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Peripheral Artery Disease: causes and consequences

Coronary Artery Disease: causes and consequences

Introduction to Atrial Fibrillation

This section covers the clinical presentation, classification and origin of AF, and its management

  • In AF the atria beat irregularly and often rapidly, as a result, the ventricles cannot adequately fill with blood, cardiac output is reduced and a thrombus can form from stagnant blood in the fibrillating left atrium
  • AF can present with a variety of symptoms (listed below), which can be mild to severe in severity, but some patients have no symptoms at all:
    • Fatigue
    • Palpitations
    • Syncope/dizziness
    • Angina/chest pains
    • Dyspnoea/breathlessness
    • Stroke/transient ischaemic attack
  • AF has a heterogeneous clinical presentation, occurring in the presence or absence of detectable heart disease or related symptoms; therefore, clinical guidelines feature recommendations for appropriate classification/definition
  • AF is classified into five categories, as summarized in the Table below:
Recommendations for classification of AF, based on a guideline document by the European Society of Cardiology1, the American College of Cardiology and the American Heart Association2
Classification Clinical presentation
First diagnosed AF
  • AF that has not been diagnosed before, irrespective of the duration of the arrhythmia or the presence and severity of AF-related symptoms
Paroxysmal
  • Spontaneous/self-terminating or with intervention
  • Episode duration: ≤7 days
Persistent
  • Sustained/not self-terminating
  • Episode duration: >7 days (including episodes terminated by cardioversion ≥7 days)
Long-standing persistent
  • Continuous AF lasting for >12 months when it is decided to adopt a rhythm control strategy
Permanent
  • AF that is accepted by the patient (and physician)
  • No further attempts to restore/maintain sinus rhythm
  • Definitions of NVAF and VAF remain a matter of debate; current definitions are summarized in the table below
  • Classification of AF as VAF or NVAF facilitates identification of risk for thromboembolic events and the need for a specific antithrombotic strategy3
Current guideline definitions for NVAF and VAF
Origin of AF Definition according to guidelines1,4
NVAF AF in the absence of moderate-to-severe mitral stenosis or a mechanical heart valve
VAF AF related to moderate-to-severe mitral stenosis or an artificial (mechanical) heart valve

Because AF is frequently intermittent and can be asymptomatic or associated with non-specific symptoms, detection and diagnosis can be difficult.

 

Investigations for the clinical evaluation of AF include5

  • ECG: Upon detection of an irregular pulse, an ECG should be performed in all cases of suspected AF, whether symptomatic or not
    • With suspected paroxysmal AF, a 24-hour ambulatory ECG monitor should be used if asymptomatic episodes are suspected or if episodes are <24 hours apart
    • An event recorder ECG should be used where symptomatic episodes are >24 hours apart
  • Echocardiograms: to assess the dimensions of the left atrium and left ventricle and left ventricular wall thickness and function, and to exclude occult valvular or pericardial disease and hypertrophic cardiomyopathy
    • TTE: performed in patients with AF when:
      • A baseline echocardiogram is important for long-term management
      • A rhythm-control strategy that includes cardioversion (electrical or pharmacological) is being considered
      • There is a high risk or a suspicion of underlying structural/functional heart disease that influences subsequent management
      • Refinement of clinical risk stratification for antithrombotic therapy is needed
    • TEE: performed in patients with AF when:
      • TTE demonstrates an abnormality (such as valvular heart disease) that warrants further specific assessment
      • TEE-guided cardioversion is being considered
  • Blood tests are important for first episodes of AF and when the ventricular rate is difficult to control – these include tests of thyroid, renal and hepatic function
  • Subsequent sections consider how management approaches differ according to the type of AF and specific patient characteristics.
    • In general, management of patients with AF involves three main objectives, which are not mutually exclusive:1
      • Optimized stroke prevention
      • Symptom control with rate or rhythm control
      • Management of cardiovascular risk factors/co-morbidities
    • To find out more about the potentially serious consequences of AF and the critical nature of its management, click on the link to next section below

 

Next section: Preventing AF-Related Stroke

References
  • Hindricks G, Potpara T, Dagres N et al. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association of Cardio-Thoracic Surgery (EACTS). Eur Heart J 2020: doi:10.1093/eurheartj/ehaa612. Return to content
  • January CT, Wann LS, Alpert JS et al. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol 2014;64:e1–76. Return to content
  • Fauchier L, Philippart R, Clementy N et al. How to define valvular atrial fibrillation? Arch Cardiovasc Dis 2015;108:530–539. Return to content
  • January CT, Wann LS, Calkins H et al. 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society in collaboration with the Society of Thoracic Surgeons. Circulation 2019;140:e125–e151. Return to content
  • National Institute for Health and Care Excellence. Atrial fibrillation: management. Clinical guideline [CG180]. 2014. Available at: https://www.nice.org.uk/guidance/cg180 [accessed 20 November 2020]. National Institute for Health and Care Excellence. Atrial fibrillation: management. Clinical guideline [CG180]. 2014. Available at: https://www.nice.org.uk/guidance/cg180 [accessed 20 November 2020]. Return to content