Atrial fibrillation
From QT interval
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| MeSH | |
Atrial fibrillation (AF or afib) is a cardiac arrhythmia (abnormal heart rhythm) that involves the two upper chambers (atria) of the heart. It can often be identified by taking a pulse and observing that the heart beats don't occur at regular intervals, but a conclusive indication of AF is the absence of P waves on an electrocardiogram (ECG). AF is the most common arrhythmia; risk increases with age, with 8% of people over 80 having AF. In AF, the normal electrical impulses that are generated by the sinoatrial node are overwhelmed by disorganized electrical impulses that originate in the atria and pulmonary veins, leading to conduction of irregular impulses to the ventricles that generate the heartbeat. The result is an irregular heartbeat. This may be continuous (persistent or permanent AF) or alternating between periods of a normal heart rhythm (paroxysmal AF). The natural tendency of AF is to become a chronic condition. Chronic AF leads to a small increase in the risk of death.<ref name="pmid9737513">[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 21, 22, 22, 23, 24, 25, 26, 26, 27, 28, 29, 30, 31, 31, 31, 31, 31, 31, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 41, 41, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 57, 58, 58, 59, 59, 60, 60, 61, 61, 62, 62, 63, 63, 64, 64, 65, 65, 66, 67, 67, 68, 68, 69, 69, 70, 70, 71, 71, 72, 72, 73, 73, 74, 74, 74, 74, 74, 75, 76, 77, 78, 79, 80, 80, 80, 81, 81, 82, 83, 83, 83, 83, 84, 85, 86, 87, 88, 89, 89, 90, 90, 91, 92, 93, 94, 95, 95, 95, 96, 97, 97, 97, 98, 99, 100, 101, 102, 102, 102, 102, 103, 104, 104, 105, 105, 106, 106, 107, 107, 107, 108, 108, 108, 108, 109, 109, 110, 110, 111, 111, 112, 113, 114, 114, 115, 116, 116, 117, 117]</ref><ref>[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 21, 22, 22, 23, 24, 25, 26, 26, 27, 28, 29, 30, 31, 31, 31, 31, 31, 31, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 41, 41, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 57, 58, 58, 59, 59, 60, 60, 61, 61, 62, 62, 63, 63, 64, 64, 65, 65, 66, 67, 67, 68, 68, 69, 69, 70, 70, 71, 71, 72, 72, 73, 73, 74, 74, 74, 74, 74, 75, 76, 77, 78, 79, 80, 80, 80, 81, 81, 82, 83, 83, 83, 83, 84, 85, 86, 87, 88, 89, 89, 90, 90, 91, 92, 93, 94, 95, 95, 95, 96, 97, 97, 97, 98, 99, 100, 101, 102, 102, 102, 102, 103, 104, 104, 105, 105, 106, 106, 107, 107, 107, 108, 108, 108, 108, 109, 109, 110, 110, 111, 111, 112, 113, 114, 114, 115, 116, 116, 117, 117]</ref>
Atrial fibrillation is often asymptomatic, and is not in itself generally life-threatening, but may result in palpitations, fainting, chest pain, or congestive heart failure. Patients with AF usually have a significantly increased risk of stroke (up to 7 times that of the general population). Stroke risk increases during AF because blood may pool and form clots in the poorly contracting atria and especially in the left atrial appendage (LAA). The level of increased risk of stroke depends on the number of additional risk factors. If the AF patient has none, the risk of stroke is similar to that of the general population.<ref name="pmid17548732">[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 21, 22, 22, 23, 24, 25, 26, 26, 27, 28, 29, 30, 31, 31, 31, 31, 31, 31, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 41, 41, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 57, 58, 58, 59, 59, 60, 60, 61, 61, 62, 62, 63, 63, 64, 64, 65, 65, 66, 67, 67, 68, 68, 69, 69, 70, 70, 71, 71, 72, 72, 73, 73, 74, 74, 74, 74, 74, 75, 76, 77, 78, 79, 80, 80, 80, 81, 81, 82, 83, 83, 83, 83, 84, 85, 86, 87, 88, 89, 89, 90, 90, 91, 92, 93, 94, 95, 95, 95, 96, 97, 97, 97, 98, 99, 100, 101, 102, 102, 102, 102, 103, 104, 104, 105, 105, 106, 106, 107, 107, 107, 108, 108, 108, 108, 109, 109, 110, 110, 111, 111, 112, 113, 114, 114, 115, 116, 116, 117, 117]</ref> However, many patients do have additional risk factors and AF is a leading cause of stroke.<ref name=Wolf1978>[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 21, 22, 22, 23, 24, 25, 26, 26, 27, 28, 29, 30, 31, 31, 31, 31, 31, 31, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 41, 41, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 57, 58, 58, 59, 59, 60, 60, 61, 61, 62, 62, 63, 63, 64, 64, 65, 65, 66, 67, 67, 68, 68, 69, 69, 70, 70, 71, 71, 72, 72, 73, 73, 74, 74, 74, 74, 74, 75, 76, 77, 78, 79, 80, 80, 80, 81, 81, 82, 83, 83, 83, 83, 84, 85, 86, 87, 88, 89, 89, 90, 90, 91, 92, 93, 94, 95, 95, 95, 96, 97, 97, 97, 98, 99, 100, 101, 102, 102, 102, 102, 103, 104, 104, 105, 105, 106, 106, 107, 107, 107, 108, 108, 108, 108, 109, 109, 110, 110, 111, 111, 112, 113, 114, 114, 115, 116, 116, 117, 117]</ref>
Atrial fibrillation may be treated with medications which either slow the heart rate or revert the heart rhythm back to normal. Synchronized electrical cardioversion may also be used to convert AF to a normal heart rhythm. Surgical and catheter-based therapies may also be used to prevent recurrence of AF in certain individuals. People with AF are often given anticoagulants such as warfarin to protect them from stroke.
Contents |
Classification
The American Heart Association, American College of Cardiology, and the European Society of Cardiology have proposed the following classification system based on simplicity and clinical relevance.<ref name="pmid16908781">[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 21, 22, 22, 23, 24, 25, 26, 26, 27, 28, 29, 30, 31, 31, 31, 31, 31, 31, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 41, 41, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 57, 58, 58, 59, 59, 60, 60, 61, 61, 62, 62, 63, 63, 64, 64, 65, 65, 66, 67, 67, 68, 68, 69, 69, 70, 70, 71, 71, 72, 72, 73, 73, 74, 74, 74, 74, 74, 75, 76, 77, 78, 79, 80, 80, 80, 81, 81, 82, 83, 83, 83, 83, 84, 85, 86, 87, 88, 89, 89, 90, 90, 91, 92, 93, 94, 95, 95, 95, 96, 97, 97, 97, 98, 99, 100, 101, 102, 102, 102, 102, 103, 104, 104, 105, 105, 106, 106, 107, 107, 107, 108, 108, 108, 108, 109, 109, 110, 110, 111, 111, 112, 113, 114, 114, 115, 116, 116, 117, 117]</ref>
| AF Category | Defining Characteristics |
|---|---|
| First detected | only one diagnosed episode |
| Paroxysmal | recurrent episodes that self-terminate in less than 7 days |
| Persistent | recurrent episodes that last more than 7 days |
| Permanent | an ongoing long-term episode |
All atrial fibrillation patients are initially in the category called first detected AF. These patients may or may not have had previous undetected episodes. If a first detected episode self-terminates in less than 7 days and then another episode begins later on, the case has moved into the category of paroxysmal AF. Although patients in this category have episodes lasting up to 7 days, in most cases of paroxysmal AF the episodes will self-terminate in less than 24 hours.<ref name="pmid16908781"/> If instead the episode lasts for more than 7 days, it is unlikely to self-terminate<ref>[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 21, 22, 22, 23, 24, 25, 26, 26, 27, 28, 29, 30, 31, 31, 31, 31, 31, 31, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 41, 41, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 57, 58, 58, 59, 59, 60, 60, 61, 61, 62, 62, 63, 63, 64, 64, 65, 65, 66, 67, 67, 68, 68, 69, 69, 70, 70, 71, 71, 72, 72, 73, 73, 74, 74, 74, 74, 74, 75, 76, 77, 78, 79, 80, 80, 80, 81, 81, 82, 83, 83, 83, 83, 84, 85, 86, 87, 88, 89, 89, 90, 90, 91, 92, 93, 94, 95, 95, 95, 96, 97, 97, 97, 98, 99, 100, 101, 102, 102, 102, 102, 103, 104, 104, 105, 105, 106, 106, 107, 107, 107, 108, 108, 108, 108, 109, 109, 110, 110, 111, 111, 112, 113, 114, 114, 115, 116, 116, 117, 117] PMID 10666661</ref> and it is called persistent AF. In this case, the episode may be terminated by cardioversion. If cardioversion is unsuccessful or it is not attempted, and the episode is ongoing for a long time (e.g. a year or more), the patient's AF is called permanent.
Using this system, it's not always clear what an AF case should be called. For example, a case may fit into the paroxysmal AF category some of the time, while other times it may have the characteristics of persistent AF. One may be able to decide which category is more appropriate by determining which one occurs most often in the case under consideration.<ref name="pmid16908781"/>
Lone atrial fibrillation (LAF) is defined as atrial fibrillation in the absence of clinical or echocardiographic findings of cardiopulmonary disease, including hypertension.<ref name="pmid16908781"/>
Signs and symptoms
Atrial fibrillation is usually accompanied by symptoms related to a rapid heart rate. Rapid and irregular heart rates may be perceived as palpitations, exercise intolerance, and occasionally produce angina (if the rate is faster and puts the heart under strain) and congestive symptoms of shortness of breath or edema. Sometimes the arrhythmia will be identified only with the onset of a stroke or a transient ischemic attack (TIA). It is not uncommon for a patient to first become aware of AF from a routine physical examination or ECG, as it may be asymptomatic in many cases.<ref name="pmid16908781"/>
As most cases of atrial fibrillation are secondary to other medical problems, the presence of chest pain or angina, symptoms of hyperthyroidism (an overactive thyroid gland) such as weight loss and diarrhea, and symptoms suggestive of lung disease would indicate an underlying cause. A previous history of stroke or TIA, as well as hypertension (high blood pressure), diabetes, heart failure and rheumatic fever, may indicate whether someone with AF is at a higher risk of complications.<ref name="pmid16908781"/>
Diagnosis
The evaluation of atrial fibrillation involves diagnosis, determination of the etiology of the arrhythmia, and classification of the arrhythmia. A minimal evaluation should be performed in all individuals with AF. This includes a history and physical examination, ECG, transthoracic echocardiogram, and routine bloodwork. Certain individuals may benefit from an extended evaluation which may include an evaluation of the heart rate response to exercise, exercise stress testing, a chest x-ray, trans-esophageal echocardiography, and other studies.
Screening
Screening for atrial fibrillation is not generally performed, although a study of routine pulse checks or ECGs during routine office visits found that the annual rate of detection of AF in elderly patients improved from 1.04% to 1.63%; selection of patients for prophylactic anticoagulation would improve stroke risk in that age category.<ref name="pmid17673732">[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 21, 22, 22, 23, 24, 25, 26, 26, 27, 28, 29, 30, 31, 31, 31, 31, 31, 31, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 41, 41, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 57, 58, 58, 59, 59, 60, 60, 61, 61, 62, 62, 63, 63, 64, 64, 65, 65, 66, 67, 67, 68, 68, 69, 69, 70, 70, 71, 71, 72, 72, 73, 73, 74, 74, 74, 74, 74, 75, 76, 77, 78, 79, 80, 80, 80, 81, 81, 82, 83, 83, 83, 83, 84, 85, 86, 87, 88, 89, 89, 90, 90, 91, 92, 93, 94, 95, 95, 95, 96, 97, 97, 97, 98, 99, 100, 101, 102, 102, 102, 102, 103, 104, 104, 105, 105, 106, 106, 107, 107, 107, 108, 108, 108, 108, 109, 109, 110, 110, 111, 111, 112, 113, 114, 114, 115, 116, 116, 117, 117]</ref>
Routine primary care visit
This estimated sensitivity of the routine primary care visit is 64%. This low result probably reflects the pulse not being checked routinely or carefully.<ref name="pmid17673732">[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 21, 22, 22, 23, 24, 25, 26, 26, 27, 28, 29, 30, 31, 31, 31, 31, 31, 31, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 41, 41, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 57, 58, 58, 59, 59, 60, 60, 61, 61, 62, 62, 63, 63, 64, 64, 65, 65, 66, 67, 67, 68, 68, 69, 69, 70, 70, 71, 71, 72, 72, 73, 73, 74, 74, 74, 74, 74, 75, 76, 77, 78, 79, 80, 80, 80, 81, 81, 82, 83, 83, 83, 83, 84, 85, 86, 87, 88, 89, 89, 90, 90, 91, 92, 93, 94, 95, 95, 95, 96, 97, 97, 97, 98, 99, 100, 101, 102, 102, 102, 102, 103, 104, 104, 105, 105, 106, 106, 107, 107, 107, 108, 108, 108, 108, 109, 109, 110, 110, 111, 111, 112, 113, 114, 114, 115, 116, 116, 117, 117]</ref>
Minimal evaluation
The minimal evaluation of atrial fibrillation should generally be performed in all individuals with AF. The goal of this evaluation is to determine the general treatment regimen for the individual. If results of the general evaluation warrant it, further studies may be then performed.
History and physical examination
The history of the individual's atrial fibrillation episodes is likely the most important part of the evaluation. Distinctions should be made to those who are entirely asymptomatic when they are in AF (in which case the AF is found as an incidental finding on an ECG or physical examination) and those who have gross and obvious symptoms due to AF and can pinpoint whenever they go into AF and revert to sinus rhythm.
Routine bloodwork
While many cases of AF have no definite cause, it may be the result of various other problems (see below). Hence, renal function and electrolytes are routinely determined, as well as thyroid-stimulating hormone (commonly suppressed in hyperthyroidism and of relevance if amiodarone is administered for treatment) and a blood count.<ref name="pmid16908781"/>
In acute-onset AF associated with chest pain, cardiac troponins or other markers of damage to the heart muscle may be ordered. Coagulation studies (INR/aPTT) are usually performed, as anticoagulant medication may be commenced.<ref name="pmid16908781"/>
Electrocardiogram
Atrial fibrillation is diagnosed on an electrocardiogram (ECG), an investigation performed routinely whenever irregular heart beat is suspected. Characteristic findings are the absence of P waves, with unorganized electrical activity in their place, and irregularity of R-R interval due to irregular conduction of impulses to the ventricles.<ref name="pmid16908781"/>
When ECGs are used for screening, the SAFE trial found that electronic software, primary care physicians and the combination of the two had the following sensitivities and specificities:<ref name="pmid17604299">[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 21, 22, 22, 23, 24, 25, 26, 26, 27, 28, 29, 30, 31, 31, 31, 31, 31, 31, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 41, 41, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 57, 58, 58, 59, 59, 60, 60, 61, 61, 62, 62, 63, 63, 64, 64, 65, 65, 66, 67, 67, 68, 68, 69, 69, 70, 70, 71, 71, 72, 72, 73, 73, 74, 74, 74, 74, 74, 75, 76, 77, 78, 79, 80, 80, 80, 81, 81, 82, 83, 83, 83, 83, 84, 85, 86, 87, 88, 89, 89, 90, 90, 91, 92, 93, 94, 95, 95, 95, 96, 97, 97, 97, 98, 99, 100, 101, 102, 102, 102, 102, 103, 104, 104, 105, 105, 106, 106, 107, 107, 107, 108, 108, 108, 108, 109, 109, 110, 110, 111, 111, 112, 113, 114, 114, 115, 116, 116, 117, 117]</ref>:
- Interpreted by software: sensitivity = 83%, specificity = 99%
- Interpreted by a primary care physician: sensitivity = 80%, specificity = 92%
- Interpreted by a primary care physician with software: sensitivity = 92%, specificity = 91%
If paroxysmal AF is suspected but an ECG during an office visit only shows a regular rhythm, AF episodes may be detected and documented with the use of ambulatory Holter monitoring (e.g. for a day). If the episodes are too infrequent to be detected by Holter monitoring with reasonable probability, then the patient can be monitored for longer periods (e.g. a month) with an ambulatory event monitor.<ref name="pmid16908781"/>
Echocardiography
A non-invasive transthoracic