Atrial Fibrillation and Paroxysmal Atrial Fibrillation Detection in Patients with Acute Ischemic Stroke Panee Sutamnartpong, MD,* Pornpatr A. Dharmasaroja, MD,* Disya Ratanakorn, MD,† and IngOrn Arunakul, MD‡
Background: Studies about continuous electrocardiographic (ECG) monitoring in detection of paroxysmal atrial fibrillation (PAF) in Asian patients with acute ischemic stroke are very limited. We looked for the prevalence and associated factors of atrial fibrillation (AF) and PAF in Thai patients with acute ischemic stroke. Methods: In all, 204 patients with acute ischemic stroke were prospectively included. Snapshot 12-lead ECG and continuous ECG monitoring for at least the first 24 hours were performed. Multivariate analyses were performed to find out the associated factors of AF and PAF. Results: AF was diagnosed in 31 patients (15%) and PAF in 15 patients (7%). Twelve and 3 patients with PAF were diagnosed by continuous ECG monitoring and snapshot 12-lead ECG, respectively. Mean duration of continuous ECG monitoring and mean time to detect PAF were 55 and 23 hours, respectively. Multivariate analysis revealed that age of 70 years or older (odds ratio [OR] 3.52, 95% confidence interval [CI] 1.68-7.35, P 5 .001) and heart diseases (OR 4.26, 95% CI 1.14-15.95, P 5 .031) were associated with AF and PAF. Conclusions: AF/ PAF was one of the common causes of ischemic stroke in Thai patients. Most PAF was detected by continuous ECG monitoring. Snapshot 12-lead ECG and continuous ECG monitoring should be recommended in all patients with acute ischemic stroke. Key Words: Paroxysmal atrial fibrillation—atrial fibrillation—stroke— Asian—Thai. Ó 2014 by National Stroke Association
Introduction Cardioembolic stroke accounts for one fourth to one third of all ischemic stroke. Atrial fibrillation (AF), the prevalence of which increases with aging, is the most common cause of cardioembolic stroke.1,2 A clinical
From the *Division of Neurology, Department of Medicine, Faculty of Medicine, Thammasat University, Pathumthani; †Division of Neurology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; and ‡Division of Cardiology, Department of Medicine, Faculty of Medicine, Thammasat University, Pathumthani, Thailand. Received June 12, 2013; revision received September 4, 2013; accepted September 30, 2013. Address correspondence to Pornpatr A. Dharmasaroja, MD, Associate Professor in Neurology, Division of Neurology, Faculty of Medicine, Thammasat University, Klong 1, Klong Luang, Pathumthani 12120, Thailand. E-mail: [email protected]. 1052-3057/$ - see front matter Ó 2014 by National Stroke Association http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2013.09.032
1138
cardiovascular examination and a 12-lead electrocardiogram (ECG) are recommended to be performed in all stroke patients, and cardiac monitoring is useful and should be conducted routinely after acute stroke to screen for serious cardiac arrhythmia.3 Paroxysmal atrial fibrillation (PAF) is associated with a comparable increase in risk of ischemic stroke as permanent AF.4 Noninvasive cardiac monitoring methods, such as Holter monitoring and continuous cardiac telemetry, were developed aiming to detect PAF. However, which method is the best method and the recommended duration of monitoring in patients with acute ischemic stroke are still debated. From previous reviews, Holter monitoring for 24-48 hours can identify AF in 1%-5% of patients undetected by initial ECG. Extended duration of monitoring and confining its use to patients with nonlacunar stroke may improve detection rates.5,6 With the approved new anticoagulants, secondary prevention of recurrent thromboembolic events was at least equally or even more effective, with less bleeding complications
Journal of Stroke and Cerebrovascular Diseases, Vol. 23, No. 5 (May-June), 2014: pp 1138-1141
ATRIAL FIBRILLATION IN PATIENTS WITH STROKE
than previous vitamin K antagonist therapy. Thus, it may be worthwhile to detect PAF. Stroke was the second cause of mortality worldwide in 1990 with two thirds of these deaths occurring in less developed countries.7 Because of the limited number of stroke experts and resources, it is not possible to perform all the recommended investigations and managements in many parts of these countries. A multicenter countrywide prospective cohort study aiming to evaluate quality of acute stroke care in Thailand showed that only 52% and 3.4% of patients with acute ischemic stroke were admitted to acute stroke units in the university hospitals and community hospitals, respectively.8 Continuous ECG monitoring is usually performed in stroke units. Thus, only a portion of Thai patients with acute ischemic stroke had early, continuous ECG monitoring. Most studies in PAF detection come from Western countries. Studies about continuous ECG monitoring in Asian patients with acute ischemic stroke are very limited. In this study, we looked for the prevalence and associated factors of AF and PAF that were diagnosed by snapshot ECG and continuous ECG monitoring in Thai patients with acute ischemic stroke.
Methods Patients with acute ischemic stroke who were treated at Thammasat University Hospital during May 2012October 2012 were prospectively included. Snapshot 12-lead ECG was performed as soon as possible at the emergency room. After admission to the stroke unit, all patients were ‘‘hooked up’’ with the continuous ECG monitoring for at least the first 24 hours, unless the patients were removed from the stroke unit for other investigations, such as carotid duplex, or having physical therapy. Lead 2 ECG was continuously displayed at overhead monitor at bedside and also at a central monitor at the nurse station. If there were any abnormalities on the ECG tracing while monitoring, another snapshot 12-lead ECG was performed at bedside. All stroke nurses and neurologic residents were trained to detect any abnormalities in the ECG. All abnormal ECG records were reviewed later by a cardiologist, blinded to clinical data of the patients. Baseline characteristics of the patients, underlying cardiovascular risk factors, coronary artery disease, other heart diseases (such as valvular heart diseases, cardiomyopathy), severity of the stroke, ECG findings, duration of continuous ECG monitoring, and duration of PAF detection were studied. Severity of stroke was evaluated by the National Institutes of Health Stroke Scale. Favorable outcome at discharge was defined by having modified Rankin scale 0-2 at discharge. The demographics and vascular risk factors were compared between patients with and without AF/PAF using Student t test (for the continuous variables) and the chi-square test (for the
1139
Table 1. Baseline characteristics of patients in the study
Baseline characteristics Mean age (y) (range) Mean NIHSS (range) Female, n (%) Hypertension, n (%) Diabetes mellitus, n (%) Hyperlipidemia, n (%) Coronary artery disease, n (%) Old ischemic stroke, n (%) Old intracerebral hemorrhage, n (%) History of transient ischemic attack, n (%) Smoking, n (%) Hyperthyroid, n (%) Intravenous thrombolytic treatment, n (%)
Total number, 204 patients 63 (16-93) 9 (0-28) 85 (42%) 142 (70%) 61 (30%) 140 (69%) 23 (11%) 21 (10%) 3 (1.5%) 3 (1.5%) 59 (29%) 1 (.5%) 60 (29%)
Abbreviation: NIHSS, National Institutes of Health Stroke Scale.
proportions). The multivariate analyses were performed by including the prespecified factors that were associated with AF and PAF in the univariate analysis. The study was approved by the Faculty of Medicine, Thammasat University’s ethical review committee.
Results In total, 204 patients were included. Baseline characteristics of the patients are presented in Table 1. Mean age of the patients was 63 with the mean National Institutes of Health Stroke Scale score of 9. AF and PAF were diagnosed in 31 patients (15%) and 15 patients (7%), respectively. In the subgroup of patients with AF, 14 patients (6.9%) had known AF and 17 patients were newly diagnosed. Snapshot 12-lead ECG was able to detect AF in all 31 patients. In subgroup of patients with PAF, 3 patients were diagnosed by snapshot 12-lead ECG and the rest (12 patients) by continuous ECG monitoring. PAF was detected within 24 hours of ECG monitoring in 11 patients. Mean and median duration of continuous ECG monitoring were 55 and 38 hours. Mean and median times to detect PAF were 23 and 16 hours (Fig 1). Duration of PAF ranged from 10 seconds to 87 hours. Besides AF/ PAF, acute myocardial infarction was diagnosed in 6 patients, and other arrhythmias, including bradycardia, Mobitz type 1, first-degree atrioventricular block, supraventricular tachycardia, and frequent premature ventricular contraction, were diagnosed in 9 patients while having either snapshot 12-lead ECG or continuous ECG monitoring. Patients with AF/PAF were older, a greater proportion was female, and a greater proportion had heart diseases (Table 2). Multivariate analysis revealed that age of 70 years or older (odds ratio [OR] 3.52, 95% confidence
P. SUTAMNARTPONG ET AL.
1140
Figure 1. Time and duration of PAF detection in each patient. Abbreviation: PAF, paroxysmal atrial fibrillation.
interval [CI] 1.68-7.35, P 5 .001) and heart diseases (OR 4.26, 95% CI 1.14-15.95, P 5 .031) were associated with AF and PAF. The heart diseases found in this study consisted of cardiomyopathy in 3 patients, valvular heart diseases in 5 patients, sick sinus syndrome on pacemaker in 2 patients, and atrial septal defect in 1 patient. Patients with AF/PAF had more severe stroke, significant lower rate of favorable outcome at discharge, and higher death rate during hospital stay as compared with patients without AF.
Discussion Prevalence of AF and PAF in Thai, unselected patients with acute ischemic stroke was not different from previous studies. The prevalence of AF was reported 13.6% in a study in Thai patients.9 The average incidence of new diagnosis of AF in an unselected population was 5.3%, whereas the average incidence in the selected population was 10.9%.10 The methods that were used to diagnose PAF may affect the reported incidence or prevalence. However, it is still debated which method is the best. Lazzaro et al11 compared continuous cardiac telemetry with
Holter monitoring and found that Holter monitoring was significantly more likely to detect arrhythmia (6% versus 0%), whereas Gumbinger et al12 did not find any additional benefit of using Holter monitoring in comparison with continuous monitoring. Douen et al13 revealed that serial ECG assessments within the first 72 hours of acute stroke provided better detection of new AF as compared with Holter monitoring. Duration of monitoring also affected the incidence rate of PAF, with an increased duration of monitoring associated with higher rates of detection.6 Flint et al14 monitored patients with cryptogenic stroke with 30-day outpatient ECG loop recording and found that PAF was detected in 11% of the patients, of which almost half of these were detected in the first 10 days and another half in days 20-30. In our study, continuous ECG monitoring in the stroke unit was used with median duration of monitoring of 38 hours. Copenhagen Stroke Study showed that increased incidence of AF in patients with ischemic stroke was found with increased age: 2%, 15%, 28%, and 40% in patients less than 50, 70-79, 80-89, and 90 years or older, respectively. Multivariate analysis also found that AF was associated with age (OR 2.0 per 10-year increase, 95% CI 1.6-2.6), ischemic heart disease (OR 3.4, 95% CI 2.4-4.8), and previous stroke (OR 1.8; 95% CI 1.2-2.6).1 In our study, old age and heart diseases were also associated with AF. Patients with AF had a higher mortality rate, longer hospital stays, and lower discharge rate to their home.1 In our study, patients with AF or PAF had more severe stroke and also had higher mortality and less favorable outcome than patients without AF. Early detection of AF or PAF, especially in patients presented with transient ischemic attack or small stroke, leads to earlier appropriate treatment for secondary prevention with
Table 2. Baseline characteristics of patients without and with atrial fibrillation
Baseline characteristics Mean NIHSS 6 SD Age $70 y, n (%) Female, n (%) Hypertension, n (%) Diabetes mellitus, n (%) Hyperlipidemia, n (%) Coronary artery disease, n (%) Old ischemic stroke, n (%) Smoking, n (%) Heart diseases, n (%) Hyperthyroid, n (%) Favorable outcome at discharge, n (%) Death during admission, n (%)
Patients without AF (N 5 156)
Patients with AF, PAF (N 5 48)
P value
Patients with PAF (N 5 15)
P value
7.8 6 5.3 40 (26) 59 (38) 106 (68) 48 (31) 110 (71) 14 (9) 18 (12) 51 (33) 5 (3) — 102 (65)
13.4 6 6.9 26 (54) 26 (54) 36 (75) 13 (27) 30 (63) 9 (19) 3 (6) 8 (17) 6 (13) 1 (2) 22 (46)
,.0001 ,.0001 .045 .353 .626 .295 .061 .417 .032 .013 .235 .015
16.3 6 6.5 8 (53) 9 (60) 8 (53) 4 (27) 12 (80) 2 (13) 1 (7) 2 (13) 2 (13) 1 (7) 4 (27)
,.0001 .023 .094 .251 .741 .559 .635 .566 .152 .117 .088 .005
3 (2)
7 (15)
.002
1 (7)
.310
Abbreviation: NIHSS, National Institutes of Health Stroke Scale.
ATRIAL FIBRILLATION IN PATIENTS WITH STROKE
anticoagulation. Also most patients with AF/PAF require rate-controlled treatment and some patients might benefit from optimal rhythm control to improve hemodynamic consequences.15 There were some limitations in our study. Variation in duration of continuous ECG monitoring was found. Patients with severe stroke trended to have longer admission in the stroke unit; thus, longer duration of monitoring in these patients was seen. Many stroke centers recommend routine ECG monitoring for the first 24 hours after admission. In our study, most of the patients (90%) had at least 24-hour ECG monitoring and most PAF detection (73%) occurred within 24 hours. In conclusion, AF/PAF was one of the common causes of ischemic stroke in Thai patients and was associated with old age and heart diseases. Most PAF was detected by continuous ECG monitoring within 24 hours in most of the patients (11 of 15 patients; 73%) in this study. Besides snapshot 12-lead ECG, continuous ECG monitoring should be recommended in all patients with acute ischemic stroke, especially those aged 70 years or older or with heart diseases.
1141
7.
8.
9.
10.
11.
12.
References 1. Jorgensen HS, Nakayama H, Reith J, et al. Acute stroke with atrial fibrillation. The Copenhagen Stroke Study. Stroke 1996;27:1765-1769. 2. Dharmasaroja P. Baseline characteristics of patients with acute ischemic stroke in a suburban area of Thailand. J Stroke Cerebrovasc Dis 2008;17:82-85. 3. Adams HP, del Zoppo G, Alberts MJ, et al. Guidelines for the early management of adults with ischemic stroke. Stroke 2007;38:1655-1711. 4. Marini C, De Santis F, Sacco S, et al. Contribution of atrial fibrillation to incidence and outcome of ischemic stroke: results from a population-based study. Stroke 2005; 36:1115-1119. 5. Bell C, Kapral M. Use of ambulatory electrocardiography for paroxysmal atrial fibrillation in patients with stroke. Canadian Task Force on Preventive Health Care. Can J Neurol Sci 2000;27:25-31. 6. Liao J, Khalid Z, Scallan C, et al. Noninvasive cardiac monitoring for detection paroxysmal atrial fibrillation
13.
14.
15.
or flutter after acute ischemic stroke. A systemic review. Stroke 2007;38:2935-2940. Feigin VL, Lawes CM, Bennett DA, et al. Stroke epidemiology: a review of population-based studies of incidence, prevalence, and case-fatality in the late 20th century. Lancet Neurol 2003;2:43-53. Nilanont Y, Nidhinandana S, Suwanwela NC, et al. Quality of acute ischemic stroke care in Thailand: a prospective multicenter countrywide cohort study. J Stroke Cerebrovasc Dis 2013; http://dx.doi.org/ 10.1016/j.jstrokecerebrovasdis.2012.12.001. pii: S1052– S3057(12)00406-5. Ratanakorn D, Keandoungchun J, Tegeler CH. Prevalence and association between risk factors, stroke subtypes, and abnormal ankle brachial index in acute ischemic stroke. J Stroke Cerebrovasc Dis 2012; 21:498-503. Raymond CS, Friedman PA, Rabinstein AA. Prolonged rhythm monitoring for the detection of occult paroxysmal atrial fibrillation in ischemic stroke of unknown cause. Circulation 2011;124:477-486. Lazzaro MA, Krishnan K, Prabhakaran S. Detection of atrial fibrillation with concurrent Holter monitoring and continuous cardiac telemetry following ischemic stroke and transient ischemic attack. J Stroke Cerebrovasc Dis 2012;21:89-93. Gumbinger C, Krumsdorf U, Veltkamp R, et al. Continuous monitoring versus Holter ECG for detection of atrial fibrillation in patients with stroke. Eur J Neurol 2012; 19:253-257. Douen AG, Pageau N, Medic S. Serial electrocardiographic assessments significantly improve detection of atrial fibrillation 2.6-fold in patients with acute stroke. Stroke 2008;39:480-482. Flint AC, Banki NM, Ren X, et al. Detection of paroxysmal atrial fibrillation by 30-day event monitoring in cryptogenic ischemic stroke. The Stroke and Monitoring for PAF in Real Time (SMART) Registry. Stroke 2012; 43:2788-2790. Fuster V, Ryden LE, Cannom DS, et al. 2011 ACCF/ AHA/HRS focused updates incorporated into the ACC/AHA/ESC 2006 Guidelines for the management of patients with atrial fibrillation: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines developed in partnership with the European Society of Cardiology and in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. J Am Coll Cardiol 2011;57:e101-e198.
Background: Studies about continuous electrocardiographic (ECG) monitoring in detection of paroxysmal atrial fibrillation (PAF) in Asian patients with acute ischemic stroke are very limited. We looked for the prevalence and associated factors of atrial fibrillation (AF) and PAF in Thai patients with acute ischemic stroke. Methods: In all, 204 patients with acute ischemic stroke were prospectively included. Snapshot 12-lead ECG and continuous ECG monitoring for at least the first 24 hours were performed. Multivariate analyses were performed to find out the associated factors of AF and PAF. Results: AF was diagnosed in 31 patients (15%) and PAF in 15 patients (7%). Twelve and 3 patients with PAF were diagnosed by continuous ECG monitoring and snapshot 12-lead ECG, respectively. Mean duration of continuous ECG monitoring and mean time to detect PAF were 55 and 23 hours, respectively. Multivariate analysis revealed that age of 70 years or older (odds ratio [OR] 3.52, 95% confidence interval [CI] 1.68-7.35, P 5 .001) and heart diseases (OR 4.26, 95% CI 1.14-15.95, P 5 .031) were associated with AF and PAF. Conclusions: AF/ PAF was one of the common causes of ischemic stroke in Thai patients. Most PAF was detected by continuous ECG monitoring. Snapshot 12-lead ECG and continuous ECG monitoring should be recommended in all patients with acute ischemic stroke. Key Words: Paroxysmal atrial fibrillation—atrial fibrillation—stroke— Asian—Thai. Ó 2014 by National Stroke Association
Introduction Cardioembolic stroke accounts for one fourth to one third of all ischemic stroke. Atrial fibrillation (AF), the prevalence of which increases with aging, is the most common cause of cardioembolic stroke.1,2 A clinical
From the *Division of Neurology, Department of Medicine, Faculty of Medicine, Thammasat University, Pathumthani; †Division of Neurology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; and ‡Division of Cardiology, Department of Medicine, Faculty of Medicine, Thammasat University, Pathumthani, Thailand. Received June 12, 2013; revision received September 4, 2013; accepted September 30, 2013. Address correspondence to Pornpatr A. Dharmasaroja, MD, Associate Professor in Neurology, Division of Neurology, Faculty of Medicine, Thammasat University, Klong 1, Klong Luang, Pathumthani 12120, Thailand. E-mail: [email protected]. 1052-3057/$ - see front matter Ó 2014 by National Stroke Association http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2013.09.032
1138
cardiovascular examination and a 12-lead electrocardiogram (ECG) are recommended to be performed in all stroke patients, and cardiac monitoring is useful and should be conducted routinely after acute stroke to screen for serious cardiac arrhythmia.3 Paroxysmal atrial fibrillation (PAF) is associated with a comparable increase in risk of ischemic stroke as permanent AF.4 Noninvasive cardiac monitoring methods, such as Holter monitoring and continuous cardiac telemetry, were developed aiming to detect PAF. However, which method is the best method and the recommended duration of monitoring in patients with acute ischemic stroke are still debated. From previous reviews, Holter monitoring for 24-48 hours can identify AF in 1%-5% of patients undetected by initial ECG. Extended duration of monitoring and confining its use to patients with nonlacunar stroke may improve detection rates.5,6 With the approved new anticoagulants, secondary prevention of recurrent thromboembolic events was at least equally or even more effective, with less bleeding complications
Journal of Stroke and Cerebrovascular Diseases, Vol. 23, No. 5 (May-June), 2014: pp 1138-1141
ATRIAL FIBRILLATION IN PATIENTS WITH STROKE
than previous vitamin K antagonist therapy. Thus, it may be worthwhile to detect PAF. Stroke was the second cause of mortality worldwide in 1990 with two thirds of these deaths occurring in less developed countries.7 Because of the limited number of stroke experts and resources, it is not possible to perform all the recommended investigations and managements in many parts of these countries. A multicenter countrywide prospective cohort study aiming to evaluate quality of acute stroke care in Thailand showed that only 52% and 3.4% of patients with acute ischemic stroke were admitted to acute stroke units in the university hospitals and community hospitals, respectively.8 Continuous ECG monitoring is usually performed in stroke units. Thus, only a portion of Thai patients with acute ischemic stroke had early, continuous ECG monitoring. Most studies in PAF detection come from Western countries. Studies about continuous ECG monitoring in Asian patients with acute ischemic stroke are very limited. In this study, we looked for the prevalence and associated factors of AF and PAF that were diagnosed by snapshot ECG and continuous ECG monitoring in Thai patients with acute ischemic stroke.
Methods Patients with acute ischemic stroke who were treated at Thammasat University Hospital during May 2012October 2012 were prospectively included. Snapshot 12-lead ECG was performed as soon as possible at the emergency room. After admission to the stroke unit, all patients were ‘‘hooked up’’ with the continuous ECG monitoring for at least the first 24 hours, unless the patients were removed from the stroke unit for other investigations, such as carotid duplex, or having physical therapy. Lead 2 ECG was continuously displayed at overhead monitor at bedside and also at a central monitor at the nurse station. If there were any abnormalities on the ECG tracing while monitoring, another snapshot 12-lead ECG was performed at bedside. All stroke nurses and neurologic residents were trained to detect any abnormalities in the ECG. All abnormal ECG records were reviewed later by a cardiologist, blinded to clinical data of the patients. Baseline characteristics of the patients, underlying cardiovascular risk factors, coronary artery disease, other heart diseases (such as valvular heart diseases, cardiomyopathy), severity of the stroke, ECG findings, duration of continuous ECG monitoring, and duration of PAF detection were studied. Severity of stroke was evaluated by the National Institutes of Health Stroke Scale. Favorable outcome at discharge was defined by having modified Rankin scale 0-2 at discharge. The demographics and vascular risk factors were compared between patients with and without AF/PAF using Student t test (for the continuous variables) and the chi-square test (for the
1139
Table 1. Baseline characteristics of patients in the study
Baseline characteristics Mean age (y) (range) Mean NIHSS (range) Female, n (%) Hypertension, n (%) Diabetes mellitus, n (%) Hyperlipidemia, n (%) Coronary artery disease, n (%) Old ischemic stroke, n (%) Old intracerebral hemorrhage, n (%) History of transient ischemic attack, n (%) Smoking, n (%) Hyperthyroid, n (%) Intravenous thrombolytic treatment, n (%)
Total number, 204 patients 63 (16-93) 9 (0-28) 85 (42%) 142 (70%) 61 (30%) 140 (69%) 23 (11%) 21 (10%) 3 (1.5%) 3 (1.5%) 59 (29%) 1 (.5%) 60 (29%)
Abbreviation: NIHSS, National Institutes of Health Stroke Scale.
proportions). The multivariate analyses were performed by including the prespecified factors that were associated with AF and PAF in the univariate analysis. The study was approved by the Faculty of Medicine, Thammasat University’s ethical review committee.
Results In total, 204 patients were included. Baseline characteristics of the patients are presented in Table 1. Mean age of the patients was 63 with the mean National Institutes of Health Stroke Scale score of 9. AF and PAF were diagnosed in 31 patients (15%) and 15 patients (7%), respectively. In the subgroup of patients with AF, 14 patients (6.9%) had known AF and 17 patients were newly diagnosed. Snapshot 12-lead ECG was able to detect AF in all 31 patients. In subgroup of patients with PAF, 3 patients were diagnosed by snapshot 12-lead ECG and the rest (12 patients) by continuous ECG monitoring. PAF was detected within 24 hours of ECG monitoring in 11 patients. Mean and median duration of continuous ECG monitoring were 55 and 38 hours. Mean and median times to detect PAF were 23 and 16 hours (Fig 1). Duration of PAF ranged from 10 seconds to 87 hours. Besides AF/ PAF, acute myocardial infarction was diagnosed in 6 patients, and other arrhythmias, including bradycardia, Mobitz type 1, first-degree atrioventricular block, supraventricular tachycardia, and frequent premature ventricular contraction, were diagnosed in 9 patients while having either snapshot 12-lead ECG or continuous ECG monitoring. Patients with AF/PAF were older, a greater proportion was female, and a greater proportion had heart diseases (Table 2). Multivariate analysis revealed that age of 70 years or older (odds ratio [OR] 3.52, 95% confidence
P. SUTAMNARTPONG ET AL.
1140
Figure 1. Time and duration of PAF detection in each patient. Abbreviation: PAF, paroxysmal atrial fibrillation.
interval [CI] 1.68-7.35, P 5 .001) and heart diseases (OR 4.26, 95% CI 1.14-15.95, P 5 .031) were associated with AF and PAF. The heart diseases found in this study consisted of cardiomyopathy in 3 patients, valvular heart diseases in 5 patients, sick sinus syndrome on pacemaker in 2 patients, and atrial septal defect in 1 patient. Patients with AF/PAF had more severe stroke, significant lower rate of favorable outcome at discharge, and higher death rate during hospital stay as compared with patients without AF.
Discussion Prevalence of AF and PAF in Thai, unselected patients with acute ischemic stroke was not different from previous studies. The prevalence of AF was reported 13.6% in a study in Thai patients.9 The average incidence of new diagnosis of AF in an unselected population was 5.3%, whereas the average incidence in the selected population was 10.9%.10 The methods that were used to diagnose PAF may affect the reported incidence or prevalence. However, it is still debated which method is the best. Lazzaro et al11 compared continuous cardiac telemetry with
Holter monitoring and found that Holter monitoring was significantly more likely to detect arrhythmia (6% versus 0%), whereas Gumbinger et al12 did not find any additional benefit of using Holter monitoring in comparison with continuous monitoring. Douen et al13 revealed that serial ECG assessments within the first 72 hours of acute stroke provided better detection of new AF as compared with Holter monitoring. Duration of monitoring also affected the incidence rate of PAF, with an increased duration of monitoring associated with higher rates of detection.6 Flint et al14 monitored patients with cryptogenic stroke with 30-day outpatient ECG loop recording and found that PAF was detected in 11% of the patients, of which almost half of these were detected in the first 10 days and another half in days 20-30. In our study, continuous ECG monitoring in the stroke unit was used with median duration of monitoring of 38 hours. Copenhagen Stroke Study showed that increased incidence of AF in patients with ischemic stroke was found with increased age: 2%, 15%, 28%, and 40% in patients less than 50, 70-79, 80-89, and 90 years or older, respectively. Multivariate analysis also found that AF was associated with age (OR 2.0 per 10-year increase, 95% CI 1.6-2.6), ischemic heart disease (OR 3.4, 95% CI 2.4-4.8), and previous stroke (OR 1.8; 95% CI 1.2-2.6).1 In our study, old age and heart diseases were also associated with AF. Patients with AF had a higher mortality rate, longer hospital stays, and lower discharge rate to their home.1 In our study, patients with AF or PAF had more severe stroke and also had higher mortality and less favorable outcome than patients without AF. Early detection of AF or PAF, especially in patients presented with transient ischemic attack or small stroke, leads to earlier appropriate treatment for secondary prevention with
Table 2. Baseline characteristics of patients without and with atrial fibrillation
Baseline characteristics Mean NIHSS 6 SD Age $70 y, n (%) Female, n (%) Hypertension, n (%) Diabetes mellitus, n (%) Hyperlipidemia, n (%) Coronary artery disease, n (%) Old ischemic stroke, n (%) Smoking, n (%) Heart diseases, n (%) Hyperthyroid, n (%) Favorable outcome at discharge, n (%) Death during admission, n (%)
Patients without AF (N 5 156)
Patients with AF, PAF (N 5 48)
P value
Patients with PAF (N 5 15)
P value
7.8 6 5.3 40 (26) 59 (38) 106 (68) 48 (31) 110 (71) 14 (9) 18 (12) 51 (33) 5 (3) — 102 (65)
13.4 6 6.9 26 (54) 26 (54) 36 (75) 13 (27) 30 (63) 9 (19) 3 (6) 8 (17) 6 (13) 1 (2) 22 (46)
,.0001 ,.0001 .045 .353 .626 .295 .061 .417 .032 .013 .235 .015
16.3 6 6.5 8 (53) 9 (60) 8 (53) 4 (27) 12 (80) 2 (13) 1 (7) 2 (13) 2 (13) 1 (7) 4 (27)
,.0001 .023 .094 .251 .741 .559 .635 .566 .152 .117 .088 .005
3 (2)
7 (15)
.002
1 (7)
.310
Abbreviation: NIHSS, National Institutes of Health Stroke Scale.
ATRIAL FIBRILLATION IN PATIENTS WITH STROKE
anticoagulation. Also most patients with AF/PAF require rate-controlled treatment and some patients might benefit from optimal rhythm control to improve hemodynamic consequences.15 There were some limitations in our study. Variation in duration of continuous ECG monitoring was found. Patients with severe stroke trended to have longer admission in the stroke unit; thus, longer duration of monitoring in these patients was seen. Many stroke centers recommend routine ECG monitoring for the first 24 hours after admission. In our study, most of the patients (90%) had at least 24-hour ECG monitoring and most PAF detection (73%) occurred within 24 hours. In conclusion, AF/PAF was one of the common causes of ischemic stroke in Thai patients and was associated with old age and heart diseases. Most PAF was detected by continuous ECG monitoring within 24 hours in most of the patients (11 of 15 patients; 73%) in this study. Besides snapshot 12-lead ECG, continuous ECG monitoring should be recommended in all patients with acute ischemic stroke, especially those aged 70 years or older or with heart diseases.
1141
7.
8.
9.
10.
11.
12.
References 1. Jorgensen HS, Nakayama H, Reith J, et al. Acute stroke with atrial fibrillation. The Copenhagen Stroke Study. Stroke 1996;27:1765-1769. 2. Dharmasaroja P. Baseline characteristics of patients with acute ischemic stroke in a suburban area of Thailand. J Stroke Cerebrovasc Dis 2008;17:82-85. 3. Adams HP, del Zoppo G, Alberts MJ, et al. Guidelines for the early management of adults with ischemic stroke. Stroke 2007;38:1655-1711. 4. Marini C, De Santis F, Sacco S, et al. Contribution of atrial fibrillation to incidence and outcome of ischemic stroke: results from a population-based study. Stroke 2005; 36:1115-1119. 5. Bell C, Kapral M. Use of ambulatory electrocardiography for paroxysmal atrial fibrillation in patients with stroke. Canadian Task Force on Preventive Health Care. Can J Neurol Sci 2000;27:25-31. 6. Liao J, Khalid Z, Scallan C, et al. Noninvasive cardiac monitoring for detection paroxysmal atrial fibrillation
13.
14.
15.
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