Implantable Loop Recorder Monitoring Research Articles

Race disparities in atrial fibrillation detection using implantable loop recorder for cryptogenic stroke

Abstract Background Cryptogenic stroke represents about 25–30% of all ischemic strokes. Continuous electrocardiographic monitoring using implantable loop recorder (ILR) can detect asymptomatic and undiagnosed atrial fibrillation (AF). Purpose To assess patient-specific factors in ILR implantation and AF detection in patients with cryptogenic strokes. Methods We retrospectively reviewed 379 patients with cryptogenic stroke indicated for ILR implantation, from January 2017 to June 2021 at our university hospital. We evaluated patient demographic and clinical characteristics to assess the risk factors associated with higher incidence of AF detection, using logistic regression models. Results Of the 379 ILRs implanted, 60.4% were males with 71.2% Caucasian, mean age 67.6 years, and mean BMI 28.5. The mean CHADSVASC score of 3.9 at the time of ischemic stroke. These patients had prior diagnosis of diabetes mellitus (27.4%), hypertension (65.7%), chronic kidney disease (19.5%), coronary artery disease (20%) and congestive heart failure (2%). Of the entire cohort, AF was diagnosed in 16% of patients with 14 months mean follow up. There were more females diagnosed with AF on ILR (20% v. 18.7%, p>0.05). Caucasians were more likely to have AF detected compared to non-Caucasians (OR 2.3, 95% CI, p<0.02). There were 52 patients with mobile cardiac outpatient telemetry (MCOT) before having ILR implantation. AF was not detected on MCOT, but 15% were diagnosed with AF with ILR monitoring. In univariate analysis, increasing age is strongly associated with the detection of AF (p=0.03). Conclusions There continues to exist race disparities in ILR implantation and eventual AF detection, leading to further socioeconomic health disparities. ILR should be considered especially in elderly with cryptogenic stroke given the higher incidence of AF detection. Funding Acknowledgement Type of funding sources: None.

Supraventricular arrhythmia following patent foramen ovale percutaneous closure

Abstract Background Randomized studies have reported low rates of atrial fibrillation (AF) after patent foramen ovale (PFO) closure (<6%) but have relied on patients-reported symptomatic episodes, thus true incidence and timing of AF after PFO closure remain unknown. Objective To prospectively determine the incidence, timing, and determinants of supraventricular arrhythmia following PFO closure based on loop recorder monitoring. Methods Cardiac monitoring was proposed to all patients after PFO closure from June 2018 to October 2021 in our center by mean of implantable loop recorder (ILR) monitoring in patients considered at higher risk of AF (age ≥55 years, associated cardiovascular risk factors, prior palpitations, or documented supraventricular ectopic activity) or 4-week external loop recorder (ELR) monitoring in other patients. The primary endpoint was the incidence of AF, flutter, or atrial tachycardia lasting >30 seconds within 28 days of the procedure. Determinants of the primary endpoint were assessed with stepwise logistic regression model. Results A total of 225 patients were included. The primary endpoint occurred in 47/225 (20.9%) patients, including n=13 (9.9%) and n=24 (28.9%) among ELR- and ILR-monitored patients, respectively. Among ILR-monitored patients, median follow-up was 428 (211–752) days, and four more cases of supraventricular arrhythmia were diagnosed beyond 28 days (Figure 1). Overall, median delay from procedure to arrhythmia was 14.0 (6.5–19.0) days and half of these patients reported symptomatic episodes. Determinants of the primary endpoint were older age (adjusted odds ratio [aOR]: 1.67, 95% confidence interval [CI]: 1.18–2.36, per 10-year increase), device left disc diameter ≥25mm (aOR: 2.67, 95% CI: 1.19–5.98) and male sex (aOR: 4.78, 95% CI: 1.96–11.66) (Figure 2). Conclusion Using prolonged loop recorder monitoring, supraventricular arrhythmia was diagnosed in one patient out of five with a median delay of 14 days suggesting that this post-procedural event has been so far, underestimated. Funding Acknowledgement Type of funding sources: None.

Management of older patients with unexplained, recurrent, traumatic syncope and bifascicular block: Implantable loop recorder versus empiric pacemaker implantation-Results of a propensity-matched analysis.

In patients with unexplained syncope and bifascicular block (BFB), syncope may be caused by intermittent atrioventricular (AV) block. When a correlation between syncope and bradyarrhythmia is not documented in these patients, 2 alternative management strategies can be adopted: (1) empiric pacemaker (PM) implantation or (2) long-term continuous electrocardiographic monitoring by implantable loop recorder (ILR). The purpose of this study was to compare the risk of syncope recurrence associated with empiric PM implantation or ILR monitoring. A prospective, multicenter, observational study enrolled consecutive patients with unexplained, recurrent, traumatic syncope and BFB who underwent ILR monitoring or empiric PM implantation. The risk and causes of syncope recurrence were assessed and compared between the 2 groups. Individual 1:1 propensity matching of baseline characteristics was performed. A total of 309 consecutive patients (age 77.2 ± 12.2 years; 60.8% male) were enrolled. Propensity matching yielded 89 matched pairs. After median follow-up of 33 months, empiric PM implantation was associated with a significantly lower risk of syncope recurrence than ILR monitoring (19.1 vs 46.1%; P <.001). A total of 35 patients (39.3%) who underwent ILR monitoring developed bradyarrhythmias (68.6% paroxysmal AV block) requiring PM implantation during follow-up. Excluding bradyarrhythmic syncope, the most frequent causes of syncope recurrence in both study groups were reflex syncope and orthostatic hypotension. In patients with unexplained, recurrent, traumatic syncope and BFB, empiric PM implantation significantly reduced the risk of syncope recurrence in comparison with ILR monitoring. A high rate of patients who underwent ILR monitoring developed bradyarrhythmias requiring PM implantation.

Impact of bundle branch block morphology on outcomes of patients with syncope and bifascicular block: A SPRITELY (POST 3) substudy

Permanent pacing is often considered for patients with syncope and bifascicular block. The purpose of this study was to determine whether QRS morphology or other electrocardiographic characteristics can identify patients who may benefit from permanent pacing. The Syncope: Pacing or Recording in the Later Years (SPRITELY) trial was a multicenter trial that randomized patients with bifascicular block and syncope (n = 115) to empiric pacemaker implantation vs implantable loop recorder (ILR) monitoring. In this SPRITELY subanalysis, baseline 12-lead electrocardiograms were evaluated for bundle branch block (BBB) morphology, QRS width, and PR and QT intervals and their impact on clinical outcomes was assessed. There were 41 patients with left BBB (36%), 69 patients with right bundle branch block (RBBB) and left anterior fascicular block (60%), and 5 patients with RBBB and left posterior fascicular block (4%). Pacemaker implant compared with ILR was associated with a significant reduction of major study-related events (MSREs) in both patients with left BBB (23.8% vs 78.9%; P = .001) and those with RBBB (27% vs 72.9%; P < .0001). Similarly, a reduction of MSREs was observed in both patients with trifascicular block (23% vs 84.6%; P < .0001) and those with bifascicular block (26.6% vs 68.9%; P = .002). In the group randomized to ILR monitoring, the type of BBB was not a predictor of recurrent syncope (P = .30), bradycardia requiring pacemaker (P = .15), or MSREs (P = .42). The presence ofPR interval prolongation or QRS width in this group did not predict MSREs (P = .22 and P = .96, respectively). In patients with syncope and bifascicular block, pacemaker implantation reduces adverse events as compared with ILR monitoring, irrespective of the type of BBB or the presence of PR interval prolongation.

Supraventricular Arrhythmia Following Patent Foramen Ovale Percutaneous Closure

BackgroundRandomized studies have reported low rates of atrial fibrillation (AF) after patent foramen ovale (PFO) closure (<6%) but have relied on patient-reported symptomatic episodes, so the true incidence and timing of AF after PFO closure remain unknown. ObjectivesThe aim of this study was to prospectively determine the incidence, timing, and determinants of supraventricular arrhythmia following PFO closure on the basis of loop recorder monitoring. MethodsCardiac monitoring was proposed to all patients after PFO closure from June 2018 to October 2021 at a single center by means of implantable loop recorder monitoring in patients considered at higher risk for AF (age ≥ 55 years, associated cardiovascular risk factors, prior palpitations, or documented supraventricular ectopic activity) or 4-week external loop recorder monitoring in other patients. The primary endpoint was the incidence of AF, atrial flutter, or supraventricular tachycardia lasting >30 seconds within 28 days of the procedure. Determinants of the primary endpoint were assessed using a stepwise logistic regression model. ResultsA total of 225 patients were included. The primary endpoint occurred in 47 patients (20.9%), including 13 (9.9%) and 24 (28.9%) among patients monitored with external loop recorders and implantable loop recorders, respectively. Overall, the median delay from procedure to arrhythmia was 14.0 days (IQR: 6.5-19.0 days), and one-half of these patients reported symptomatic episodes. Determinants of the primary endpoint were older age (adjusted OR: 1.67 per 10-year increase; 95% CI: 1.18-2.36), device left disc diameter ≥25 mm (adjusted OR: 2.67; 95% CI: 1.19-5.98) and male sex (adjusted OR: 4.78; 95% CI: 1.96-11.66). ConclusionsUsing loop recorder monitoring for ≥28 days, supraventricular arrhythmia was diagnosed in 1 in 5 patients, with a median delay of 14 days, suggesting that this postprocedural event has so far been underestimated.

DISTRIBUTION OF FALSE ARRHYTHMIC ALERTS FROM IMPLANTABLE LOOP RECORDERS IN THE PHILIPS GENEVA HEALTH SOLUTIONS IMPLANTABLE DEVICE REMOTE MONITORING DATABASE

BackgroundImplantable loop recorders (ILR) are the gold standard for extended diagnostic cardiac monitoring. Accurate detection of arrhythmias is paramount to data integrity. Unnecessary remote transmissions generated due to oversensing or undersensing of the cardiac electrogram (EGM) is a significant source of data deluge in ILR monitoring.ObjectiveIllustrate the distribution of transmissions archived with False detection of Atrial Fibrillation (AF), Pause, Bradycardia, and Tachycardia due to oversensing or undersensing on ILR transmissions.MethodsA retrospective analysis of ILR transmissions processed in 2021 was performed utilizing discrete data from the Philips Geneva Health Solutions database. Transmissions were either forwarded to a practitioner for review or archived, if adjudicated as non-clinically actionable. Discrete data statements categorizing false triggers due to oversensing or undersensing were queried to obtain total transmissions with false events. In addition, data was stratified by manufacturer.ResultsIn 2021, 485,755 ILR transmissions were processed by Geneva Remote Technicians; 36% were forwarded to practitioners, 64% were archived. Transmissions archived due to oversensing or undersensing of the EGM were identified in 20% (97,691) of all processed transmissions; a False AF event occurred in 54% (59,661), False Pause in 33% (35,755), False Tachycardia in 10% (10,561), and False Bradycardia in 3% (3,673).ConclusionFigure 2: Distribution of ILR transmissions in 2021 archived due to oversensing or undersensing by event type.View Large Image Figure ViewerDownload Hi-res image Download (PPT) BackgroundImplantable loop recorders (ILR) are the gold standard for extended diagnostic cardiac monitoring. Accurate detection of arrhythmias is paramount to data integrity. Unnecessary remote transmissions generated due to oversensing or undersensing of the cardiac electrogram (EGM) is a significant source of data deluge in ILR monitoring. Implantable loop recorders (ILR) are the gold standard for extended diagnostic cardiac monitoring. Accurate detection of arrhythmias is paramount to data integrity. Unnecessary remote transmissions generated due to oversensing or undersensing of the cardiac electrogram (EGM) is a significant source of data deluge in ILR monitoring. ObjectiveIllustrate the distribution of transmissions archived with False detection of Atrial Fibrillation (AF), Pause, Bradycardia, and Tachycardia due to oversensing or undersensing on ILR transmissions. Illustrate the distribution of transmissions archived with False detection of Atrial Fibrillation (AF), Pause, Bradycardia, and Tachycardia due to oversensing or undersensing on ILR transmissions. MethodsA retrospective analysis of ILR transmissions processed in 2021 was performed utilizing discrete data from the Philips Geneva Health Solutions database. Transmissions were either forwarded to a practitioner for review or archived, if adjudicated as non-clinically actionable. Discrete data statements categorizing false triggers due to oversensing or undersensing were queried to obtain total transmissions with false events. In addition, data was stratified by manufacturer. A retrospective analysis of ILR transmissions processed in 2021 was performed utilizing discrete data from the Philips Geneva Health Solutions database. Transmissions were either forwarded to a practitioner for review or archived, if adjudicated as non-clinically actionable. Discrete data statements categorizing false triggers due to oversensing or undersensing were queried to obtain total transmissions with false events. In addition, data was stratified by manufacturer. ResultsIn 2021, 485,755 ILR transmissions were processed by Geneva Remote Technicians; 36% were forwarded to practitioners, 64% were archived. Transmissions archived due to oversensing or undersensing of the EGM were identified in 20% (97,691) of all processed transmissions; a False AF event occurred in 54% (59,661), False Pause in 33% (35,755), False Tachycardia in 10% (10,561), and False Bradycardia in 3% (3,673). In 2021, 485,755 ILR transmissions were processed by Geneva Remote Technicians; 36% were forwarded to practitioners, 64% were archived. Transmissions archived due to oversensing or undersensing of the EGM were identified in 20% (97,691) of all processed transmissions; a False AF event occurred in 54% (59,661), False Pause in 33% (35,755), False Tachycardia in 10% (10,561), and False Bradycardia in 3% (3,673). Conclusion

Embolic Stroke of Undetermined Source: Role of Implantable Loop Recorder in Secondary Prevention.

Atrial fibrillation (AF) is the most important cause of embolic stroke of undetermined source (ESUS). Implantable loop recorder (ILR) demonstrated the highest sensitivity for detecting it. This register was created to confirm the high prevalence of AF in patients after ESUS and to verify possible benefits on clinical outcomes such as TIA (Transient Ischaemic Attack)/stroke recurrence and death using ILR. A total of 278 patients admitted to "Molinette" Hospital in Stroke Unit department between 2011 and 2016, diagnosed with ESUS, underwent ILR implantation if they had at least one risk factor for AF. A total of 165 patients admitted to other departments in the same center for the same pathology, without ILR, represent the control group. We used propensity score to select 132 patients from each group (matching age, sex, CHADS-VASC, and HAS-BLEED baseline characteristics). The detection rate of AF episodes was significantly higher in the ILR group (p < 0.001). No significant protective role of ILR for clinical endpoints was found on univariate analysis, although a trend towards significance has been pointed for the composite outcome of death and ischemic events recurrence (OR 0.52, CI 0.26-1.04, p = 0.06). A protective role of ILR was found for deaths (OR 0.4, CI 0.17-0.94, p 0.03) and for the composite outcome (OR 0.41, CI 0.19-0.87, p 0.02) on multivariate analysis in the best subsets. With our statistical models, we identified a significant clinical benefit from ILR monitoring, evidenced by a trend of less death and TIA/stroke recurrence and relevant ILR protection for prediction of TIA/stroke recurrence.

Incidence and time course of atrial fibrillation following patent foramen ovale closure.

Determine the true incidence and time course of atrial fibrillation (AF) after patent foramen ovale closure (PFOc) using implantable loop recorders (ILR) placed during cryptogenic stroke evaluation. Published trials report a 2%-6.6% incidence of postimplant atrial fibrillation (PIAF) after PFOc, which is probably a gross underestimation, as only patients presenting in AF were captured. Episodes of paroxysmal and silent AF would have been missed. Of 761 patients who underwent PFOc at a single center between January 2016 and December 2020, 35 patients had an ILR implanted before PFOc, without documentation of AF, and had ≥1 month of monitoring post-PFOc. The incidence, onset, and conclusion of AF episodes were determined from a review of patient records. The mean duration of ILR monitoring was 54.6 ± 39.4 weeks after PFOc. AF occurred in 13/35 (37%) patients. PFOc patients who developed PIAF were older than those who did not (62 ± 11 vs. 52 ± 14 years, p = 0.03). In 12/13, the initial PIAF event occurred within 4 weeks of PFOc, with the greatest frequency around 2 weeks and conclusion by 12 weeks in all. No recurrent strokes occurred during ILR monitoring. The actual incidence of PIAF was far greater than previously reported and was significantly associated with older age at PFOc. The timing of PIAF onset and termination were consistent with a postimplant inflammatory mechanism. The higher actual PIAF incidence underscores its low stroke potential in this population. A larger prospective trial is required to validate these preliminary results.

Adenosine, adenosine- deaminase and implantable recorder outcome in syncopal patients.

Adenosine test was proposed as atool for identification of syncopal patients who benefit from pacemaker implantation. Aim of the study was to assess the relationship between adenosine levels, the outcome of adenosine test and results of implantable loop recorder (ILR) monitoring in patients with syncope. In 29 patients (mean age 59±11 years, 15 men, 14 women) with unexplained syncope ILR was implanted. In addition, adenosine test (intravenous injection of 20mg adenosine bolus) and assays of plasmatic adenosine and adenosine-deaminase were performed. Adenosine test was positive in 15 patients and negative in 14 patients. Patients with positive adenosine test had lower adenosine levels compared to patients with negative test (8.86±2.07ng/ml vs. 15.18±2.14ng/ml, p=.04). No difference was observed in adenosine deaminase levels (16.35±2.20 IU/l vs. 13.20±2.48 IU/l, p=.40). There was a negative correlation between adenosine level and AVB duration during adenosine test (p=.04; R2 =0.22). Patients with positive adenosine test had more frequent asystole during ILR monitoring than patients with negative test (9pts vs. 1pt, p=.005). Adenosine levels were lower in patients with asystolic syncope on ILR compared to vasodepressor syncope 8.20±2.86ng/ml versus 13.27±7.26ng/ml, p=.05). Patients with positive adenosine test have decreased production of endogenous adenosine compared to patients with negative adenosine test. Positivity of adenosine test and low adenosine level in the peripheral blood were associated with more frequent asystolic episodes during ILR monitoring.

Atrial CARdiac Magnetic resonance imaging in patients with embolic stroke of unknown source without documented Atrial Fibrillation (CARM-AF): Study design and clinical protocol.

BackgroundInitiation of anticoagulation therapy in ischemic stroke patients is contingent on a clinical diagnosis of atrial fibrillation (AF). Results from previous studies suggest thromboembolic risk may predate clinical manifestations of AF. Early identification of this cohort of patients may allow early initiation of anticoagulation and reduce the risk of secondary stroke.ObjectiveThis study aims to produce a substrate-based predictive model using cardiac magnetic resonance imaging (CMR) and baseline noninvasive electrocardiographic investigations to improve the identification of patients at risk of future thromboembolism.MethodsCARM-AF is a prospective, multicenter, observational cohort study. Ninety-two patients will be recruited following an embolic stroke of unknown source (ESUS) and undergo atrial CMR followed by insertion of an implantable loop recorder (ILR) as per routine clinical care within 3 months of index stroke. Remote ILR follow-up will be used to allocate patients to a study or control group determined by the presence or absence of AF as defined by ILR monitoring.ResultsBaseline data collection, noninvasive electrocardiographic data analysis, and imaging postprocessing will be performed at the time of enrollment. Primary analysis will be performed following 12 months of continuous ILR monitoring, with interim and delayed analyses performed at 6 months and 2 and 3 years, respectively.ConclusionThe CARM-AF Study will use atrial structural and electrocardiographic metrics to identify patients with AF, or at high risk of developing AF, who may benefit from early initiation of anticoagulation.

Role of subcutaneous implantable loop recorder for the diagnosis of arrhythmias in Brugada syndrome: A United Kingdom single-center experience.

Experience with implantable loop recorders (ILRs) in Brugada syndrome (BrS) is limited. The purpose of this study was to evaluate the indications and yield of ILR monitoring in a single-center BrS registry. Demographic, clinical and follow-up data of BrS patients with ILR were collected. Of 415 BrS patients recruited consecutively, 50 (12%) received an ILR (58% male). Mean age at ILR implantation was 44 ± 15 years. Thirty-one (62%) had experienced syncopal or presyncopal episodes, and 23 (46%) had palpitations. During median follow-up of 28 months (range 1-68), actionable events were detected in 11 subjects (22%); 7 had recurrences of syncope/presyncope, with 4 showing defects in sinus node function or atrioventricular conduction. New supraventricular tachyarrhythmias were recorded in 6 subjects; a run of fast nonsustained ventricular tachycardia was detected in 1 patient. Patients implanted with an ILR were less likely to show a spontaneous type 1 pattern or depolarization electrocardiographic (ECG) abnormalities compared to those receiving a primary prevention implantable-cardioverter defibrillator. Age at implantation, gender, Shanghai score, and ECG parameters did not differ betweensubjects with and those without actionable events. ILR-relatedcomplications occurred in 3 cases (6%). In a large cohort of BrS patients, continuous ILR monitoring yielded a diagnosis of tachy- or bradyarrhythmic episodes in 22% of cases. Recurrences of syncope were associated with bradyarrhythmic events. Use of ILR can be helpful in guiding the management of low-/intermediate-risk BrS patients and ascertaining the cause of unexplained syncope.

Left Atrial Remodeling and Cerebrovascular Disease Assessed by Magnetic Resonance Imaging in Continuously Monitored Patients

Background: Atrial remodeling is associated with future atrial fibrillation (AF) and stroke. AF has been associated with cognitive impairment and cerebral white matter lesions. We wished to investigate the possible direct association between atrial remodeling and cerebrovascular disease in patients with and without AF documented by implantable loop recorder (ILR). Methods: Cardiac and cerebral magnetic resonance imaging were acquired in a cross-sectional study, including participants ≥70 years of age with stroke risk factors without known AF. Cerebrovascular disease was visually rated using the Fazekas scale and number of lacunar strokes. Left atrial (LA) and ventricular volumes and function were analyzed. Associations between atrial remodeling and cerebrovascular disease were assessed with logistic regression models. The analyses were stratified according to sinus rhythm or any AF during 3 months of continuous ILR monitoring to account for subclinical AF. Results: Of 200 participants investigated, 87% had a Fazekas score ≥1 and 45% had ≥1 lacunar infarct. Within 3 months of ILR monitoring, AF was detected in 28 (14%) participants. For participants with sinus rhythm (n = 172), lower LA passive emptying fraction was associated with Fazekas score after multivariable adjustment (OR [95% CI]: 0.51 [0.27; 0.86] p = 0.02), and increased LA maximum (OR [95% CI]: 1.38 [1.07; 1.82] p = 0.01) and minimum volumes (OR [95% CI]: 1.48 [1.03; 2.17] p = 0.04) were associated with lacunar infarcts. There were no significant associations in patients with AF. Conclusion: In AF-free patients, as documented by ILR monitoring, we found an independent association between LA passive emptying fraction and Fazekas score and between atrial volumes and lacunar infarcts.

Implantable Loop Recorder Monitoring and the Incidence of Previously Unrecognized Atrial Fibrillation in Patients on Hemodialysis

IntroductionAtrial fibrillation (AF) is common in patients with kidney failure on hemodialysis (KF-HD). We determined both AF incidence and burden in patients with KF-HD using implantable loop recorder (ILR) monitoring.MethodsPatients with KF-HD were enrolled and received an ILR. In 6 monitoring months, the incidence of AF events lasting ≥6 minutes was captured. Demographic, clinical, and dialysis characteristics were collected, and associations with incident AF were estimated using negative binomial regression models and expressed as incidence rate ratios and 95% CIs.ResultsWe enrolled 66 patients with KF-HD (mean age = 56 years, 70% male); 59 (90%) were without previously diagnosed AF. AF lasting ≥6 minutes was detected in 18 of 59 subjects (31%) without previously diagnosed AF and in 5 of 7 subjects (71%) with a previous AF diagnosis. Among the 23 with detected AF, episodes were present on 16% of patient days. Although 14 of 23 patients (61%) had AF on <5% of monitored days, the average duration of AF episodes was <1 hour in 13 of 23 patients (52%). Among patients with AF ≥6 minutes, 19 of 23 (83%) had a CHA2DS2-VASc score ≥2. When investigating individual HD parameters, higher dialysate calcium (>2.5 vs. 2.5 mEq/l: incidence rate ratio = 0.62; 95% CI, 0.48–0.80) was associated with lower AF risk whereas higher dialysate bicarbonate concentrations (>35 vs. 35 mEq/l: incidence rate ratio = 3.18; 95% CI, 1.13–8.94) were associated with higher AF risk.ConclusionNew AF was detected in approximately one-third of patients with KF-HD. AF affects a substantial proportion of patient days and may be an underappreciated cause of stroke in KF-HD.

Effectiveness of implanted cardiac rhythm recorders with electrocardiographic monitoring for detecting arrhythmias in peripartum cardiomyopathy (PPCM)

Abstract Introduction Peripartum cardiomyopathy (PPCM) is a form of dilated cardiomyopathy that occurs within the last months of pregnancy or up to 5 months postpartum. Previous studies have shown that up to 30% of deaths in PPCM are related to sudden cardiac death (SCD). However, little is known about the burden of arrythmias in PPCM and their contribution to SCD. Purpose We aimed to compare implantable loop recorder (ILR) plus 24-hour Holter monitoring to 24h Holter monitoring alone to assess its utility in the detection of arrhythmias in PPCM. Methods In this single-centre, prospective clinical trial, 20 consecutive patients with PPCM were randomized to either standard care (SC cohort: ECG &amp; 24-hour Holter) or SC plus ILR (SC-ILR cohort: ECG, 24-hour Holter, ILR). Follow-up included the first six months after ILR implantation. Results The median age of this cohort was 31.7 years with a parity of 2 (IQR 1–4). They presented with a median left ventricular ejection fraction (LVEF) of 28% (IQR 24–35) and LVEDD of 60mm (IQR 55–66). The 12-lead ECG recorded sinus tachycardia in half of the patients, with median heart rate of 90bpm (IQR 79–106) compared to 94.5bpm (IQR 85–99) on 24h-Holter-monitoring. The median QTc-interval was 464ms (IQR 424–494). Ambulatory ECG monitoring detected major arrhythmias in three women (one in SC cohort, two in SC-ILR cohort). One patient (5%) died shortly after ILR implantation. Her ILR detected sinus arrest with an escape rhythm (figure 1A) that failed and resulted in an out of hospital cardiac arrest. Non-sustained ventricular tachycardia (nsVT) occurred in two women (10%), one of which was detected by Holter monitoring and the other on ILR (figure 1B, 1C). Both women presented with acute heart failure with severely impaired systolic function (LVEF 12% and 21% respectively). One of these patients had persistent LV systolic dysfunction despite optimal medical therapy and received an implantable cardioverter-defibrillator (ICD). The other patient had intractable heart failure requiring recurrent intensive-care treatment and underwent heart transplantation. There was no atrial fibrillation or atrioventricular block detected in any patient by ECG, Holter or ILR monitoring throughout the study period. Conclusion This study on ambulatory ECG monitoring in PPCM showed a high prevalence of potentially fatal arrhythmias, which occurred predominantly in the acute phase of the disease. One patient had sinus arrest and asystole detected by ILR as the terminal arrhythmia. Both Holter monitoring and ILR played an important role in ventricular arrhythmia detection, which in two cases had a direct influence on clinical decision making. ILR is more effective than 24-hour Holter monitoring in paroxysmal arrhythmia detection because of extended monitoring. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): Medtronic South Africa Ambulatory ECG monitoring in PPCM

Left atrial remodeling and cerebrovascular disease assessed by magnetic resonance imaging in patients undergoing continuous heart rhythm monitoring

Abstract Background Atrial remodeling and atrial fibrillation (AF) have both been associated with cerebrovascular lesions. We wished to investigate the possible direct association between atrial remodeling and cerebrovascular disease including white matter lesions and lacunar infarcts in patients with and without atrial fibrillation (AF) as documented by implantable loop recorder (ILR). Methods Cardiac and cerebral MRI scans were acquired in a cross-sectional study including participants ≥70 years of age with stroke risk factors (history of hypertension, diabetes mellitus, congestive heart failure and/or previous stroke) but without known AF. Cerebrovascular disease was visually rated using the Fazekas scale and number of lacunar strokes. Left atrial (LA) (see figure) and ventricular volumes and function were analyzed, and associations between atrial remodeling and cerebrovascular disease were assessed with logistic regression models. Multivariable models were adjusted for sex, age, diabetes, hypertension, heart failure and history of stroke/transient ischemic attack. The analyses were stratified according to sinus rhythm or any AF during three months of continuous ILR monitoring to account for subclinical AF. Results Of 200 participants investigated, 87% had a Fazekas score≥1 and 45% had ≥1 lacunar infarct. Within three months of ILR implantation, AF was detected in 28 (14%) participants, while 172 (86%) had sinus rhythm only. Results are summarized in table. For participants with sinus rhythm, lower LA passive emptying fraction was associated with Fazekas score after multivariable adjustment, while LA total emptying fraction was borderline significant, and increased LA maximum and minimum volumes were associated with lacunar infarcts. There were no significant associations in patients with AF. Sensitivity analyses showed similar results with longer screening periods for AF. Conclusions In patients free from AF as documented by ILR monitoring, we found an independent association between LA passive emptying and Fazekas score, and between atrial volumes and lacunar infarcts. This supports that atrial remodeling alone without AF is associated with an increased risk of cerebrovascular lesions. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): The Innovation Fund, DenmarkThe Research Foundation for the Capital Region of Denmark

Implantable loop recorder detection of atrial fibrillation to prevent stroke (The LOOP Study): a randomised controlled trial

It is unknown whether screening for atrial fibrillation and subsequent treatment with anticoagulants if atrial fibrillation is detected can prevent stroke. Continuous electrocardiographic monitoring using an implantable loop recorder (ILR) can facilitate detection of asymptomatic atrial fibrillation episodes. We aimed to investigate whether atrial fibrillation screening and use of anticoagulants can prevent stroke in individuals at high risk. We did a randomised controlled trial in four centres in Denmark. We included individuals without atrial fibrillation, aged 70-90 years, with at least one additional stroke risk factor (ie, hypertension, diabetes, previous stroke, or heart failure). Participants were randomly assigned in a 1:3 ratio to ILR monitoring or usual care (control) via an online system in permuted blocks with block sizes of four or eight participants stratified according to centre. In the ILR group, anticoagulation was recommended if atrial fibrillation episodes lasted 6 min or longer. The primary outcome was time to first stroke or systemic arterial embolism. This study is registered with ClinicalTrials.gov, NCT02036450. From Jan 31, 2014, to May 17, 2016, 6205 individuals were screened for inclusion, of whom 6004 were included and randomly assigned: 1501 (25·0%) to ILR monitoring and 4503 (75·0%) to usual care. Mean age was 74·7 years (SD 4·1), 2837 (47·3%) were women, and 5444 (90·7%) had hypertension. No participants were lost to follow-up. During a median follow-up of 64·5 months (IQR 59·3-69·8), atrial fibrillation was diagnosed in 1027 participants: 477 (31·8%) of 1501 in the ILR group versus 550 (12·2%) of 4503 in the control group (hazard ratio [HR] 3·17 [95% CI 2·81-3·59]; p<0·0001). Oral anticoagulation was initiated in 1036 participants: 445 (29·7%) in the ILR group versus 591 (13·1%) in the control group (HR 2·72 [95% CI 2·41-3·08]; p<0·0001), and the primary outcome occurred in 318 participants (315 stroke, three systemic arterial embolism): 67 (4·5%) in the ILR group versus 251 (5·6%) in the control group (HR 0·80 [95% CI 0·61-1·05]; p=0·11). Major bleeding occurred in 221 participants: 65 (4·3%) in the ILR group versus 156 (3·5%) in the control group (HR 1·26 [95% CI 0·95-1·69]; p=0·11). In individuals with stroke risk factors, ILR screening resulted in a three-times increase in atrial fibrillation detection and anticoagulation initiation but no significant reduction in the risk of stroke or systemic arterial embolism. These findings might imply that not all atrial fibrillation is worth screening for, and not all screen-detected atrial fibrillation merits anticoagulation. Innovation Fund Denmark, The Research Foundation for the Capital Region of Denmark, The Danish Heart Foundation, Aalborg University Talent Management Program, Arvid Nilssons Fond, Skibsreder Per Henriksen, R og Hustrus Fond, The AFFECT-EU Consortium (EU Horizon 2020), Læge Sophus Carl Emil Friis og hustru Olga Doris Friis' Legat, and Medtronic.

Atrial fibrillation burden and cognitive decline in elderly patients undergoing continuous monitoring

To study the relationship between subclinical atrial fibrillation (AF) and changes in cognitive function in a large cohort of individuals with stroke risk factors. Individuals with no prior AF diagnosis but with risk factors for stroke were recruited to undergo annual cognitive assessment with the Montreal Cognitive Assessment (MoCA) along with implantable loop recorder (ILR) monitoring for AF for 3 years. If AF episodes lasting ≥6 minutes were detected, oral anticoagulation (OAC) treatment was initiated. A total of 1194 participants (55.2 % men, mean age 74.5 (±3.9)) had a combined duration of heart rhythm monitoring of ≈1.3 million days. Among these, 339 participants (28.3%) had adjudicated AF, with a median AF burden of 0.072% (0.02, 0.39), and 324 (96%) initiated OAC. When stratifying the participants into AF burden groups (No AF, AFlow (AF burden <0.25%), and AFhigh, (AF burden >0.25%)), only participants in the AFlow group had a decrease in MoCA score over time (P=.03), although this was not significant after adjustment for stroke risk factors. A subgroup analysis of 175 participants (14.6%) with a MoCA <26 at 3 years found no association to AF diagnosis or burden. In a high-risk population, subclinical AF detected by continuous monitoring and subsequently treated with OAC was not associated with a significant change in MoCA score over a 3-year period.

Effect of Implantable vs Prolonged External Electrocardiographic Monitoring on Atrial Fibrillation Detection in Patients With Ischemic Stroke

The relative rates of detection of atrial fibrillation (AF) or atrial flutter from evaluating patients with prolonged electrocardiographic monitoring with an external loop recorder or implantable loop recorder after an ischemic stroke are unknown. To determine, in patients with a recent ischemic stroke, whether 12 months of implantable loop recorder monitoring detects more occurrences of AF compared with conventional external loop recorder monitoring for 30 days. Investigator-initiated, open-label, randomized clinical trial conducted at 2 university hospitals and 1 community hospital in Alberta, Canada, including 300 patients within 6 months of ischemic stroke and without known AF from May 2015 through November 2017; final follow-up was in December 2018. Participants were randomly assigned 1:1 to prolonged electrocardiographic monitoring with either an implantable loop recorder (n = 150) or an external loop recorder (n = 150) with follow-up visits at 30 days, 6 months, and 12 months. The primary outcome was the development of definite AF or highly probable AF (adjudicated new AF lasting ≥2 minutes within 12 months of randomization). There were 8 prespecified secondary outcomes including time to event analysis of new AF, recurrent ischemic stroke, intracerebral hemorrhage, death, and device-related serious adverse events within 12 months. Among the 300 patients who were randomized (median age, 64.1 years [interquartile range, 56.1 to 73.7 years]; 121 were women [40.3%]; and 66.3% had a stroke of undetermined etiology with a median CHA2DS2-VASc [congestive heart failure, hypertension, age ≥75 years, diabetes, stroke or transient ischemic attack, vascular disease, age 65 to 74 years, sex category] score of 4 [interquartile range, 3 to 5]), 273 (91.0%) completed cardiac monitoring lasting 24 hours or longer and 259 (86.3%) completed both the assigned monitoring and 12-month follow-up visit. The primary outcome was observed in 15.3% (23/150) of patients in the implantable loop recorder group and 4.7% (7/150) of patients in the external loop recorder group (between-group difference, 10.7% [95% CI, 4.0% to 17.3%]; risk ratio, 3.29 [95% CI, 1.45 to 7.42]; P = .003). Of the 8 specified secondary outcomes, 6 were not significantly different. There were 5 patients (3.3%) in the implantable loop recorder group who had recurrent ischemic stroke vs 8 patients (5.3%) in the external loop recorder group (between-group difference, -2.0% [95% CI, -6.6% to 2.6%]), 1 (0.7%) vs 1 (0.7%), respectively, who had intracerebral hemorrhage (between-group difference, 0% [95% CI, -1.8% to 1.8%]), 3 (2.0%) vs 3 (2.0%) who died (between-group difference, 0% [95% CI, -3.2% to 3.2%]), and 1 (0.7%) vs 0 (0%) who had device-related serious adverse events. Among patients with ischemic stroke and no prior evidence of AF, implantable electrocardiographic monitoring for 12 months, compared with prolonged external monitoring for 30 days, resulted in a significantly greater proportion of patients with AF detected over 12 months. Further research is needed to compare clinical outcomes associated with these monitoring strategies and relative cost-effectiveness. ClinicalTrials.gov Identifier: NCT02428140.

Heart failure and central sleep apnea in the era of implantable recorders.

Sleep-disordered breathing (SDB) is a complex syndrome with a high prevalence and a significant impact on the general well-being of the overall population. Heart failure (HF) is a major health issue with an increasing incidence, a high rate of hospitalizations, and high mortality in developing countries. Focusing on early recognition and management of HF comorbidities may have an important role in reducing the economic burden and public health impact of HF. The close interconnection between HF, heart rhythm disturbances, and sleep apnea is supported by the mutual risk factors such as age, smoking, obesity, and male sex. Central sleep apnea (CSA) may be considered a marker of advanced HF, often being associated with elevated pulmonary capillary wedge pressure, brain natriuretic peptide (BNP), and noradrenaline levels and with low left ventricular ejection fraction. In the same way, there is an important correlation between CSA and different types of arrhythmias. The large intraindividual rhythm variability reported in patients with SDB who underwent continuous monitoring by implantable loop recorder (ILR) demonstrated the incapacity of 24-hour and 48-hour Holter monitoring to accurately determine the incidence of cardiac arrhythmias. In patients with HF and CSA, the extended cardiac monitoring by ILR becomes compulsory because in-time interventions could be life saving, but with the absolute lack of solid evidence in this field, there is an acute need for extensive randomized trials to further highlight the potential beneficial effect of ILR monitoring in patients with CSA and HF.

Economic evaluation of extended electrocardiogram monitoring for atrial fibrillation in patients with cryptogenic stroke.

Timely identification of occult atrial fibrillation following cryptogenic stroke facilitates consideration of oral anticoagulation therapy. Extended electrocardiography monitoring beyond 24 to 48 h Holter monitoring improves atrial fibrillation detection rates, yet uncertainty remains due to upfront costs and the projected long-term benefit. We sought to determine the cost-effectiveness of three electrocardiography monitoring strategies in detecting atrial fibrillation after cryptogenic stroke. A decision-analytic Markov model was used to project the costs and outcomes of three different electrocardiography monitoring strategies (i.e. 30-day electrocardiography monitoring, three-year implantable loop recorder monitoring, and conventional Holter monitoring) in acute stroke survivors without previously documented atrial fibrillation. The lifetime discounted costs and quality-adjusted life years were $206,385 and 7.77 quality-adjusted life years for conventional monitoring, $207,080 and 7.79 quality-adjusted life years for 30-day extended electrocardiography monitoring, and $210,728 and 7.88 quality-adjusted life years for the implantable loop recorder strategy. Additional quality-adjusted life years could be attained at a more favorable incremental cost per quality-adjusted life year with the implantable loop recorder strategy, compared with the 30-day electrocardiography monitoring strategy, thereby eliminating the 30-day strategy by extended dominance. The implantable loop recorder strategy was associated with an incremental cost per quality-adjusted life year gained of $40,796 compared with conventional monitoring. One-way sensitivity analyses indicated that the model was most sensitive to the rate of recurrent ischemic stroke. An implantable loop recorder strategy for detection of occult atrial fibrillation in patients with cryptogenic stroke is more economically attractive than 30-day electrocardiography monitoring compared to conventional monitoring and is associated with a cost per quality-adjusted life year gained in the range of other publicly funded therapies. The value proposition is improved when considering patients at the highest risk of recurrent ischemic stroke. However, the implantable loop recorder strategy is associated with increased health care costs, and the opportunity cost of wide scale implementation must be considered.