This document summarizes guidelines on subclinical atrial fibrillation (SCAF) from the 2020 European Society of Cardiology. It finds that SCAF is common in patients with pacemakers and ICDs. While the risk of stroke from SCAF is lower than from overt atrial fibrillation, it increases with longer durations and a higher CHADS2 score. The guidelines recommend evaluating SCAF patients for risk factors and monitoring burden to help guide treatment, which may include oral anticoagulants in high-risk patients. However, diagnosing and managing SCAF remains challenging due to a lack of clear consensus criteria.

1. Subclinical
Atrial Fibrilation
Dr. Ameel Toma
Cardiologist
Azadi Teaching Hospital
Duhok-Iraq
10th May 2021

2. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation
(European Heart Journal 2020-doi/10.1093/eurheartj/ehaa612)
www.escardio.org/guidelines
©ESC
Figure 2 (1) Epidemiology of AF: prevalence

3. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation
(European Heart Journal 2020-doi/10.1093/eurheartj/ehaa612)
www.escardio.org/guidelines
©ESC
Figure 3 Summary of risk factors for incident AF

4. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation
(European Heart Journal 2020-doi/10.1093/eurheartj/ehaa612)
www.escardio.org/guidelines
©ESC
Table 4 Classification of AF (1)
AF pattern Definition
First
diagnosed
AF not diagnosed before, irrespective of its duration or the presence/severity of
AF-related symptoms.
Paroxysmal AF that terminates spontaneously or with intervention within 7 days of onset.
Persistent AF that is continuously sustained beyond 7 days, including episodes that are terminated
by cardioversion (drugs or direct current cardioversion) after 7 days or more.
Long-standing
persistent
Continuous AF of >12 months’ duration when decided to adopt a rhythm control strategy.
Permanent AF that is accepted by the patient and physician, and no further attempts to restore/maintain
sinus rhythm will be undertaken. Permanent AF represents a therapeutic attitude of the
patient and physician rather than an inherent pathophysiological attribute of AF, and the
term should not be used in the context of a rhythm control strategy with antiarrhythmic drug
therapy or AF ablation. Should a rhythm control strategy be adopted, the arrhythmia would
be re-classified as ‘long-standing persistent AF’.

5. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation
(European Heart Journal 2020-doi/10.1093/eurheartj/ehaa612)
www.escardio.org/guidelines
©ESC
Table 4 Classification of AF (2)
Terminology that should be abandoned
AF pattern Definition
Lone AF A historical descriptor. Increasing knowledge about the pathophysiology of AF shows that
in every patient a cause is present. Hence, this term is potentially confusing and should be
abandoned.
Valvular/non-
valvular AF
Differentiates patients with moderate/severe mitral stenosis and those with mechanical
prosthetic heart valve(s) from other patients with AF, but may be confusing and should
not be used.
Chronic AF Has variable definitions and should not be used to describe populations of AF patients.

6. THE MORE WE SEE THE MORE WE FIND !
…. from memory of the device
ICM
PMK
ICD
CRT

7. ASSERT, NEJM 2012
Atrial Tachyarrhythmia > 6 min, >190 bpm
Years of Follow-up
Cumulative
Hazard
Rates
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
# at Risk Year 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
2580 2059 1842 1663 1371 1008 706 446 243
ASSERT : Time to Adjudicated AHRE(>6 minutes,>190/minute)
3 month
Visit
SCAF is VERY
Common in the
Pacemaker/ICD
Populations

8. Diagnosis of subclinical AF:

9. Definition:
SCAF(subclinical atrial fibrillation):
is defined as episodes of asymptomatic AF detected by
intracardiac, implantable, or wearable monitors and
confirmed by intracardiac electrogram or review of the
recorded rhythm on the ECG.

13. Subclinical AF:
Outcome and complications ??

14. SCAF and stroke:
• Each year, 16.9 million people worldwide have a stroke.
• The cause of which remains unexplained in 20% to 40% of cases.
• 10% to 30% may be caused by AF that has could not be detected.

15. In the EMBRACE trial
55 years or older, had experienced an Embolic stroke unknown
source(ESUS)

16. CRYSTAL-AF trial : >40 y, with ESUS

17. Stroke Risk for SCAF is Lower than AF
1Healey JS et al. N Engl J Med. 2012;366:120–9
2Gage BF et al. JAMA. 2001;285:2864–70
Annual
stroke
risk
(%/yr)
≥
0.28
0.7
0.97
0.56
1.29
3.78
2.8
4.0
5.9
0
1
2
3
4
5
6
CHADS 1 CHADS 2 CHADS ≥3
SCAF: no
SCAF: yes
overt AF 2
1
1

18. Temporal relationship(casual or not ?)

19. Progression to clinical AF:
• SCAF was associated with a 5.6-fold higher hazard of clinical AF
during the 2.5-year mean follow-up.

20. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation
(European Heart Journal 2020-doi/10.1093/eurheartj/ehaa612)
www.escardio.org/guidelines
©ESC
Figure 24 Progression of atrial high-rate episode burden
(left panel) and stroke rates according to AHRE daily burden
and CHA2DS2-VASc score (right panel)
aThe higher the burden at diagnosis, the greater the incidence of progression in the next 6 months and thereafter. bStroke rates above the threshold for OAC are
shown in red.
©ESC

21. Effect on heart function:

22. Physician attitude and uncertainty:
No clear criteria for:
1- Diagnosis
2-Best method to diagnose.
3-Period of tachyarrhythmia.
4-Which patient should be treated or at risk.
5- Type of treatment.

23. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation
(European Heart Journal 2020-doi/10.1093/eurheartj/ehaa612)
www.escardio.org/guidelines
©ESC
Central Illustration Management of AF (2)
©ESC

24. Treatment of
SCAF ??

25. Decision making depend:
a- The method of SCAF detection(check false positive ?)
b- The duration and daily burden.
c- Assess traditional risk factors(CHADS-vasc score).
d- Assess the bleeding risk.

26. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation
(European Heart Journal 2020-doi/10.1093/eurheartj/ehaa612)
www.escardio.org/guidelines
©ESC
Recommendations for management of patients with AHRE
Recommendations Class Level
In patients with AHRE/subclinical AF detected by CIED or insertable cardiac
monitor, it is recommended to conduct:
• Complete cardiovascular evaluation with ECG recording, clinical risk
factors/comorbidity evaluation, and thromboembolic risk assessment using
the CHA2DS2-VASc score.
• Continued patient follow-up and monitoring (preferably with the support of
remote monitoring) to detect progression to clinical AF, monitor the
AHRE/subclinical AF burden (especially transition to ≥24 hours), and detect
changes in underlying clinical conditions.
I B

27. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation
(European Heart Journal 2020-doi/10.1093/eurheartj/ehaa612)
www.escardio.org/guidelines
©ESC
Figure 25 Proposed management of AHRE/subclinical AF
aHighly selected
patients (e.g. with
previous stroke and/or
age ≥75 years, or ≥3
CHA2DS2-VASc risk
factors, and additional
non-CHA2DS2-VASc
stroke factors such as
CKD, elevated blood
biomarkers,
spontaneous echo
contrast in dilated LA,
etc); selected patients
(e.g. with previous
stroke and/or age
≥75 years, or ≥3
CHA2DS2-VASc risk
factors , etc).
©ESC

28. Take home message:
• Initially detected in implanted devices in asymptomatic patients.
• Still no clear criteria for diagnosis and treatment.
• Risk of stroke is higher than general population and less than AF.
• Risk of stroke related to the burden of arrhythmia and CHADS-vasc
score.
• Look at benefit/risk ratio.
• Discuss with the patient.
• Future target: screening !

32. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation
(European Heart Journal 2020-doi/10.1093/eurheartj/ehaa612)
www.escardio.org/guidelines
©ESC
Recommendations for the search for AF in patients with
cryptogenic stroke
Recommendations Class Level
In patients with acute ischaemic stroke or TIA and without previously
known AF, monitoring for AF is recommended using a short-term ECG
recording for at least the first 24 hours, followed by continuous ECG
monitoring for at least 72 hours whenever possible.
I B
In selecteda stroke patients without previously known AF, additional ECG
monitoring using long-term non-invasive ECG monitors or insertable
cardiac monitors should be considered, to detect AF.
IIa B
aNot all stroke patients would benefit from prolonged ECG monitoring; those deemed at risk of developing AF (e.g. elderly, with cardiovascular risk factors or
comorbidities, indices of LA remodelling, high C2HEST score, etc.) or those with cryptogenic stroke and stroke characteristics suggestive of an embolic stroke should be
scheduled for prolonged ECG monitoring.

33. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation
(European Heart Journal 2020-doi/10.1093/eurheartj/ehaa612)
www.escardio.org/guidelines
©ESC
Central Illustration Management of AF (1)
©ESC

34. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation
(European Heart Journal 2020-doi/10.1093/eurheartj/ehaa612)
www.escardio.org/guidelines
©ESC
Central Illustration Management of AF (2)
©ESC

35. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation
(European Heart Journal 2020-doi/10.1093/eurheartj/ehaa612)
www.escardio.org/guidelines
©ESC
Figure 20 (1) Post-procedural management of patients with AF and ACS/PCI (full-
outlined arrows represent a default strategy; graded/dashed arrows show treatment
modifications depending on individual patient’s ischaemic and bleeding risks)
©ESC

36. • AF ------- symptoms ???
• Subsequently, with the spread of implantable devices, for monitoring
only or by stimulation, it emerged that more than 90% of atrial
arrhythmias are asymptomatic and, conversely, the patient’s
symptoms correspond in 20% of cases to arrhythmic episodes

37. Risk of stroke:
• recent study showed that short AT/AF episodes (<15–20 seconds) were not
associated with clinical events.
• Stroke risk also seems to depend on traditional risk factors.
• Botto et stratified risk according to AF duration and CHADS2 score, with a
CHADS2 score of 1 increasing the risk only if the AF duration was >24 hours,
whereas for CHADS2 scores ≥2, episodes lasing >5 minutes increased risk.
• In the EMBRACE trial, 572 patients with ESUS or TIA with previously negative 24-
hour Holter monitor were randomized to monitoring with a 30-day event-
triggered loop recorder or repeat 24-hour Holter monitoring. Detection rates of
SCAF (duration ≥30 seconds) were significantly higher with monitoring (16.1%)
• The risk of stroke in patients with SAF was 2.4 times higher than in the control
group without SAF.

38. THE DARK SIDE OF THE MOON …..
TEMPORAL RELATIONSHIP BETWEEN SCAFAND TE EVENTS
POOR
of TE events without SCAF in the privious 30 days)
Device-detected subclinical atrial tachyarrhythmias: definition, implication and management – an European Heart Rhythm Association
(EHRA) consensus document, endorsed by Heart Rhythm Society (HRS), Asia Pacific Heart Rhythm Society (APHRS), Sociedad
Latinoamericana de Estimulatìon Cardiaca y Electrofisiologia (SOLEACE), Europace 2017, 19:1556-1578

39. Prevalence of SCAF:
• A meta-analysis of 32 trials that used either external cardiac monitors
or ICMs for AF detection after ESUS documented a detection rate of
11.5%
• Depend on method used,duration and the criteria for diagnosis.