Silent atrial fibrillation after cryptogenetic stroke. Mexico City 2016
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1) Asymptomatic atrial fibrillation (AF) is commonly found in patients with cryptogenic stroke when prolonged ECG monitoring is performed. 2) While silent AF seems to confer the same prognosis as symptomatic AF, the episode duration and arrhythmia burden that increase stroke risk are still uncertain. 3) In most patients, there is no close temporal relationship between silent AF and stroke, suggesting AF may be a marker rather than direct cause of stroke.
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Silent atrial fibrillation after cryptogenetic stroke. Mexico City 2016
- 1. Asymptomatic AF after cryptogenetic stroke: Incidence, clinical significance & therapeutic implications Antonio Raviele, MD, FESC, FHRS President ALFA – Alliance to Fight Atrial fibrillation - Venice, Italy Curso de Actualizaciòn en Arritmias, Mexico City, Mexico - 16-18 November, 2016
- 2. AF & Symptoms Atrial Fibrillation Symptomatic palpitations, dyspnea, fatigue, angina, dizziness, syncope Asymptomatic or Silent not perceived at all by the patient
- 3. Intermittent AF monitoring • Standard-12 lead ECG • 24-h / 7-d Holter monitoring • In-hospital telemetry • Mobile continuous outpatient telemetry • Event recorder / Intermittent TTEM Continuous AF monitoring • PM - ICD Device memory • External & Implantable loop recorder Asymptomatic AF / Detection Methods
- 4. EURObservational Research Programme-AF (EORP-AF) Pilot General Registry Total EHRA I (%) EHRA II (%) EHRA III (%) EHRA IV (%) N° of Patients 3119 1237 (39.7%) 963 (30.9%) 746 (23.9%) 173 (5.5%) Boriani G et al. Am J Med. 2015 May;128(5):509-18
- 5. Prevalence of Asymptomatic AF Clinical Settings Percent Incidental finding at standard ECG ECG 16-25 Pts treated with AADs TTEM 56-70 PM – ICD recipients Device memory 51-74 Pts with criptogenetic ischemic stroke HM - ILR 0-42 Pts after AF ablation HM - MCOT - PM/ICD - ILR 0-31 Raviele A. CircArrhythmElectrophysiol 2015; 8: 249-251
- 6. Definition Stroke without a cause after extensive investigations Incidence 30-40% of all strokes Cryptogenetic Stroke
- 7. Occult or subclinical AF Possible explanation
- 8. Prevalence of Asymptomatic AF in pts initially diagnosed with cryptogenetic stroke ECG monitoring system Percent Standard12-lead ECG 2-4 Mobile cardiac outpatient telemetry (MCOT) 9.0 Continuous ECG monitoring for 24-72 h 2.4-18.5 Event recorder (up to 30 d) 14.2-16.1 PM-ICD 28% ILR 8.9-33.7 All systems 0-42 Andrade JG, et al. Frontiers in Physiology 2015; 6 Article 100
- 9. Metaregression analysis assessing the relationship between duration of ECG monitoring and the AF detection after cryptogenetic stroke. y axis, Logarithm of the event rate. x axis, Logarithm of the number of hours of monitoring. Charles Dussault et al. Circ Arrhythm Electrophysiol. 2015;8:263-269
- 10. Incidence of Silent AF • Asymptomatic AF is a common finding in patients with a stroke of undetermined origin if prolonged ECG monitoring is performed soon after the index event, reaching 30% or more at 3 months if an implantable loop recorder is used
- 11. • Clinical / prognostic significance • Causal relationship with stroke • Therapeutic implications Silent AF / Main Issues
- 12. Glotzer TV et al. Heart Rhythm 2014; Epub before Print these data show that silent AF detected by these devices is associated with an increased risk of thrombo- embolic events with an hazard ratio ranging from 2.2 to 9.4.
- 13. • It is not yet known what is the length of asymptomatic AF episodes or the amount of asymptomatic AF burden that convey a substantial risk. Silent AF / Significance
- 14. Glotzer TV et al. Heart Rhythm 2014; Epub before Print Indeed, according to literature data, the length of asymptomatic episodes of AF that are associated with an increased risk of stroke varies from a minimum of 5 minutes in the Ancillary MOST trial to a maximum of 24 hours in the Italian AT500 Registry
- 15. Circulation 2016; 134: 11340-1140 Shorter episodes of device-detected atrial tachyarrhythmias, lasting less than 15-20 seconds, do not seem to confer an increased risk of stroke
- 16. Univariate and multivariable logistic regression (pacemaker patients). Swiryn S. et al. Circulation. 2016;134:1130-1140 Univariate and multivariable logistic regression (ICD patients).
- 17. • The episode duration and burden of asymptomatic AF that best predict subsequent stroke are still matters of debate and need to be addressed by future studies Silent AF / Significance
- 18. • Clinical / prognostic significance • Causal relationship with stroke • Therapeutic implications Silent AF / Main Issues
- 19. Silent AF & Stroke • Direct cause of stroke ? • Marker of an increased risk ?
- 20. Glotzer TV et al. Heart Rhythm 2014; Epub before Print The TRENDS, ASSERT and IMPACT trials have tried to answer this question. They found that in the majority of patients (73-94%) no AF was detected on device recordings in the 30 days before the thromboembolic events. Moreover, when an AF was detected, this happened more than 30 days before thrombo-embolic events in 29-50% of cases and only after thrombo-embolic events in 13-16% of cases
- 21. • These results indicate that a proximate temporal relationship between asymptomatic AF and stroke occurrence does not exist and suggest that AF is not the direct cause of stroke in the majority of patients. • They also call into question our current understanding of how AF causes embolic events. Silent AF & Stroke
- 22. • It is likely that multiple mechanisms contribute to stroke in patients with asymptomatic AF. • In some cases, stroke may be due to stasis from an actual AF episode, in others to chronic atrial and endothelial changes caused by multiple prior AF episodes; and in other cases again, to non-AF mechanisms. Silent AF & Stroke
- 23. • In these latter cases, it may be that the AF is simply a marker of increased stroke from any cause because of its relationship to other comorbidities, such as heart failure, hypertension, diabetes mellitus, occult atrial myopathy, endothelial dysfunction, or other vascular disease risk factors summarized by the CHA2DS2- VASc score system. Silent AF & Stroke
- 24. • Clinical / prognostic significance • Causal relationship with stroke • Therapeutic implications Silent AF / Main Issues
- 25. • Need for Oral Anticoagulation Asymptomatic AF / Therapy
- 26. • Detection of asymptomatic AF theoretically may allow early initiation of anticoagulation, instead of the usual care with antiplatelet therapy, and may lead to a reduction in the risk of recurrent stroke. • However, whether pts with subclinical AF have to be anticoagulated currently remains an unanswered question. Asymptomatic AF / Need for OAC
- 27. • Indeed, no prospective randomized trials using OAC have been performed in this field to date. • Furthermore, the lack of proximate temporal relationship between asymptomatic AF and stroke observed in the majority of patients in the ASSERT, TRENDS, and IMPACT trials suggests that OAC may not be systematically required for stroke prevention in asymptomatic patients Asymptomatic AF / Need for OAC
- 28. Eur Heart J 2015; 36: 1660-1668
- 29. IMPACT / Study Hypothesis • The trial was designed to test the hypothesis that initiation and withdrawal of OAC guided by continuous ambulatory monitoring of subclinical AF would reduce the rate of stroke and major bleeding compared to conventional clinical management.
- 30. Primary Outcome Events (Stroke, systemic embolism or major bleed) Martin DT, et al. Eur Heart J 2015; 36: 1660-1668
- 31. IMPACT / Comment (1) • The trial was performed with warfarin. We do not know if, with the use of NOACs, the results would have been different. • The preliminary results of REACT.COM pilot trial, performed with Dabigatran, seems to suggest so.
- 32. IMPACT / Comment • But we have to wait for the final results of the study as well as for the results of other 2 ongoing trials, ARTESiA trial and NOAH-AFNET trial, that will compare, respectively, apixaban and edoxaban with aspirin in patients with device-detected AHRE and high thromboembolic risk, to have the final answer to this question.
- 33. Kirchhof P et al. Eur Heart J 2016; Aug 27. pii: ehw210. [Epub ahead of print]
- 34. • Asymptomatic or silent AF is a common finding after a cryptogenetic stroke when prolonged ECG monitoring is performed. Conclusions (1)
- 35. • Patients with asymptomatic AF seem to have the same prognosis than patients with symptomatic AF. • However, the length of silent AF episodes and the burden of the arrhythmia that convey a greater risk of stroke are still uncertain and need to be clarified by further large prospective studies Conclusions (2)
- 36. • In the majority of patients, there is no proximate temporal relationship between asymptomatic AF and stroke occurrence. • This suggests that silent AF is not the direct cause of stroke, but rather represents only a marker of increased thromboembolism Conclusions (3)
- 37. • Future studies have to establish if and when patients with asymptomatic AF really benefit from oral anticoagulant therapy. Conclusions (4)