Insertion of miniaturized cardiac monitors outside the catheter operating room: experience and practical advice

Strategic reprogramming of implantable cardiac monitors reduces the false-positive remote alert burden in a nurse-led service

AIMS

Implantable cardiac monitors (ICMs) can generate false-positive (FP) alerts. Although these devices have an extended programmability, there are no recommendations on their optimization to reduce not-relevant activations.We tested a strategic programming optimization guide based on the type of FP and investigated the safety and feasibility of the nurse-led insertion of ICMs with a long-sensing vector.

METHODS AND RESULTS

Consecutive patients implanted by trained nurses with long-sensing vector ICM were enrolled in a 1-month observational stage (Phase A). Patients who had ≥10 FP episodes underwent ICM reprogramming based on the predefined guide and were followed for an additional month (Phase B). A total of 78 patients had successful ICM insertion by nurses with a mean R wave amplitude of 0.96 ± 0.43 mV and an 86% P wave visibility. Only one patient reported a significant device-related issue, and nurse-delivered ICM was generally well accepted by the patients. During Phase A, 11 patients (14%) generated most of FP (3,627/3,849; 94%) and underwent ICM reprogramming. In the following month (Phase B), five patients (45%) were free from FP and six (55%) transmitted 57 FP alerts (98% reduction compared with Phase A). The median number of FP per patient was significantly reduced after reprogramming [195 (interquartile range, 50-311) vs. one (0-10), P = 0.0002].

CONCLUSION

A strategic reprogramming of ICM in those patients with a high FP alert burden reduces the volume of erroneous activations with potential benefits for the remote monitoring service. No concerns were raised regarding nurse-led insertion of ICMs with a long-sensing vector.

A comparison of Atrial Fibrillation Detection Strategies After Ischemic Stroke-A Retrospective Study

Objective of this retrospective study was to determine if long-term continuous cardiac monitoring with Implantable loop recorder (ILR) in patients with Cryptogenic strokes or TIA is superior at detecting Atrial Fibrillation (AF) than 30-day Event Monitor (EM) and 48-hour Holter Monitor (HM). Furthermore, we aimed to deduce if uncovering AF leads to lower risk of future ischemic strokes, or reduction in mortality. In 20%-30% cases, the cause of stroke remained unexplained after diagnostic workup which has led to coining of the term, Cryptogenic Stroke (CS). Undiagnosed AF is a prime suspect in CS, but guidelines do not recommend initiation of anticoagulation unless AF has formally been detected. IRB approved retrospective study included patients with at least 1 episode of ischemic stroke or TIA without identifiable cause and was monitored with either HM, EM or ILR to diagnose any undiscovered AF. All patients (n = 531) had at least 1 year, and up to 3 years, of follow-up after device placement. Chi-Squared analysis and Multivariable logistic regression demonstrated no statistically significant difference among 3 devices for detection of AF within 1 month of index stroke but a significant difference in AF detection was observed at 6, 12 and 24 months. Cox proportional hazard model showed device type had no significant impact on secondary outcomes: Subsequent ischemic stroke or TIA, Initiation of anticoagulation, Mortality and Incidence of major bleeding. Despite the superiority of AF detection by ILR, it is not superior to HM or EM in lowering the risk of subsequent stroke or TIA, or in reducing mortality.

Insertable cardiac monitor with a long sensing vector: Impact of obesity on sensing quality and safety

Background

Fat layers in obese patients can impair R-wave detection and diagnostic performance of a subcutaneous insertable cardiac monitor (ICM). We compared safety and ICM sensing quality between obese patients [body mass index (BMI) ≥ 30 kg/m²] and normal-weight controls (BMI <30 kg/m²) in terms of R-wave amplitude and time in noise mode (noise burden) detected by a long-sensing-vector ICM.

Materials and methods

Patients from two multicentre, non-randomized clinical registries are included in the present analysis on January 31, 2022 (data freeze), if the follow-up period was at least 90 days after ICM insertion, including daily remote monitoring. The R-wave amplitudes and daily noise burden averaged intraindividually for days 61-90 and days 1-90, respectively, were compared between obese patients (n = 104) and unmatched (n = 268) and a nearest-neighbour propensity score (PS) matched (n = 69) normal-weight controls.

Results

The average R-wave amplitude was significantly lower in obese (median 0.46 mV) than in normal-weight unmatched (0.70 mV, P < 0.0001) or PS-matched (0.60 mV, P = 0.003) patients. The median noise burden was 1.0% in obese patients, which was not significantly higher than in unmatched (0.7%; P = 0.056) or PS-matched (0.8%; P = 0.133) controls. The rate of adverse device effects during the first 90 days did not differ significantly between groups.

Conclusion

Although increased BMI was associated with reduced signal amplitude, also in obese patients the median R-wave amplitude was >0.3 mV, a value which is generally accepted as the minimum level for adequate R-wave detection. The noise burden and adverse event rates did not differ significantly between obese and normal-weight patients.Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04075084 and NCT04198220.

The BIOMONITOR III Injectable Cardiac Monitor: Clinical Experience with a Novel Injectable Cardiac Monitor

Background: Injectable cardiac monitors (ICMs) are leadless subcutaneous devices for long-term monitoring of arrhythmias. The BIOTRONIK BIOMONITOR III is a novel ICM with a miniaturized profile, long sensing vector, and simplified implantation technique. Methods: R-wave amplitude was recorded immediately after implantation, the day after implantation, and after 3 months. Follow-up was scheduled after 3 months or after an event. All data from the ICM were retrieved. The anatomical position of the ICM was determined post-implantation and after 3 months. A patient questionnaire was conducted after 3 months. Results: In 36 patients (mean age 67 ± 13 years; 40% male) an ICM was inserted. Six patients were not included in the final analysis. The median time from skin cut to wound closure was 6 [IQR 5–7] minutes. Mean R-wave amplitude increased over time (0.73 ± 32 mV vs. 0.78 ± 0.38 mV vs. 0.81 ± 0.39 mV; p = ns). Three months after implantation, the ICM was in an anatomically stable position. In 14 (47%) patients, true episodes were detected. False arrhythmia alerts were detected in 13 (43%) patients. The total number of false detections was low, and the patient satisfaction rate was high. Conclusion: Implantation of the novel BIOMONITOR III is fast and uncomplicated; its sensing characteristics are excellent and improve over time, and patient satisfaction is high.

Subcutaneouscardiac Rhythm Monitors: A Comprehensive Review

Subcutaneous loop recorders (SCRMs) are subcutaneous electronic devices which have revolutionized the field of arrhythmia detection. They have become increasingly appealing due to advances such as miniaturization of device, longer battery life, bluetooth capabilities and relatively simple implantation technique without the need for complex surgical suites. They can be implanted in the office, patient bedside without the need to go to the operating room. One of the most common indications for their implantation is detection of atrial fibrillation (AF) after a cryptogenic stroke. They have also been utilized for assessing the success of rhythm control strategies such post pulmonary venous isolation. More recently studies have assessed the utility of SCRMs for detecting silent AF in at risk populations such as patients with sleep apnea or those on hemodialysis. In this paper, we review the evolution of SCRMs, the clinical studies assessing their value for different indications, their role incurrent clinical practice and future avenues in the era of smart wearable devices like apple watch etc.

Subcutaneous cardiac rhythm monitors: state of the art review

Introduction: Subcutaneous cardiac rhythm monitors (SCRMs) provide continuous ambulatory electrocardiographic monitoring for surveillance of known and identification of infrequent arrhythmias. SCRMs have proven to be helpful for the evaluation of unexplained symptoms and correlation with intermittent cardiac arrhythmias. Successful functioning of SCRM is dependent on accurate detection and successful transmission of the data to the device clinic. As the use of SCRM is steadily increasing, the amount of data that requires timely adjudication requires substantial resources. Newer algorithms for accurate detection and modified workflow systems have been proposed by physicians and the manufacturers to circumvent the issue of data deluge.Areas covered: This paper provides an overview of the various aspects of ambulatory rhythm monitoring with SCRMs including indications, implantation techniques, programming strategies, troubleshooting for issue of false positive and intermittent connectivity and strategies to circumvent data deluge.Expert opinion: SCRM is an invaluable technology for prolonged rhythm monitoring. The clinical benefits from SCRM hinge on accurate arrhythmia detection, reliable transmission of the data and timely adjudication for possible intervention. Further improvement in SCRM technology is needed to minimize false-positive detection, improve connectivity to the central web-based server, and devise strategies to minimize data deluge.

BioMonitor 2 in-office setting insertion safety and feasibility evaluation with device functionality assessment: results from the prospective cohort BioInsight study

BACKGROUND

Insertable cardiac monitors are utilized for the diagnosis of arrhythmias and traditionally have been inserted within hospitals. Recent code updates allow for reimbursement of office-based insertions; however, there is limited information regarding the resources and processes required to support in-office insertions. We sought to determine the safety and feasibility of in-office insertion of the BioMonitor 2 and better understand in-office procedures, including patient selection, pre-insertion protocols, resource availability, and staff support.

METHODS

Patients meeting an indication for a rhythm monitor were prospectively enrolled into this single-arm, non-randomized trial. All patients underwent insertion in an office setting. Two follow-up visits at days 7 and 90 were required. Information on adverse events, device performance, office site preparations, and resource utilization were collected.

RESULTS

Eighty-two patients were enrolled at six sites. Insertion was successful in all 77 patients with an attempt. Oral anticoagulation was stopped in 20.8% of patients and continued through insertion in 23.4%, while prophylactic antibiotics were infrequently utilized (37.7% of study participants). On average, the procedure required a surgeon plus two support staff and 35 min in an office room to complete the 8.4 min insertion procedure. The mean R-wave amplitude was 0.77 mV at insertion and 0.67 mV at 90-days with low noise burden (2.7%). There were no procedure related complications. Two adverse events were reported (event rate 2.7% [95% CI 0.3, 9.5%]).

CONCLUSIONS

In-office insertion of the BioMonitor 2 is safe and feasible. Devices performed well with high R-wave amplitudes and low noise burden. These results further support shifting cardiac monitor insertions to office-based locations.

TRIAL REGISTRATION

clinicaltrials.gov, NCT02756338. Registered 29 April 2016.

Miniaturized implantable cardiac monitor with a long sensing vector (BIOMONITOR III): Insertion procedure assessment, sensing performance, and home monitoring transmission success

BACKGROUND

Implantable Cardiac Monitors (ICMs) are used for long-term monitoring of arrhythmias. BIOMONITOR III is a novel ICM with a miniaturized profile, long sensing vector due to a flexible antenna, simplified implantation with a dedicated insertion tool for pocket formation and ICM placement in a single step, and daily automatic Home Monitoring (HM) function.

METHODS

In 47 patients undergoing BIOMONITOR III insertion for any ICM indication, 16 investigators at 10 Australian sites assessed handling characteristics of the insertion tool, R-wave amplitudes, noise burden, P-wave visibility, and HM transmission success. Patients were followed for 1 month.

RESULTS

All 47 attempted insertions were successful. Median time from skin incision to removal of the insertion tool after ICM insertion was 39 s (IQR 19-65) and to wound closure and cleaning was 4.7 min (IQR 3.5-7.8). All aspects of the insertion tool were rated as "good" or "excellent" in ≥97.9% and "fair" in ≤2.1% of patients, except for "force needed for tunnelling" (91.5% good/excellent, 8.5% fair). Based on HM data, R-waves in the first month were stable at 0.70 ± 0.37 mV. Median noise burden (disabling automatic rhythm evaluation) was 0.19% (IQR 0.00-0.93), equivalent to 2.7 min (IQR 0.0-13.4) per day. In HM-transmitted ECG strips with regular sinus rhythm, P-waves were visible in 89 ± 24% of heart cycles. Patient-individual automatic Home Monitoring transmission success was 98.0% ± 5.5%.

CONCLUSIONS

The novel ICM performed well in all aspects studied, including fast insertion, reliable R-wave sensing, good P-wave visibility, and highly successful HM transmissions.

Clinical evaluation of a small implantable cardiac monitor with a long sensing vector

Introduction

We conducted this study to show the safety and efficacy of a new implantable cardiac monitor (ICM), the BioMonitor 2 (Biotronik SE & Co. KG; Berlin, Germany), and to describe the arrhythmia detection performance.

Methods

The BioMonitor 2 has an extended sensing vector and is implanted close to the heart. It can transmit up to six subcutaneous electrocardiogram strips by Home Monitoring each day. We enrolled 92 patients with a standard device indication for an ICM in a single‐arm, multicenter prospective trial. Patients were followed for 3 months, and 48‐h Holter recordings were used to evaluate the arrhythmia detection performance.

Results

One patient withdrew consent and in one patient, the implantation failed. Two study device‐related serious adverse events were reported, satisfying the primary safety hypothesis. Implantations took 7.4 ± 4.4 min from skin cut to suture. At 1 week, the R‐wave amplitude was 0.75 ± 0.53 mV. In the 82 patients with completed Holter recordings, all patients with arrhythmias were correctly identified. False positive detections of arrhythmia were mostly irregular rhythms wrongly detected as atrial fibrillation (episode‐based positive predictive value 72.5%). Daily Home Monitoring transmission was 94.9% successful.

Conclusion

Safety and efficacy of the new device has been demonstrated. The detected R‐wave amplitudes are large, leading to a low level of inappropriate detections due to over‐ or undersensing.

Insertable cardiac monitors: current indications and devices

INTRODUCTION

Recurrent unexplained syncope is a well-established indication for an insertable cardiac monitor (ICM). Recently, the indications for an ICM have been expanded.

AREAS COVERED

This review article discusses the current indications for ICMs and gives an overview of the latest generation of commercially available ICMs.

EXPERT COMMENTARY

The 2018 ESC Syncope guidelines have expanded the indications for an ICM to patients with inherited cardiomyopathy, inherited channelopathy, suspected unproven epilepsy, and unexplained falls. ICMs are also increasingly used for the detection of subclinical atrial fibrillation (AF) in patients with cryptogenic stroke. Whether treatment of subclinical AF (SCAF) with oral anticoagulation prevents recurrent stroke is yet unknown. The current generation of ICMs are smaller, easier to implant, have better diagnostics, and are capable of remote monitoring. The Reveal LINQ (Medtronic) is the smallest ICM and has the most extensive performance and clinical data. The BioMonitor 2 (Biotronik) is the largest ICM but has excellent R-wave amplitudes, longest longevity, and reliable remote monitoring. The Confirm Rx (Abbott) is capable to provide mobile data transmission enabled by a smartphone app. Future generation of ICMs will incorporate heart failures indices to facilitate remote monitoring of heart failure patients.

Detection and management of atrial fibrillation using remote monitoring

Atrial fibrillation (AF) is the most common dysrhythmia encountered in the United States. Symptoms may be similar to those of other cardiac conditions, which can delay the timely detection, diagnosis, and management of AF. This article provides an overview of AF and modalities used in remote monitoring.

Sensing performance, safety, and patient acceptability of long-dipole cardiac monitor: An innovative axillary insertion

BACKGROUND

The recommended location for implantable cardiac monitor (ICM) insertion is the left pectoral region. We tested whether an innovative left axillary implantation approach could be applicable for a new ICM, characterized by a long sensing dipole.

METHODS

We considered a series of 55 patients consecutively implanted with a long-dipole ICM (BioMonitor 2); the first 30 subjects underwent prepectoral location insertion, while the subsequent 25 received the ICM in the axillary region. Sensing performances collected at 1-month follow-up were compared between the two groups. During the visit, each patient was also asked to fill in a brief questionnaire to assess patient acceptability of the device.

RESULTS

All patients had a successful insertion of ICM. Mean R-wave amplitude was 0.87 ± 0.44 mV in the prepectoral group and 1.00 ± 0.45 mV in the axillary one, without any significant difference. The percentage of patients with visible P wave was also comparable between the two approaches (65.5% vs 68.2%, P = 0.84). None of the patients reported device-related issues or discomfort, and ICM was generally well accepted and tolerated by all the involved patients.

CONCLUSION

Axillary insertion may represent a valid alternative to the standard one for long-dipole ICM technology providing not only patient acceptability but also high-quality sensing performances.