Atrial Fibrillation & Stroke Prevention Scores

4S-AF Scheme Assessment Tool – Structured Atrial Fibrillation Characterization

Clinical calculation support · Verify results before clinical use

Patient Characterization

Enter patient findings to generate a domain-based 4S-AF profile.

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1. Stroke Risk

Calculate CHA₂DS₂-VASc to classify low versus non-low stroke risk using the original 4S-AF operational definition.

0–1 point
CHA₂DS₂-VASc clinical components

Age points are calculated automatically: 65–74 years = 1; ≥75 years = 2. Prior stroke/TIA/thromboembolism = 2 points.

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2. Symptom Severity

Select the European Heart Rhythm Association (EHRA) symptom class attributable to AF.

0–2 points

Class I: no symptoms; II: mild-to-moderate symptoms; III: severe symptoms with limitation of ordinary activity; IV: disabling symptoms.

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3. Severity of AF Burden

Select the documented temporal pattern of AF. This is a clinical proxy for episode duration and frequency, not a measured AF-burden percentage.

0–2 points

Paroxysmal AF terminates spontaneously or with intervention within 7 days; persistent AF is continuous and does not self-terminate within 7 days; long-standing persistent AF lasts ≥12 months; permanent AF reflects a shared decision not to pursue further rhythm restoration.

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4. Substrate Severity

Assess cardiovascular risk factors and left atrial enlargement.

0–4 points
Cardiovascular risk factors / comorbidities

0 points: none; 1 point: one risk factor; 2 points: two or more. Count each listed condition once.

Registry-based substrate definition: <40 mm = 0; 40–50 mm inclusive = 1; >50 mm = 2. Use the measurement convention applied in the source study; this diameter-based classification is not interchangeable with LAVI.

About the 4S-AF Scheme

The 4S-AF scheme is a structured characterization framework designed to capture four complementary dimensions of atrial fibrillation: stroke risk, symptom severity, severity of AF burden, and substrate severity. It supports comprehensive clinical assessment and communication; it does not replace established risk tools or individualized clinical judgement.

Scoring framework used in this tool

DomainOperational definitionPoints
Stroke riskCHA₂DS₂-VASc low risk: 0 in males or ≤1 in females; otherwise non-low risk.0–1
SymptomsEHRA I = 0; II = 1; III–IV = 2.0–2
AF burdenFirst-diagnosed/paroxysmal = 0; persistent = 1; long-standing persistent/permanent = 2.0–2
Substrate: CV risk factorsNone = 0; one = 1; two or more = 2. Risk factors: hypertension, hypercholesterolaemia, diabetes, CAD, HF, PAD.0–2
Substrate: LA sizeLA diameter <40 mm = 0; 40–50 mm = 1; >50 mm = 2.0–2

Clinical use and limitations

  • The scheme is intended for adults with documented AF; confirm clinical AF using ECG documentation.
  • AF temporal pattern is a proxy for burden. When available, report monitored AF burden as total time in AF over a clearly specified monitoring period, longest episode, and episode frequency.
  • LA diameter thresholds are the operational definition used in the EORP-AF registry implementation. Do not substitute LAVI thresholds without explicitly selecting a different published version.
  • The original 4S-AF framework is a characterization tool, not a replacement for CHA₂DS₂-VASc, CHA₂DS₂-VA, bleeding assessment, or guideline-directed management.

References

Potpara TS, Lip GYH, Blomström-Lundqvist C, et al.The 4S-AF Scheme (Stroke Risk; Symptoms; Severity of Burden; Substrate): A Novel Approach to In-Depth Characterization (Rather than Classification) of Atrial Fibrillation. Thromb Haemost. 2021;121(3):270–278. DOI: 10.1055/s-0040-1716408.
Ding WY, Proietti M, Boriani G, et al.Clinical utility and prognostic implications of the novel 4S-AF scheme to characterize and evaluate patients with atrial fibrillation: a report from ESC-EHRA EORP-AF Long-Term General Registry. Europace. 2022;24(5):721–728. DOI: 10.1093/europace/euab280.
Chao TF, Tse HF, Teo WS, et al.Clinical utility and prognostic implications of the 4S-AF scheme: Report from Asia Pacific Heart Rhythm Society Atrial Fibrillation Registry. Eur J Clin Invest. 2022;52(10):e13825. DOI: 10.1111/eci.13825.
Hindricks G, Potpara T, Dagres N, et al.2020 ESC Guidelines for the diagnosis and management of atrial fibrillation. Eur Heart J. 2021;42(5):373–498. DOI: 10.1093/eurheartj/ehaa612.
Van Gelder IC, Rienstra M, Bunting KV, et al.2024 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS. Eur Heart J. 2024;45(36):3314–3414. DOI: 10.1093/eurheartj/ehae176.
Clinical disclaimer: This tool provides structured characterization and educational decision support. It does not diagnose AF, determine an anticoagulant prescription, or replace individualized clinical assessment. Anticoagulation decisions must follow current applicable guidelines, validated stroke-risk assessment, contraindications, bleeding risk, and shared decision-making. The 4S-AF total score must not be interpreted as an independently validated treatment threshold.
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