Implantable Loop Recorder Monitoring Research Articles

Predicting atrial fibrillation risk following embolic stroke of unknown source using cardiac magnetic resonance imaging

Abstract Background Approximately 25% of embolic strokes of unknown source (ESUS) are attributed to undiagnosed atrial fibrillation (AF).1 The European Stroke Organisation (ESO) recommends implantable loop recorder (ILR) monitoring to identify ESUS patients with AF, permit the initiation of anticoagulation and reduce risk of recurrent stroke.2 However, this approach delays treatment and carries significant cost and resource implications. An alternative approach, where early anticoagulation is initiated in the absence of AF has failed to reduce recurrent stroke in four randomised controlled trials (NAVIGATE ESUS, RE-SPECT ESUS, ATTICUS and ARCADIA).3-6 An urgent need exists for new strategies to identify ESUS patients with undiagnosed AF that are at high risk of future thromboembolism. Purpose The primary objective of this study was to produce a substrate-based predictive model for AF in ESUS patients using atrial cardiac magnetic resonance imaging (CMRi). Method The Atrial CARdiac Magnetic resonance imaging in patients with embolic stroke of unknown source without documented AF (CARM-AF) Study is a prospective, multi-centre, observational study. All patients underwent CMRi and ILR insertion for AF detection within 3 months of ESUS. The main inclusion criteria were expected survival >12 months, CHA2DS2VASc≥3 and eGFR >30ml/min. Patients were allocated to the study group if AF >30 seconds was detected by ILR during the first year of follow-up and control group if no AF detected (Figure 1). Univariable analysis was used to identify clinical, echocardiographic and CMR parameters associated with AF diagnosis. Parameters with p<0.2 and no co-linearity were used to develop multivariable logistic regression models for AF prediction. Results From September 2020 to September 2022, 102 patients were enrolled and 91 were included in the final analysis. AF was detected in 17 patients during the first year of follow-up (18.6%). In univariable analysis, patients with AF were more likely to be female (p=0.02), but there were no significant differences in age, race, body mass index (BMI) or CHA2DS2VASc score (p=0.06, 0.272, 0.195, 0.211) between groups. Increased left atrial (LA) volume, surface area and reduced LA ejection fraction were associated with increased risk of AF detection at 1 year (p=0.006, 0.044, 0.008). LA fibrosis and sphericity were not associated with AF (p=0.84, 0.98). Logistic regression models for AF risk prediction were developed using patient, echocardiographic and CMR parameters. A combined model of patient and CMR parameters outperformed assessment of patient characteristics alone, achieving an AUC of 0.85 for predicting AF occurrence (p<0.005). Pseudo R2 of 0.30 (McFadden) indicated excellent model fit (Figure 2). Conclusion CARM-AF is the first study to demonstrate feasibility and utility of CMR imaging to predict AF risk following ESUS. A randomised controlled trial initiating anticoagulation using the developed model is recommended.Study DesignModel Comparison (ROC Curves)

IMPLANTABLE LOOP RECORDER IN BRUGADA SYNDROME: INSIGHTS FROM A SINGLE–CENTER EXPERIENCE

Abstract Brugada syndrome (BrS) is characterized by a “coved” ST segment elevation of ≥2 mm in the right precordial electrocardiographic (ECG) leads, either spontaneously or drug–induced. Risk stratification in individuals with BrS remains challenging. Currently, miniaturized and remotely monitored implantable loop recorders (ILRs) are available, providing physicians with a diagnostic tool that can help guide intervention or therapy decisions for these patients. The objective of this study was to investigate the characteristics and outcomes of patients diagnosed with BrS who underwent ICM insertion during routine clinical activity. This is a retrospective single center cohort study. We screened 147 consecutive patients who were diagnosed with BrS based on the presence of spontaneous or drug–induced type 1 ECG pattern between January 2009 and May 2023. Once this comprehensive diagnostic pathway was completed, we engaged in detailed counseling with patients to discuss the potential need for ICD implantation or ILR insertion, if deemed indicated. Compared to patients who did not receive a device, those who received an ILR had a higher prevalence of suspected arrhythmic syncope (43% vs. 22%, p=0.012) and tended to be younger (median age 38 years, IQR 30–52, vs. 43 years, IQR 35–55, p=0.044) and with a higher presence of SCN5A gene mutations (17% vs. 6%). On the other hand, compared to patients who received an ICD, those with an ICM underwent programmed ventricular stimulation less frequently (40% vs. 85%, p=0.010) and, as a result, had a lower frequency of positive result of this test (0% vs. 91%, p< 0.001). During a median follow–up period of 14.7 months (IQR, 4.7–44.8), no deaths occurred among the patients with ILR. Eight individuals (19%) were diagnosed with arrhythmic findings through continuous ILR monitoring. Among these findings, three patients experienced AF (including one case of new–onset AF), two patients exhibited symptomatic asystolic pauses lasting 16 seconds and 3.6 seconds respectively, two patients had non–sustained ventricular tachycardia, and one patient had episodes of paroxysmal supraventricular tachycardia. Except for a history of AF, no significant differences were observed between patients with arrhythmic findings and those without any events. In the ICD group, the median follow–up period was 32.2 months (IQR, 23.2–95.0). During this period, no deaths occurred and no appropriate or inappropriate ICD therapies were delivered.

Arrhythmia detection using an implantable loop recorder after a negative electrophysiology study in Brugada syndrome: Observations from a multicenter international registry

BackgroundRisk stratification in Brugada syndrome (BrS) remains controversial. In this respect, the role of the electrophysiology study (EPS) has been a subject of debate. In some centers, it is common practice to use an implantable loop recorder (ILR) after a negative EPS to help in risk stratification. However, the diagnostic value of this approach has never been specifically addressed. ObjectiveThe aim of this study was to describe the baseline characteristics and the main findings of a diagnostic workup strategy with an ILR after a negative EPS in BrS. MethodsWe conducted a retrospective international registry including patients with BrS and negative EPS (ie, noninducible ventricular tachycardia or ventricular fibrillation) before ILR monitoring. ResultsThe study included 65 patients from 8 referral hospitals in The Netherlands, Spain, and the United Kingdom (mean age, 39 ± 16 years; 72% male). The main indication for ILR monitoring was unexplained syncope/presyncope (66.2%). During a median follow-up of 39.0 months (Q1 25.0–Q3 47.6 months), 18 patients (27.7%) experienced 21 arrhythmic events (AEs). None of the patients died during follow-up. Bradyarrhythmias were the most common finding (47.6%), followed by atrial tachyarrhythmias (38.1%). Only 3 patients presented with ventricular arrhythmias. AEs were considered incidental in 12 patients (66.7%). In 11 patients (61.1%), AEs led to specific changes in treatment. ConclusionThe use of ILR after a negative EPS in BrS is a safe strategy that reflected the high negative predictive value of EPS for ventricular arrhythmia in this syndrome. In addition, it allowed the detection of AEs in a significant proportion of patients, with therapeutic implications in most of them.

Implantable loop recorder in Brugada syndrome: Insights from a single-center experience

BackgroundThis study aimed to investigate the characteristics and outcomes of patients diagnosed with Brugada syndrome (BrS) who underwent implantable loop recorder (ILR) insertion during routine clinical activity. MethodsWe conducted a comprehensive screening of all consecutive patients diagnosed with BrS at our institution. We analyzed baseline clinical characteristics, arrhythmic findings, and outcomes. ResultsOut of 147 BrS patients, 42 (29 %) received an ILR, 13 (9 %) underwent implantable cardioverter-defibrillator (ICD) placement, and 92 patients (63 %) continued regular cardiological follow-up. Patients who received an ILR had a higher prevalence of suspected arrhythmic syncope (43 % vs. 22 %, p = 0.012) and tended to be younger (median age 38 years, interquartile range 30–52, vs. 43 years, 35–55, p = 0.044) with a higher presence of SCN5A gene mutations (17 % vs. 6 %, p = 0.066) compared to those who continued regular follow-up. Additionally, compared to patients with an ICD, those with an ILR had a significantly lower frequency of positive programmed ventricular stimulation (0 % vs. 91 %, p < 0.001). During a median follow-up period of 14.7 months (4.7–44.8), no deaths occurred among the patients with ILR. Eight individuals (19 %) were diagnosed with arrhythmic findings through continuous ILR monitoring, primarily atrial fibrillation, and asystolic pauses. The median time from insertion to the occurrence of these events was 8.7 months (3.6–46.4). No adverse events related to ILR were reported. ConclusionContinuous monitoring with ILR may facilitate the timely detection of non-malignant rhythm disorders in BrS patients with risk factors but without an indication for primary prevention ICD implantation.

Women have less progression of paroxysmal atrial fibrillation: data from the RACE V study

BackgroundSex differences in atrial fibrillation (AF) are observed in terms of comorbidities, symptoms, therapies received, AF progression and cardiovascular complications.MethodsWe assessed the differences in prevalence and the determinants of AF...

Implantable loop recorder monitoring in inherited cardiomyopathies: yield of clinically relevant arrhythmias

Abstract Background Implantable loop recorders (ILRs) are a minimally invasive tool for the diagnosis of arrhythmias in patients with unexplained syncope or asymptomatic arrhythmias. Their use in patients with inherited arrhythmia syndromes has been recommended in the recent 2022 ESC Guidelines (1). However, the clinical utility of ILRs in patients with inherited cardiomyopathies remains unexplored. Purpose The purpose of this study was to evaluate the yield of ILR monitoring in detecting clinically relevant events in a single cohort of patients with inherited cardiomyopathies. Methods We prospectively collected demographic, clinical, and follow-up data from patients with inherited cardiomyopathies (Arrhythmogenic Cardiomyopathy, ACM; Hypertrophic Cardiomyopathy, HCM; Dilated Cardiomyopathy, DCM; Left Ventricular Non-Compaction, LVNC) who were implanted with an ILR and were followed with telemedicine. The primary endpoint was a clinically significant event recorded with the ILR that required an update to an implantable cardioverter defibrillator (ICD). Results The study cohort included 53 consecutive patients (55% males; mean age at ILR implantation 35±14 years) with inherited cardiomyopathies: 33/53 (62%) with ACM, 9/53 (17%) with HCM, 7/53 (13%) LVNC, 4/33 (8%) DCM. None of the patients implanted had previously experienced life-threatening arrhythmias. During a median follow-up of 2.6 years (IQR 1.4-3.7 years) after ILR implantation, clinically relevant arrhythmic events were documented in 9/53 (17%) of patients. Specifically, sustained or non-sustained ventricular tachycardia episodes were detected in 8 patients (5 with ACM, 2 with LVNC, 1 with LMNA-related DCM), whereas one patient with HCM showed symptomatic pauses &amp;gt; 3 seconds due to sick sinus syndrome. In all cases, the detection of such episodes led to the upgrade to ICD implantation. Conclusions ILR monitoring of patients with inherited cardiomyopathies identified clinically relevant events in almost one-fifth of patients, suggesting that the use of ILR may substantially improve the management of these patients. Figure 1. Representative example of clinically actionable event detected by implantable loop recorder (ILR) in a patient with inherited cardiomyopathy. The patient, a 19-year-old male with a definitive diagnosis of Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) and a pathogenic PKP2 truncating variant, presented with palpitations and vertigo during physical exertion one year after the implantation of an ILR. ILR monitoring documented a rapid tachycardia with a mean frequency of 250 bpm lasting 3 minutes, prompting an indication for an implantable cardioverter defibrillator (ICD).Figure 1.

Impact of atrial fibrillation burden on longitudinal changes in left ventricular structure and function: a post-hoc analysis of a randomized clinical trial

Abstract Background Atrial fibrillation (AF) is a well-established risk factor for heart failure (HF), stroke, and left ventricular (LV) dysfunction. However, only limited longitudinal data exist regarding the impact of AF burden on left ventricular (LV) structure and function. Purpose The aim of this study was to investigate the association between AF burden and longitudinal changes in LV structure and function in an older patient population with cardiac risk factors. Methods This study was a post-hoc analysis of a randomized clinical trial, which investigated whether AF screening with implantable loop recorders (ILRs) and subsequent initiation of anticoagulation could prevent stroke in high-risk individuals. As a substudy, a group of participants had extensive transthoracic echocardiography performed at baseline and a re-examination after ILR end-of-life. We included participants with available ILR data and echocardiographic data from both baseline and follow-up. We excluded participants with ongoing AF during the baseline echocardiogram. AF episodes were adjudicated by two cardiologists and AF burden was calculated as the percentage of time spent in AF during the total ILR monitoring period. Univariable and multivariable linear regression models were used to investigate the association between AF burden and changes in echocardiographic measures. The multivariable model was adjusted for age, sex, systolic blood pressure, diabetes, smoking status, previously acute myocardial infarction, previous coronary artery bypass grafting, prevalent HF, body mass index, estimated glomerular filtration rate, number of days monitored by ILR, and the number of days between the two echocardiographic examinations. Both models included adjustment for the baseline value of the echocardiographic measure. Results The study population consisted of 640 participants with available baseline and follow-up echocardiograms. Mean age was 73.6 years (±3.4 years) and 278 (43.4%) were women. AF was documented in 188 (29.4%) participants during a median ILR monitoring period of 3.2 years (IQR 2.9-3.4 years). The mean timespan between the echocardiographic examinations was median 5.0 (IQR 4.6-5.2) years. Among participants with AF, the median AF burden was 0.098% (IQR 0.026-0.758%). Over the course of echocardiographic follow-up, mean ∆GLS was -0.59% (±3.49%), mean ∆LVEF was -1.44% (±8.5%), and mean ∆E/e’ was -1.12(±3.23) in those with AF. Increasing AF burden was significantly associated with an accelerated decline in absolute global longitudinal strain in both univariable (ß= -0.12, p=0.002) and multivariable (ß= -0.11, p=0.003) models (Table 1/Figure 1). Conclusions In an older at-risk population, AF was frequent, and increasing AF burden was found to be independently associated with an accelerated decline in LV function. These findings support AF as an independent risk factor in the development of HF.

The Role of Implantable Loop Recorder in Patients with Cryptogenic Stroke

Objective: The objective of this study was to provide data on implantable loop recorder (ILR)-based atrial fibrillation (AF) rates, recurrent stroke rates, and predictors of AF in patients with cryptogenic stroke (CS) after 1, 6, 12, 24, and 36 months of follow-up. Methods: We searched MEDLINE/PubMed, Cochrane Central Register of Controlled Trials, EMBASE, Web of Science, and reference lists of retrieved reports, which were published by April 30, 2023, which was the date of our last search. We utilized random-effects meta-analysis for detection rates, and meta-regression analysis, t-test (for normally distributed variables), and Mann-Whitney (for skewed variables) for predictor factors. Results: Thirteen studies were analyzed, which included data from 3,377 patients with CS or embolic stroke of undetermined source. The ILR-based AF rates in patients with CS were 4.73% (95% confidence interval [CI] 3.91–5.71) at 1 month, 13.45% (95% CI 12.19–14.81) at 6 months, 17.5% (95% CI 16.25–18.82) at 12 months, 20.69% (95% CI 19–22.49) at 24 months, and 25.98% (95% CI 23.21–28.58) at 36 months. Age and CHA2DS2-VASc score were positively associated with AF detection. Specifically, the mean difference of age and CHA2DS2-VASc score in the group with AF versus the group without AF was 7.47 (95% CI 4.58–10.36, P &lt; 0.001) and 0.75 (95% CI 0.22–1.28, P = 0.01), respectively. Finally, AF detection was positively associated with recurrent strokes with an estimated risk ratio of 1.27 (95% CI 0.69–2.31). Conclusions: There is a correlation between AF detection rate and ILR monitoring duration. One out of eight patients was diagnosed with AF after 6 months of follow-up and about one quarter after 3 years. Our results demonstrate the critical use of ILRs, especially in older patients, and in patients with high CHA2DS2-VASc scores.

Electrocardiographic markers of subclinical atrial fibrillation detected by implantable loop recorder

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): The LOOP Study was funded by Innovation Fund Denmark [grant number 12-1352259], The Research Foundation for the Capital Region of Denmark, The Danish Heart Foundation [grant number 11-04-R83-A3363-22625], Aalborg University Talent Management Program, Arvid Nilssons Fond, Skibsreder Per Henriksen, R og Hustrus Fond, the European Union’s Horizon 2020 program [grant number 847770], Læge Sophus Carl Emil Friis og hustru Olga Doris Friis’ Legat, and an unrestricted grant from Medtronic. Background Atrial fibrillation (AF) is a well-known and treatable risk factor for stroke, which has sparked a substantial interest in AF screening. However, further insights into subclinical AF development are warranted to inform strategies of screening and subsequent clinical management upon AF detection. Purpose This study sought to identify 12-lead electrocardiogram (ECG) parameters associated with the onset, burden and progression of subclinical AF detected by long-term continuous monitoring. Methods We included AF-naïve individuals aged 70-90 years with ≥1 additional stroke risk factors (hypertension, diabetes, heart failure, or prior stroke) who underwent implantable loop recorder (ILR) monitoring in the LOOP Study. Using data from daily ILR recordings and computerized analysis of baseline ECG, we studied empirically selected ECG parameters for AF detection (≥6 minutes), cumulative AF burden, long-lasting AF (≥24 hours), and AF progression. Results Of 1370 individuals included, 419 (30.6%) developed AF during follow-up, with a mean cumulative AF burden of 1.5% [95% confidence interval (CI): 1.2-1.8%]. Several P-wave-related and ventricular ECG parameters were associated with new-onset AF as well as with cumulative AF burden in AF patients. P-wave duration (PWD), P-wave terminal force in lead V1, and interatrial block (IAB) further demonstrated significant associations with the risk of AF episode ≥24 hours. Among AF patients, we observed an overall reduction in cumulative AF burden over time (incidence rate ratio 0.70 [95% CI: 0.51-0.96]), whereas IAB was related to an increased risk of progression to AF episodes ≥24 hours (hazard ratio 1.86 [95% CI: 1.02-3.39]). Further spline analysis revealed longer PWD to also be associated with this progression in AF duration. Conclusions We identified several ECG parameters associated with new-onset AF detected by ILR. Especially PWD and IAB were robustly related to the onset and the burden of subclinical AF as well as progression over time.

Invasive risk stratification and implantable loop recorders in brugada syndrome: a single centre experience

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Risk stratification in Brugada syndrome (BrS) is challenging. Cardiogenic syncope, family history of sudden cardiac death and ECG markers are useful variables in determining patient risk. Invasive risk stratification is sometimes needed in those with an intermediate risk phenotype. Implantable loop recorders (ILR) may be considered in those patients with no inducible ventricular arrythmias during programmed ventricular stimulation (PVS). Objective The aim of this study was to retrospectively evaluate the outcome of BrS patients referred for PVS and ILR implantation. Methodology Demographic, clinical and follow-up data of BrS patients seen in clinic were retrospectively analysed from hospital databases. A p vale of &amp;lt;0.05 was considered significant. Results 129 patients have been diagnosed with BrS since launching the inherited arrhythmia clinic service (53.5% males). 15 (high risk patients) had an ICD (n=13, 10.1%) or PM (n=2, 1.6%) implanted because of a hospital cardiac arrest, ventricular arrhythmias, high grade AV Block or cardiogenic syncope. 26 (20.2%) were placed in the intermediate risk category, (65.4% males). Patients were offered an electrophysiology study (EPS/PVS) or an ILR depending on the clinical indication (Figure 1). Most were male (65.4%), with a mean age of 41.8±17.7 years at the time of risk stratification. 6 had a likely or definite pathogenic mutation (n=5 19.2% SCN5A, n=1 3.8% MYBPC3). This group had a median Shanghai score of 4.0±0.9. Gender (p=0.429), age (p=0.246), genotype (p=0.273) and shanghai score (p=0.746) did not differ between strategies. Most (n=12, 9.3%) were offered an EPS/PVS from the offset. Ventricular arrhythmias were induced in 1 (8.3%), an ICD was then implanted. The rest were implanted with an ILR on the day. Patients not offered an EPS (n=14, 10.9%) were initially implanted with an ILR because of insufficient grounds to proceed with an EP study. Patients with an ILR (n=25, 19.4%) were followed up for a median 39 ± 21 months. ILR monitoring identified actionable events in 3 (12.0%) patients. One (4.0%) needed a pacemaker for sick sinus syndrome. Two (8.0%) recorded non-sustained ventricular arrhythmias. Both were subjected to an EPS/PVS, one needed an ICD. None of the patients who had an EPS initially had any significant events during follow up. Conclusion ILR implantation has a role in risk stratifying intermediate risk patients who do not fulfil criteria for EPS referral. This may also be considered in intermediate risk patients who are not keen on an invasive risk assessment with EPS.

PO-03-048 CLINICAL UTILITY OF IMPLANTABLE LOOP RECORDERS AFTER CRYPTOGENIC STROKE: INSIGHTS FROM A LARGE ACADEMIC STROKE CENTER

Detection of occult AF using implantable loop recorders (ILR) has become routine practice in the evaluation of cryptogenic stroke, yet there are few data demonstrating that ILRs reduce risk of recurrent stroke. Our aim was to determine if the diagnostic yield for ILR-detected AF in patients with cryptogenic stroke may be improved using clinical characteristics, and if ILR-directed changes in medical therapy reduce risk of recurrent stroke. We observed 282 consecutive patients with cryptogenic stroke (n=255) or transient ischemic attack (TIA, n=27) implanted with ILR at an academic stroke center for the clinical outcomes of first detected AF, recurrent stroke or TIA, and the temporal relation between AF and recurrent stroke/TIA. Collected data included demographics, comorbid medical conditions, stroke and imaging details, ECG and echocardiographic findings, and routine laboratory testing. During 557 days median follow-up, 50 (18%) patients manifested AF after a median 107 days, including 15% at 1 year, 20% at 2 years, and 23% at 3 years. All but 1 patient were started on a direct anticoagulant (n=48) or warfarin (n=1) upon AF diagnosis. Age (HR 1.04 per year, 95% CI 1.02-1.07; p<0.001) and middle cerebral artery stroke (HR 2.20, 95% CI 1.06-4.58; p=0.035) were independently associated with shorter time to first detected AF. Only 2 of 20 patients with recurrent stroke (n=17) or TIA (n=3) had ILR-detected AF; in both cases AF was first seen >1 year after recurrent stroke or TIA despite continuous monitoring. Age 65-years old best delineated risk of detected AF (area under ROC curve 0.66, p<0.001). Among 157 patients <65 years old, only 13 (8%) had AF; all had left ventricular end-diastolic dimension >4.60 cm (median LVEDD 4.90) and cortical stroke. Among 125 patients ≥65 years old, 37 (30%) had AF; mitral regurgitation (HR 1.98, 95% CI 1.06-3.72; p=0.03) was independently associated with shorter time to first AF detection. Detection of AF after cryptogenic stroke is highest within the first year of ILR monitoring. Consideration of age, stroke territory, and mitral valvular disease increases specificity for detecting AF and thus informs who should receive ILR. Correlation between recurrent AF and recurrent stroke or TIA is poor, raising concern that routine ILR use may not prevent additional strokes.

Electrocardiographic markers of subclinical atrial fibrillation detected by implantable loop recorder: insights from the LOOP Study.

Insights into subclinical atrial fibrillation (AF) development are warranted to inform the strategies of screening and subsequent clinical management upon AF detection. Hence, this study sought to characterize the onset and progression of subclinical AF with respect to 12-lead electrocardiogram (ECG) parameters. We included AF-naïve individuals aged 70-90 years with additional stroke risk factors who underwent implantable loop recorder (ILR) monitoring in the LOOP Study. Using data from daily ILR recordings and the computerized analysis of baseline ECG, we studied empirically selected ECG parameters for AF detection (≥6 min), cumulative AF burden, long-lasting AF (≥24 h), and AF progression. Of 1370 individuals included, 419 (30.6%) developed AF during follow-up, with a mean cumulative AF burden of 1.5% [95% CI: 1.2-1.8]. Several P-wave-related and ventricular ECG parameters were associated with new-onset AF and with cumulative AF burden in AF patients. P-wave duration (PWD), P-wave terminal force in Lead V1, and interatrial block (IAB) further demonstrated significant associations with long-lasting AF. Among AF patients, we observed an overall reduction in cumulative AF burden over time (IRR 0.70 [95% CI: 0.51-0.96]), whereas IAB was related to an increased risk of progression to AF ≥24 h (HR 1.86 [95% CI: 1.02-3.39]). Further spline analysis also revealed longer PWD to be associated with this progression in AF duration. We identified several ECG parameters associated with new-onset subclinical AF detected by ILR. Especially PWD and IAB were robustly related to the onset and the burden of AF as well as progression over time.

Abstract WP33: Bedside Insertion Of Implantable Loop Recorders Prior To Hospital Discharge Improves Detection Of Atrial Fibrillation After Cryptogenic Stroke And May Reduce Stroke Recurrence

Atrial fibrillation (AF) is responsible for 15-20% of ischemic strokes. AF can be asymptomatic and remain undetected following acute stroke, initially classifying the event as cryptogenic. Implantable loop recorders (ILRs) provide long-term cardiac monitoring and are superior to traditional methods for detecting AF in patients with cryptogenic stroke. ILR placement is often performed by a cardiologist in an outpatient setting. Our institution identified that some patients were missing or cancelling appointments for device implantation. Failure to detect AF is associated with a greater risk of stroke recurrence. An interdisciplinary inpatient process was developed to place ILRs at the bedside on the stroke unit, prior to discharge. The purpose of the program was to increase patient compliance with ILRs, improve detection of asymptomatic AF, and reduce incidence of stroke recurrence through timely initiation of oral anticoagulants. To evaluate the program and provide recommendations, measures of success included rates of patient compliance with ILR implantation using inpatient vs. outpatient procedure and the percentage of patients who received a diagnosis of AF after ILR placement. Using 18 months of pre-implementation data as a benchmark, the average implant rate increased in the first 12 months following implementation. Of 97 patients who received ILR placement, nine (9%) have received a diagnosis of AF. Since three-year ILR monitoring has shown significantly higher AF detection than 30-day cardiac monitoring after cryptogenic stroke, more patients with AF may yet be identified. This presentation will demonstrate an increase in ILR implant rates and AF detection and highlight positive results using advanced practice professionals to perform the procedure. The program produced financial benefit and mitigated access to care barriers, with no poor outcomes or compromise in quality, and no negative impact on inpatient length of stay. In conclusion, bedside insertion of ILRs prior to discharge after cryptogenic stroke is a safe, efficient, cost-effective process that increases patient compliance when compared to outpatient return visits, improving detection of AF and prompt initiation of oral anticoagulants, and may reduce stroke recurrence.

Abnormal left atrial strain is associated with eventual diagnosis of atrial fibrillation in patients with embolic stroke of undetermined source

Abstract Funding Acknowledgements Type of funding sources: None. Background Patients with embolic stroke of undetermined source (ESUS) have no immediate attributable cause despite initial evaluation. Occult paroxysmal atrial fibrillation (pAF) diagnosed on prolonged electrocardiographic monitoring may be subsequently found in 20% of patients initially classified as ESUS [1]. Anatomic and functional alterations of left atrium (LA) are known to predict pAF in the general population [2]. Recent studies have suggested that LA dysfunction is linked to the risk of development of pAF in stroke patients and may precede LA enlargement [1]. LA strain analysis may be helpful to predict the development of pAF as it can detect subclinical functional impairment [2]. The aim of this study was to analyse whether LA strain can be a marker for the development of new-onset AF in patients with ESUS and sinus rhythm. Methods Our single-centre observational cohort study examined 157 patients hospitalised for ESUS in our tertiary hospital between October 2014 and October 2017 who underwent AF monitoring with an implantable loop recorder (ILR). These patients were followed up for occurrence of new-onset pAF and recurrence of ischaemic stroke. All patients underwent transthoracic echocardiography (TTE) during index hospitalisation as part of the workup for ESUS. Echocardiographic images were obtained and analysed post-hoc for two-dimensional (2D) speckle tracing deformation parameters. These LA strain parameters were analysed against the primary outcome of AF detection and secondary outcome of recurrent ischaemic stroke. Results A total of 157 ESUS patients, with a mean age of 61.0 (±11.6) years, were followed up for a median duration of 3.5 (interquartile range 3.29) years. ILR monitoring detected AF in 27 patients (17.2%). 27 patients developed recurrent ischaemic strokes. Of the 27 patients with newly diagnosed AF on ILR, 24 (88.9%) were commenced on oral anticoagulation; the remaining 3 patients were not on anticoagulation due to high bleeding risk and frailty. Patients who had newly diagnosed AF had more impaired left atrial reservoir strain (LASr; 23.5% ± 10.3%, P = 0.042) and left atrial conduit strain (LAScd; -10.5% ± 5.3%, P = 0.003) compared with patients who remained in sinus rhythm. Multivariable logistic regression analysis adjusting for age, sex, hypertension, hyperlipidaemia, diabetes mellitus and left ventricular ejection fraction (LVEF) showed that LAScd was associated with occult AF (adjusted odds ratio [aOR] = 1.110, 95% CI, 1.019-1.209, P = 0.017) and the composite outcome of AF and recurrent ischaemic stroke (OR = 1.069, 95% CI, 1.014-1.138, P = 0.038). Abnormal LAScd was significantly associated with occult AF even when stratified by normal LA volume index (LAVI) (OR = 2.672, 95% CI, 1.035-8.548, P = 0.048) and high LAVI (OR = 1.713, 95% CI, 1.023-2.869, P = 0.041). Conclusion Impaired left atrial strain was associated with occult AF detection in patients with ESUS undergoing ILR monitoring.

Effectiveness and safety of implantable loop recorder and clinical utility of remote monitoring in patients with unexplained, recurrent, traumatic syncope

ABSTRACT Background Implantable loop recorder (ILR) is still underutilized in clinical practice, especially in the setting of elderly patients with recurrent, traumatic, unexplained syncope. Data on the actual risk of traumatic syncopal recurrence during ILR monitoring in this specific patient setting are lacking. Research design and methods Prospective, multicentre registry enrolling consecutive patients undergoing ILR insertion for unexplained, recurrent, traumatic syncope. In a proportion of enrolled patients, remote monitoring (RM) was used for device follow-up. The risk of traumatic and non-traumatic syncopal recurrences during ILR observation were prospectively assessed. Results A total of 483 consecutive patients (68±14 years, 59% male) were enrolled. During a median follow-up of 18 months, a final diagnosis was reached in 270 patients (55.9%). The risk of syncopal and traumatic syncopal recurrence was of 26.5 and 9.3%, respectively. RM significantly reduced the time to diagnosis (19.7±10.3 vs. 22.1±10.8 months; p=0.015) and was associated with a significant reduction in the risk of syncope recurrence of 48% (p<0.001), and of traumatic syncope recurrence of 49% (p=0.018). Conclusions ILR monitoring is effective and safe in patients with unexplained, recurrent, traumatic syncope. RM reduces the time to diagnosis and significantly reduces the risk of traumatic and non-traumatic syncopal relapses.

421 CARDIO-NEURO ABLATION WORKFLOW OPTIMIZATION USING THE CARTO 3 SYSTEM CFAE MODULE

Abstract Introduction Ganglionated Plexi (GP) ablation has been revived by the recent interest in cardioneuroablation (CNA) in the field of vasovagal syncope (VVS). Many small observational studies and a multicenter registry showed a valuable effect of GP ablation on vagal hyperactivity modulation, eliminating the need for a permanent pacing device implantation in both functional atrioventricular block (AVB) and sinus node block (SNB). We suggest a standardized approach to fragmented activity signal analysis and automated workflow using CARTO3 mapping system (Johnson &amp; Johnson Biosense Webster Inc., CA, USA) built-in CFAE software to pursue vagal denervation in different clinical settings. Methods The first patient enrolled was a 28-year-old lady admitted to the emergency department of IRCCS Cà Granda Hospital, in Milan, for yet another episode of syncope of undetermined origin complicated by facial trauma. Since the rest electrocardiogram (ECG) was completely normal and family screening was negative for sudden cardiac death (SCD), we decided for long term ECG monitoring with an implantable loop recorder (ILR). During follow-up, another traumatic syncope occurred and a 26 sec sinus arrest interrupted by a single escape beat was recorded. We advised a pacemaker implant proposing the CNA as a therapeutic alternative. Technique: We used CARTO3 mapping system and the ablation and mapping catheter for electroanatomical model creation of both atria. Left atrial access was granted via transeptal puncture using a Brockenbrough Needle (BRK1, Abbott) and a Preface 8.5 f transeptal sheath. We used the complex atrial fractionated electrograms (CFAE) software to localize the GP. The target signal was characterised by more than 3 deflections, named confidence interval levels (ICL) on the system, lasting at least 2 msec each and an amplitude above 0.06 millivolts. Since the system acquires points analyzing 2.5 sec (2 sec before and 0.5 sec after the reference), in this time the total number of ICL is strongly dependent on the heart rate (HR). The settings for the color bar confidence level extremities should be established considering the number of beats every 2.5 sec and the desired minimum number of ICL plus the ventricular deflection in the areas surrounding the mitral and tricuspid valves. It must be considered that this feature, whose intention was to map AF, interferes with the accuracy of the window of interest including the ventricular far fields in the counts. We choose duration value intervals ranging from 2 msec, to include rapid deflections of the fragmented activity, to 140 msec to be as inclusive as possible. The selected threshold values ranged from 0.06 millivolts, in order to exclude noise and necrotic areas, to 1.5 millivolts, trying to avoid ventricular far field signals. We set the color bar limits from 15 to 20, eliminating the less fragmented signals as we decided to target areas with more than 7 deflections (Figure 1). The maps we obtained showed fragmented activity in the areas corresponding to the right superior GP in the superior vena cava, the right inferior GP close to the fossa ovalis, the left superior GP on the anterior aspect of the left superior pulmonary vein antrum and the left posteromedial GP in the posteromedial region, behind the aortic non coronary cusp. We started the CNA in the right atrium and then in the left atrium and we observed progressive increase of HR. ILR monitoring after ablation highlighted a reduction of daily heart rate variability and an increase of average heart rate especially at rest, confirming the effectiveness of CNA. Conclusions We find that CARTO3 mapping system may be used for GP detection and ablation as effectively as other mapping systems in a “non-visual” approach. Automatization and optimization of the workflow requires further improvements in the CFAE module. The opportunity to avoid device implantation in younger with functional syncope is, in our humble opinion, a milestone in the history of electrophysiology. In our ongoing center experience, the GP ablation is proving to be a promising option also for quality of life improvements in brady-tachy patients.

890 ARTIFICIAL INTELLIGENCE EMPOWERS REMOTE MONITORING OF IMPLANTABLE LOOP RECORDERS

Abstract Background The implantable loop recorder (ILR) is a subcutaneous device used to diagnose heart rhythm disorders, allowing the detection of any arrhythmic episodes which are related to the onset of patient-reported symptoms. Although the importance of implantable cardiac monitors has been widely recognized, it is also true that due to their subcutaneous nature, they are inclined to detect false-positive episodes which generate several warnings requiring additional checks from the health care personnel. For this reason implanted cardiac devices monitoring has been recently implemented by the use of artificial intelligence (AI), which applies deep learning algorithms for speeding up the telemetry follow-up checks without affecting the accuracy. Considering the increased need of remote monitoring during pandemics, such achievement should reduce the overwork superimposed on healthcare providers, but to date it is not known to what extent this technology confers a quantitative gain. Our main purpose is to demonstrate how AI can enhance remote monitoring of patients with implantable cardiac monitors, reducing false positives and improving the accuracy of information received by cardiologist. Methods we included twenty-six patients who undergoing ILR implantation between May 2019 and April 2022. Mean age was 58 ± 28 years and there was a higher prevalence of male subjects (n = 20; 76,9%). Fifteen patients received ILR implemented by the use of AI, eleven patients received ILR with standard remote monitoring system. We did follow up from April 2022 to September 2022 with dedicated remote monitoring platforms. The main events detected by ILR were atrial fibrillation (AF), pauses &amp;gt; 3 sec, supraventricular and ventricular arrhythmias, patient's symptom. Results among AI-ILR a total of 25 events were recorded and 92% (n= 23) of these were correctly identified, meanwhile 4% (n= 1) event was considered as false positive. AI implementation showed a sensitivity of 93% (95% CI 0,7018 to 0,9966) and specificity of 90% (95% CI 0,5958 to 0,9949) Among the ILR not supported by AI a total of 26 events were registered, in 76,9% (n=20) of these there was a true correspondence between the event reported and the real event, while in 19,1% (n=5) there wasn't correspondence with a sensitivity of 91% (95% CI 0,6461 to 0,9957) and specificity of 64% (95% CI 0,3876 to 0,8366). Based on these data, AI improves the accuracy of diagnosis, reducing the incidence of false positives with an important saving time for health care providers. Conclusions with our analysis we support the hypothesis that AI algorithms can augment diagnostic capabilities and provides an important contribute to clinical decision-making. The implementation of ILR monitoring with AI is still at the beginning, but continuously further investigations will determine the real added value of these algorithm. The wider adoption of AI technology in cardiovascular medicine seems eventually inevitable in the digital world of 21st century healthcare.

Abstract 14466: Recurrent Heart Block Due to Cardiac Sarcoidosis in a Patient With Interrupted Glucocorticoid Therapy

Background: Cardiac involvement is a major cause for mortality in patients with systemic sarcoidosis. Atrioventricular (AV) block caused by inflammation involving the conduction system is one of the major manifestations of cardiac involvement. The mainstay of management is immunosuppressive therapy and device implantation if high degree AV block is present. However, there is lack of evidence regarding the appropriate dose and duration of corticosteroids in the treatment of cardiac sarcoidosis. Case summary: We describe the case of a 62-year-old man who presented with symptoms of dyspnea and bradycardia and was found to be in second degree AV block type II. Computed tomography of the chest showed hilar lymphadenopathy. Echocardiography revealed reduced systolic function (LVEF of 35-40%). A FDG-PET scan showed hypermetabolic activity of the interventricular septum and pericardium consistent with sarcoidosis. Bronchoscopy with BAL and EUS biopsies revealed necrotizing granulomas consistent with pulmonary sarcoidosis. ICD/pacemaker implantation was discussed; however the patient deferred and ultimately underwent Boston Scientific ILR placement to monitor for arrhythmias. He was started on methotrexate and prednisone with improvement in heart rate from 2:1 AV block (rates 30's) to sinus rhythm with rates in the 60's. Subsequent stress testing demonstrated improvement in heart rate with exercise to 113 bpm. His AV block had decreased in frequency per Implantable loop recorder (ILR) monitoring. A month later, the patient stopped taking prednisone and methotrexate and developed a symptomatic recurrence of 2:1 AV block. He then underwent dual chamber pacemaker implantation with ILR explant. Discussion: This case highlights the importance of maintaining and educating patients about long term immunosuppressive treatment in cardiac sarcoidosis to prevent recurrence of conduction abnormalities. The initial dose for those receiving prednisone is typically 40mg daily, while for those patients receiving an additional immunosuppressive agent, the initial dose can be 20mg daily. Based on response to treatment after 1 to 3 months, immunosuppressive therapy should be continued for an additional 9 to 12 months.

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&amp;gt;0.05). Caucasians were more likely to have AF detected compared to non-Caucasians (OR 2.3, 95% CI, p&amp;lt;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 (&amp;lt;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 &amp;gt;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.