fibrillation." American family physician." American Family Physician 80 (10) (2009): 1089-1094.

Talmage, J. B. , J. M. Melhorn, and M. H. Hyman, eds. Work Ability and Return to Work, AMA Guides to the Evaluation of. Second ed. Chicago: AMA Press, 2011.

Terasawa, T. , et al. "Systematic review: comparative effectiveness of radiofrequency catheter ablation for atrial fibrillatio." Annals of Internal Medicine 151 3 (2009): 191-202.

Source: Medical Disability Advisor