A 12-lead ECG showing<unk>  at approximately 132 beats per minute Diagram of normal sinus rhythm as seen on ECG. In<unk>  the P waves, which represent depolarization of the top of the heart, are absent. The evaluation of<unk>  involves a determination of the cause of the arrhythmia, and classification of the arrhythmia. Diagnostic investigation of<unk>  typically includes a complete history and physical examination, ECG, transthoracic echocardiogram, complete blood count, and serum thyroid stimulating hormone level. Screening Numerous guidelines recommend opportunistic screening for<unk>  in those 65 years and older. These organizations include the: • European Society of Cardiology, • National Heart Foundation of Australia and the Cardiac Society of Australia and New Zealand • European Heart Rhythm Society, •<unk> -SCREEN International Collaboration, • Royal College of Physicians of Edinburgh • European Primary Care Cardiovascular Society, and • Irish Health Information and Quality Authority. Single timepoint screening detects undiagnosed<unk> , which is often asymptomatic, in approximately 1.4% of people in this age group. A Scottish inquiry into<unk>  estimated that as many as one-third of people with<unk>  are undiagnosed. Despite this, in 2018, the United States Preventive Services Task Force found insufficient evidence to determine the usefulness of routine screening. Given the importance of having a pathway to treatment, general practice is potentially an ideal setting to conduct<unk>  screening. General practice was identified as a 'preferred' setting for<unk>  screening by the<unk> -SCREEN international collaboration report due to the availability of nursing support and the natural pathway to treatment. Screening in primary care has been trialled in a number of countries. These include: a recent Canadian study conducted in 184 general practices; a screening program conducted alongside influenza vaccinations in 10 Dutch practices; and several Australian studies showed that opportunistic screening in primary care by GPs and nurses using eHealth tools was feasible. Minimal evaluation In general, the minimal evaluation of<unk>  should be performed in all individuals with<unk> . The goal of this evaluation is to determine the general treatment regimen for the individual. If the results of the general evaluation warrant it, further studies may then be performed. History and physical examination The history of the individual's<unk>  episodes is probably the most important part of the evaluation. Distinctions should be made between those who are entirely asymptomatic when they are in<unk>  (in which case the<unk>  is found as an incidental finding on an ECG or physical examination) and those who have gross and obvious symptoms due to<unk>  and can pinpoint whenever they go into<unk>  or revert to sinus rhythm. Routine bloodwork While many cases of<unk>  have no definite cause, it may be the result of various other problems. Hence, kidney 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. In acute-onset<unk>  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. Electrocardiogram ECG of<unk>  (top) and normal sinus rhythm (bottom). The purple arrow indicates a P wave, which is lost in<unk> .<unk>  is diagnosed on an electrocardiogram (ECG), an investigation performed routinely whenever an irregular heartbeat is suspected. Characteristic findings are the absence of P waves, with disorganized electrical activity in their place, and irregular R–R intervals due to irregular conduction of impulses to the ventricles. At very<unk> st heart rates,<unk>  may look more regular, which may make it more difficult to separate from other supraventricular tachycardias or ventricular tachycardia. QRS complexes should be narrow, signifying that they are initiated by normal conduction of atrial electrical activity through the intraventricular conduction system. Wide QRS complexes are worrisome for ventricular tachycardia, although, in cases where there is a disease of the conduction system, wide complexes may be present in<unk>  with a rapid ventricular response. If paroxysmal<unk>  is suspected, but an ECG during an office visit shows only a regular rhythm,<unk>  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 person can be monitored for longer periods (e.g., a month) with an ambulatory event monitor. Echocardiography In general, a non-invasive transthoracic echocardiogram (TTE) is performed in newly diagnosed<unk> , as well as if there is a major change in the person's clinical state. This ultrasound-based scan of the heart may help identify valvular heart disease (which may greatly increase the risk of stroke and alter recommendations for the appropriate type of anticoagulation), left and right atrial size (which predicts the likelihood that<unk>  may become permanent), left ventricular size and function, peak right ventricular pressure (pulmonary hypertension), presence of left atrial thrombus (low sensitivity), presence of left ventricular hypertrophy and pericardial disease. Significant enlargement of both the left and right atria is associated with long-standing<unk>  and, if noted at the initial presentation of<unk> , suggests that the<unk>  is likely to be of a longer duration than the individual's symptoms. Extended evaluation In general, an extended evaluation is not necessary for most individuals with<unk>  and is performed only if abnormalities are noted in the limited evaluation, if a reversible cause of the<unk>  is suggested, or if further evaluation may change the treatment course. Chest X-ray In general, a chest X-ray is performed only if a pulmonary cause of<unk>  is suggested, or if other cardiac conditions are suspected (in particular congestive heart<unk> ilure). This may reveal an underlying problem in the lungs or the blood vessels in the chest. In particular, if underlying pneumonia is suggested, then treatment of the pneumonia may cause the<unk>  to terminate on its own. Transesophageal echocardiogram A regular echocardiogram (transthoracic echo/TTE) has a low sensitivity for identifying blood clots in the heart. If this is suspected (e.g., when planning urgent electrical cardioversion), a transesophageal echocardiogram/TEE (or TOE where British spelling is used) is preferred. The TEE has much better visualization of the left atrial appendage than transthoracic echocardiography. This structure, located in the left atrium, is the place where a blood clot forms in more than 90% of cases in non-valvular (or non-rheumatic)<unk> . TEE has a high sensitivity for locating thrombi in this area and can also detect sluggish blood flow in this area that is suggestive of blood clot formation. If a blood clot is seen on TEE, then cardioversion is contraindicated due to the risk of stroke, and anticoagulation is recommended. Ambulatory Holter monitoring A Holter monitor is a wearable ambulatory heart monitor that continuously monitors the heart rate and heart rhythm for a short duration, typically 24 hours. In individuals with symptoms of significant shortness of breath with exertion or palpitations regularly, a Holter monitor may be of benefit to determine whether rapid heart rates (or unusually slow heart rates) during<unk>  are the cause of the symptoms. Exercise stress testing Some individuals with<unk>  do well with normal activity but develop shortness of breath with exertion. It may be unclear whether the shortness of breath is due to a blunted heart rate response to exertion caused by excessive atrioventricular node-blocking agents, a very rapid heart rate during exertion, or other underlying conditions such as chronic lung disease or coronary ischemia. An exercise stress test will evaluate the individual's heart rate response to exertion and determine whether the AV node blocking agents are contributing to the symptoms. Classification +Classification system<unk>  category Defining characteristics First detected only one diagnosed episode Paroxysmal recurrent episodes that stop on their own in less than seven days Persistent recurrent episodes that last more than seven days Longstanding Persistent recurrent episodes that last more than twelve months Permanent<unk>  that has been accepted, and for which a solely rate control strategy has been decided upon. The American College of Cardiology (ACC), American Heart Association (AHA), and the European Society of Cardiology (ESC) recommend in their guidelines the following classification system based on simplicity and clinical relevance. All people with<unk>  are initially in the category called first detected<unk> . These people may or may not have had previous undetected episodes. If a first detected episode stops on its own in less than seven days and then another episode begins, later on, the category changes to paroxysmal<unk> . Although people in this category have episodes lasting up to seven days, in most cases of paroxysmal<unk> , the episodes will stop in less than 24 hours. If the episode lasts for more than seven days, it is unlikely to stop on its own and is then known as persistent<unk> . In this case, cardioversion can be attempted to restore a normal rhythm. If an episode continues for a year or more, the
Atrial fibrillation
Arrhythmia
Atrial flutter
Sinus arrhythmia
Ventricular flutter
Supraventricular tachycardia
Torsades de pointes
Atrial tachycardia