Electrophysiology CINRE, hospital BORY
Atrial Fibrillation: Guidelines (2026) Compendium / 1.1 Atrial Fibrillation – Guidelines (2026) in Practice

Atrial Fibrillation – Guidelines (2026) in Practice

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Fundamentals and Diagnosis of AF

1.1Prevention of AF
1.2Diagnosis of AF
1.3Screening for AF
1.4Symptoms of AF
1.5Classification of AF
1.6Terminology of AF
1.7Investigations in a Patient with Newly Diagnosed AF

Anticoagulant Therapy and Stroke Prevention in AF

2.1Anticoagulant Therapy and Thromboembolism in AF
2.2Bleeding Risk and Anticoagulant Therapy
2.3Left Atrial Appendage Occlusion
2.4ESUS and AF

Specific Clinical Situations in AF

3.1Acute Conditions and AF
3.2Atrial Flutter and AF
3.3Coronary Syndrome and AF
3.4Postoperative AF
3.5Pregnancy and AF

Antiarrhythmic Therapy and AF

4.1Antiarrhythmic Drugs - Rate Control in AF
4.2Antiarrhythmic Drugs - Rhythm Control in AF
4.3Antiarrhythmic Drugs - Main Contraindications

Cardioversion of AF

5.1Cardioversion of AF

AF Ablation

6.1AF Ablation
6.2Anticoagulant Therapy and AF Ablation
Infographic of key Slovak recommendations for atrial fibrillation illustrating treatment strategies including catheter ablation, antithrombotic therapy, ECG monitoring, and guideline classes I, IIa, IIb, and III.

These guidelines are unofficial and do not represent formal guidelines issued by any professional cardiology society. They are intended for educational and informational purposes only.

Peter Blahut, MD

Peter Blahut, MD (Twitter(X), LinkedIn, PubMed)

Fundamentals and Diagnosis of AF


1.1 Prevention of AF

Comorbidities and Risk Factors of Atrial Fibrillation Class
Diagnosis and treatment of comorbidities (associated diseases) and elimination of risk factors are fundamental components of the prevention and management of atrial fibrillation. Comorbidities and risk factors of atrial fibrillation:
  • Arterial hypertension
  • Heart failure
  • Diabetes mellitus
  • Overweight and obesity
  • Lack of physical activity
  • Alcohol
  • Smoking
  • Sleep apnoea syndrome
 I

1.2 Diagnosis of AF

Diagnosis of Atrial Fibrillation Class

Atrial fibrillation is diagnosed primarily using ECG:

  • Smart devices with ECG (ECG watch, blood pressure monitor with ECG, ECG card)
  • 12-lead ECG
  • ECG Holter monitoring
  • Implantable loop recorder
 I
The diagnosis of atrial fibrillation based on ECG must be confirmed by a physician in the outpatient setting or online via a reliable platform, for example www.ECGsmart.com I

1.3 Screening for AF

Screening for atrial fibrillation and devices Class

For AF screening, any device capable of recording an ECG is recommended:

  • Smart device with ECG (ECG watches, blood pressure monitors with ECG, ECG cards)
  • 12-lead ECG
  • ECG Holter monitoring
  • Implantable loop recorder
 I
The diagnosis of atrial fibrillation based on ECG must be confirmed by a physician in an outpatient setting, or online via a trusted platform, e.g. www.ECGsmart.com I

1.4 Symptoms of AF

Classification of atrial fibrillation symptoms Class
Symptoms in patients with AF are classified into 5 classes:
  • Asymptomatic AF (I)
  • Oligosymptomatic AF (IIa)
  • Mildly symptomatic AF (IIb)
  • Moderately symptomatic AF (III)
  • Severely symptomatic AF (IV)
 I
AF symptoms are assessed regularly, especially before and after major treatment or after significant modification of risk factors. I

1.5 Classification of AF

Classification of Atrial Fibrillation Class

Atrial fibrillation is classified according to episodes and valvular disease into:

  • Newly diagnosed AF (date of first documented AF on ECG)
  • Paroxysmal AF
  • Persistent AF
  • Permanent AF
  • Valvular AF
    • (mechanical valve or mitral stenosis – moderate or severe)
 I

1.6 Terminology of AF

Terminology of Atrial Fibrillation in Clinical Practice Class

The most commonly used AF terminology in clinical practice:

  • Clinical AF
  • Subclinical AF (AHRE)
  • Asymptomatic AF
  • Silent AF
  • New-onset AF
  • Triggered AF
  • AF burden
  • Tachycardia-induced cardiomyopathy
 I

1.7 Investigations in a Patient with Newly Diagnosed AF

Investigations in a Patient with Newly Diagnosed Atrial Fibrillation Class

In every patient with newly diagnosed AF, the following investigations are recommended:

  • Blood pressure measurement
  • BMI assessment
  • Laboratory tests
  • 12-lead ECG
  • Transthoracic echocardiography
  • Exercise testing or CT coronary angiography
 I
Endocrinopathies and atrial fibrillation Class
In every patient with newly diagnosed atrial fibrillation, the following are recommended:
  • TSH, fT4 (thyroid parameters)
  • Fasting glucose, HbA1c (diabetes mellitus)
  • K (primary hyperaldosteronism)
  • Ca, P (primary hyperparathyroidism)
 I

Anticoagulant Therapy and Stroke Prevention in AF


2.1 Anticoagulant Therapy and Thromboembolism in AF

Antithrombotic therapy and atrial fibrillation Class
For prevention of thromboembolism in AF, anticoagulant therapy (not antiplatelet therapy) is recommended. Anticoagulant therapy is indicated according to the CHA2DS2-VA score. I
For the prevention of thromboembolism in patients with AF, the combination of anticoagulation and antiplatelet therapy is not recommended. III
Thromboembolic risk and atrial fibrillation Class
Atrial fibrillation is one of the major risk factors for thromboembolism, regardless of whether AF is paroxysmal, persistent, permanent, symptomatic, or asymptomatic. I
Annual thromboembolic risk in % is estimated using the CHA2DS2-VASc score or the newer CHA2DS2-VA score (since 2024). I
Thromboembolism (Ischemic Stroke) and Atrial Fibrillation Class
Oral anticoagulant therapy in patients with AF is indicated according to the CHA2DS2-VA score,
  • regardless of whether AF is paroxysmal, persistent, permanent, symptomatic, or asymptomatic.
 I
Oral anticoagulant therapy is recommended in patients with AF and CHA2DS2-VA score ≥ 2. I
Oral anticoagulant therapy should be considered in patients with AF and CHA2DS2-VA score = 1. IIa
Oral anticoagulant therapy (preferably NOAC) is indicated in all patients regardless of the CHA2DS2-VA score with
  • hypertrophic cardiomyopathy or
  • cardiac amyloidosis
 I
Warfarin as anticoagulant therapy is indicated in all patients regardless of the CHA2DS2-VA score with
  • a mechanical valve or
  • mitral stenosis (moderate or severe)
 I
Oral anticoagulant therapy may be considered in patients with subclinical AF (with detected AHRE). IIb
It is recommended to reassess the CHA2DS2-VA score regularly (every 6–12 months), or when the patient’s condition changes (reaches 65 years of age, develops hypertension, diabetes mellitus, etc.). I
Anticoagulation therapy and atrial fibrillation Class
In valvular atrial fibrillation:
  • mechanical valve, or
  • mitral stenosis (moderate or severe),
warfarin (not NOAC) is always recommended as anticoagulation therapy irrespective of CHA2DS2-VA score.		 I
During warfarin therapy, a target INR of 2–3 is recommended. I
Switching from warfarin to NOAC is recommended if anticoagulation is inadequate (Time in Therapeutic Range < 70 %). I
Dose reduction of NOAC is recommended only if dose reduction criteria are fulfilled. I
In patients with body weight >120 kg or BMI >40 kg/m2, warfarin is recommended according to CHA2DS2-VA score. I
In patients with body weight >120 kg or BMI >40 kg/m2, NOAC may be considered according to CHA2DS2-VA score. IIb
Thromboembolism and Atrial Fibrillation During Anticoagulation Therapy Class
In a patient with atrial fibrillation (AF) receiving anticoagulation therapy who develops a stroke, comprehensive evaluation is recommended. I
In a patient with AF receiving anticoagulation therapy who develops a stroke, switching anticoagulation therapy may be considered. IIb
In a patient with AF receiving anticoagulation therapy who develops a stroke, adding antiplatelet therapy to anticoagulation may be considered. IIb

2.2 Bleeding Risk and Anticoagulant Therapy

Bleeding Risk and Anticoagulation Therapy Class
During anticoagulation therapy, adequate control of modifiable factors that increase bleeding risk is recommended. I
Anticoagulation therapy should not be discontinued based on bleeding risk scores (e.g. HAS-BLED). Bleeding scores serve only to estimate bleeding risk. III
PPIs (proton pump inhibitors) may be added to anticoagulation therapy in patients at higher risk of gastrointestinal bleeding. IIa

2.3 Left Atrial Appendage Occlusion

Percutaneous Left Atrial Appendage Occlusion Class
In patients with non-valvular AF and CHA2DS2-VA ≥ 2 who have a contraindication to long-term anticoagulation therapy, percutaneous left atrial appendage occlusion may be considered. IIa
Surgical Left Atrial Appendage Closure Class
Surgical left atrial appendage closure is recommended (as adjunctive “anticoagulation” therapy) in all patients with AF undergoing cardiac surgery. I
Thoracoscopic surgical left atrial appendage closure may be considered in patients with a contraindication to long-term anticoagulation therapy who are unsuitable for percutaneous appendage closure. IIb
In non-valvular AF after surgical left atrial appendage closure, anticoagulation therapy is indicated according to the CHA2DS2-VA score. I
In valvular AF after surgical left atrial appendage closure, warfarin is administered regardless of the CHA2DS2-VA score. I

2.4 ESUS and AF

Screening for atrial fibrillation in patients after ESUS (Embolic Stroke of Undetermined Source) Class
Implantation of a loop recorder is recommended. I
During symptoms (specific or non-specific), immediate ECG recording using a smart device with ECG capability (ECG watch, blood pressure monitor with ECG, ECG card) is recommended. I
ECG Holter monitoring may be considered: 24-hour or 7-day (preferably). IIa
Anticoagulation therapy and ESUS (Embolic Stroke of Undetermined Source) Class
Anticoagulation therapy is not recommended in patients after ESUS without documented AF. III

Specific Clinical Situations in AF


3.1 Acute Conditions and AF

Acute conditions and atrial fibrillation Class
Electrical cardioversion is recommended in a haemodynamically unstable patient with atrial fibrillation (AF). I
Intravenous landiolol is recommended for acute rate control in a relatively haemodynamically unstable patient with AF. I
Intravenous beta-blocker (esmolol, atenolol, metoprolol) may be considered for acute rate control in a relatively haemodynamically unstable patient with AF. IIa

3.2 Atrial Flutter and AF

Atrial Flutter and Atrial Fibrillation Class
Anticoagulation therapy in atrial flutter is indicated according to the CHA2DS2-VA score. I
For treatment of atrial flutter, radiofrequency ablation is recommended. I
When treating atrial fibrillation with class IC antiarrhythmics (Propafenone, Flecainide), it is recommended to also administer
  • AV nodal blocking drugs (beta-blockers, Verapamil, or Diltiazem),
  • to prevent unblocked 1:1 atrial flutter
  • (20 % of patients with atrial fibrillation also have atrial flutter).
 I

3.3 Coronary Syndrome and AF

Acute coronary syndrome and atrial fibrillation Class
In patients with AF and ACS after PCI (low ischaemic risk), the following is recommended:
  • Triple therapy (NOAC + clopidogrel + aspirin) for < 1 week, then discontinue aspirin.
  • Then dual therapy (NOAC + clopidogrel) and discontinue clopidogrel after 12 months.
  • Then continue NOAC.
 I
In patients with AF and ACS after PCI (high ischaemic risk), the following is recommended:
  • Triple therapy (NOAC + clopidogrel + aspirin) for < 1 month, then discontinue aspirin.
  • Then dual therapy (NOAC + clopidogrel) and discontinue clopidogrel after 12 months.
  • Then continue NOAC.
 IIa
Chronic coronary syndrome and atrial fibrillation Class
In patients with AF and CCS after PCI (low ischaemic risk), the following is recommended:
  • Triple therapy (NOAC + clopidogrel + aspirin) for < 1 week, then discontinue aspirin.
  • Then dual therapy (NOAC + clopidogrel) and discontinue clopidogrel after 6 months.
  • Then continue NOAC.
 I
In patients with AF and CCS after PCI (high ischaemic risk), the following is recommended:
  • Triple therapy (NOAC + clopidogrel + aspirin) for < 1 month, then discontinue aspirin.
  • Then dual therapy (NOAC + clopidogrel) and discontinue clopidogrel after 6 months.
  • Then continue NOAC.
 IIa

3.4 Postoperative AF

Postoperative atrial fibrillation Class
Amiodarone is recommended for prevention of cardiac surgery postoperative AF in patients at increased risk of postoperative cardiac surgery AF. I
Posterior pericardiotomy should be considered as prevention of cardiac surgery postoperative AF. IIa
Anticoagulation therapy should be considered in new-onset postoperative AF according to CHA2DS2-VA score. IIa
Preoperative administration of beta-blockers for prevention of postoperative AF (non-cardiac) is not recommended. III

3.5 Pregnancy and AF

Pregnancy and atrial fibrillation Class
Electrical cardioversion is recommended in AF with haemodynamic instability. I
Electrical cardioversion is recommended in pre-excited AF with haemodynamic instability. I
β₁-selective beta-blockers (except atenolol) are recommended for rate control of AF. I
Electrical cardioversion should be considered in hypertrophic cardiomyopathy and persistent AF. IIa
Digoxin may be administered for rate control of AF if beta-blockers are ineffective or not tolerated. IIa
Ibutilide or flecainide (intravenous) may be considered for termination of AF in a stable patient without structural heart disease. IIb
Flecainide or propafenone may be considered for long-term rhythm control if rate-control drugs (beta-blockers, digoxin) fail. IIb
In pre-excited AF, the following are contraindicated:
  • adenosine
  • verapamil
  • diltiazem
  • beta-blockers
  • digoxin
  • amiodarone
 III
If anticoagulation therapy is indicated, LMWH is recommended. I
Warfarin is contraindicated in the first trimester and after week 36 of pregnancy. III

Antiarrhythmic Therapy and AF


4.1 Antiarrhythmic Drugs - Rate Control in AF

Rate control of atrial fibrillation Class
Acute rate control in AF is recommended in every haemodynamically stable patient with newly diagnosed AF in whom left atrial thrombus has not been excluded. I
In pre-excited AF, drugs that slow AV nodal conduction are contraindicated:
  • Beta-blockers
  • Digoxin
  • Verapamil
  • Diltiazem
  • Amiodarone
  • Adenosine
 III
For rate control (acute or chronic) in a patient with AF and EF <40% the following are recommended:
  • Beta-blocker
  • Digoxin
 I
For rate control (acute or chronic) in a patient with AF and EF >40% the following are recommended:
  • Beta-blocker
  • Digoxin
  • Diltiazem
  • Verapamil
 I
Combination therapy for rate control should be considered if the effect of a single drug is inadequate. IIa
The target rate during long-term rate control of AF should be:
  • <100/min during usual activity (walking, cooking)
  • <80/min at rest (watching TV, lying down, working on a computer)
 IIa
Pace-and-ablate strategy (AV node ablation + pacemaker) should be considered if AF is symptomatic and there has been failure of:
  • pharmacological therapy and
  • ≥2 pulsed-field ablations.
 IIa

4.2 Antiarrhythmic Drugs - Rhythm Control in AF

Rhythm control of atrial fibrillation – Long-term therapy Class
Amiodarone is recommended for long-term maintenance of sinus rhythm in patients with EF <40 % or structural heart disease. I
Amiodarone is among the most effective antiarrhythmic drugs; however, it has a high incidence of adverse effects and therefore should not be used long term (>12 months). IIb
Dronedarone is recommended for long-term maintenance of sinus rhythm in patients with EF >40 %, including those with structural heart disease. I
Flecainide or propafenone are recommended for long-term maintenance of sinus rhythm in patients without structural heart disease. I
During treatment with flecainide or propafenone, concomitant administration of AV nodal–blocking drugs (beta-blockers, verapamil, or diltiazem) should be considered to prevent 1:1 atrial flutter conduction. IIa

4.3 Antiarrhythmic Drugs - Main Contraindications

Antiarrhythmic treatment – Main contraindications Class
Antiarrhythmic treatment is not recommended in patients:
  • with sick sinus syndrome (without a pacemaker). Do not administer:
    • Beta-blockers
    • Sotalol
    • Amiodarone, Dronedarone
    • Flecainide, Propafenone
  • with second- or third-degree AV block (without a pacemaker). Do not administer:
    • Beta-blockers
    • Sotalol
    • Amiodarone, Dronedarone
    • Flecainide, Propafenone
    • Verapamil, Diltiazem
  • with QTc interval >500 ms. Do not administer:
    • Amiodarone, Dronedarone
    • Sotalol
    • Ibutilide
    • Procainamide, Disopyramide
    • Flecainide, Propafenone
 III

Cardioversion of AF


5.1 Cardioversion of AF

Cardioversion of atrial fibrillation Class
Urgent electrical cardioversion is recommended in a hemodynamically unstable patient with atrial fibrillation/flutter (exclusion of left atrial thrombus is not required). I
Before elective cardioversion (pharmacological or electrical) of atrial fibrillation/flutter, at least 4 weeks of anticoagulation (NOAC or warfarin) is recommended, irrespective of CHA₂DS₂-VA score. I
Before elective cardioversion (pharmacological or electrical) of atrial fibrillation/flutter, transoesophageal echocardiography (not older than 24 hours) is recommended to exclude left atrial thrombus if the patient has not received anticoagulation for at least 4 weeks before cardioversion. I
Transoesophageal echocardiography is recommended before any cardioversion (pharmacological or electrical) if the patient has a history of:
  • left atrial thrombus,
  • stroke,
  • transient ischaemic attack (TIA).
 I
Left atrial thrombus is considered excluded if all of the following criteria are met:
  • Non-valvular newly diagnosed AF lasting < 24 hours (based on symptoms)
  • CHA₂DS₂-VA score 0–1
  • No history of TIA or stroke
  • EF > 50 %
 I
Every patient with persistent atrial fibrillation/flutter should undergo at least one attempt at cardioversion (electrical or pharmacological). IIa
Electrical cardioversion as a diagnostic procedure should be considered in persistent atrial fibrillation/flutter with suspected tachycardia-induced cardiomyopathy. IIa
Elective cardioversion (pharmacological or electrical) is not recommended if atrial fibrillation lasts > 24 hours and left atrial thrombus has not been excluded (insufficient anticoagulation ≥ 4 weeks or missing transoesophageal echocardiography not older than 24 hours). III
After cardioversion (pharmacological or electrical), anticoagulation is recommended for at least 4 weeks, irrespective of sinus rhythm presence (during these 4 weeks) and irrespective of CHA₂DS₂-VA score. I
In pre-excited AF, the following are contraindicated:
  • Adenosine
  • Verapamil
  • Diltiazem
  • Beta-blockers
  • Digoxin
  • Amiodarone
 III
Pharmacological (intravenous) cardioversion of atrial fibrillation Class
Left atrial thrombus is considered excluded if all of the following criteria are met:
  • Non-valvular newly diagnosed AF lasting < 24 hours (based on symptoms)
  • CHA₂DS₂-VA score 0–1
  • No history of TIA or stroke
  • EF > 50 %
 I
Flecainide or propafenone (intravenous) are recommended for pharmacological cardioversion of atrial fibrillation in patients without structural heart disease. I
Before administration of Class IC antiarrhythmic drugs (flecainide, propafenone), AV nodal–blocking agents (beta-blocker, verapamil, diltiazem) should be administered to prevent 1:1 conducted atrial flutter. IIa
Vernakalant (intravenous) is recommended for pharmacological cardioversion of atrial fibrillation in patients with EF >40%, without myocardial infarction within the last 30 days and without severe aortic stenosis. I
Amiodarone (intravenous) is recommended for pharmacological cardioversion of atrial fibrillation in patients with structural heart disease. I
Pharmacological cardioversion is not recommended in patients (without a pacemaker) who have:
  • sick sinus syndrome,
  • second- or third-degree AV block,
  • QTc interval > 500 ms.
 III
In pre-excited AF, the following are contraindicated:
  • Adenosine
  • Verapamil
  • Diltiazem
  • Beta-blockers
  • Digoxin
  • Amiodarone
 III

AF Ablation


6.1 AF Ablation

Atrial fibrillation ablation Class
Pulsed field ablation (not radiofrequency or cryoablation) is recommended as the preferred method of atrial fibrillation ablation. I
Pulsed field ablation is recommended in patients with paroxysmal or persistent atrial fibrillation if atrial fibrillation is symptomatic:
  • despite optimized anti-arrhythmic therapy or
  • if anti-arrhythmic therapy is not possible due to adverse effects or contraindications
 I
Pulsed field ablation is recommended in patients with tachycardia-induced cardiomyopathy due to atrial fibrillation. I
Pulsed field ablation should be considered in patients with atrial fibrillation who have symptomatic pre-automatic pauses. IIa
In atrial fibrillation recurrence, pulsed field ablation may be repeated (not earlier than 3 months) if atrial fibrillation is symptomatic:
  • despite optimized anti-arrhythmic therapy or
  • if anti-arrhythmic therapy is not possible due to adverse effects or contraindications
 IIa
Before atrial fibrillation ablation, CT or MR angiography of the left atrium and pulmonary veins should be considered to assess pulmonary vein anatomy. IIa
The “pace and ablate” strategy may be considered in patients with symptomatic atrial fibrillation in whom the following have failed:
  • pharmacological therapy and
  • ≥2 ablations (pulsed field)
 IIa
Atrial fibrillation ablation during cardiac surgery Class
In a patient undergoing cardiac surgery on the mitral valve, concomitant surgical atrial fibrillation ablation using the Cox-Maze IV procedure is recommended. I
In a patient undergoing cardiac surgery other than mitral valve surgery, concomitant surgical atrial fibrillation ablation using the Cox-Maze IV procedure should be considered. IIa
During cardiac surgery, the presence of thrombus in the left atrium is recommended to be excluded before surgical atrial fibrillation ablation. I

6.2 Anticoagulant Therapy and AF Ablation

Anticoagulation therapy and atrial fibrillation ablation Class
Anticoagulation therapy is recommended for at least 4 weeks before atrial fibrillation ablation, regardless of the CHA₂DS₂-VA score. I
NOAC anticoagulation therapy is recommended not to be taken in the morning on the day of atrial fibrillation ablation. I
NOAC anticoagulation therapy is recommended to be started 6 h after atrial fibrillation ablation if there are no signs of bleeding. I
During warfarin therapy, atrial fibrillation ablation is recommended to be performed with a therapeutic INR of approximately 2.0 on the day of the procedure. I
Anticoagulation therapy is recommended for the first 2 months after atrial fibrillation ablation, regardless of ablation success and regardless of the CHA₂DS₂-VA score. I
Two months after atrial fibrillation ablation, long-term anticoagulation is indicated according to the CHA₂DS₂-VA score, regardless of ablation success. I
Anti-arrhythmic therapy (propafenone, flecainide, sotalol, beta-blockers) is recommended for the first 3 months after atrial fibrillation ablation, regardless of ablation success. I
Three months after atrial fibrillation ablation, anti-arrhythmic therapy is indicated according to atrial fibrillation recurrence. I
Atrial fibrillation ablation may be considered if the patient is receiving dual antithrombotic therapy (e.g. NOAC + clopidogrel). IIa