Atrial Fibrillation - Diagnosis and Management

Effective Date: April 1, 2015

Recommendations and Topics


This guideline provides recommendations for the diagnosis and management of atrial fibrillation (AF) including the primary prevention of stroke and transient ischemic attack (TIA) in adults aged ≥19 years. This guideline focuses primarily on non-valvular AF.

This guideline is part of the - Stroke and Atrial Fibrillation series. The series includes three other guidelines: Stroke and Transient Ischemic Attack – Acute and Long-Term Management; Use of Non-Vitamin K Antagonist Oral Anticoagulants (NOAC) in Non-Valvular Atrial Fibrillation; and Warfarin Therapy Management.

Key Recommendations

  • Determine the patient’s cardiac stability and provide emergency stabilization if needed.
  • Consider all patients with atrial fibrillation for antithrombotic therapy (short and long term).
  • Establish the risk of stroke in patients with atrial fibrillation using age (≥ 65) and CHADS2.
  • Oral anticoagulants are recommended in patients with CHADS2 = 0 and age ≥ 65 years.
  • The goals of rate and/or rhythm control strategies are to improve patient symptoms, exercise tolerance, quality of life, prevent hospitalizations and improve left ventricular function.
  • Manage co-morbidities that may raise atrial fibrillation risk, such as hypertension, diabetes and heart failure.



Atrial fibrillation (AF) is a supraventricular tachyarrhythmia characterized by uncoordinated atrial activation with resulting deterioration of atrial mechanical function.1 For practical purposes, because the management differs, AF can be divided into two main types, valvular or non-valvular AF (for definitions of AF subgroups see Appendix A: Types of Atrial Fibrillation). Valvular AF is caused by significant structural changes in the valves or congenital heart disease. Therefore, valvular AF occurs in the presence of rheumatic mitral stenosis, a mechanical or bioprosthetic heart valve, or mitral valve repair. Non-valvular AF occurs in absence of rheumatic mitral stenosis, a mechanical or bioprosthetic heart valve, or mitral valve repair.

Epidemiology and Risk Factors

Individuals with AF have a 3 to 5 times greater risk for ischemic stroke.2 It is estimated that 20% of all strokes are caused by AF.2 The majority (70 - 95%)3,4 of AF cases are non-valvular.  

Approximately 44,000, or 6%, of British Columbians aged > 65 years live with AF.5,6 Key risk factors for the development of AF include increasing age, hypertension, myocardial infarction (MI), congestive heart failure, and valvular heart disease.7 Lifetime risks for the development of AF, based on the Framingham Heart Study, are 1 in 4 for men and women 40 years of age and older.8 The Rotterdam study showed that prevalence and incidence of AF increases with age.9 After the age of 55, the risk of developing AF doubles with each decade of life.5,10  

Established associations exist between AF and other cardiovascular disease processes, such as coronary heart disease, diabetes, hypertension, congestive heart failure and valvular heart disease.7,11-13 Possible causes of AF are listed in Appendix B:  Possible Causes of Atrial Fibrillation.


Patients may present with or without symptoms such as palpitations, dyspnea, dizziness, presyncope, syncope, chest pain, weakness or fatigue. Ask about palpitations and check for irregular heart rhythm during a routine exam in patients at risk for stroke.2,14,15

For patients who present with the above symptoms, ascertain if any of these symptoms are present during AF. If so, they are likely caused by AF. Refer to Appendix C: Assessing Atrial Fibrillation Symptom Severity with the CCS-SAF Scale.

A pulse check that detects an irregularity can be confirmed by an electrocardiogram (ECG).2 Ambulatory ECG monitoring (e.g., Holter) for intermittent AF can be considered after clinical evaluation, risk assessment, and baseline ECG have been completed. See - Ambulatory ECG Monitoring - Holter Monitor and Other Devices.

Standard tests used to evaluate cardiac function, identify precipitating factors and/or identify common co-morbidities, include:

  • Complete blood count – To identify comorbid conditions (e.g., anemia, infection)
  • Thyroid stimulating hormone – To identify hyperthyroidism
  • Serum creatinine & electrolytes – To assess kidney function
  • Fasting blood glucose OR hemoglobin A1c – To screen for diabetes
  • Lipid profile – To identify hyperlipidemia
  • Echocardiogram – To assess heart size and shape; chamber sizes and pressures; valve structure and function; presence of pericardial effusion; wall motion abnormalities; systolic and diastolic function.




Patients with valvular AF (AF in the presence of rheumatic mitral stenosis, a mechanical or bioprosthetic heart valve or mitral valve repair) are at significantly increased risk for ischemic stroke, and warfarin is recommended. Treatment with a non-vitamin K antagonist oral anticoagulant (NOAC; e.g., dabigatran, rivaroxaban, apixaban) is not recommended in patients with valvular AF and these drugs are not approved for use in this patient group. This is because at this time, the clinical trials for NOACs were conducted in patients with non-valvular AF only.  Rate and rhythm control recommendations are the same in valvular AF as in non-valvular AF (see below).16


Review the following 3 considerations for newly detected non-valvular AF (see Figure 1).

1. How symptomatic is the patient?

2. Should an anticoagulant be used for stroke prevention?

3. Is this a rate or rhythm control strategy?

Figure 1. Management of newly detected non-valvular atrial fibrillation17


STEP 1: How symptomatic is the patient?

Determine the patient’s cardiac stability and provide emergency stabilization if needed. Consider utilizing the Canadian Cardiovascular Society Severity of Atrial Fibrillation (CCS-SAF) scale to assess AF symptom severity and impact on quality of life. Details on classification can be found in Appendix C: Assessing Atrial Fibrillation Symptom Severity with the CCS-SAF Scale.

  • Refer for or start acute management if hemodynamically unstable.
  • Consider referral to the emergency department or start acute management if highly symptomatic (e.g., CCS-SAF = 4, severe effects on patient’s quality of life).
  • Start rate/rhythm control if not highly symptomatic (e.g., CCS-SAF ≤ 3, minimal to moderate effects on patient’s quality of life) and hemodynamically stable (systolic blood pressure > 90 mmHg, a heart rate < 120 beats per minute (BPM) and without clinical signs of shock).

STEP 2: Should an anticoagulant be used for stroke prevention?

Consider all patients with AF, including those with paroxysmal AF or intermittent AF, for antithrombotic therapy (see Figure 2). The decision to place a patient on long-term anticoagulation must be based on an analysis of risk and benefit, with consideration of patient values and preferences.

A predisposition to falls, even when considering potential head trauma, is rarely a contraindication to the use of anticoagulants in elderly patients with AF.18 Even when taking anticoagulants, the risk of subdural hematoma is so low that persons with an average risk of stroke from AF (5% per year in the absence of anticoagulation) must fall approximately 300 times in a year for the risks of anticoagulation to outweigh its benefits on a statistical basis.19

Figure 2. Recommendations for antithrombotic agent use based on age and CHADS2 Score20


Stratification of Stroke Risk

Risk stratification tools exist that use the overlapping characteristics that make up the major risk factors for ischemic stroke and systematic embolism in patients with non-valvular AF.20 There is also similar factors that are associated with increased risk of bleeding.

Scoring Stroke Risk: CHADS2

Establish the risk of stroke in patients with AF using the Cardiac failure, Hypertension, Age, Diabetes, Stroke system (CHADS2) Risk Scoring System.13

Details can be found in Appendix D: Stroke Risk Assessment in Atrial Fibrillation: CHADS2 Score. The score and the patient’s age aids in determining best treatment recommendations (see Figure 2).

Scoring Bleeding Risk: HAS-BLED

The HAS-BLED score may aid decision making as it estimates major bleeding risk in patients with AF.21 HAS-BLED is commonly used in trials but is only validated in AF patients treated with warfarin. It should be noted that ischemic stroke (and its consequences) is relatively frequent, so the competing risk of bleeding due to anticoagulant treatment may be acceptable. It is important to address and manage the causes of potential bleeding. Details can be found in Appendix E:  HAS-BLED Score for Major Bleeding.

Antithrombotic Therapy

Patients for whom anticoagulation is recommended for stroke prevention, warfarin or NOACs are available options. Existing evidence does not provide a definitive ability to recommend one class of OAC over another (see Controversies in Care below). In addition to current evidence, both the clinician and patient are encouraged to carefully consider the advantages and disadvantages of warfarin compared to the NOACs. When making a decision, the patient’s values and preferences should be taken into account.

For more information, refer to Appendix F: Comparisons of Anticoagulants for Atrial Fibrillation, Appendix G: Prescription Medication Tables for Atrial Fibrillation; and to BCGuidelines.caUse of Non-Vitamin K Antagonist Oral Anticoagulants (NOAC) in Non-Valvular Atrial Fibrillation and Warfarin Therapy Management.

There are no randomized controlled trial data for NOAC treatment for dialysis dependent patients with non-valvular AF (hemodialysis and peritoneal). Therefore, routine use of NOACs in this patient group cannot be recommended. Anticoagulation with warfarin can be considered in cases if the stroke risk is considered very high and bleeding risk low.

When any chronic anticoagulation is contraindicated and the patient is at high risk of a stroke, then alternative interventions can be considered (e.g., left atrial appendage occlusion/resection). Consider urgent consultation and/or referral to a specialist. Use of ASA might have some benefit while waiting for consultation. There is insufficient evidence to recommend an ASA dose in this setting; however, common practice is to use 81 mg/day.

Concomitant use of ASA along with anticoagulants is not recommended in most cases.19 In cases where the patient is already on ASA, consider consulting with the patient’s cardiologist first before stopping ASA when there is an indication for ASA use such as the presence of a stent.


Controversies in Care: Warfarin versus NOACs

Since the available evidence does not provide a definitive ability to recommend one class of OAC over another, international organizations provide different recommendations based on their interpretation of the same studies (see Table 1).

Table 1. Comparison of organizations’ recommendations on oral anticoagulants

STEP 3: Is this a rate or rhythm control strategy?

Table 2. Factors favouring rate versus rhythm control

Rate Control

The goals of rate control are to improve patient symptoms, exercise tolerance and quality of life, prevent hospitalizations and, where possible, to improve left ventricular function. Substantial periods of excessively rapid ventricular rates during AF or atrial flutter can lead to deterioration of cardiac function.19

The optimal level of heart rate control is unknown. A lenient rate control strategy (resting heart rate < 110 BPM) is easier to achieve and is as effective for preventing cardiovascular morbidity and mortality as a strict rate control (resting heart rate < 80 BPM and heart rate during moderate exercise < 110 BPM).26 At present, the consensus is that a resting heart rate of < 100 BPM is recommended, but the heart rate target may need modification based on patient symptoms, preferences and tolerance of rate controlling medications.17

Assess ventricular rate in all patients with persistent and permanent AF or atrial flutter. Patients with exertional symptoms may need titration according to their response to moderate exercise (e.g., brisk walking or climbing stairs).


Rate Control Drug Choices

Beta-blockers or non-dihydropyridine calcium channel blockers (non-DHP CCBs; i.e., verapamil or diltiazem) are recommended as initial treatment for rate control in most AF or atrial flutter patients without a history of MI or left ventricular dysfunction. Beta-blockers are preferred in patients with coronary artery disease.27 Digoxin is not recommended as an initial therapy for active patients because during exercise vagal tone is withdrawn, so that digoxin controls the heart less effectively than beta-blockers or non-DHP CCBs. Digoxin may be considered for patients who are sedentary or who have left ventricular systolic dysfunction in combination with beta-blockers. Digoxin may be considered as monotherapy only in particularly sedentary individuals. Refer to Appendix G: Prescription Medication Table for Atrial Fibrillation.

Figure 3. Rate control drug therapy

Rhythm Control

The goals of rhythm control therapy are to improve patient symptoms (e.g., palpitations, fatigue, exercise intolerance, or symptoms of heart failure), quality of life, as well as improve left ventricular function by restoring sinus rhythm.17

Randomized controlled trials have shown no improvement in major outcomes, including thromboembolism, of a rhythm control strategy versus rate control; however, individual patients may gain symptomatic benefit and even long-term freedom from AF after electrical or pharmacologic cardioversion. The strongest predictor of initial and persistent success with cardioversion is short (< 48 hours) duration of the AF before cardioversion.17 Rhythm control can improve left ventricular function in patients with AF and left ventricular systolic dysfunction.

Rhythm Control Drug Choices

Figure 4. Antiarrhythmic drug therapy

Consider referral for catheter ablation after failed antiarrhythmic drug therapy in patients with highly symptomatic or recurrent paroxysmal AF.2,15,17,30 Prior to either electrical or pharmacological cardioversion patients should be adequately anticoagulated to prevent thromboembolic events.1,31,32 Successful ablation does not alleviate the need for long-term anticoagulation. Long-term anticoagulation should be considered based on age and CHADS2 score model (i.e., independent of current rhythm).


Potential Indications for Referral

Cardiology or Internal Medicine:

  • A review by a specialist can be considered for patient eligibility for long-term OAC or for an alternative treatment if the patient has a contraindication to anticoagulants.
  • Consider referral if poor or incomplete response, or ongoing symptoms.

Neurology or Internal Medicine:

  • Recurrent TIA/minor stroke.

Specialty Clinics:

  • AF clinics.
  • Management of co-morbid conditions (e.g., diabetes clinics, heart failure clinics).

Management with Co-Morbid Conditions

Co-morbidities such as hypertension, diabetes33 and congestive heart failure34 raise AF risk and should be adequately managed to decrease morbidity and mortality. Bleeding risk can be reduced by managing hypertension. Hypertension control can also reduce the recurrence of AF and decrease ER visits and hospitalizations. For more recommendations on managing these conditions, refer to


Transient AF

Episodes of transient AF as short as 5 - 6 minutes have been shown to be associated with a 2 - 2.5 fold increase in strokes in patients with implanted devices.  Evidence is unclear on the risk of stroke with these transient AF events.23 Until further information is available it is reasonable to consider OAC therapy for patients age ≥ 65 years or CHADS2 score ≥ 1 who have episodes of AF lasting > 24 hours, or for shorter episodes in high-risk patients. AF is considered a marker of vascular ill health. Managing other risk factors such as hypertension and or diabetes may reduce the risk of recurring AF episodes.

Post-Operative AF

Transient AF in the post-operative setting may be a harbinger of future stroke risk. Closer monitoring of these patients for further episodes of AF may be warranted. At the present time there is no data to support use of OAC to prevent stroke or systemic emboli in patients with AF in the post-operative setting.35 But, beta-blockers are recommended as prevention and treatment of post-operative AF unless contraindicated in patients that are undergoing cardiac or thoracic surgery.16,36  Preoperative amiodarone reduces the incidence of AF with cardiac surgery and is reasonable as prophylactic therapy for patients at high risk of post-operative AF.16


Beta-blockers are recommended to control ventricular rate with AF complicating thyrotoxicosis unless contraindicated. Non-DHP CCBs are recommended to control the ventricular rate with AF and thyrotoxicosis when beta-blockers cannot be used.36

Hypertrophic Cardiomyopathy (HCM)

Anticoagulation is indicated in HCM with AF independent of the stroke risk score. Antiarrhythmic drugs can be useful to prevent recurrent AF in HCM. Amiodarone, or disopyramide combined with beta-blockers or Non-DHP CCBs are reasonable.37

Ongoing Care

In most patients the burden of AF is a progressive condition where they spend longer in AF leading to permanent AF. Screen for other conditions that impact vascular health. Reassess age and CHADS2 risk especially if previous score was 0. Patients require regular monitoring for possible adverse events from anticoagulants and assessment of renal function on a 6 monthly basis for those on NOACs. See Use of Non-Vitamin K Oral Anticoagulants in Non-Valvular Atrial Fibrillation.




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  37. Gersh BJ, Maron BJ, Bonow RO, et al. 2011 ACCF/AHA Guideline for the diagnosis and treatment of hypertrophic cardiomyopathy: A report of the American College of Cardiology Foundation/American Heart Association Task Force on practice guidelines. Circulation. 2011;124:e783-e831.



Diagnostic code: 427.3, I48


Associated Documents

The following documents accompany this guideline:


This guideline is based on scientific evidence current as of the Effective Date.

This guideline was developed by the Guidelines and Protocols Advisory Committee, approved by the British Columbia Medical Association, and adopted by the Medical Services Commission.

The principles of the Guidelines and Protocols Advisory Committee are to:

  • encourage appropriate responses to common medical situations
  • recommend actions that are sufficient and efficient, neither excessive nor deficient
  • permit exceptions when justified by clinical circumstances.

Contact Information

Guidelines and Protocols Advisory Committee
Victoria BC V8W 9P1


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The Clinical Practice Guidelines (the “Guidelines”) have been developed by the Guidelines and Protocols Advisory Committee on behalf of the Medical Services Commission. The Guidelines are intended to give an understanding of a clinical problem, and outline one or more preferred approaches to the investigation and management of the problem. The Guidelines are not intended as a substitute for the advice or professional judgment of a health care professional, nor are they intended to be the only approach to the management of clinical problem. We cannot respond to patients or patient advocates requesting advice on issues related to medical conditions. If you need medical advice, please contact a health care professional.

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