Summary
Background
Many studies have suggested that longer duration of cardiac monitoring is suitable for the detection of occult paroxysmal atrial fibrillation (AF) after stroke; however, most studies involved patients aged ≥ 65 years – a population with a high stroke rate.
Aims
To assess the incidence of paroxysmal AF in unselected young patients presenting with stroke.
Methods
We included consecutive patients aged < 60 years with a stroke diagnosis on magnetic resonance imaging. Aetiological screening included clinical history and examination, and biological and cardiac tests. Patients were included if they had no history of AF and if a 24-hour electrocardiogram recording detected no AF or atrial flutter. Patients wore the SpiderFlash ® monitor for 21 days after discharge from hospital. The primary outcome was detection of paroxysmal AF episodes lasting > 30 seconds during monitoring. The secondary outcome was detection of paroxysmal AF episodes lasting < 30 seconds and any arrhythmia during monitoring.
Results
Among the 56 patients included (mean age 48 ± 9 years), 39 had cryptogenic stroke (CS) and 17 had stroke of known cause (SKC). Cardiac monitoring was achieved in 54 patients (37 CS, 17 SKC); one CS patient had a paroxysmal AF episode lasting > 30 seconds and one CS patient had a paroxysmal AF episode lasting < 30 seconds (versus no patients in the SKC group). Two CS patients and one SKC patient presented numerous premature atrial complexes. Non-sustained ventricular tachycardia was detected in one CS patient.
Conclusion
This prospective observational study showed a low rate of paroxysmal AF among young patients presenting with stroke, on the basis of 21-day cardiac monitoring. This result highlights the need to identify patients who would benefit from such long monitoring.
Résumé
Contexte
De nombreuses études ont suggéré qu’une durée plus étendue d’enregistrement électrocardiographique améliorait le taux de détection de la fibrillation auriculaire (FA) paroxystique occulte après un accident vasculaire cérébral (AVC) ischémique, mais la plupart de ces études ont porté sur les patients ≥ 65 ans d’âge – une population avec un taux élevé d’AVC ischémique.
Objectif
Évaluer l’incidence de la FA paroxystique chez les patients jeunes présentant un AVC ischémique.
Méthodes
Nous avons inclus de manière consécutive des patients âgés de 18 à 60 ans avec un diagnostic d’AVC ischémique à l’imagerie par résonance magnétique. Les explorations à visée étiologique ont inclus l’anamnèse, l’examen clinique et des tests biologiques et cardiaques. Les patients ont été inclus s’ils n’avaient pas d’antécédent de FA et si un enregistrement de l’électrocardiogramme des 24 heures n’a détecté aucune FA ou flutter auriculaire. Après la sortie de l’hôpital, les patients ont porté le moniteur SpiderFlash ® pendant 21 jours. Le critère principal de jugement était la détection d’épisodes de FA paroxystique > 30 secondes pendant la surveillance. Les critères secondaires étaient la détection d’épisodes de FA paroxystique < 30 secondes ou de toute autre arythmie.
Résultats
Parmi les 56 patients inclus (âge moyen 48 ± 9 ans), 39 avaient un AVC cryptogénique (CS) et 17 un AVC de cause connue (SKC). L’enregistrement de 21 jours a été obtenu chez 54 patients (37 CS, 17 SKC) ; un patient dans le groupe des CS a présenté des épisodes de FA paroxystique > 30 secondes et un patient avec un CS a eu un épisode de FA paroxystique < 30 secondes (contre aucun patient dans le groupe SKC). Deux patients dans le groupe des CS et un patient avec un SKC ont présenté de nombreuses extrasystoles auriculaires. Un épisode de tachycardie ventriculaire non soutenue a été détecté chez un patient ayant un CS.
Conclusion
Cette étude observationnelle prospective a montré un faible taux de FA paroxystique chez les jeunes patients présentant un AVC ischémique, après un enregistrement de 21 jours. Ce résultat met en évidence la nécessité de sélectionner les patients qui pourraient bénéficier de ce suivi électrocardiographique prolongé.
Background
Atrial fibrillation (AF) is the cause of 20–25% of all ischaemic strokes, which are more severe and associated with higher mortality rates than strokes resulting from other causes . Oral anticoagulation is recommended in patients diagnosed with AF, leading to an additional 40% reduction in the risk of recurrent stroke compared with that achieved with antiplatelet therapy . The detection of arrhythmias associated with a high cardioembolic risk after stroke/transient ischaemic attack (TIA) is particularly important in the management of such patients.
Despite a thorough aetiological workup, around one third of ischaemic strokes in young patients remain unexplained . Occult paroxysmal AF is a possible cause of cryptogenic stroke and TIA in these patients, as individuals with paroxysmal AF have the same risk of ischaemic stroke as those with sustained AF .
Early diagnosis triggers earlier treatment for secondary prevention of stroke . In a systematic review of five studies, in which the duration of electrocardiogram (ECG) recording ranged from 24 to 72 hours, the overall rate of newly detected AF or flutter was 4.6% among consecutive patients with ischaemic stroke . Current guidelines from the European Stroke Organization estimate that extending the duration of monitoring (prolonged event-loop recording) may improve the rate of detection of paroxysmal AF .
Many devices are now available to manage such patients . However, the feasibility and results of longer monitoring remain conflicting: for example, supplementary paroxysmal AF rates ranging from 5.3% to 20.0% have been detected in patients with cryptogenic stroke/TIA in observational studies versus 0% in one randomized study . Most of these studies involved patients aged ≥ 65 years. The value of longer monitoring in younger patients has been poorly studied, as the rate of paroxysmal AF in patients with stroke increases with age .
We aimed to assess the incidence of paroxysmal AF in unselected patients with stroke aged between 18 and 60 years, using the SpiderFlash ® external loop recorder (ELA Medical, Minneapolis, MN, USA) for 21 days.
Methods
Study design and population
This prospective study consecutively included patients aged < 60 years admitted to the Neurology Department of Annecy Hospital with a diagnosis of stroke confirmed on magnetic resonance imaging (MRI) between February 2011 and July 2012. The diagnosis of stroke required imaging evidence of cerebral or spinal cord infarction consistent with the presenting neurological syndrome, persistent neurological deficits attributable to cerebral ischaemia or confirmed evidence of retinal ischaemia on ophthalmological examination .
Data were collected on patient demographics, clinical history, cardiac test results and radiological test results. All patients underwent 24-hour ECG recording, biological tests, transthoracic echocardiography and carotid Doppler assessment. Transoesophageal echocardiography and limb venous Doppler assessment were performed if required.
Patients with a history of AF or any supraventricular tachycardia, those presenting with AF on the resting ECG recording and/or on the 24-hour ECG recording, and those taking antiarrhythmic agents were excluded. Other exclusion criteria were patients with a Rankin score > 4, patients in whom baseline screening was not completed, patients not living in the province and those who refused consent. Patients were classified into two stroke groups according to the results of the stroke evaluation: stroke of known cause (SKC) or cryptogenic stroke (CS).
Patients were advised to undergo monitoring for 21 days; they removed and applied the electrodes themselves. Patients were instructed to write in a diary if they had acute cardiac or neurological symptoms.
Device
The SpiderFlash external loop recorder device was used. Patients wear the SpiderFlash device like a necklace. This event recorder monitor, coupled with its analyser EventScope™ (Sorin Group, Milan, Italy), comprises three cardiac leads attached to a small pocket-sized recording device; continuous two-channel ECG data are recorded.
SpiderFlash is programmed to take 12 automatic recordings daily, but it also takes recordings started by the patient in the event of symptom onset. SpiderFlash is based on secure Datacard technology (Datacard Group, Minnetonka, MN, USA), providing markedly expanded memory capacity.
SpiderFlash can record an ECG for up to 6 minutes before and 3 minutes after arrhythmia detection or patient activation – as often as is needed. Therefore, an event can be recorded even if SpiderFlash is activated after symptom resolution (e.g. after a syncopal episode when the patient has regained consciousness).
The device uses an event detection algorithm well suited to capturing asymptomatic paroxysmal events, including intermittent AF. The event detection algorithm uses RR interval variability and QRS morphology analysis to detect all possible AF events, which are then transmitted to a physician for manual review and confirmation, based on standard diagnostic criteria (absence of P-wave activity and irregular RR interval). In our study, the manual review was done by one of two cardiologists specialized in heart rhythm management who were participating in the study, to confirm the presence or absence of paroxysmal AF episodes.
Outcomes
The primary outcome was the detection of paroxysmal AF episodes lasting > 30 seconds on the 21-day recording. The secondary outcome was the detection of paroxysmal AF episodes lasting < 30 seconds and any arrhythmia on the 21-day recording.
Statistical analysis
Continuous variables are expressed as means ± standard deviations or medians ± interquartile ranges; categorical variables are expressed as percentages. Student’s t -test was used for continuous variables and the Chi 2 test or Fisher’s exact test was used for categorical variables. All tests were two-sided and P values < 0.05 were considered statistically significant. Statistical analysis was performed using Epi Info™ version 7 (CDC, Atlanta, GA, USA).
Results
Overall, 56 patients with ischaemic stroke were included; the mean age was 48 ± 9 years (range 31–60 years). Thirty-nine patients were classified as having CS and 17 as having SKC. Two CS patients were excluded because of premature discontinuation of monitoring ( Fig. 1 ). Table 1 shows the patients’ baseline characteristics; there were significant proportions of obese and diabetic patients in the SKC group.
| Characteristics | Total ( n = 56) | CS group ( n = 39) | SKC group ( n = 17) | P a |
|---|---|---|---|---|
| Age (years) | 48 ± 9 | 47 ± 8 | 51 ± 9 | 0.16 |
| Women | 21 (38) | 15 (38) | 6 (35) | 0.82 |
| White ethnicity | 56 (100) | 39 (100) | 17 (100) | |
| BMI > 25 kg/m 2 | 8 (14) | 3 (8) | 5 (29) | 0.046 |
| Hypertension | 15 (27) | 8 (20.5) | 7 (41) | 0.11 |
| Diabetes mellitus | 4 (7) | 1 (3) | 3 (18) | 0.045 |
| Hyperlipidaemia | 16 (29) | 9 (23) | 7 (41) | 0.17 |
| Current smoker | 20 (37) | 12 (31) | 8 (47) | 0.24 |
| Coronary artery disease | 3 (5) | 1 (3) | 2 (12) | 0.21 |
| Cardiovascular disease b | 3 (5) | 3 (8) | 0 (0) | |
| History of TIA/stroke | 3 (5) | 3 (8) | 0 (0) | 0.32 |
| NHISS | 2 (0–6) | 2 (0–6) | 3.5 (1–7) | 0.94 |
| Positive AIDS test | 1 (2) | 1 (3) | 0 (0) | 0.78 |
| uTSH | 1.5 (0.9) | 1.6 (0.9) | 1.3 (0.8) | 0.30 |
| HbA 1C | 5.9 (1.6) | 5.6 (0.9) | 6.4 (2.5) | 0.11 |
| LDL-C (mg/L) | 124 (47) | 127 (49) | 117 (43) | 0.51 |
| Obstructive sleep apnoea | 1 (2) | 0 (0) | 1 (6) | 0.30 |
| Migraine | 5 (9) | 4 (10) | 1 (6) | 0.52 |
b One interatrial communication, one ventricular septal defect and one hypertrophic cardiomyopathy.
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