Original Paper Received: July 29, 2014 Accepted: November 9, 2014 Published online: January 8, 2015
Eur Neurol 2015;73:158–163 DOI: 10.1159/000369793
Atrial Fibrillation in Young Ischemic Stroke Patients: An Underestimated Cause? Daniel Šaňák a Martin Hutyra b Michal Král a Andrea Bártková a Jana Zapletalová c Marián Fedorco b Tomáš Veverka a David Vindiš b Tomáš Dorňák a Tomáš Skála b David Školoudík d Miloš Táborský b Petr Kaňovský a
a
Comprehensive Stroke Center, Department of Neurology, and b Department of Cardiology, University Hospital Olomouc, Department of Medical Biophysics and Biometry, Palacký University Medical School, and d Department of Nursing, School of Health Sciences, Palacký University, Olomouc, Czech Republic c
Key Words Young ischemic stroke · Atrial fibrillation · ECG Holter monitoring · Cardiac markers
prevailed. Using of long-term ECG Holter monitoring improved the detection of AF. Patients with presence of AF had more frequently elevated serum specific cardiac markers. © 2015 S. Karger AG, Basel
© 2015 S. Karger AG, Basel 0014–3022/15/0734–0158$39.50/0 E-Mail [email protected] www.karger.com/ene
Introduction
Ischemic stroke still represents one of the most important causes of morbidity and mortality [1], even in younger population [2, 3]. Although the incidence of ischemic stroke (IS) is relatively low in young patients [3, 4], the cause remains unclear (cryptogenic) in more than one third of all young IS, very often even despite of an extensive diagnostic work-up [3, 5–7]. The common causes of stroke in this population are arterial dissection, migraine, hypercoagulation, and particularly cardiac abnormalities [3, 8, 9]. Atrial fibrillation (AF) represents a frequent cardiac cause of stroke also in younger patients [3, 7–9]. Thus, undetected paroxysmal AF is often suspected as the cause in patients with cryptogenic stroke [10, 11]. In young IS patients, the prevalence of AF, particularly the paroxysmal form, is not established to the required extent. A few previous studies showed a presence Daniel Šaňák, MD, PhD Comprehensive Stroke Center, Department of Neurology University Hospital, I.P. Pavlova 6 CZ–77520 Olomouc (Czech Republic) E-Mail daniel.sanak @ centrum.cz
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Abstract Background: Undetected atrial fibrillation (AF) is often suspected as the possible cause in patients with cryptogenic ischemic stroke (IS), especially in elderly population. In young IS patients, the prevalence of AF, particularly paroxysmal form, remains still not enough established. Our aim was to assess the presence of AF in young patients using a longterm electrocardiography (ECG) Holter monitoring. Methods: The study set consisted of acute IS patients ≤50 years enrolled in the prospective HISTORY (Heart and Ischemic STrOke Relationship studY) study (NCT01541163). In all patients, admission ECG, serum cardiac markers, transesophageal echocardiography, 24-h and 3-week ECG Holter monitoring were performed. Results: Out of 634 enrolled patients in the HISTORY study, 98 were ≤50 years (56 males, mean age 39.7 ± 8.4). In total, AF was detected in 10.2% of patients and 70% of them had a paroxysmal form of AF. The elevated serum cardiac markers were present in 70% of patients with detected AF (p = 0.0001). Conclusion: AF was detected in 10.2% of young stroke patients and paroxysmal form of AF
the Netherlands) and 3-week monitoring using a Holter monitor MDT Vitaphone Loop 3100 BT (Vitaphone GmbH, Germany). All records from 3-week Loop Holter were processed in an external medical data transfer (MDT) center and evaluated by specially trained and blinded cardiologists. The presence of atrial fibrillation was defined as at least 1 period of 30 s duration of an absolute arrhythmia without detectable P waves and without a pattern more consistent with an alternative diagnosis [19, 20]. SPSS software (version 15.0; SPSS Chicago) was used for statistical analysis. The normality of distribution was checked using the Shapiro-Wilk test. All parameters with non-normal distributions are presented as means ± SD, medians, and interquartile ranges. The Mann-Whitney test was used for nonparametric values and the chi-square test and Fisher’s exact test were used for parametric values. All tests used an α-level of 0.05 for significance.
Results
The study set consisted of consecutive acute IS patients ≤50 years enrolled in the prospective single-center observational HISTORY (Heart and Ischemic STrOke Relationship studY) study registered on ClinicalTrials.gov (identifier NCT01541163) between 2011 and 2014 [18]. In all included patients, the brain ischemia was confirmed on computed tomography (CT) or magnetic resonance (MRI) including CT or MRI angiography. The study protocol was in compliance with the Declaration of Helsinki and was approved by the Ethical Committee of our hospital. In all enrolled patients, medical history, baseline characteristics, epidemiologic data, and risk factors were recorded at admission or during hospitalization at the stroke unit. Stroke severity was quantified using the National Institutes of Health Stroke Scale (NIHSS) at admission. Following the diagnostic protocol was performed in all patients: (1) admission ECG, (2) serial laboratory samples, (3) ultrasound of cervical and cerebral arteries within first 48 h, (4) transoesophageal echocardiography (TEE) with the use of contrast agent for bubble test, (5) 24-h and 3-week ECG Holter monitoring. Serial laboratory panel done in this study contained the following samples: (1) standard biochemistry panel, (2) standard coagulation parameters including markers of thrombophilia, (3) serum cardiac markers (12 h after stroke onset: N-terminal probrain natriuretic peptide (NT-proBNP) and high-sensitive Troponin T (hsTnT), 4) serum markers 125 ng/l, % hsTnT >0.014 μg/l, % Creatinine >90 μmol/l, % Baseline serum level of GLU >5.6 mmol/l, % Glycosylated hemoglobin >40 mmol/l, % Baseline serum level of TCH >5.0 mmol/l, % Left atrial diameter, mm (mean ± SD) Left ventricular ejection fraction, % PFO with an evident right-left shunt, % Other defect of atrial septum, % Severe structural heart pathology, %
3 (3) 2 (2) 3 (3) 38 (43) 1 (1.3) 26 (34) 35±5 55 21 (24) 3 (3) 2 (2)
7 (70) 7 (70) 0 4 (40) 0 3 (30) 36±8 60 1 (10) 0 1 (10)
0.0001 0.0001 1.000 0.962 1.000 1.000 1.000 0.989 0.301 1.000 0.907
GLU = Glucose; hsTnT = high-sensitive Troponin T; NT-proBNP = N-terminal pro-brain natriuretic peptide; PFO = patent foramen ovale; SD = standard deviation; TCH = total cholesterol.
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Eur Neurol 2015;73:158–163 DOI: 10.1159/000369793
cardiomyopathy with thrombus in left ventricle) and in two patients without the presence of AF (severe structural lesion of heart valve) (table 2). Patent foramen ovale with an evident right-left shunt on TEE was detected in 22 (22%) patients (table 2) and its frequency did not differ between the groups. In three patients without detected AF, the other defects of atrial septum were observed on TEE (table 2); the defect of atrial septum type II (ostium secundum) with a right-left shunt was present in one patient. In two remaining patients, the small PFO with inŠaňák et al.
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The baseline stroke severity was similar in patients with detected AF as compared to those without the presence of AF (table 1). The number of patients treated with IV thrombolysis did not differ significantly between both the groups (table 1), but patients with detected AF underwent significantly more frequent endovascular treatment (thrombectomy) for symptomatic cerebral vessel occlusion (40 vs. 14%, p = 0.033) (table 1). Severe structural heart pathology on TEE was observed in one patient with detected AF (idiopathic dilated
In our study, AF was detected in 10.2% of young IS patients aged up to 50. In most previous studies the rate of detected AF did not exceed 5% [5, 6, 13, 21–23]. The higher detection rate of AF in our study was achieved probably due to the use of 3-week ECG Holter monitoring, and our results confirmed the previously reported positive impact of the length of monitoring on the ability of the detection of AF in elderly stroke population [10, 17, 24, 25]. Most patients with detected AF in our study had a paroxysmal form of AF, which is often considered the cause of cryptogenic IS, especially in elderly population due to known age-dependent higher frequency of AF [24]. More episodes of PAF were detected in our study during a prolonged 3-week Holter monitoring with a mean time 11.5 days to the first detection of PAF. The increased diagnostic effort to detect PAF may be supported by the fact that PAF represents a same risk for a recurrent IS as a permanent form of AF [14]. Although the duration of AF is considered being necessary for thrombus formation, the TEE-based studies have shown that short intervals of AF may also generate a thrombus [26, 27]. The rate of detected PAF (7.1%) in our study was lower than the previously reported rates achieved during a 7-day Holter monitoring (12–13%) [10, 24]. We explain this difference by our substantially younger study population (≤50 years) and known age-dependent yield of screening for undetected AF in stroke patients, which supports this explanation [24]. As reported previously, in young IS patients the use of a 24-h ECG Holter and a prolonged ECG Holter monitoring (up to 7 days) did not increase the generally low detection rate [10, 24, 28, 29]. By contrast, the prolongation of Holter monitoring up to 3 weeks in our study substantially increased the rate of detected PAF. Recently published results from the randomized EMBRACE (Cardiac Event Monitor Belt for Recording Atrial Fibrillation after a Cerebral Ischemic Event) trial with 30-day
ECG Holter monitoring showed the detection rate of PAF 16.1%, but in elderly CIS patients (≥55 years) [30]. For the detection of PAF, the loop recorder was used in the present study. This recorder detects arrhythmias trigged by a patient and thus the detection rate may be limited in case of an asymptomatic episode of AF. Continuous telemetric or implantable monitors may provide a more accurate PAF detection. These devices are also able to record user-defined, automatic, and patient-activated episodes of atrial fibrillation or other arrhythmias [26, 27]. Nevertheless, the recently published results of the CRYSTAL AF (Cryptogenic Stroke and Underlying AF) trial showed the detection rate of PAF only as 8.9% at 6 months of monitoring in patients with CIS >40 years, who randomly received an implantable cardiac monitor (Reveal XT, Medtronic) [31]. In our study, the presence of AF was associated with an organic structural heart disease only in one (10%) patient; however, recently, Prefasi et al. reported the presence of an organic heart disease in most of young IS patients (71%) with detected AF [13]. Moreover, we did not observe any difference in the diameter of the left atrium on TEE between patients with detected AF and those without AF (table 2). This finding might be explained by the fact that most forms of AF detected in our patients were paroxysmal and probably with a short history of duration and a low impact on the remodeling of the left atrium. Otherwise, PFO with evident right-left shunt on TEE was present in one patient (10%) with detected AF in our study. We consider no relevance of PFO in patients with AF regarding the fact that the thrombus formation due to AF occurs in the left atrium and ventricle primarily. Moreover, the relevance of PFO as a risk factor for IS is still being discussed. Although PFO is more prevalent in IS patients, recently published results from the PC Trial showed no significant benefit of the PFO closure for patients with CIS [32]. Similarly, results from the RESPECT trial were negative in the primary intention-to-treat analysis. However, the additional results from the per-protocol analysis suggested a certain benefit of closure [33]. In our study, patients with the presence of AF underwent significantly more frequently endovascular treatment (thrombectomy) for symptomatic cerebral arterial occlusion (table 1). This finding may correspond to previous reports that AF is associated with more severe strokes and with occlusions of large cerebral arteries [21, 34–36]; however, no significant difference was observed in the initial stroke severity between the groups (table 1). Interestingly, a relatively high number of patients were also treated with IVT in both groups (40 resp. 60%; table 2).
Long-Term ECG Holter Monitoring Study
Eur Neurol 2015;73:158–163 DOI: 10.1159/000369793
Discussion
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significant constant left-right shunt was detected. Patients with detected AF had a similar size of the left atrium diameter and left ventricle ejection fraction on TEE as those without AF (table 2). Patients with detected AF had an elevated serum level of hsTnT and NT-proBNP more frequently than other patients (70 vs. 2% and 70 vs. 3%, p = 0.0001) (table 2). After the detection of AF, the oral anticoagulant therapy was initiated in all patients for the secondary prevention of recurrent ischemic stroke.
We may speculate that the stroke in younger patients is probably more alarming and thus patients may be admitted and treated earlier. The significantly more frequent serum elevation of hsTnT and NT-proBNP in patients with detected AF in our study (table 2) confirmed the previously reported findings that the elevation of hsTnT was associated with the presence of AF and that NT-proBNP was a robust predictor of AF, especially in younger patients [22, 23]. This might help better identify IS patients with a potential risk of presence of undetected PAF, in whom a diagnostic effort with using a long-term ECG Holter monitoring is warranted. The presented study does have limitations. A singlecenter study design with a relatively small sample size was used. Nevertheless, the ischemic strokes are not so frequent in young population and thus the study enrollment was limited. The interval from stroke onset to the start of 24-h and 3-week ECG Holter was relatively long. For a 3-week monitoring, the loop recorder with a limited ability of arrhythmias records was used. Thus, we cannot exclude the possibility of a higher detection rate if continuous telemetry or implantable recorders were used.
Conclusion
In our study, AF was detected in 10.2% of young IS patients ≤50 years and paroxysmal form of AF prevailed. The use of long-term ECG Holter monitoring improved the detection of AF also in young stroke population. In our study, patients with the presence of AF were more frequently treated with mechanical thrombectomy and had more frequently elevated serum specific cardiac markers.
Acknowledgment This study was supported by the Grants of the Internal Grant Agency of the Ministry of Health of the Czech Republic: NT/11046– 6/2010 and NT/14288–3/2013 and by the Institutional Support RVO FNOL 00098892.
Disclosure Statement All authors have no conflict of interest.
References
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Eur Neurol 2015;73:158–163 DOI: 10.1159/000369793
Atrial Fibrillation in Young Ischemic Stroke Patients: An Underestimated Cause? Daniel Šaňák a Martin Hutyra b Michal Král a Andrea Bártková a Jana Zapletalová c Marián Fedorco b Tomáš Veverka a David Vindiš b Tomáš Dorňák a Tomáš Skála b David Školoudík d Miloš Táborský b Petr Kaňovský a
a
Comprehensive Stroke Center, Department of Neurology, and b Department of Cardiology, University Hospital Olomouc, Department of Medical Biophysics and Biometry, Palacký University Medical School, and d Department of Nursing, School of Health Sciences, Palacký University, Olomouc, Czech Republic c
Key Words Young ischemic stroke · Atrial fibrillation · ECG Holter monitoring · Cardiac markers
prevailed. Using of long-term ECG Holter monitoring improved the detection of AF. Patients with presence of AF had more frequently elevated serum specific cardiac markers. © 2015 S. Karger AG, Basel
© 2015 S. Karger AG, Basel 0014–3022/15/0734–0158$39.50/0 E-Mail [email protected] www.karger.com/ene
Introduction
Ischemic stroke still represents one of the most important causes of morbidity and mortality [1], even in younger population [2, 3]. Although the incidence of ischemic stroke (IS) is relatively low in young patients [3, 4], the cause remains unclear (cryptogenic) in more than one third of all young IS, very often even despite of an extensive diagnostic work-up [3, 5–7]. The common causes of stroke in this population are arterial dissection, migraine, hypercoagulation, and particularly cardiac abnormalities [3, 8, 9]. Atrial fibrillation (AF) represents a frequent cardiac cause of stroke also in younger patients [3, 7–9]. Thus, undetected paroxysmal AF is often suspected as the cause in patients with cryptogenic stroke [10, 11]. In young IS patients, the prevalence of AF, particularly the paroxysmal form, is not established to the required extent. A few previous studies showed a presence Daniel Šaňák, MD, PhD Comprehensive Stroke Center, Department of Neurology University Hospital, I.P. Pavlova 6 CZ–77520 Olomouc (Czech Republic) E-Mail daniel.sanak @ centrum.cz
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Abstract Background: Undetected atrial fibrillation (AF) is often suspected as the possible cause in patients with cryptogenic ischemic stroke (IS), especially in elderly population. In young IS patients, the prevalence of AF, particularly paroxysmal form, remains still not enough established. Our aim was to assess the presence of AF in young patients using a longterm electrocardiography (ECG) Holter monitoring. Methods: The study set consisted of acute IS patients ≤50 years enrolled in the prospective HISTORY (Heart and Ischemic STrOke Relationship studY) study (NCT01541163). In all patients, admission ECG, serum cardiac markers, transesophageal echocardiography, 24-h and 3-week ECG Holter monitoring were performed. Results: Out of 634 enrolled patients in the HISTORY study, 98 were ≤50 years (56 males, mean age 39.7 ± 8.4). In total, AF was detected in 10.2% of patients and 70% of them had a paroxysmal form of AF. The elevated serum cardiac markers were present in 70% of patients with detected AF (p = 0.0001). Conclusion: AF was detected in 10.2% of young stroke patients and paroxysmal form of AF
the Netherlands) and 3-week monitoring using a Holter monitor MDT Vitaphone Loop 3100 BT (Vitaphone GmbH, Germany). All records from 3-week Loop Holter were processed in an external medical data transfer (MDT) center and evaluated by specially trained and blinded cardiologists. The presence of atrial fibrillation was defined as at least 1 period of 30 s duration of an absolute arrhythmia without detectable P waves and without a pattern more consistent with an alternative diagnosis [19, 20]. SPSS software (version 15.0; SPSS Chicago) was used for statistical analysis. The normality of distribution was checked using the Shapiro-Wilk test. All parameters with non-normal distributions are presented as means ± SD, medians, and interquartile ranges. The Mann-Whitney test was used for nonparametric values and the chi-square test and Fisher’s exact test were used for parametric values. All tests used an α-level of 0.05 for significance.
Results
The study set consisted of consecutive acute IS patients ≤50 years enrolled in the prospective single-center observational HISTORY (Heart and Ischemic STrOke Relationship studY) study registered on ClinicalTrials.gov (identifier NCT01541163) between 2011 and 2014 [18]. In all included patients, the brain ischemia was confirmed on computed tomography (CT) or magnetic resonance (MRI) including CT or MRI angiography. The study protocol was in compliance with the Declaration of Helsinki and was approved by the Ethical Committee of our hospital. In all enrolled patients, medical history, baseline characteristics, epidemiologic data, and risk factors were recorded at admission or during hospitalization at the stroke unit. Stroke severity was quantified using the National Institutes of Health Stroke Scale (NIHSS) at admission. Following the diagnostic protocol was performed in all patients: (1) admission ECG, (2) serial laboratory samples, (3) ultrasound of cervical and cerebral arteries within first 48 h, (4) transoesophageal echocardiography (TEE) with the use of contrast agent for bubble test, (5) 24-h and 3-week ECG Holter monitoring. Serial laboratory panel done in this study contained the following samples: (1) standard biochemistry panel, (2) standard coagulation parameters including markers of thrombophilia, (3) serum cardiac markers (12 h after stroke onset: N-terminal probrain natriuretic peptide (NT-proBNP) and high-sensitive Troponin T (hsTnT), 4) serum markers 125 ng/l, % hsTnT >0.014 μg/l, % Creatinine >90 μmol/l, % Baseline serum level of GLU >5.6 mmol/l, % Glycosylated hemoglobin >40 mmol/l, % Baseline serum level of TCH >5.0 mmol/l, % Left atrial diameter, mm (mean ± SD) Left ventricular ejection fraction, % PFO with an evident right-left shunt, % Other defect of atrial septum, % Severe structural heart pathology, %
3 (3) 2 (2) 3 (3) 38 (43) 1 (1.3) 26 (34) 35±5 55 21 (24) 3 (3) 2 (2)
7 (70) 7 (70) 0 4 (40) 0 3 (30) 36±8 60 1 (10) 0 1 (10)
0.0001 0.0001 1.000 0.962 1.000 1.000 1.000 0.989 0.301 1.000 0.907
GLU = Glucose; hsTnT = high-sensitive Troponin T; NT-proBNP = N-terminal pro-brain natriuretic peptide; PFO = patent foramen ovale; SD = standard deviation; TCH = total cholesterol.
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cardiomyopathy with thrombus in left ventricle) and in two patients without the presence of AF (severe structural lesion of heart valve) (table 2). Patent foramen ovale with an evident right-left shunt on TEE was detected in 22 (22%) patients (table 2) and its frequency did not differ between the groups. In three patients without detected AF, the other defects of atrial septum were observed on TEE (table 2); the defect of atrial septum type II (ostium secundum) with a right-left shunt was present in one patient. In two remaining patients, the small PFO with inŠaňák et al.
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The baseline stroke severity was similar in patients with detected AF as compared to those without the presence of AF (table 1). The number of patients treated with IV thrombolysis did not differ significantly between both the groups (table 1), but patients with detected AF underwent significantly more frequent endovascular treatment (thrombectomy) for symptomatic cerebral vessel occlusion (40 vs. 14%, p = 0.033) (table 1). Severe structural heart pathology on TEE was observed in one patient with detected AF (idiopathic dilated
In our study, AF was detected in 10.2% of young IS patients aged up to 50. In most previous studies the rate of detected AF did not exceed 5% [5, 6, 13, 21–23]. The higher detection rate of AF in our study was achieved probably due to the use of 3-week ECG Holter monitoring, and our results confirmed the previously reported positive impact of the length of monitoring on the ability of the detection of AF in elderly stroke population [10, 17, 24, 25]. Most patients with detected AF in our study had a paroxysmal form of AF, which is often considered the cause of cryptogenic IS, especially in elderly population due to known age-dependent higher frequency of AF [24]. More episodes of PAF were detected in our study during a prolonged 3-week Holter monitoring with a mean time 11.5 days to the first detection of PAF. The increased diagnostic effort to detect PAF may be supported by the fact that PAF represents a same risk for a recurrent IS as a permanent form of AF [14]. Although the duration of AF is considered being necessary for thrombus formation, the TEE-based studies have shown that short intervals of AF may also generate a thrombus [26, 27]. The rate of detected PAF (7.1%) in our study was lower than the previously reported rates achieved during a 7-day Holter monitoring (12–13%) [10, 24]. We explain this difference by our substantially younger study population (≤50 years) and known age-dependent yield of screening for undetected AF in stroke patients, which supports this explanation [24]. As reported previously, in young IS patients the use of a 24-h ECG Holter and a prolonged ECG Holter monitoring (up to 7 days) did not increase the generally low detection rate [10, 24, 28, 29]. By contrast, the prolongation of Holter monitoring up to 3 weeks in our study substantially increased the rate of detected PAF. Recently published results from the randomized EMBRACE (Cardiac Event Monitor Belt for Recording Atrial Fibrillation after a Cerebral Ischemic Event) trial with 30-day
ECG Holter monitoring showed the detection rate of PAF 16.1%, but in elderly CIS patients (≥55 years) [30]. For the detection of PAF, the loop recorder was used in the present study. This recorder detects arrhythmias trigged by a patient and thus the detection rate may be limited in case of an asymptomatic episode of AF. Continuous telemetric or implantable monitors may provide a more accurate PAF detection. These devices are also able to record user-defined, automatic, and patient-activated episodes of atrial fibrillation or other arrhythmias [26, 27]. Nevertheless, the recently published results of the CRYSTAL AF (Cryptogenic Stroke and Underlying AF) trial showed the detection rate of PAF only as 8.9% at 6 months of monitoring in patients with CIS >40 years, who randomly received an implantable cardiac monitor (Reveal XT, Medtronic) [31]. In our study, the presence of AF was associated with an organic structural heart disease only in one (10%) patient; however, recently, Prefasi et al. reported the presence of an organic heart disease in most of young IS patients (71%) with detected AF [13]. Moreover, we did not observe any difference in the diameter of the left atrium on TEE between patients with detected AF and those without AF (table 2). This finding might be explained by the fact that most forms of AF detected in our patients were paroxysmal and probably with a short history of duration and a low impact on the remodeling of the left atrium. Otherwise, PFO with evident right-left shunt on TEE was present in one patient (10%) with detected AF in our study. We consider no relevance of PFO in patients with AF regarding the fact that the thrombus formation due to AF occurs in the left atrium and ventricle primarily. Moreover, the relevance of PFO as a risk factor for IS is still being discussed. Although PFO is more prevalent in IS patients, recently published results from the PC Trial showed no significant benefit of the PFO closure for patients with CIS [32]. Similarly, results from the RESPECT trial were negative in the primary intention-to-treat analysis. However, the additional results from the per-protocol analysis suggested a certain benefit of closure [33]. In our study, patients with the presence of AF underwent significantly more frequently endovascular treatment (thrombectomy) for symptomatic cerebral arterial occlusion (table 1). This finding may correspond to previous reports that AF is associated with more severe strokes and with occlusions of large cerebral arteries [21, 34–36]; however, no significant difference was observed in the initial stroke severity between the groups (table 1). Interestingly, a relatively high number of patients were also treated with IVT in both groups (40 resp. 60%; table 2).
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Discussion
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significant constant left-right shunt was detected. Patients with detected AF had a similar size of the left atrium diameter and left ventricle ejection fraction on TEE as those without AF (table 2). Patients with detected AF had an elevated serum level of hsTnT and NT-proBNP more frequently than other patients (70 vs. 2% and 70 vs. 3%, p = 0.0001) (table 2). After the detection of AF, the oral anticoagulant therapy was initiated in all patients for the secondary prevention of recurrent ischemic stroke.
We may speculate that the stroke in younger patients is probably more alarming and thus patients may be admitted and treated earlier. The significantly more frequent serum elevation of hsTnT and NT-proBNP in patients with detected AF in our study (table 2) confirmed the previously reported findings that the elevation of hsTnT was associated with the presence of AF and that NT-proBNP was a robust predictor of AF, especially in younger patients [22, 23]. This might help better identify IS patients with a potential risk of presence of undetected PAF, in whom a diagnostic effort with using a long-term ECG Holter monitoring is warranted. The presented study does have limitations. A singlecenter study design with a relatively small sample size was used. Nevertheless, the ischemic strokes are not so frequent in young population and thus the study enrollment was limited. The interval from stroke onset to the start of 24-h and 3-week ECG Holter was relatively long. For a 3-week monitoring, the loop recorder with a limited ability of arrhythmias records was used. Thus, we cannot exclude the possibility of a higher detection rate if continuous telemetry or implantable recorders were used.
Conclusion
In our study, AF was detected in 10.2% of young IS patients ≤50 years and paroxysmal form of AF prevailed. The use of long-term ECG Holter monitoring improved the detection of AF also in young stroke population. In our study, patients with the presence of AF were more frequently treated with mechanical thrombectomy and had more frequently elevated serum specific cardiac markers.
Acknowledgment This study was supported by the Grants of the Internal Grant Agency of the Ministry of Health of the Czech Republic: NT/11046– 6/2010 and NT/14288–3/2013 and by the Institutional Support RVO FNOL 00098892.
Disclosure Statement All authors have no conflict of interest.
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