Outpatient Telemetry Research Articles

Diagnosis of atrial fibrillation after stroke and transient ischaemic attack: a systematic review and meta-analysis

Among patients with atrial fibrillation, the risk of stroke is highest for those with a history of stroke; however, oral anticoagulants can lower the risk of recurrent stroke by two-thirds. No consensus has been reached about how atrial fibrillation should be investigated in patients with stroke, and its prevalence after a stroke remains uncertain. We did a systematic review and meta-analysis to estimate the proportion of patients newly diagnosed with atrial fibrillation after four sequential phases of cardiac monitoring after a stroke or transient ischaemic attack. We searched PubMed, Embase, and Scopus from 1980 to June 30, 2014. We included studies that provided the number of patients with ischaemic stroke or transient ischaemic attack who were newly diagnosed with atrial fibrillation. We stratified cardiac monitoring methods into four sequential phases of screening: phase 1 (emergency room) consisted of admission electrocardiogram (ECG); phase 2 (in hospital) comprised serial ECG, continuous inpatient ECG monitoring, continuous inpatient cardiac telemetry, and in-hospital Holter monitoring; phase 3 (first ambulatory period) consisted of ambulatory Holter; and phase 4 (second ambulatory period) consisted of mobile cardiac outpatient telemetry, external loop recording, and implantable loop recording. The primary endpoint was the proportion of patients newly diagnosed with atrial fibrillation for each method and each phase, and for the sequential combination of phases. For each method and each phase, we estimated the summary proportion of patients diagnosed with post-stroke atrial fibrillation using random-effects meta-analyses. Our systematic review returned 28,290 studies, of which 50 studies (comprising 11,658 patients) met the criteria for inclusion in the meta-analyses. The summary proportion of patients diagnosed with post-stroke atrial fibrillation was 7·7% (95% CI 5·0-10·8) in phase 1, 5·1% (3·8-6·5) in phase 2, 10·7% (5·6-17·2) in phase 3, and 16·9% (13·0-21·2) in phase 4. The overall atrial fibrillation detection yield after all phases of sequential cardiac monitoring was 23·7% (95% CI 17·2-31·0). By sequentially combining cardiac monitoring methods, atrial fibrillation might be newly detected in nearly a quarter of patients with stroke or transient ischaemic attack. The overall proportion of patients with stroke who are known to have atrial fibrillation seems to be higher than previously estimated. Accordingly, more patients could be treated with oral anticoagulants and more stroke recurrences prevented. Heart and Stroke Foundation of Canada, and Natural Science and Engineering Research Council of Canada.

Prospective Assessment of the CryoMaze Procedure With Continuous Outpatient Telemetry in 136 Patients

Only 40% of patients with atrial fibrillation (AF) undergoing cardiac surgery are treated with surgical AF correction. We prospectively studied endocardial cryoablation of the Cox-maze III lesion set following prespecified rhythm assessment with outpatient telemetry. Between 2007 and 2011, 136 patients underwent surgical AF correction using an argon-powered cryoablation device. Patients wore continuous electrocardiogram monitoring prior to and at 6, 12, and 24 months after surgery. The average length of monitoring was 6.5±1 days prior to surgery and 11±4 days at each time point after surgery. Patients were assessed for cardiac rhythm, interval cardioversion or ablation procedures, pacemaker placement, and the use of warfarin or antiarrhythmic medications. The primary endpoint of this study was freedom from AF at 1 year. Mean patient age was 66±12 years, 50% (69 of 138) were male and 41% (55 of 134) had persistent AF. CryoMaze was done in conjunction with mitral valve operation in 95% (131 of 138) and other procedures in 41% (56 of 138). Follow-up was 96% complete at 1 year and 90% at 2 years. Freedom from AF was 76% at 1 year. Perioperative mortality and stroke rates were both 1.5% (2 of 138). Perioperative pacemaker implantation was required in 7% (9 of 136). In univariate analysis, younger age, female gender, decreased height and weight, smaller preoperative and postoperative left atrial diameter, intermittent AF, and freedom from AF at discharge were associated with freedom from AF at 1 year. Actuarial 2- and 4-year (Kaplan-Meier) survival were 93% and 80%, respectively. The CryoMaze procedure is safe and is associated with 76% freedom from AF at 1 year.

Abstract 24: Predictors of Occult Atrial Fibrillation in Cryptogenic Stroke

Background and Purpose: Prolonged cardiac monitoring may identify paroxysmal atrial fibrillation (AF) in patients with cryptogenic stroke. We aimed to identify clinical, echocardiographic, and neuroimaging features which may increase the efficiency of detecting AF on cardiac monitoring. Methods: We studied a retrospective cohort of 227 subjects with cryptogenic ischemic stroke referred for 28 day mobile cardiac outpatient telemetry (MCOT). Patients with large artery disease or high risk sources of cardioembolism were excluded. We reviewed medical records, brain images, and echocardiograms, blinded to MCOT results. Acute and/or chronic infarctions were characterized by size, location, and as cortical, subcortical, or both; wedge-shaped; lacunar; borderzone; and/or multiple territories. Cardiac features included left atrial (LA) size, ejection fraction, aortic arch atheroma, and PFO. Variables were tested in univariate analyses and further incorporated in a multivariate logistic regression model to determine independent predictors of detecting AF. Results: The cohort age was 62.9±2.9 years, 42% were men, and 53% were white. Median CHADS was 3 and CHADS2Vasc was 5. Infarcts were >1.5 cm in 62% of subjects, predominantly cortical in 47%, subcortical in 39%. Only 9% were single, deep, and <1.5 cm. LA size was 3.6±0.7 cm and ejection fraction was 61±9%. MCOT detected AF in 30 (13%) patients. In multivariate analysis, AF was only associated with age>60 (OR 3.6 [1.2-10.4], p=0.02) and prior (chronic) cortical or cerebellar infarction (OR 3.3 [1.3-8.6], p=0.013) (C-statistic 0.72). There was no association with any other clinical, echocardiographic, or radiographic parameter. AF was detected in 32% of patients with age >60 and the presence of prior cortical or cerebellar infarction, compared to 4% with neither of these factors. Conclusion: Atrial fibrillation is detected on MCOT in a substantial minority of cryptogenic stroke patients. Age>60 and the presence of prior cortical or cerebellar strokes are predictive of detecting AF in these patients. Other brain and cardiac characteristics were not found to be helpful. These data may aid in the selection of patients for prolonged arrhythmia monitoring.

Abstract 23: Neuroimaging and Echocardiographic Predictors of Paroxysmal Atrial Fibrillation on Outpatient Mobile Cardiac Outpatient Telemetry in Cryptogenic Ischemic Stroke and TIA Patients

Background: The objective of our study was to identify factors on MRI neuroimaging and echocardiography as part of routine workup of patients with cryptogenic ischemic stroke (IS) or transient ischemic attack (TIA) to identify those patients who are likely to have paroxysmal atrial fibrillation (PAF) as detected by subsequent outpatient mobile cardiac outpatient telemetry (MCOT). Methods: All cryptogenic IS or TIA patients seen at Emory University Hospital and The Emory Clinic from 2009-2013 and who underwent outpatient MCOT were included in this analysis.Using logistic regression, we analyzed the association between lesions seen on MRI FLAIR sequences with PAF and categorized them as the following: Cortical lesions (CL), defined as T2-hyperintense cortical-based infarcts; high subcortical (HS) T2-hyperintense lesions, defined as <5mm beneath the cortex without any cortical involvement, or none. Left atrium (LA) functional and dimensional echocardiographic parameters were evaluated to determine their association with PAF. Results: Of 132 patients included in this analysis, 17 (13%) had evidence of newly diagnosed PAF on MCOT (mean duration of monitoring=25 days); median age was 72 (IQR: 64-79), 50% were women, diabetes was present in 23%, hypertension in 76%, dyslipidemia in 64%, and active tobacco use in 8%. CL seen on baseline MRI were found to be significant predictors of PAF (OR 5.2, 95 % CI: 1.3-19; p=0.01). HS lesions were not found to be a significant predictor of PAF. On baseline echocardiography, patients who had PAF (vs non-PAF) had significantly higher mean LA diameter (4.2 vs 3.7 cm, p=0.03), lower tissue Doppler velocity (a’) (5.5 vs 13.5 cm/s, p=0.03), a trend toward higher left atrium volume index (LAVI) (37.5 vs 29.2, p=0.07) and mean LAVI/late diastolic Doppler velocity (A) (0.67 vs. 0.37, P= 0.006). The Areas under the Curve (AUC) for the parameters were: LA diameter 71.4%, a’ 92.6%, LAVI 74.6%, LAVI/A 62.5%, LAVI/a’ 67.9%. Conclusion: Cortical-based infarcts seen on MRI FLAIR sequences and baseline echocardiographic variables may help to predict cryptogenic ischemic stroke or TIA patients who are likely to have PAF identified on outpatient MCOT.

Indecision in the Clinical Practice of Anticoagulation for Brief Atrial Arrhythmias after Cryptogenic Stroke

Long-term cardiac monitoring has a substantial yield for paroxysmal atrial fibrillation (PAF) detection in cryptogenic stroke or transient ischemic attack (TIA) patients; however, many of these episodes were brief. We analyzed treatment decisions taken by the clinicians regarding anticoagulation in these short-duration PAF patients. We performed a retrospective analysis on all mobile cardiac outpatient telemetry records between June 2009 and January 2012, initiated by neurologists from a large tertiary care institution stroke center. In all, 39 patients were found to have atrial fibrillation (AF), and their records were reviewed. AF episodes were categorized as less than 30 seconds in 24 (62%) patients and 30 seconds or more in 15 (38%) patients. Among the 16 patients without a cardiology evaluation, the rate of anticoagulation was high and did not differ for patients with short AF (90%, 9 of 10) and long AF (83%, 5 of 6) (P>.99). However, among the 23 patients with a cardiology evaluation, the difference in rates of anticoagulation was significant between patients with short AF (43%, 6 of 14) and long AF (89%, 8 of 9) (P=.039). Our study demonstrates the differences in anticoagulant prescribing practices between neurologists and cardiologists and the inherent indecision these findings have produced. Further study is needed to better define the risks and benefits associated with anticoagulation of brief episodes of atrial arrhythmias lasting less than 30 seconds in patients with cryptogenic stroke or TIA.

Stroke: Highlights of Selected Articles

HomeStrokeVol. 44, No. 2Stroke: Highlights of Selected Articles Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBStroke: Highlights of Selected Articles Originally published1 Feb 2013https://doi.org/10.1161/STROKEAHA.111.000183Stroke. 2013;44:320An Observational Study of Thrombolysis Outcomes in Wake-up Ischemic Stroke PatientsPatients who wake up with stroke symptoms account for ≈8% to 27% of all ischemic strokes. Because of their unknown symptom onset time, they are not thrombolyzed. These patients have worse functional outcome. This study sought to determine the outcome of a specific subset of wake-up stroke patients who received thrombolysis. Wake-up stroke patients made up 10.5% (193/1836) of all stroke admissions. The inclusion criteria consisted of the following: (1) last seen normal >4.5 hours and <12 hours before presentation; (2) National Institutes of Health Stroke Scale score ≥5; (3) no or early ischemic changes <1/3 middle cerebral artery territory on computed tomography scan; and (4) no absolute contraindications to thrombolysis. Inclusion criteria were met by 122 patients, of whom 68 (56%) were thrombolyzed. There was no difference in modified Rankin Scale 0 to 2, death, and symptomatic intracerebral hemorrhage between thrombolyzed and nonthrombolyzed patients. After adjusting for age, sex, and baseline National Institutes of Health Stroke Scale score, thrombolysis was associated with an odds ratio of 5.2 for modified Rankin Scale 0 to 2 at 90 days and odds ratio of 0.09 for death. This study suggests that thrombolysis in a subset of wake-up stroke patients based on clinical and imaging criteria is feasible and may be associated with better outcomes. Further data from prospective clinical trials, such as MR WITNESS, are needed before making changes to current treatment guidelines for thrombolysis in wake-up ischemic stroke patients. See p 427.Pilot Randomized Trial of Outpatient Cardiac Monitoring After Cryptogenic StrokeSeveral studies have recently shown that the detection rate of atrial fibrillation with outpatient cardiac monitoring in patients with recent stroke is 5% to 20%. This study by Kamel et al is the first randomized trial of cardiac monitoring after cryptogenic stroke and transient ischemic attack (TIA). In this pilot trial, 40 patients with cryptogenic stroke or high-risk TIA (ABCD2 score ≥4) were randomized to mobile cardiac outpatient telemetry monitor by CardioNet for 21 days or to receive routine clinical follow-up. In the cardiac monitoring group, compliance was an issue. Patients wore monitors for 64% of the assigned days, and 25% of patients were not compliant with the monitoring at all. No patients in either group were diagnosed with atrial fibrillation. Although cardiac monitoring revealed atrial fibrillation in zero patients, brief episodes (<10 seconds) of atrial tachycardia were found in 2 patients and nonsustained ventricular tachycardia were found in 2 patients. These results are clearly in contrast to previous studies using similar monitoring techniques. This highlights the need for further clinical trials. The Cryptogenic Stroke and underlying Atrial Fibrillation (CRYSTAL AF) trial is one such trial that uses implantable cardiac monitors and aims to help clarify this question. See p 528.Effect of Medical Treatment on Stroke/TIA Risk in Asymptomatic Carotid StenosisCarotid endarterectomy has been shown in several trials to reduce the risk of stroke in asymptomatic carotid stenosis. The absolute benefit of carotid endarterectomy in these trials is small because of the low risk of stroke per year (2%) in medically treated patients. These trials were also performed in a time when medical therapy is not up to today’s standards. In fact, recent evidence suggests that with newer and more effective medical treatments, the stroke risk is even lower. Using Asymptomatic Carotid Emboli Study (ACES) prospective data, this current study sought to determine the effect of current treatment on the risk of future stroke and TIA. Four hundred seventy-seven patients with asymptomatic carotid stenosis were followed every 6 months for 2 years. On univariate analysis, statins, antihypertensives, blood pressure, antiplatelets, and smoking were all associated with lower risk of ipsilateral stroke/TIA and any stroke/cardiovascular disease death. On multivariate analysis, antiplatelets and lower mean blood pressure were independent predictors of reduced risk of ipsilateral stroke/TIA. Antiplatelets and antihypertensives were independent predictors of a lower risk of any stroke/cardiovascular disease death. These results highlight the importance of controlling risk factors in patients with asymptomatic carotid stenosis. See p 542. Previous Back to top Next FiguresReferencesRelatedDetails February 2013Vol 44, Issue 2 Advertisement Article InformationMetrics © 2011 American Heart Association, Inc.https://doi.org/10.1161/STROKEAHA.111.000183 Originally publishedFebruary 1, 2013 PDF download Advertisement SubjectsTreatment

Pilot Randomized Trial of Outpatient Cardiac Monitoring After Cryptogenic Stroke

Observational studies indicate that outpatient cardiac monitoring detects previously undiagnosed atrial fibrillation (AF) in 5% to 20% of patients with recent stroke. However, it remains unknown whether the yield of monitoring exceeds that of routine clinical follow-up. In a pilot trial, we randomly assigned 40 patients with cryptogenic ischemic stroke or high-risk transient ischemic attack to wear a Cardionet mobile cardiac outpatient telemetry monitor for 21 days or to receive routine follow-up alone. After thorough investigation, we excluded patients with documented AF or other apparent stroke pathogenesis. We contacted patients and their physicians at 3 months and at 1 year to ascertain any diagnoses of AF or recurrent stroke or transient ischemic attack. The baseline characteristics of our cohort broadly matched those of previous observational studies of monitoring after stroke. In the monitoring group, patients wore monitors for 64% of the assigned days, and 25% of patients were not compliant at all with monitoring. No patient in either study arm received a diagnosis of AF. Cardiac monitoring revealed AF in zero patients (0%; 95% confidence interval, 0%-17%), brief episodes of atrial tachycardia in 2 patients (10%; 95% confidence interval, 1%-32%), and nonsustained ventricular tachycardia in 2 patients (10%; 95% confidence interval, 1%-32%). In the first reported randomized trial of cardiac monitoring after cryptogenic stroke, the rate of AF detection was lower than expected, incidental arrhythmias were frequent, and compliance with monitoring was suboptimal. Our findings highlight the challenges of prospectively identifying stroke patients at risk for harboring paroxysmal AF and ensuring adequate compliance with cardiac monitoring. Clinical Trial Registration- URL: http://clinicaltrials.gov. Unique Identifier: NCT00715533.

Outpatient cardiac telemetry detects a high rate of atrial fibrillation in cryptogenic stroke

BackgroundThe etiology of cerebral ischemia is undetermined in one-third of patients upon discharge. Occult paroxysmal atrial fibrillation (PAF) is considered a potential etiology. A high rate of PAF detection with 21-day mobile cardiac outpatient telemetry (MCOT) has been reported in two small studies. Optimal monitoring duration and factors predicting PAF have not been adequately defined. MethodsWe performed a retrospective analysis on patients evaluated by MCOT monitoring within 6months of a cryptogenic stroke or TIA. Multivariate analysis with survival regression methods was performed using baseline characteristics to determine predictive risk factors for detection of PAF. Kaplan–Meier estimates were computed for 21-day PAF rates. ResultsWe analyzed 156 records; PAF occurred in 27 of 156 (17.3%) patients during MCOT monitoring of up to 30days. The rate of PAF detection significantly increased from 3.9% in the initial 48h, to 9.2% at 7days, 15.1% at 14days, and 19.5% by 21days (p<0.05). Female gender, premature atrial complex on ECG, increased left atrial diameter, reduced left ventricular ejection fraction and greater stroke severity were independent predictors of PAF detection on multivariate analysis with strongest correlation seen for premature atrial complex on ECG (HR 13.7, p=0.001). ConclusionMCOT frequently detects PAF in patients with cryptogenic stroke and TIA. Length of monitoring is strongly associated with detection of PAF, with an optimal monitoring period of at least 21days. Of the predictors of PAF detection, the presence of premature atrial complexes on ECG held the strongest correlation with PAF.

Detection of Atrial Fibrillation After Cryptogenic Stroke

Patients with ischemic stroke and atrial fibrillation (AF) are treated with long-term oral anticoagulation (OAC) because it is considerably more effective than antiplatelet (AP) therapy for the prevention of subsequent strokes and systemic emboli. Therefore, detecting AF changes therapy and makes secondary prevention more effective. Technology for detection of rare episodes of paroxysmal AF (PAF) has improved recently. AF that is only detectable by prolonged monitoring (occult AF, or oAF) may underlie some strokes of unknown cause (cryptogenic stroke). However, the ideal method and duration of cardiac monitoring to detect oAF after stroke is unknown. Furthermore, new technologies allow the detection of brief, rare episodes of AF that would not have been detectable at the time classic studies establishing the benefit of OAC were conducted. Therefore, it is unknown what the minimum threshold of oAF burden or duration is that mandates OAC instead of AP therapy. Here we review the available technologies, and discuss the therapeutic implications and uncertainties when oAF is found after ischemic stroke. There is evidence that 3weeks of outpatient cardiac telemetry has a high yield of detection of AF after cryptogenic stroke; however, ongoing studies may show that even longer monitoring periods have higher yield.

Joint association of ankle-brachial index and serum uric acid on the outcomes of six-year all-cause mortality and cardiovascular mortality in Chinese patients

[1] The Stroke Risk in Atrial Fibrillation Working Group. Independent predictors of stroke in patients with atrial fibrillation. A systematic review. Neurology 2007;69:546–54. [2] Tayal AH, Tian M, Kelly KM, et al. Atrial fibrillation detected by mobile cardiac outpatient telemetry in cryptogenic TIA or stroke. Neurology 2008;7:1696–701. [3] Haft JI, Teichholz LE. Echocardiographic and clinical risk factors for atrial fibrillation in hypertensive patients with ischemic stroke. Am J Cardiol 2008;102:1348–51. [4] Haft JI, Teichholz LE. Atrial fibrillation or flutter is found in 45.4% of elderly patients with nonhemorrhagic stroke. Stroke 2012:A2349. [5] Coats AJS, Shewan LG. Statement on authorship and publishing ethics in the International Journal of Cardiology. Int J Cardiol 2011;153:239–40.

Outpatient Cardiac Telemetry Detects a High Rate of Atrial Fibrillation among Patients with Cryptogenic Cerebral Ischemia (PD2.006)

Objective: In one-third of patients discharged with stroke or TIA the etiology of the event remains undetermined. Paroxysmal atrial fibrillation (PAF) is reported as a potential etiology. The factors predicting PAF in these patients have not been defined. This study aims to define these factors and duration of remote cardiac telemetry needed to detect PAF. Background 1) A high rate of PAF can be detected during 21 days of mobile cardiac outpatient telemetry (MCOT). 2) There will be a set of risk factors which can predict the detection of PAF with MCOT. Design/Methods: We performed a retrospective analysis on patients evaluated by MCOT monitoring within 6 months of a cryptogenic stroke or TIA. The ECG data were analyzed with an algorithm verified against the MIT-BIH arrhythmia database. Multivariate analysis with survival regression analysis was performed using demographic, clinical, neuroimaging and cardiac imaging characteristics to determine predictive risk factors for detection of PAF on MCOT. Kaplan-Meier estimates were computed for the 21-day PAF rates. Results: We analyzed 156 records; 97% of patients were not on anticoagulation. PAF occurred in 27 of 156 (17.3%) patients during MCOT monitoring of up to 30 days. The rate of PAF detection significantly increased from 3.9% in the initial 48hrs, to 9.2% at 7 days, to 15.1% at 14 days, and to 19.5% by 21 days (p Conclusions: MCOT is a robust diagnostic tool for the identification of PAF in patients with cryptogenic stroke and TIA. Length of monitoring is strongly associated with the likelihood of detection of PAF. Female gender, PAC on ECG, increased left atrial diameter (LAD), reduced left ventricular ejection fraction and greater NIHSS increase the likelihood of PAF detection. Disclosure: Dr. Khan has nothing to disclose. Dr. Miller has nothing to disclose. Dr. Schultz has nothing to disclose. Dr. Simpson has nothing to disclose. Dr. Russman has nothing to disclose. Dr. Mitsias has nothing to disclose.

New insights in prevention, diagnosis and treatment of stroke: its relation with atrial fibrillation

New insights in prevention, diagnosis and treatment of stroke: its relation with atrial fibrillation

Abstract 150: Outpatient Cardiac Telemetry Detects A High Rate of Atrial Fibrillation Among Patients with Cryptogenic Cerebral Ischemia

Introduction: In one-third of patients discharged with stroke or TIA the etiology of the event remains undetermined. Occult paroxysmal atrial fibrillation (PAF) was reported as a potential etiology. The factors predicting PAF in these patients have not been defined. Hypothesis: 1) A high rate of PAF can be detected during 21 days of mobile cardiac outpatient telemetry (MCOT). 2) There will be a set of risk factors which can predict the detection of PAF with MCOT. Methods: We performed a retrospective analysis on patients evaluated by MCOT monitoring within 6 months of a cryptogenic stroke or TIA. The ECG data were analyzed with an algorithm verified against the MIT-BIH arrhythmia database. Multivariate analysis with survival regression analysis was performed using demographic, clinical, neuroimaging and cardiac imaging characteristics to determine predictive risk factors for detection of PAF on MCOT. Kaplan-Meier estimates were computed for the 21-day PAF rates. Results: We analyzed 156 records; 97% of patients were not on anticoagulation. PAF occurred in 27 of 156 (17.3%) patients during MCOT monitoring of up to 30 days. The rate of PAF detection significantly increased from 3.9% in the initial 48hrs, to 9.2% at 7 days, to 15.1% at 14 days, and to 19.5% by 21 days (p&lt;0.05) ( figure ). Multivariate analysis defined several independent predictors of PAF detection ( table ). Premature atrial complex (PAC) on baseline ECG held the strongest correlation with PAF (HR 13.65, p=0.001). Conclusion: MCOT is a robust diagnostic tool for the identification of PAF in patients with cryptogenic stroke and TIA. Length of monitoring is strongly associated with the likelihood of detection of PAF. Female gender, PAC on ECG, increased left atrial diameter (LAD), reduced left ventricular ejection fraction (LV EF) and greater NIHSS increase the likelihood of PAF detection.

Abstract 3513: Randomized Trial of Outpatient Cardiac Monitoring After Cryptogenic Stroke

Background: Diagnosis of atrial fibrillation (AF) as a cause of stroke or TIA is important because it identifies patients who may benefit from anticoagulation. Observational studies indicate that outpatient cardiac monitoring detects previously undiagnosed AF in 5-20% of patients with stroke, but these studies may overestimate the rate of AF if selection bias prompts analysis and publication. It is also unknown whether the yield of cardiac monitoring is higher than that of routine clinical follow-up. Methods: In a pilot trial, we randomly assigned consecutive patients with cryptogenic ischemic stroke or high-risk TIA (ABCD 2 score ≥ 4) to wear a Cardionet mobile cardiac outpatient telemetry monitor for 21 days after discharge, or to not wear a monitor. We excluded patients with a known history of AF, AF detected by inpatient cardiac telemetry (at least 24 hours required), a definite small-vessel etiology, a source found by vascular imaging or echocardiography, an obvious culpable systemic illness such as endocarditis, or inability to provide written, informed consent. All patients received routine clinical follow-up from their primary care physician and neurologist. We contacted patients and their physicians 3 months after discharge and used validated questionnaires to inquire about clinical diagnoses of AF and recurrent stroke or TIA. Results: The target enrollment of 40 patients was completed over 18 months. The mean age was 67 years (± 13), 23 (58%) were men, and 32 (80%) had at least one vascular risk factor; the baseline characteristics of our cohort were broadly similar to those in prior observational studies of cardiac monitoring after stroke. Our prespecified feasibility criteria were met, with full follow-up on 38 patients (95%) and successful completion of monitoring in 15 of the 20 patients (75%) randomized to monitoring. Overall, patients wore monitors for 64% of the assigned days. No patient in either study arm received a diagnosis of AF. Cardiac monitoring revealed AF in zero patients (0%, 95% CI 0-17%), brief episodes (&lt; 10 seconds) of atrial tachycardia in two patients (10%, 95% CI 1-32%) and nonsustained ventricular tachycardia in two patients (10%, 95% CI 1-32%). There were no recurrent strokes; recurrent TIAs occurred in two patients assigned to the control group. Conclusions: The results of our pilot trial indicate that randomizing patients to outpatient cardiac monitoring after stroke is feasible. However, rates of AF detection were lower than expected, which may be due to publication bias in prior observational studies or selection of lower risk patients in our trial. Furthermore, 25% of patients assigned to undergo monitoring were not compliant. These results suggest that an adequately powered randomized trial of cardiac monitoring after stroke may require large numbers of participants.

Abstract 2437: Timing of Mobile Cardiac Outpatient Telemetry May Increase Diagnostic Yield of Atrial Fibrillation in Select Patients with Cryptogenic Strokes

Introduction: Cryptogenic stroke accounts for 30-40% of ischemic strokes. Routine Holter monitoring detects atrial fibrillation (AF) in only 5-7% of patients with ischemic strokes. However, prolonged cardiac monitoring increases the diagnostic yield of AF. Objective: In this study we used mobile cardiac outpatient telemetry (MCOT)and sought to determine 1)what percentage of our patients with cryptogenic stroke had underlying AF, 2) whether a period of highest diagnostic yield for AF could be derived and 3) whether there are clinical and electrocardiogram(EKG) parameters that predict AF in a select population. Methodology: Between March 2009 and December 2010, the data for 50 consecutive patients with MCOT at the stroke follow up clinic were analyzed. All had imaging, echocardiogram, EKG, hypercoagulable panel and at least 48 hours of in-patient cardiac telemetry monitoring. Of these, 16 were excluded because they either had no restricted diffusion on Diffusion Weighted Imaging (DWI) or had procedure-related strokes, hypercoagulable state or TEE detected mobile plaques in the ascending aorta. Results: The final 34 patients (19 males, 15 females, mean age of 62.8±12.9) had a diagnosis of cryptogenic stroke.Magnetic rasonance imaging( MRI) detected anterior circulation strokes in 67.6% (23/34) of the cases with the remaining being posterior circulation strokes or a combination of both. MCOT of 21 days duration was initiated up to a median of 8 weeks (2-24 weeks) post discharge. Overall, AF was detected in 29.4% (10/34) of the patients within a median of 8.5 days. Of these, the detection rates were 8.8% within the first 7 days and 26.5% within 14 days. Beyond 14 days, AF detection rate increased by only 3%. Regression analysis indicated that enlarged left atrial size (&gt;4 cm) was not a significant predictor of AF in our patient population. The combination of stroke, dyslipidemia, coronary artery disease, atrio-ventricular block II type 1, supraventricular tachycardia and regional wall motion abnormality on echocardiogram however was correlated with a higher diagnostic yield of detecting AF on MCOT (r 2 =0.72). Conclusion: Occult AF is common in patients with cryptogenic stroke. We found increased detection of atrial fibrillation with monitoring between 7 to 14 days, especially in those with an underlying history of stroke, coronary artery disease and certain EKG rhythm abnormalities.

Prolonged Rhythm Monitoring for the Detection of Occult Paroxysmal Atrial Fibrillation in Ischemic Stroke of Unknown Cause

Atrial fibrillation (AF), commonly encountered in patients with ischemic stroke and transient ischemic attack (TIA), confers a 5-fold increased risk of ischemic stroke.1,2 AF-related strokes are associated with an ≈50% increased risk of disability and 60% increased risk of death at 3 months compared with strokes of other etiologies.3 Paroxysmal AF (PAF), a self-terminating recurrent form of cardiac arrhythmia that comprises between 25% and 62% of AF cases, may present as a brief single episode of arrhythmia or as clusters of abnormal rhythm of variable duration, sometimes evolving into a more persistent or permanent form.4 The self-terminating nature of PAF may lead to its underdiagnosis and consequent use of less effective treatment strategies (aspirin instead of oral anticoagulation) in poststroke patients. To address the underdiagnosis of PAF in patients with ischemic stroke and TIAs, several treatment guidelines have singled out the identification of PAF as an important goal after a stroke/TIA.5–8 The diagnosis of PAF, however, poses a challenge. Several features of AF (such as its brief duration, episodic frequency, and asymptomatic presentations) make its detection difficult and elusive to bedside screening measures, such as pulse monitoring and routine ECGs. To date, several studies have explored the use of prolonged noninvasive and invasive cardiac monitoring devices to identify AF but with variable success. After detection of AF, a cardioembolic mechanism is often inferred and anticoagulation occasionally prescribed for secondary stroke prevention. The routine use of cardiac monitoring to identify patients with PAF who will benefit from anticoagulation has been reported to be cost-effective.9 In this review, we provide an overview of the different methods of cardiac monitoring, summarize studies that investigated the incidence of PAF after stroke, and highlight gaps in our understanding of the pathogenic and prognostic significance of AF …

Utility of Noninvasive, Mobile, Continuous Outpatient Rhythm Monitoring to Diagnose Seizure‐Related Arrhythmias

The identification of patients with a diagnosis of seizure disorder who are also at risk for clinically significant bradycardia and/or tachycardia may require long-term cardiac rhythm monitoring. Noninvasive, continuous, outpatient cardiac rhythm monitoring may be useful for such clinical scenarios. The study group consisted of two male patients with a history of seizure disorder involving loss of consciousness. Clinical data and results of electrocardiography, echocardiography, electroencephalography, and continuous, mobile, outpatient cardiac rhythm monitoring are described. In the first patient, while cardiac bradyarrhythmias were secondary to seizures, sinus arrest most likely complicated the episodes by leading to more prolonged states of unconsciousness. In the second patient, permanent pacemaker implantation for AV block averted all clinical events previously attributed to seizures. Despite the different causal relationships between seizures and bradyarrhythmias in these two patients, mobile, cardiac outpatient telemetry was successful in diagnosing the contribution of cardiac dysrhythmia, leading to permanent pacemaker implantation. A diagnostic strategy that incorporates mobile, noninvasive, continuous, outpatient cardiac rhythm monitoring can effectively be utilized to diagnose significant seizure-related arrhythmias.

Atrial fibrillation detected by mobile cardiac outpatient telemetry in cryptogenic TIA or stroke

Atrial fibrillation detected by mobile cardiac outpatient telemetry in cryptogenic TIA or stroke

Atrial fibrillation detected by mobile cardiac outpatient telemetry in cryptogenic TIA or stroke

Atrial fibrillation (AF) may be present within a subset of patients with presumed cryptogenic TIA or stroke and remains undetected by standard diagnostic methods. We hypothesized that AF may be an under-recognized mechanism for cryptogenic TIA/stroke. A consecutive series of 56 patients with cryptogenic TIA/stroke was analyzed after diagnostic evaluation and Mobile Cardiac Outpatient Telemetry (MCOT) for up to 21 days. Demographic, radiographic, echocardiographic, and MCOT results were reviewed. Predictors of AF detection by MCOT were determined by univariate analysis including Student t test and Fisher exact tests and multivariate analysis. The median MCOT monitoring duration was 21 (range 5-21) days resulting in an AF detection rate of 23% (13/56). AF was first detected after a median of 7 (range 2-19) days of monitoring. Twenty-seven asymptomatic AF episodes were detected in the 13 patients, of which 85% (23/27) were <30 seconds and the remaining 15% (4/27) were 4-24 hours in duration. Diabetes was predictive of AF detection by both univariate (p = 0.024) and multivariate analysis (OR 6.15; 95% CI 1.16 to 32.73; p = 0.033). There is a high rate of atrial fibrillation (AF) detection by Mobile Cardiac Outpatient Telemetry (21 days) in patients with cryptogenic TIA/stroke that may be related to extended monitoring duration, patient selection, and inclusion of all new onset AF episodes. Brief AF episodes (<30 seconds) may be biomarkers of more prolonged and clinically significant AF.

Initial Experience with Novel Mobile Cardiac Outpatient Telemetry for Children and Adolescents with Suspected Arrhythmia

To report use of a novel mobile cardiac outpatient telemetry (MCOT) system for evaluation of children and adolescents with suspected cardiac arrhythmia. Prospective data collection and retrospective analysis. All patients who received MCOT from The Children's Hospital at the Cleveland Clinic between 1/14/04 and 2/12/05 were screened. Patients older than 21 years and those with previously documented arrhythmia were excluded. Fifty-nine consecutive MCOT studies were performed. Five patients met exclusion criteria leaving 54 subjects (mean age 12.4+/-4.5 years; range 3.2-19.7 years; 46% male) for inclusion. The MCOT system (CardioNet, USA) consists of a 3-electrode, 2-channel sensor that transmits wirelessly to a portable monitor. Monitors continuously store, analyze, and transmit the electrocardiogram through cellular and land telephone networks to a central station. MCOT was performed for 9-32 consecutive days (mean 24.5+/-7.4). Results. Twenty-one subjects (39%) did not experience symptoms during MCOT, yielding a diagnostic rate of 61% (N = 33). Of the 33 diagnostic studies, 9% (N = 3; mean age 16.9+/-0.6 years; range 16.2-17.3 years; 1 male) showed supraventricular tachycardia and 9% (N = 3; mean age 11.1+/-2.7 years; range 8.2-13.5 years; 1 male) showed supraventricular or ventricular ectopy. Minor skin irritation at sites of electrode placement was the only complication of MCOT (N = 5). MCOT is safe and useful for evaluation of children and adolescents with suspected arrhythmia, providing a diagnosis in 61% of subjects. The diagnostic yield of MCOT was superior to that expected from traditional event and Holter monitors in this pediatric population.