Reveal LINQTM Research Articles

Translation of an existing implantable cardiac monitoring device for measurement of gastric electrical slow-wave activity.

Despite evidence that slow-wave dysrhythmia in the stomach is associated with clinical conditions such as gastroparesis and functional dyspepsia, there is still no widely available device for long-term monitoring of gastric electrical signals. Actionable biomarkers of gastrointestinal health are critically needed, and an implantable slow-wave monitoring device could aid in the establishment of causal relationships between symptoms and gastric electrophysiology. Recent developments in the area of wireless implantable gastric monitors demonstrate potential, but additional work and validation are required before this potential can be realized. We hypothesized that translating an existing implantable cardiac monitoring device, the Reveal LINQ™ (Medtronic), would present a more immediate solution. Following ethical approval and laparotomy in anesthetized pigs (n = 7), a Reveal LINQ was placed on the serosal surface of the stomach, immediately adjacent to a validated flexible-printed-circuit (FPC) electrical mapping array. Data were recorded for periods of 7.5 min, and the resultant signal characteristics from the FPC array and Reveal LINQ were compared. The Reveal LINQ device recorded slow waves in 6/7 subjects with a comparable period (p = 0.69), signal-to-noise ratio (p = 0.58), and downstroke width (p = 0.98) to the FPC, but with reduced amplitude (p = 0.024). Qualitatively, the Reveal LINQ slow-wave signal lacked the prolonged repolarization phase present in the FPC signals. These findings suggest that existing cardiac monitors may offer an efficient solution for the long-term monitoring of slow waves. Translation toward implantation now awaits.

Renal denervation alleviates chronic obstructive sleep apnea-induced atrial fibrillation via inhibition of atrial fibrosis and sympathetic hyperactivity.

Previous studies have reported that renal denervation (RDN) prevents the occurrence of atrial fibrillation (AF) related to obstructive sleep apnea (OSA). However, the effect of RDN on chronic OSA (COSA)-induced AF is still unclear. Healthy beagle dogs were randomized into the OSA group (sham RDN + OSA), OSA-RDN group (RDN + OSA), and CON group (sham RDN + sham OSA). The COSA model was built via repeated apnea and ventilation rounds for 4h each day lasting 12weeks, and RDN was employed after 8weeks of modeling. All dogs were implanted Reveal LINQ™ to detect spontaneous AF and AF burden. Circulating levels of norepinephrine, angiotensin II, and interleukin-6 were determined at baseline and end of the study. In addition, measurements of the left stellate ganglion, AF inducibility, and effective refractory period were conducted. The bilateral renal artery and cortex, left stellate ganglion, and left atrial tissues were collected for molecular analysis. Of 18 beagles, 6 were randomized to each ofthe groups described above.RDN remarkably attenuated ERP prolongation and AF episodes and duration. RDN markedly suppressed the LSG hyperactivity and atrial sympathetic innervation, decreased the serum concentrations of Ang II and IL-6, further inhibited fibroblast-to-myofibroblast transformation via the TGF-β1/Smad2/3/α-SMA pathway, and reduced the expression of MMP-9, thus decreasing OSA-induced AF. RDN may reduce AF by inhibiting sympathetic hyperactivity and AF in a COSA model.

Abstract 12591: Atrial Fibrillation Detection (Incidence And Accuracy) By Implantable Loop Recorders For The Indications: Cryptogenic Stroke, Syncope, Or Palpitations: A Real World Cohort Study

Introduction: Cryptogenic Stroke (CS), syncope, and palpitations are common indications for implantable loop recorder (ILR) insertion, however the incidence of new-onset atrial fibrillation (AF) in these groups in a real world clinical setting is not well characterized. Methods: At a single US center, we evaluated 273 consecutive patients who had a Medtronic Reveal LINQ™ LNQ11 implanted for the indications of CS, syncope, or palpitations from 2016-2021. All patients were followed remotely by Carelink. Patients with known AF were excluded. For each patient with an AF episode ≥ 2 minutes, the longest AF electrogram was adjudicated by an electrophysiologist and a cardiology fellow to confirm or refute the AF diagnosis. Results: Mean follow-up time was 21 months. There was no difference in mean age between the 3 groups. True, adjudicated AF was diagnosed more often in patients with palpitations and syncope than in patients with CS (table) [p < 0.001]. The ILR reported AF in 92 patients (all groups), of which only 56 (61%) were adjudicated to be true AF. Of the 20 patients with a longest detected AF episode <6 minutes, only 5 (25%) were true AF . Of the 72 patients with a longest detected AF of ≥ 6 minutes, 51 (71%) were true AF (p < 0.001). Conclusions: True, adjudicated AF ≥ 6 minutes was detected in 11% of patients with CS, consistent with prior studies. However, in this real world cohort study, AF ≥ 6 minutes was more likely to be detected in patients with palpitations, followed by patients with syncope. The accuracy of ILR detected AF was significantly improved when the AF episode was ≥ 6 minutes duration.

302 MONITORING FALLS RISK IN THE COMMUNITY USING AN IMPLANTABLE CARDIAC MONITOR WITH EMBEDDED ACCELEROMETER

Abstract Background Falls are the most common cause of injury amongst older adults. Falls can lead to hospitalisation, functional decline and are associated with increased morbidity and mortality. The holy grail for clinicians would be to predict increased likelihood of falls occurring and intervene before the event. Understanding underlying dynamic biophysiological changes may therefore inform novel predictor models and falls prevention. This study examines activity and cardiac data acquired from an implanted Medtronic Reveal LINQ™ Insertable Cardiac Monitor (ICM) with an embedded tri-axial accelerometer. Methods Thirty participants with at least one unexplained fall in the previous two years were prospectively recruited. All met criteria for ICM insertion following comprehensive assessment. Participants were followed for one year and attended every three-months for cardiac and gait assessment. Information pertaining to activity levels, posture changes and cardiac parameters were collected daily from the device. Summary metrics and trends were collected for inclusion in a continual assessment of falls risk. Results Mean age of participants was 68.0 years (±9.3). 19/30 (63.3%) were female. 22/30 (73.3%) had at least one cardiovascular condition documented in their medical history. There was seasonal variation in activity levels. Twelve participants had falls and cardiovascular, gait and activity variables were examined at the time of a fall to determine any trends in biophysiological changes. Conclusion Causes of falls are usually multifactorial. A holistic approach is necessary to manage and minimise risk factors. The use of an ICM with an embedded tri-axial accelerometer allows clinicians to formulate an algorithm to determine if a person is at an increased risk of falling based on biophysiological changes. This may create an opportunity for falls to be predicted and prevented.

Revisiting where to apply preimplant mapping to improve P-wave sensing of insertable cardiac monitors.

BackgroundInsertable cardiac monitors (ICMs) are used for long‐term cardiac rhythm monitoring. They have proven useful in diagnosing arrhythmias. They are conventionally inserted at the 4th intercostal space without preimplant mapping.MethodWe develop a new method, VisP, that finds an optimal insertion position by applying the lightweight preimplant mapping to nine candidate positions beyond the conventional ones. We retrospectively analyze consecutive 60 patients who underwent ICM insertion (Reveal LINQ™) between April 2019 and March 2021 and compare the two groups with and without VisP.ResultsAfter 9 patients were excluded because of ectopic atrial rhythms or atrial fibrillation, 51 patients were analyzed. Thirty‐one patients underwent the conventional insertion (non‐mapping), whereas 20 patients underwent VisP. VisP achieved large P‐wave amplitudes while retaining the R‐wave amplitude for all patients; in contrast, P waves were not detected for 11 patients out of the 31 patients in the non‐mapping group (35%). On average, the P‐wave amplitude was 0.065 mV for VisP, compared to 0.029 mV for the non‐mapping group (p‐value< .001). The average R‐wave amplitude was 0.69 mV for VisP and 0.71 mV for non‐mapping (p‐value = .88), indicating the R‐wave difference is insignificant between the two groups. VisP selected the 4th, 3rd, and 2nd intercostal spaces for 7, 11, and 2 patients, respectively, meaning that 13 out of the 20 cases (65%) fell out of the conventional insertion location of the 4th intercostal space.ConclusionsVisP improves the diagnostic ability of ICMs by finding an optimal position that yields reliable sensing of P waves while keeping high R‐wave sensing.

Abstract 12056: Incidence of Actionable Events on Implantable Cardiac Monitors: A Prospective Study Comparing Reveal LINQ TM and Confirm Rx TM Implantable Cardiac Monitors

Introduction: Implantable cardiac monitors (ICM) are increasingly being used to detect and treat arrhythmias in various clinical settings such as cryptogenic stroke. However, the incidence of actionable events in ICMs is unknown. Hypothesis: Confirm Rx TM has more actionable event detection rate than Reveal LINQ TM Methods: We prospectively studied 411 patients who received Reveal LINQ TM (Medtronic Inc., Dublin, Ireland) or Confirm Rx TM (Abbott, Sylmar, CA) ICM system for diagnosis of actionable arrhythmic events. Actionable arrhythmic events were defined as atrial fibrillation (AF) requiring anticoagulation, pauses requiring pacemaker, and tachycardia requiring ablation or medication changes. All actionable events were adjudicated for accuracy. Results: This study evaluated 411 patients with baseline characteristics of: 52.1% females, an average age of 65.81 years, and an average body mass index of 29.9 kg/m 2 . Reasons for ICM implants were, in descending order: cryptogenic stroke (44.3%), syncope (35%), and palpitations (20.9%). The Reveal LINQ TM was used in 56.4% (n=232) of patients and Confirm Rx TM was used in the other 43.6% (n=179). On univariate analysis, the composite outcome of actionable events were similar in both groups (Reveal LINQ TM 19% vs Confirm Rx TM 19%, p&gt;0.9). The individual actionable event outcome were also similar in both groups: AF (Reveal LINQ TM 11% vs Confirm Rx TM 8.5%, p=0.6), pauses (Reveal LINQ TM 1.3% vs Confirm Rx TM 4.0%, p=0.2), tachycardia (Reveal LINQ TM 6.0% vs Confirm Rx TM 5.6%, p&gt;0.9). However, the time to actionable event or last follow-up was significantly reduced (p&lt;0.001) in the Confirm Rx TM (median 203 days, interquartile range 90-371 days) as compared to Reveal LINQ TM (median 300 days, interquartile range 128-488 days). Conclusions: This study showed that although Reveal LINQ TM and Confirm Rx TM have similar actionable event detection rates, Confirm Rx TM has a shorter duration to diagnose true arrhythmic events. This difference may be due to their intrinsic detection algorithm. Larger studies are required to confirm this finding.

Abstract 9778: Insertable Cardiac Monitoring in Unexplained Syncope Patients is Cost-Saving Compared to External ECG Monitoring Followed by Insertable Cardiac Monitor

Background: Insertable cardiac monitors (ICMs) are recommended early in the evaluation of unexplained syncope patients after a non-diagnostic initial evaluation, and have been demonstrated as cost-effective for arrhythmia detection in this population. However, pathways frequently include short-term external cardiac monitors (ECM) prior to ICM. Objective: We aimed to evaluate the cost-effectiveness of immediate ICM versus a delayed ICM approach (30-day ECM followed by ICM in patients remaining undiagnosed), in unexplained syncope patients in the U.S. Methods: A discrete state Markov model assessed the cost-effectiveness of immediate vs. delayed ICM, from a U.S. payer perspective. Cohort characteristics were informed using the 2008-2016 Optum ® Clinformatics ® U.S. claims database. Syncope recurrence was modeled based on the EasyAs trial, with risks of mortality, injury, and quality of life consequences identified from the literature. ICM data capture was based on data for Reveal LINQ™ ICM. Diagnostic success with ECM was simulated based on the likelihood of monitoring occurring simultaneously to syncopal recurrence and patient adherence. Cost inputs were derived from claims and national average payment data. All diagnostic and arrhythmia-related treatment costs and benefits were modeled over a lifetime horizon, and future costs/effects were discounted at 3% per annum. Results: Immediate ICM was associated with lower lifetime per-patient costs compared to delayed ICM ($36,348 vs.$36,826), and a gain of 0.013 quality-adjusted life-years. This was largely driven by the cost of ECMs in the delayed ICM strategy, totaling $616,600 per 1,000 patients but with a small diagnostic yield such that 92.8%of patients required an ICM. The immediate ICM approach remained the dominant strategy when the assumed patient adherence to prescribed ECM was increased to 100%, and regardless of the choice of initial ECM (1, 2, 14, or 30-day monitor). Cost savings with immediate ICM increased further in scenarios assuming some delayed ICM patients are loss to follow-up after the initial ECM. Conclusions: A strategy of immediate ICM was cost-saving compared to delayed ICM, due to the cost and low diagnostic yield of ECM and the delay in arrhythmia detection and treatment.

Diagnostic accuracy of R-wave detection by insertable cardiac monitors.

Insertable cardiac monitors (ICM) allow prolonged rhythm monitoring, but the diagnostic performance can be hampered by false positive arrhythmia alerts related to inadequate R-wave sensing. This study assesses the prevalence and predictors of inadequate R-wave sensing (both over- and undersensing) among different ICM types. Patients implanted with an ICM at Ghent University Hospital between January 2017 and August 2018 were included. ICM tracings recorded at interrogation or transmitted by remote monitoring were reviewed for inadequate R-wave sensing leading to false arrhythmia alerts. Patient and implant characteristics were retrieved from the medical records and implant reports. The study screened 135 patients (age 59 ± 19 years, 44% female) implanted with different ICM types: Reveal LINQ™ and XT (Medtronic): n=92 (68%), Confirm and Confirm Rx (Abbott): n=35 (26%), and BioMonitor 2 (Biotronik): n=8 (6%). ICM tracings were analyzed in 112 patients (83%). False arrhythmia alerts occurred in 22 (20%) patients, most frequently related to undersensing (77%). False diagnosis of bradycardia or pause was documented in 64%, false high ventricular rates in 14%, and false atrial fibrillation alerts in 22%. Occurrence of R-wave changes was not related to patient characteristics or implant R-wave sensing. A trend toward higher number of inadequate R-wave sensing seems to occur with nonparasternal implant sites (P=.074). False arrhythmia alerts due to inadequate R-wave sensing occurred in 20% of ICM patients independent of implant features and patient characteristics.

P5648Efficiency and accuracy of arrhythmia detection using implantable cardiac monitor: A prospective multicenter randomized clinical trial comparing Reveal LINQ and Confirm Rx

Abstract Background Implantable cardiac monitor (ICM) has been used to detect occult cardiac arrhythmias in a variety of clinical situations. The reliability and accuracy of diagnosing cardiac arrhythmia could impact patient care. However, it is not clear the efficiency and reliability of detecting cardiac arrhythmias between currently available two ICMs. Purpose To compare the efficiency and accuracy of diagnosing cardiac arrhythmias between Reveal LINQ™ and Confirm Rx™. Methods In the prospective multicenter randomized study, a total of 80 patients (age: 61±17 years, men: 41 [51%]) with cryptogenic stroke (n=52) or recurrent unexplained episodes of palpitations (n=3) or syncope (n=25) received an ICM for detection of arrhythmias. Patients were randomized one to one into receiving either Reveal LINQ™ or Confirm Rx™. Arrhythmic events are defined as pauses of ≥3.0 seconds, bradycardia with heart rate of ≤40 bpm, tachycardia with heart rate of ≥150 bpm, and atrial fibrillation (AF). The time of detected arrhythmic events and patient activated events to the time of data availability on respective website site for analysis were compared between the two ICM. All of the arrhythmia events were adjudicated by two cardiologists to assess the accuracy. Results A total of 680 arrhythmic events including 352 AFs, 109 bradycardias, 167 tachycardias and 52 pauses were transmitted over a mean follow-up of 4.2±2.5 months. The mean time to data transmission was significantly faster in Confirm Rx™ than in Reveal LINQ™ (24±103 vs 475±426 min, P&lt;0.0001). One-hundred fifty-nine of 352 AF events (45%) and 237 of 328 non-AF events (72%) were accurately detected by ICMs (P&lt;0.0001). Twenty-eight of 51 AF events (55%) were detected accurately by Reveal LINQ™ and 131 of 301 AF events (44%) were accurately detected by Confirm Rx™ (P=0.13). The reason for inaccurate AF detection was frequent ectopic beats (n=134), P-wave oversensing (n=15), T-wave oversensing (n=8), both P- and T-waves oversensing (n=18) and sinus tachycardia with R-wave undersensing (n=18). Conclusions Data transmission of arrhythmic events using Confirm Rx™ is significantly faster than Reveal LINQ™. The accuracy of AF detection with current algorithms in both ICM remains suboptimal. More patients and longer follow-up is required to confirm these findings.

Detection of arrhythmias in adult congenital heart disease patients with LINQTM implantable loop recorder.

Rhythm disorders are the leading cause of morbidity and mortality in adults with congenital heart disease (ACHD). Infrequent or asymptomatic arrhythmias may not be detected by routine monitoring. Implantable loop recorders (ILRs), such as the Reveal LINQTM , have been useful in long-term monitoring for arrhythmias in adults with cryptogenic stroke. We propose the Reveal LINQTM will detect arrhythmias, not documented by other monitoring modalities, resulting in change in management in ACHD patients. This is a single center retrospective review of Reveal LINQTM use in ACHD patients from 2014-2017. Medical records were reviewed to determine cardiac diagnosis, indication for implant, ILR findings, and changes in management. Twenty-two patients, median age 25years, underwent ILR implantation. ILR findings resulted in change in management in nine (41%) patients. One-third (3/9) of the patients with clinically relevant events were asymptomatic. Patients with Fontan palliation had the highest number of pertinent positive events (57%). ACHD physiologic class D patients were more likely to have a positive finding (P=.034) compared to other physiologic classes. Majority (75%) of patients with positive events had arrhythmias documented on ILR which were not demonstrated on prior Holter/event monitors. Pertinent negative event occurred in one patient with Fontan palliation (5%) who had syncope corresponding to sinus rhythm. ILRs are a useful adjunct for arrhythmia monitoring in the ACHD population with clinically relevant events in 41% of patients. A special consideration for ILRs could be made for high-risk asymptomatic patients.

Data Transmission Delay in Medtronic Reveal LINQ&amp;lt;sup&amp;gt;TM&amp;lt;/sup&amp;gt; Implantable Cardiac Monitor: Clinical Experience in 520 Patients

Background: The Implantable Cardiac Monitor (ICM) is an invaluable tool for detecting cardiac arrhythmias by providing physicians. Critical to the success of ICMs depends on how quickly and accurately the data can be transmitted to a physician’s office after an arrhythmic event. Then, the clinical event can be analyzed and the treatment will be provided accordingly. However, no reports have been published as to how efficiently the ICM data is transmitted. Methods: There is a retrospective review of 520 patients who received a Medtronic Reveal LINQTM between 2/01/2015 and 6/01/2017. The time from the arrhythmic event to the time of physician notification was calculated and reason for delay was noted. Results: One hundred and twenty patients out of 520 patients (23%) had arrhythmic events transmitted over a mean follow up of 14 ± 4 months. The mean time between cardiac events and physician notification was 15 ± 8 days. Sixty-three percent (63%) of data transmission delay (defined as >24 hours) was due to the MyCareLinkTM Monitor not being in proximity to the patient. Connection failure between the monitor and the network accounted for 34% of data transmission delay. Conclusion: Significant delay in data transmission from Medtronic Reveal LINQTM cardiac monitor occurs frequently impacting patient care. Newer generations of the implantable cardiac monitors utilize Bluetooth technology, enabling immediate transfer of data from ICM to a patient’s cellular phone and subsequently to their physician’s office. This technology could potentially improve efficiency and reliability eliminating the issues of proximity and connectivity.

Treatment of sleep apnea in patients with paroxysmal atrial fibrillation: design and rationale of a randomized controlled trial

Rationale. Atrial fibrillation is associated with increased mortality as well as morbidity. There is strong evidence for an association between atrial fibrillation and sleep apnea. It is not known whether treatment of sleep apnea with continuous positive airway pressure (CPAP) will reduce the burden of atrial fibrillation.Objective. The Treatment of Sleep Apnea in Patients with Paroxysmal Atrial Fibrillation study will investigate the effects of CPAP in patients with paroxysmal atrial fibrillation and sleep apnea.Design: The trial has a dual center, randomized, controlled, open-label, parallel design.Methods. Two centers will enroll a total of 100 patients with both paroxysmal atrial fibrillation and sleep apnea (apnea-hypopnea index [AHI] ≥ 15 events/h) who are scheduled for catheter ablation. Patients will be randomized in a 1:1 ratio to CPAP or control group (50 patients in each arm). The effects of CPAP treatment on atrial fibrillation will be determined using an implanted loop recorder (Reveal LINQ™, Medtronic) that detects all arrhythmia episodes. The primary endpoint is a reduction of the total burden of atrial fibrillation in the intervention group, after 5 months’ follow-up (preablation). Reduction in the arrhythmia recurrence rate after ablation is the main secondary endpoint. All patients will be followed up for 12 months after ablation.Conclusion. This study is the first randomized controlled trial that will provide data on the effects of CPAP therapy in patients with paroxysmal atrial fibrillation and sleep apnea. The results are expected to improve our understanding of the interaction between paroxysmal atrial fibrillation and sleep apnea.Trial registration: ClinicalTrials.gov identifier: NCT02727192.

A single center experience on the clinical utility evaluation of an insertable cardiac monitor

BackgroundThe evaluation of insertable cardiac monitor (ICM) has been largely on the device performance and safety with only limited studies on the clinical utility. The aim of this study was to evaluate the clinical utility of ICM in patients with a variety of clinical presentations. MethodsA single-center retrospective study on the clinical utility, as measured by both expected and unexpected clinical useful ICM findings and the initiation of therapeutic interventions, was conducted. ResultsNinety-five consecutive patients (median age 68 years) received ICM Reveal LINQ™ for clinical indications of unexplained syncope (53), cryptogenic stroke (19), unexplained infrequent palpitations (14) and AF management (9). During a median follow-up of 414 days, the causes for unexplained syncope were arrhythmia-related (11.3%), arrhythmia-unrelated (32%) and undetermined (56.6%). Atrial fibrillation in patients with cryptogenic stroke was detected in 31.6% (6/19). The clinical utility occurrence was 48.4% with the expected and incidental (unexpected) clinical utility of 41% and 7.4% patients respectively. Of these, therapeutic interventions based on ICM diagnoses were initiated in 18.9% (18/95) of patients. ConclusionsICM (Reveal LINQ™) offers substantial expected and unexpected clinical utility in patients with a variety of clinical presentations. The causes of nearly one third of patients receiving ICM for unexplained syncope were unrelated to cardiac arrhythmia. Nearly one fifth of patients with newly diagnosed arrhythmia from ICM received therapeutic interventions.

Injectable loop recorder implantation in an ambulatory setting by advanced practice providers: Analysis of outcomes.

Implantable loop recorder (ILR) insertion has historically been performed in a surgical environment such as the electrophysiology (EP) lab. The newest generation loop recorder (Medtronic Reveal LINQ™, Minneapolis, MN, USA) is injectable with potential for implantation in a non-EP lab setting by advanced practice providers (APPs) facilitating improved workflow and resource utilization. We report the safety and efficacy of injectable ILR placement in the ambulatory care setting by APPs. A retrospective review was performed including all patients referred for injectable ILR placement from March 2014 to November 2015. All device placement procedures were performed in an ambulatory care setting using the standard manufacturer deployment kit with sterile technique and local anesthetic following a single dose of intravenous antibiotics. Acute procedural success and complication rates following injectable ILR placement in the ambulatory setting were reviewed. During the study period, 125 injectable ILRs were implanted. Acute procedural success with adequate sensing (R-waves ≥0.2 mV) occurred in 100% of patients. There were no acute procedural complications. Subacute complications occurred in two patients (1.6% of implantations), including one possible infection treated with oral antibiotics and one device removal due to pain at the implant site. In this retrospective single-center study, implantation of injectable ILR in an ambulatory care setting by APPs following a single dose of intravenous antibiotics and standard manufacturer technique yielded a low complication rate with high acute procedural success. Use of this implantation strategy may improve EP lab workflow while providing a safe and effective technique for device placement.

Clinical impact, safety, and accuracy of the remotely monitored implantable loop recorder Medtronic Reveal LINQTM.

Implantable loop recorders (ILR) are indicated in a variety of clinical situations when extended cardiac rhythm monitoring is needed. We aimed to assess the clinical impact, safety, and accuracy of the new Medtronic Reveal LINQTM ILR that can be inserted outside the electrophysiology (EP) laboratory and remotely monitored. All 154 consecutive patients (100 males, 63 ± 15 year-old) who received the Reveal LINQTM ILR during the period July 2014-June 2016 were enrolled. The device was implanted in a procedure room and all patients where provided with the MyCareLinkTM remote monitoring system. Data were reviewed every working day via the Carelink® web system by a specialist nurse who, in case of significant events, consulted an electrophysiologist. During a mean follow-up of 12.1 (6.7-18.4) months (range 2-24 months), a diagnosis was made in 99 (64%) patients and in 60 (39%) ≥1 therapeutic interventions were established following recording of arrhythmias. In 26 of these 60 patients, remote monitoring prompted therapeutic interventions following asymptomatic arrhythmic events 3.8 months before the next theoretical scheduled in-office data download. False bradycardia detection for undersensing occurred in 44 (29%) patients and false tachycardia detection for oversensing in 4 (3%). One patient experienced skin erosion requiring explantation and none suffered from infection. The remote monitoring feature of the Reveal LINQTM allowed earlier diagnosis of asymptomatic but serious arrhythmias in a significant proportion of patients. Implantation of the device outside the EP laboratory appeared safe. However, R-wave undersensing and consequent false recognition of bradyarrhythmias remains a clinically important technical issue.

Long-term detection of atrial fibrillation with insertable cardiac monitors in a real-world cryptogenic stroke population

The long-term incidence of atrial fibrillation (AF) in cryptogenic stroke (CS) patients has been explored in carefully controlled clinical trials but real-world data are limited. We investigated the two-year incidence of AF in real-world clinical practice among a large cohort of patients with an insertable cardiac monitor (ICM) placed for AF detection following CS. Patients in the de-identified Medtronic Discovery™ Link database who received an ICM (Reveal LINQ™) for the purpose of AF detection following CS were included and monitored for up to 2years. All detected AF episodes (≥2min) were adjudicated. We quantified the AF detection rate using Kaplan-Meier survival estimates, analyzed the median time to initial detection of AF, and simulated the ability of various intermittent monitoring strategies to detect AF. A total of 1247 patients (65.3±13.0years, 53% male) were included and followed for 579±222days. AF episodes (n=4183) were detected in 238 patients, resulting in an AF detection rate of 21.5% at 2years. The median time to AF detection was 112 [IQR 35-293] days. Intermittent monitoring for AF detection was inferior to continuous ICM monitoring with sensitivities ranging from 2.9% (annual 24-hour Holter) to 29.9% (quarterly 7-day Holters), p<0.001. AF episodes were detected via continuous monitoring with ICMs in approximately 1 of every 5 CS patients within 2years of follow-up. The vast majority of patients with AF would not have been detected with conventional external ambulatory monitors. ICMs should therefore be considered in the evaluation of CS patients.

Complications after implantation of a new-generation insertable cardiac monitor: Results from the LOOP study

BackgroundInsertable cardiac monitors (ICM) are leadless devices utilized in long-term monitoring of the heart rhythm. The implantation procedure of the new-generation ICMs is minimally invasive, but little experience exists regarding complications. We thus aimed to investigate adverse events (AE) according to procedure-related characteristics after implantation of a large number of new-generation ICMs. MethodsThe study population consisted of participants randomized to receive ICM in a multi-center trial. The Reveal LINQ™ ICM was implanted using provided insertion tools, either in an electrophysiology laboratory or outpatient procedure room. If device sensing was insufficient in the first subcutaneous position, one or more repositions were performed. Patients were urged to make contact if they suspected any AE. Furthermore, follow-up for safety endpoints consisted of evaluation of medical records and planned study visits. Results1420 patients received an ICM, 753 (53%) in a procedure room and 667 (47%) in an electrophysiology laboratory. During a median follow-up of 499days, 9 (0.63%) and 15 (1.13%) patients experienced AEs with and without need for device explantation, respectively. In the 38 patients requiring device repositioning, more AEs requiring explantation were seen (3 (7.9%) vs. 6 (0.4%), p=0.001). Patients undergoing implantation in a procedure room had more infections (12 (1.6%) vs. 1 (0.1%), p=0.004), though no significant difference was reached in AEs requiring explantation (7 (0.9%) vs. 2 (0.3%), p=0.19). ConclusionThe Reveal LINQ™ ICM can be inserted with a very low risk of complications, both in the traditional electrophysiology laboratory setting and in an outpatient procedure room.

P- and R-wave Amplitude Sensed by Reveal LINQ™ Loop Recorder in Pediatric Patients.

Implantable loop recorders are commonly used to sense arrhythmias. The purpose of this study is to assess the P- and R-wave amplitudes at implantation (I) and follow-up (F) following insertion of the Reveal LINQ™ Insertable Cardiac Monitor (Medtronic, Minneapolis, MN) in an institutional review board-approved, multicenter study performed on pediatric patients younger than 18 years old. Collected data included demographics, presence of congenital heart disease (CHD), P- and R-wave-sensed amplitude at I and F, and the method of implant (i.e. mapping or standard.) P waves were manually measured and R-wave sensing was recorded by the device. A total of 87 patients had a Reveal LINQ™ (Medtronic, Minneapolis, MN) device implanted; the mean patient age was 11.8 years (0.5 years to 18 years) with 48% of patients being female and 19% of patients having CHD; mapping was used in 43% of patients. The Reveal LINQ™ (Medtronic, Minneapolis, MN) experienced no change in average sensed R-wave amplitude at either I or F (1.28 mV vs 1.26 mV, p = NS). There was no difference in sensed R-wave amplitude noted with or without mapping used at I (1.29 mV vs 1.26 mV, p = NS) or F (1.48 mV vs 1.18 mV, p = NS). Additionally, no difference could be found in R-wave sensing of patients with CHD or without CHD at I (1.26 mV vs 1.4 mV, p = NS) or F (1.32 mV vs 1.32 mV, p = NS). R-wave sensing trended towards being inversely proportional to patient body surface area (BSA) (p = NS). P waves were detected on 48% of tracings in all patients at I and/or F, irrespective of whether the Reveal LINQ™ (Medtronic, Minneapolis, MN) device was placed with mapping. The R wave was (0.37–3.5 mV) at I and (0.3–3 mV) (p = NS) at F when P waves were detected. From these results, it can be said that the Reveal LINQ™ Insertable Cardiac Monitor (Medtronic, Minneapolis, MN) has an excellent ability to sense R-wave amplitude in pediatric patients. No significant difference in the sensing ability of the device could be identified with respect to the presence of CHD, use of mapping or BSA. P waves tended to be identified when there was a higher baseline R-wave amplitude.

Maintaining Accurate Long-Term Sensing Ability Despite Significant Size Reduction of Implantable Cardiac Monitors.

The Reveal LINQ™ implantable cardiac monitor (ICM; Medtronic, Minneapolis, MN, USA) is obviously smaller than its precursor (the Reveal XT™), but little is known about its long-term safety. Here, we investigated the long-term R-wave sensing reliability of the Reveal LINQ™ ICM. We analyzed the sensing quality of the Reveal LINQ™ ICM over time between March 2014 and January 2015. A total of 30 patients underwent Reveal LINQ™ implantation. The main reason for implantation was unexplained syncope (60%). We evaluated a total of 305.8 patient-months (median, 10.7 months) of R-wave sensing quality. A comparison of baseline and follow-up R-wave sensing values revealed no difference (0.401 mV ± 0.244 mV vs 0.447 mV ± 0.323 mV; P = 0.225). The consistent detection of events is an important safety feature of an ICM and linked to secure R-wave sensing. Despite the noticeable size reduction, the Reveal LINQ™ ICM retains reliable sensing quality over time.

Abstract TMP40: Impact of Age on Atrial Fibrillation Detection among a Large, Real-World Population of Cryptogenic Stroke Patients with Insertable Cardiac Monitors

Introduction: Detection of atrial fibrillation (AF) in patients with a cryptogenic stroke (CS) is critical for reducing the risk of recurrent stroke by enabling oral anticoagulation therapy. However, the impact of age on AF detection and the optimum duration of AF monitoring in patients following a CS is not well characterized. We investigated the impact of age on AF detection among a large, real-world cohort of unselected patients with an implantable cardiac monitor (ICM) placed following CS. Methods: Patients in the de-identified Medtronic Discovery™ Link database who received an ICM (Reveal LINQ™) for AF detection following CS were included and monitored for up to 182 days. All AF episodes were adjudicated. We compared the mean age between patients with vs. without AF detected and compared the median time to detection of the first AF episode between younger (age ≤65) and older (age &gt;65) patients. Results: Among 1247 patients (mean age 65.3±13.0, 53% male) followed for 182 [IQR 182-182] days, 1521 AF episodes were detected in 147 patients and resulted in an AF detection rate of 12.2%. Patients with AF detected were significantly older than patients without AF detected (71.3±10.9 vs. 64.5±13.1 years, respectively; p&lt;0.001). The median time to detection of the first AF episode was shorter for older vs. younger patients (43 [10-91] vs. 89 [29-127] days, respectively; p=0.016; Figure). Conclusion: Continuous monitoring of CS patients with an ICM resulted in an AF detection rate of 12.2% within the initial 6 months. Patients with AF detected were older and patients &gt;65 years of age had shorter times to initial AF detection. However even among older patients, the majority of AF occurred outside the range of external monitoring devices and thus highlights the importance of long-term monitoring with ICMs in the management of CS patients.