Cryptogenic Stroke and underlying Atrial Fibrillation (CRYSTAL AF): design and rationale. Pilot Randomized Trial of Outpatient Cardiac Monitoring After Cryptogenic Stroke Intermittent atrial fibrillation may account for a large proportion of otherwise cryptogenic stroke: a study of 30-day cardiac event monitors. Cost-effectiveness of an insertable cardiac monitor to detect atrial fibrillation in patients with cryptogenic stroke Uncovering Atrial Fibrillation Beyond Short-Term Monitoring in Cryptogenic Stroke Patients: Three-Year Results From the Cryptogenic Stroke and Underlying Atrial Fibrillation Trial Unexpected low prevalence of atrial fibrillation in cryptogenic ischemic stroke: a prospective study Cryptogenic stroke and underlying atrial fibrillation. Noninvasive Cardiac Event Monitoring to Detect Atrial Fibrillation After Ischemic Stroke: A Randomized, Controlled Trial A Structured Reading Algorithm Improves Telemetric Detection of Atrial Fibrillation After Acute Ischemic Stroke Multicenter randomized study of anticoagulation guided by remote rhythm monitoring in patients with implantable cardioverter-defibrillator and CRT-D devices: Rationale, design, and clinical characteristics of the initially enrolled cohort The IMPACT study. Predictors of newly diagnosed atrial fibrillation in cryptogenic stroke: a cohort study. Prevalence of atrial fibrillation with insertable cardiac monitors in cryptogenic stroke: A single-center experience. Detection of atrial fibrillation in patients with embolic stroke of undetermined source by prolonged monitoring with implantable loop recorders. Total atrial conduction time to predict occult atrial fibrillation after cryptogenic stroke The BioMonitor 2 insertable cardiac monitor: Clinical experience with a novel implantable cardiac monitor. Performance of a New Leadless Implantable Cardiac Monitor in Detecting and Quantifying Atrial Fibrillation Results of the XPECT Trial 96 hours ECG monitoring for patients with ischemic cryptogenic stroke or transient ischaemic attack
BACKGROUND Patients with atrial fibrillation ( AF ) are at increased risk for ischemic stroke . In patients who have suffered a stroke , screening for AF is routinely performed only for a short period after the stroke as part of the evaluation for possible causes . If AF is detected after an ischemic stroke , oral anticoagulation therapy is recommended for secondary stroke prevention . In 25 % to 30 % of stroke patients , the stroke mechanism can not be determined ( cryptogenic stroke ) . The incidence of paroxysmal AF undetected by short-term monitoring in patients with cryptogenic stroke is unknown , but has important therapeutic implication s on patient care . The optimum monitoring duration and method of AF detection after stroke are unknown . The purpose of this study is to evaluate the incidence of AF and time to AF detection in patients with cryptogenic stroke using an insertable cardiac monitor . STUDY DESIGN The CRYSTAL AF trial is a r and omized prospect i ve study to evaluate a novel approach to long-term monitoring for AF detection in patients with cryptogenic stroke . Four hundred fifty cryptogenic stroke patients ( by definition , without a history of AF ) will be enrolled at approximately 50 sites in Europe , Canada , and the United States . Patients will be r and omized in a 1:1 fashion to st and ard arrhythmia monitoring ( control arm ) or implantation of the subcutaneous cardiac monitor ( Reveal XT ; Medtronic , Inc , Minneapolis , MN ) ( continuous monitoring arm ) . OUTCOMES The primary end point is time to detection of AF within 6 months after stroke . The clinical follow-up period will be at least 12 months . Study completion is expected at the end of 2012 Background and Purpose — 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 . Methods — In a pilot trial , we r and omly 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 . Results — 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 % ) . Conclusions — In the first reported r and omized 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 prospect ively identifying stroke patients at risk for harboring paroxysmal AF and ensuring adequate compliance with cardiac monitoring . Clinical Trial Registration — URL : http:// clinical trials.gov . Unique Identifier : INTRODUCTION Despite extensive inpatient workup including telemetry monitoring , a significant proportion of stroke is classified as cryptogenic at hospital discharge . It is possible that a significant proportion of cryptogenic stroke is a result of intermittent atrial fibrillation ( AF ) . Thirty-day cardiac event monitors ( 30-DEM ) may increase the rate of AF detection compared with st and ard investigations that include a combination of electrocardiography , cardiac telemetry , and short-term Holter monitoring . METHODS Charts were review ed of patients who were admitted to a university stroke center or who were evaluated in the outpatient clinic during a 9-month period to determine whether the cause of stroke was cryptogenic . As a matter of protocol , such patients typically underwent 30-DEM and the results of such monitoring were documented along with the duration of inpatient cardiac monitoring if relevant . RESULTS In all , 218 patients with a diagnosis of ischemic stroke or transient ischemic attack were identified . Of the strokes , 36 ( 16.5 % ) were classified as cryptogenic . Twenty patients with cryptogenic stroke or transient ischemic attack were evaluated with 30-DEM . Four ( 20 % ) were found to have AF , and all 4 patients were treated with warfarin . CONCLUSION The 30-DEM changed the medical treatment of 20 % of patients with otherwise cryptogenic stroke because of the detection of intermittent AF despite no detection of AF on electrocardiography and inpatient telemetry monitoring in the majority of patients . Further prospect i ve studies of extended cardiac event monitors in the setting of cryptogenic stroke are warranted Background and aims Documentation of atrial fibrillation is required to initiate oral anticoagulation therapy for recurrent stroke prevention . Atrial fibrillation often goes undetected with traditional electrocardiogram monitoring techniques . We evaluated whether atrial fibrillation detection using continuous long-term monitoring with an insertable cardiac monitor is cost-effective for preventing recurrent stroke in patients with cryptogenic stroke , in comparison to the st and ard of care . Methods A lifetime Markov model was developed to estimate the cost-effectiveness of insertable cardiac monitors from a UK National Health Service perspective using data from the r and omized CRYSTAL-AF trial and other published literature . We also conducted scenario analyses ( CHADS2 score ) and probabilistic sensitivity analyses . All costs and benefits were discounted at 3.5 % . Results Monitoring cryptogenic stroke patients with an insertable cardiac monitor was associated with fewer recurrent strokes and increased quality -adjusted life years compared to the st and ard of care ( 7.37 vs 7.22 ) . Stroke-related costs were reduced in insertable cardiac monitor patients , but overall costs remained higher than the st and ard of care ( £ 19,631 vs £ 17,045 ) . The incremental cost-effectiveness ratio was £ 17,175 per quality -adjusted life years gained , compared to st and ard of care in the base-case scenario , which is below established quality -adjusted life years willingness-to-pay thresholds . When warfarin replaced non-vitamin-K oral anticoagulants as the main anticoagulation therapy , the incremental cost-effectiveness ratio was £ 13,296 per quality -adjusted life years gained . Conclusion Insertable cardiac monitors are a cost-effective diagnostic tool for the prevention of recurrent stroke in patients with cryptogenic stroke . The cost-effectiveness results have relevance for the UK and across value-based healthcare systems that assess costs relative to outcomes Background —Atrial fibrillation ( AF ) can be a cause of previously diagnosed cryptogenic stroke . However , AF can be paroxysmal and asymptomatic , thereby making detection with routine ECG methods difficult . Oral anticoagulation is highly effective in reducing recurrent stroke in patients with AF , but its initiation is dependent on the detection of AF . Cryptogenic Stroke and Underlying Atrial Fibrillation ( CRYSTAL AF ) is the first r and omized study to report the detection of AF in cryptogenic stroke patients using continuous long-term monitoring via insertable cardiac monitors ( ICM ) . Methods and Results — Patients with prior cryptogenic stroke were r and omized to control ( n=220 ) or ICM ( n=221 ) and followed for ⩽36 months . Cumulative AF detection rates in the ICM arm increased progressively during this period ( 3.7 % , 8.9 % , 12.4 % , and 30.0 % at 1 , 6 , 12 , and 36 months , respectively ) , but remained low in the control arm ( 3.0 % at 36 months ) . This result ed in oral anticoagulation prescription in 94.7 % of ICM patients with AF detected at 6 months , 96.6 % at 12 months , and 90.5 % at 36 months . Among ICM patients with AF detected , the median time to AF detection was 8.4 months , 81.0 % of first AF episodes were asymptomatic , and 94.9 % had at least 1 day with > 6 minutes of AF . Conclusions —Three-year monitoring by ICM in cryptogenic stroke patients demonstrated a significantly higher AF detection rate compared with routine care . Given the frequency of asymptomatic first episodes and the long median time to detection , these findings highlight the limitations of using traditional AF detection methods . The majority of patients with AF were prescribed oral anticoagulation therapy . Clinical Trial Registration — Clinical trials.gov ; Unique identifier : NCT00924638 Purpose Ischemic stroke is a frequent pathology with high rate of recurrence and significant morbidity and mortality . There are several causes of stroke , affecting prognosis , outcomes , and management , but in many cases , the etiology remains undetermined . We hypothesized that atrial fibrillation was involved in this pathology but underdiagnosed by st and ard methods . The aim of the study was to determine the incidence of atrial fibrillation in cryptogenic ischemic stroke by using continuous monitoring of the heart rate over several months . The secondary objective was to test the value of atrial vulnerability assessment in predicting spontaneous atrial fibrillation . Methods and results We prospect ively enrolled 24 patients under 75 years of age , 15 men and 9 women of mean age 49 years , who within the last 4 months had experienced cryptogenic stroke diagnosed by clinical presentation and brain imaging and presumed to be of cardioembolic mechanism . All causes of stroke were excluded by normal 12-lead ECG , 24-h Holter monitoring , echocardiography , cervical Doppler , hematological , and inflammatory tests . All patients underwent electrophysiological study . Of the patients , 37.5 % had latent atrial vulnerability , and 33.3 % had inducible sustained arrhythmia . Patients were secondarily implanted with an implantable loop recorder to look for spontaneous atrial fibrillation over a mean follow-up interval of 14.5 months . No sustained arrhythmia was found . Only one patient had non-significant episodes of atrial fibrillation . Conclusion In this study , symptomatic atrial fibrillation or AF with fast ventricular rate has not been demonstrated by the implantable loop recorder  in patients under 75 years with unexplained cerebral ischemia . The use of this device should not be generalized in the systematic evaluation of these patients . In addition , this study attests that the assessment of atrial vulnerability is poor at predicting spontaneous arrhythmia in such patients BACKGROUND Current guidelines recommend at least 24 hours of electrocardiographic ( ECG ) monitoring after an ischemic stroke to rule out atrial fibrillation . However , the most effective duration and type of monitoring have not been established , and the cause of ischemic stroke remains uncertain despite a complete diagnostic evaluation in 20 to 40 % of cases ( cryptogenic stroke ) . Detection of atrial fibrillation after cryptogenic stroke has therapeutic implication s. METHODS We conducted a r and omized , controlled study of 441 patients to assess whether long-term monitoring with an insertable cardiac monitor ( ICM ) is more effective than conventional follow-up ( control ) for detecting atrial fibrillation in patients with cryptogenic stroke . Patients 40 years of age or older with no evidence of atrial fibrillation during at least 24 hours of ECG monitoring  underwent r and omization within 90 days after the index event . The primary end point was the time to first detection of atrial fibrillation ( lasting > 30 seconds ) within 6 months . Among the secondary end points was the time to first detection of atrial fibrillation within 12 months . Data were analyzed according to the intention-to-treat principle . RESULTS By 6 months , atrial fibrillation had been detected in 8.9 % of patients in the ICM group ( 19 patients ) versus 1.4 % of patients in the control group ( 3 patients ) ( hazard ratio , 6.4 ; 95 % confidence interval [ CI ] , 1.9 to 21.7 ; P<0.001 ) . By 12 months , atrial fibrillation had been detected in 12.4 % of patients in the ICM group ( 29 patients ) versus 2.0 % of patients in the control group ( 4 patients ) ( hazard ratio , 7.3 ; 95 % CI , 2.6 to 20.8 ; P<0.001 ) . CONCLUSIONS ECG monitoring with an ICM was superior to conventional follow-up for detecting atrial fibrillation after cryptogenic stroke . ( Funded by Medtronic ; CRYSTAL AF Clinical Trials.gov number , NCT00924638 . ) Background and Purpose — Atrial fibrillation ( AF ) elevates risk of recurrent stroke but is incompletely identified by st and ard investigation after stroke , though detection rates correlate with monitoring duration . We hypothesized that 7 days of noninvasive cardiac-event monitoring early after stroke would accelerate detection of AF and thus uptake of effective therapy . Methods — We performed a pragmatic r and omized trial with objective outcome assessment among patients presenting in sinus rhythm with no AF history , within 7 days of ischemic stroke symptom onset . Patients were r and omized to st and ard practice investigations ( SP ) to detect AF , or SP plus additional monitoring ( SP-AM ) . AM comprised 7 days of noninvasive cardiac-event monitoring reported by an accredited cardiac electrocardiology laboratory . Primary outcome was detection of AF at 14 days . Results — One-hundred patients were enrolled from 2 centers . Within 14 days of stroke , sustained paroxysms of AF were detected in 18 % of patients undergoing SP-AM versus 2 % undergoing SP ( P<0.05 ) . Paroxysms of any- duration were detected in 44 % of patients undergoing SP-AM versus 4 % undergoing SP ( P<0.001 ) . These differences persisted at 90 days . Anticoagulant therapy was commenced within 14 days in 16 % of SP-AM patients versus none r and omized to SP ( P<0.01 ) . This difference persisted to 90 days ( 22 % versus 6 % ; P<0.05 ) . Conclusions — Routine noninvasive cardiac-event monitoring after acute stroke enhances detection of paroxysmal AF and early anticoagulation . Extended monitoring should be offered to all eligible patients soon after acute stroke . Guidelines on investigation for AF in stroke patients could be strengthened . Clinical Trial Registration — URL : http://www.controlled-trials.com/is rct n/. Unique identifier : IS RCT N97412358 Background and Purpose — Anticoagulation is a highly effective secondary prevention in patients with cardioembolic stroke and atrial fibrillation/flutter ( AF ) . However , the condition remains underdiagnosed , because paroxysmal AF may be missed by diagnostic tests in the acute phase . In this study , the sensitivity of AF detection was assessed for serial electrocardiographic recordings and continuous stroke unit telemetric monitoring with or without a structured algorithm to analyze telemetric data ( SEA-AF ) . Methods — Three hundred forty-six consecutive patients with acute ischemic stroke were prospect ively included and subjected to st and ard telemetric monitoring . In addition , telemetric data were separately analyzed following SEA-AF , consisting of a structured evaluation of episodes with high risk for AF and a chronological beat-to-beat screening of the full registration . Serial electrocardiograms  were conducted in 24-hour intervals . Results — Median effective telemetry monitoring time was 75.5 hours ( interquartile range 64–86 hours ) . Overall , AF was diagnosed in 119 of 346 patients ( 34.4 % ) . The structured reading algorithm was the most sensitive method to detected AF . Conventional telemetry and serial electrocardiographic assessment s were less effective . However , only 35 % of patients with previously documented paroxysmal AF and negative baseline electrocardiogram demonstrated AF episodes during monitoring . Conclusions — Continuous stroke unit telemetry using SEA-AF shows a significantly higher detection rate for AF compared with daily electrocardiographic assessment s and st and ard telemetry without structured reading . The low overall probability to detect paroxysmal AF with either method during the first days after stroke demonstrates the urgent need for complementary diagnostic strategies such as long-term monitoring and frequent follow-up assessment s. Clinical Trial Registration — URL : www . clinical trials.gov . Unique identifier : NCT01177748 Atrial fibrillation and atrial flutter are common cardiac arrhythmias associated with an increased risk of stroke in patients with additional risk factors .  Anticoagulation ameliorates stroke risk , but because these arrhythmias may occur intermittently without symptoms , initiation of prophylactic therapy is often delayed until electrocardiographic documentation is obtained . The IMPACT study is a multicenter , r and omized trial of remote surveillance technology in patients with implanted dual-chamber cardiac resynchronization therapy defibrillator ( CRT-D ) devices design ed to test the hypothesis that initiation and withdrawal of oral anticoagulant therapy guided by continuous ambulatory monitoring of the atrial electrogram improve clinical outcomes by reducing the combined rate of stroke , systemic embolism , and major bleeding compared with conventional clinical management . For those in the intervention group , early detection of atrial high-rate episodes ( AHRE ) generates an automatic alert to initiate anticoagulation based on patient-specific stroke risk stratification . Subsequently , freedom from AHRE for predefined periods prompts withdrawal of anticoagulation to avoid bleeding . Patients in the control arm are managed conventionally , the anticoagulation decision prompted by incidental detection of atrial fibrillation or atrial flutter during routine clinical follow-up . The results will help define the clinical utility of wireless remote cardiac rhythm surveillance and help establish the critical threshold of AHRE burden warranting anticoagulant therapy in patients at risk of stroke . In this report , we describe the study design and baseline demographic and clinical features of the initial cohort ( 227 patients ) BACKGROUND AND PURPOSE A significant proportion of cryptogenic ischaemic strokes are due to paroxysmal atrial fibrillation ( AF ) . As paroxysmal AF appears to inexorably progress to persistent or permanent AF , this study with long-term follow-up was design ed to establish the profile of patients who developed AF after hospital discharge . METHODS All patients with cryptogenic ischaemic stroke over a 1-year period were included ( n = 164 ) . Patients were prospect ively followed up at the outpatient clinic . Information on long-term outcome included the presence of newly diagnosed AF ( NDAF ) . A specific NDAF assessment was performed at least 2 years after the index stroke using a structured telephone interview .  Baseline clinical , laboratory , and echocardiographic data of these patients were retrospectively recorded . Independent predictive factors were then used to produce a predictive grading score for NDAF , derived by logistic regression analysis . RESULTS With a median follow-up of 854 days , 22 cases of NDAF ( 13 % ) were observed . On multivariate analysis , factors associated with NDAF were age ≥72 years ( two points ) , history of coronary artery disease ( one point ) or stroke ( one point ) , and left atrial area ≥16 cm(2 ) ( two points ) ( total score ranging from 0 to 6 ) . Patients with a score ≤1 point did not have NDAF during follow-up . CONCLUSIONS In cryptogenic ischaemic stroke , the NDAF score can be used to target patients at high risk of developing AF after hospital discharge , as a score of 0 - 1 was highly predictive of the absence of NDAF during follow-up . These results need to be confirmed in prospect i ve studies BACKGROUND The use of insertable cardiac monitors ( ICM ) has increased the rate of detection of atrial fibrillation ( AF ) among cryptogenic stroke ( CS ) patients . We describe a single-center experience for AF detection among CS patients receiving ICMs upon discharge after the index stroke event and attempt to identify predictors for AF detection . METHODS From April 2014 to October 2017 , patients receiving ICMs for CS who underwent > 60 days of monitoring were review ed . Chronic underlying medical illnesses , presence of left atrial enlargement ( LAE ) on echocardiography , and PR interval on admission electrocardiogram were assessed as predictors of AF detection . RESULTS A total of 234 patients ( median age 72 [ 61 , 78 ] years , 45 % women ) met inclusion criteria and were followed for a median of 536 [ 282 , 848 ] days . Among studied patients , 68 patients ( 29 % ) were found to have AF at a median of 94.5 [ 16 , 239 ] days from ICM placement . CS patients with AF were significantly older ( p < 0.001 ) , and there was a significantly higher proportion of women ( p = 0.003 ) when compared to CS patients without AF . Neither presence of LAE nor prolonged PR interval was predictive of AF detection . CONCLUSION Almost one-third of CS patients monitored with an ICM were found to have previously undiagnosed AF . CS patients found to have AF were older and more commonly women . Prospect i ve studies are needed to better identify predictors for early AF among the broader population of all CS patients Recently , the clinical entity embolic stroke of undetermined source ( ESUS ) has been defined for patients with ischemic strokes , where neither a cardioembolic nor a non-cardiac source can be detected . These patients may suffer from asymptomatic atrial fibrillation ( AF ) , terminating spontaneously and thus eluding detection . Implantable loop recorders ( ILR ) with automatic AF detection algorithms can detect short-lasting , sub clinical AF . The aim of this study was to prospect ively assess and predict AF detection in patients with ESUS using ILR with daily remote interrogation . Patients with acute ESUS received an ILR , were seen every 6 months and additionally interrogated their ILR daily using remote monitoring . The incidence of AF detection was assessed and parameters which might predict AF detection ( clinical and from magnetic resonance tomography ) were analysed . ILR implantation was performed in 123 patients on average 20 days after stroke . During a mean follow-up of 12.7±5.5 months , AF was documented and manually confirmed in 29 of 123 patients ( 23.6 % ) . First AF detection occurred on average after 3.6±3.4 months of monitoring . Patients with AF were on average older , had a higher CHA2DS2-VASc score and more often cerebral microangiopathy . In conclusion , AF can be documented in approximately 25 % of patients with the diagnosis of ESUS after careful work-up within a year of monitoring by an ILR and daily remote interrogation . This had important therapeutic consequences ( initiation of anticoagulation for secondary stroke prevention ) in these patients Background Insertable cardiac monitor ( ICM ) increases the detection rate of occult atrial fibrillation ( AF ) after cryptogenic stroke . The aim of this study was to evaluate the prognostic significance of  total atrial conduction time ( TACT )  assessed by tissue Doppler imaging ( PA-TDI interval ) to predict AF presence in patients with cryptogenic stroke . Methods Ninety patients ( 57.7 ± 12.3 years , 48 % women ) after acute cryptogenic stroke and ICM implantation were prospect i ve recruited at four centers for continuous rhythm monitoring . In all patients , TACT was measured by PA-TDI interval via echocardiography . Patients were followed up ( 331 ± 186 days ) for detection of AF ( defined by episode lasting ≥30 s ) . Results AF was detected in 16 patients ( 18 % ) during follow-up ( 331 ± 186 days ) . The median period to AF detection was 30 days ( q1–q3 ; 16–62 days ) . Patients who exhibited occult AF were characterized by significantly longer PA-TDI intervals ( 154.7 ± 12.6 vs. 133.9 ± 9.5 ms , p < 0.0001 ) . The cut-off value of PA-TDI interval at 145 ms demonstrated sensitivity and specificity for AF detection of 93.8 and 90.5 % , respectively . In multivariate analysis , CHA2DS2–VASc score ( HR 1.96 per 1 point , p < 0.01 ) and longer PA-TDI interval ( HR 4.05 per 10 ms , p < 0.0001 ) were independent predictors of occult AF . Conclusion Our data suggest that measurement of TACT could help to predict future AF detection in patients with cryptogenic stroke . The clinical importance of prolonged rhythm monitoring or indication of direct anticoagulation therapy after cryptogenic stroke based on TACT should be further investigated INTRODUCTION Implantable loop recorders ( ILR ) are leadless subcutaneous devices that allow cardiac monitoring for up to 3 years and are a valuable tool in the diagnosis of arrhythmias , cryptogenic stroke and unexplained syncope . The Biotronik BioMonitor 2 is a novel , insertable ILR allowing long-term continuous monitoring with wireless telemetry options . METHODS A single-center , prospect i ve , observational study investigating the reliability of sensing quality and detection performance in the BioMonitor 2 ILR , as well as post-implantation patient satisfaction . R-wave amplitude was recorded immediately post implantation and 1 day post implantation , followed by extensive patient instruction . Follow-up was scheduled after 3 months , or after an event . Data from the ILR were retrieved , with documentation of all episodes , R-wave amplitude and noise burden . The anatomical position of the ILR was determined 1 day post implantation and after 3 months . A patient question naire was conducted after 3 months . RESULTS 30 consecutive patients ( mean age 71 ± 12 years , 56 % male ) were analyzed . Indications for ILR implantation were : unexplained syncope ( n = 24 , 80 % ) , suspected atrial fibrillation ( n = 4 , 13 % ) , cryptogenic stroke ( n = 1 , 3 % ) and palpitations ( n = 1 , 3 % ) . Median time from skin cut to suture was 8 min . No complications occurred . Mean R-wave amplitude at implantation was 0.84 ± 0.32 mV , at day 1 post implantation 0.96 ± 0.31 mV , and after a mean follow-up of 85 ± 24 days 1.02 ± 0.47 mV ( p = 0.01 ) . The mean noise burden was 1.4 ± 2 % . CONCLUSION Implantation of the novel BioMonitor 2 ILR is fast and uncomplicated . Initial sensing values are good and improve over time Background —Current methods for detecting atrial fibrillation ( AF ) have limited diagnostic yield . Continuous monitoring with automatic arrhythmia detection and classification may improve detection of symptomatic and asymptomatic AF and subsequent patient treatment . The study purpose was to quantify the performance of the first implantable leadless cardiac monitor ( ICM ) with dedicated AF detection capabilities . Methods and Results — Patients ( n=247 ) with an implanted ICM ( Reveal XT , Medtronic Inc , Minneapolis , Minn ) who were likely to present with paroxysmal AF were selected . A special Holter device stored 46 hours of subcutaneously recorded ECG , ICM markers , and 2 surface ECG leads . The ICM  automatic arrhythmia classification was compared with the core laboratory classification of the surface ECG . Of the 206 analyzable Holter recordings collected , 76 ( 37 % ) contained at least 1 episode of core laboratory classified AF . The sensitivity , specificity , positive predictive value , and negative predictive value for identifying patients with any AF were 96.1 % , 85.4 % , 79.3 % , and 97.4 % , respectively . The AF burden measured with the ICM was very well correlated with the reference value derived from the Holter ( Pearson coefficient=0.97 ) . The overall accuracy of the ICM for detecting AF was 98.5 % . Conclusions —In this ICM validation study , the dedicated AF detection algorithm reliably detected the presence or absence of AF and the AF burden was accurately quantified . The ICM is a promising new diagnostic and monitoring tool for the clinician to treat AF patients independently of symptoms . Long-term studies are needed to evaluate the clinical benefits of the technology . Clinical Trial Registration — clinical trials.gov Identifier NCT00680927 Atrial fibrillation ( AF ) is intermittent in 30 % of patients with cardioembolic stroke and , therefore , might not be seen in a single st and ard ECG recording . The aim of this study was to evaluate if prolonged ECG monitoring ( 96 h ) finds episodes of intermittent AF beyond the 24 h ECG monitoring in patients with cryptogenic stroke or transient ischemic attack ( TIA ) . We prospect ively evaluated consecutive patients affected by cryptogenic stroke or TIA who had sinus rhythm on a 12-lead ECG on admission , and during ECG monitoring performed in the acute phase ( for at least 24 h ) . Patients had continuous 96 h Holter ECG monitoring within 30 days from stroke onset . 114 patients were included in the study ( mean age 63.1 ± 15.1 , 59 males ) .  AF was found in 29 patients ( 24.3 % ) . In 20 patients , AF was found in the first 24 h of recording , and in nine patients after 24 h. In addition , several other dysrhythmias such as supraventricular ectopic activity ( 33 ) , ventricular tachycardia ( 10 ) , sinus pause ( 4 ) and sinus-atrial block ( 1 ) were found . In patients with cryptogenic stroke or TIA , 96 h ECG monitoring detected a high rate of AF . One-third of AF was seen beyond 24 h of ECG monitoring
When each device is compared incrementally , BioMonitor 2-AF dominates Reveal LINQ and Confirm RX .
BACKGROUND Cryptogenic stroke is a stroke for which no cause is identified after st and ard diagnostic tests .
Long-term implantable cardiac monitors may be better at diagnosing atrial fibrillation and provide an opportunity to reduce the risk of stroke recurrence with anticoagulants .
OBJECTIVES The objectives were to assess the diagnostic test accuracy , clinical effectiveness and cost-effectiveness of three implantable monitors [ BioMonitor 2-AF ™ ( Biotronik SE & Co. KG , Berlin , Germany ) , Confirm Rx ™ ( Abbott Laboratories , Lake Bluff , IL , USA ) and Reveal LINQ ™ ( Medtronic plc , Minneapolis , MN , USA ) ] in patients who have had a cryptogenic stroke and for whom no atrial fibrillation is detected after 24 hours of external electrocardiographic monitoring .