Remote monitoring of implantable loop recorders reduces time to diagnosis in patients with unexplained syncope: a multicenter propensity score-matched study

Importance of Raw-Data Analysis When Determining the Cause of Pause Alerts Transmitted by an Implantable Loop Recorder Remote Monitoring Devices

INTRODUCTION

Use of implantable loop recorder (ILR) for the diagnosis and documentation of cardiac arrhythmia has gained popularity during the last decade. Most ILRs are accompanied by remote monitoring (RM) devices, which allow automated daily interrogations of the ILR. These transmit arrhythmic or pause alerts to the treating clinic, enabling timely medical attention and treatment. Although ILR RM transmissions have been shown to have significant false positive alerts, a true positive alert suggesting a wrong arrhythmia diagnosis has not been shown to date.

METHODS AND RESULTS

We revised all ILR pause transmissions arriving to our hospital device clinic during 2024, looking for pause alerts which were initially misdiagnosed. We report a case series of patients in whom a RM pause alert has been transmitted with a suspected apparent diagnosis of sinus arrest. However, when interrogating the ILR in clinic, these episodes were diagnosed as high-degree atrioventricular block (AVB) pauses, for which an urgent permanent pacemaker (PPM) might be indicated. Review of these cases revealed that in contrast with the automated RM PDF alerts, in which the figure resolution cannot be changed (and thus small P waves may be unnoticed), the raw-data episode recording on the RM web page enables one to increase the image resolution to clearly discern initially unnoticed non-conducted P waves.

CONCLUSION

ILR RM pause alerts should always be reviewed via the raw-data RM web page or alternatively via ILR device interrogations, to achieve a sufficiently high-resolution image to assure these pauses are not due to AVB.

Clinical presentation and genetic characterization of early-onset atrial fibrillation in patients affected by long QT syndrome: A single-center experience

INTRODUCTION

Early-onset atrial fibrillation (AF) has already been observed in approximately 2% of patients with genetically proven long QT syndrome (LQTS). This frequency is higher than population-based estimates of early-onset AF. However, the concomitant expression of AF in LQTS is likely underestimated. The purpose of this study was to examine the clinical presentation, genetic background, and outcomes of a cohort of patients with LQTS and early-onset AF referred to a single tertiary center.

METHODS

Twenty-seven patients diagnosed with congenital LQTS were included in the study based on the documentation of early-onset (age ≤50 years) clinical or subclinical AF episodes in all available medical records, including standard electrocardiograms, wearable monitor or cardiac implantable electronic devices.

RESULTS

Seventeen patients experienced clinical AF during the follow-up period. Subclinical AF was detected in 10 patients through insertable or wearable cardiac monitors. In our series, the mean heart rate during AF episodes was found to be relatively low despite the patients' young age and the low or minimal effective doses of beta-blockers used for QTc interval control. All patients exhibiting LQTS and early-onset AF were genotype positive, carrying mutations in the KCNQ1 (66%), KCNH2, KCNE1, and SCN5A genes. Notably, most of these patients carried the same p.(R231C) mutation in the KCNQ1 gene (59%) and were from the same families, suggesting concurrent expression of familial AF and LQTS.

CONCLUSION

LQTS patients are prone to developing clinical and subclinical AF, even at a younger age. The occurrence of early-onset AF in the LQTS population could be more frequent than previously assumed. AF should be considered as a potential dysrhythmia related to LQTS. Our study emphasizes the importance of carefully researching clinical and/or subclinical episodes of AF through strict heart rhythm monitoring in the LQTS population.

[Diagnostics and treatment of syncope]

The 2018 guidelines of the European Society of Cardiology (ESC) provide improved algorithms for the diagnostics and treatment of syncope. New guidelines on ventricular tachycardia, on the prevention of sudden cardiac death and on cardiomyopathies and pacemakers have refined the recommendations. The detailed medical history and examination are crucial for differentiating between cardiac and noncardiac causes and determining the appropriate treatment. High-risk patients need urgent and comprehensive diagnostics. The basic diagnostics include medical history, physical examination and a 12-lead electrocardiography (ECG). Further tests, such as long-term ECG monitoring, implantable loop recorders and electrophysiological investigations are helpful in unclear cases. The treatment depends on the cause, with pacemaker implantation and implantable cardioverter defibrillators (ICD) being important for cardiac causes, while behavioral measures and medication management have priority for noncardiac syncope.

Migration of long-sensing vector implantable loop recorder unmasked by remote monitoring in patient with unexplained syncope

A 75-year-old man with hypertrophic obstructive cardiomyopathy underwent placement of a long-sensing vector implantable loop recorder (ILR) for unexplained syncope. One month later, ILR remote monitoring revealed unstable R-wave amplitudes ranging from very high (>1.9 mV) to very low (<0.2 mV) values. During an in-hospital clinic visit, the only site to establish communication with the ILR was the left posterior axillary area. Chest computed tomography confirmed ILR migration into the anterior costophrenic recess. The device was retrieved with forceps during video thoracoscopy without further complications.

LEARNING OBJECTIVE

This is the first case report of migration of an implantable loop recorder diagnosed by remote monitoring.

Digital health and cardiovascular healthcare professionals in Portugal: Current status, expectations and barriers to implementation

INTRODUCTION AND OBJECTIVES

Digital health (DH) is a broad concept, bringing together technology and healthcare, that is playing an increasingly important role in the daily routine of healthcare professionals (HCPs) and promises to contribute to the prevention and treatment of cardiovascular disease. There are no solid data on the position of Portuguese HCPs toward the implementation of DH in cardiovascular medicine. This national cross-sectional study aims to provide a snapshot of DH implementation in Portuguese cardiovascular HCP routines and to identify both expectations and barriers to its adoption.

METHODS

An 18-question survey was created specifically for this study and distributed to 1174 individuals on the Portuguese Society of Cardiology mailing list.

RESULTS

We collected 117 valid responses (response rate 10%). Almost all participants had smartphones and laptops, and two-thirds had tablets. Electronic medical information systems were the most used DH tool (84% of respondents) and were considered the most important for improving cardiovascular care. Implantable technologies (sensors and devices), telemedicine and social media were used by more than two out of three respondents and considered «very important» or «extremely important» by most of them. Most participants showed positive expectations regarding the impact of DH in cardiovascular medicine: 78% agreed that DH could improve health outcomes, 64% that it promotes health literacy and 63% that it could decrease healthcare costs. The top-rated barriers were patients' inability to use smartphones, limited access to electronic devices, and lack of legal regulation of DH.

CONCLUSION

Most Portuguese cardiovascular HCPs had at least three electronic devices (mainly smartphones, laptops and tablets) and showed positive expectations regarding DH's current and future impact on cardiovascular medicine. Patient DH literacy, technology adoption, and DH regulation were identified as the most important barriers to increasing the adoption of DH tools in cardiovascular medicine.

A More Targeted and Selective Use of Implantable Loop Recorders Improves the Effectiveness of Syncope Units: A Single-Center Experience

PURPOSE

Syncope remains a common medical problem. Recently, the role of dedicated syncope units and implantable loop recorders has emerged in the investigation of unexplained syncope. This study aims to investigate the possibilities for a more rational and targeted use of various diagnostic tools.

METHODS

In this retrospective single-center study, 196 patients with unexplained syncope were included between March 2019 and February 2023. Various diagnostic tools were utilized during the investigation, according to clinical judgement. Patients were retrospectively allocated into Group A (including those who, among other tests, underwent loop recorder insertion) and Group B (including patients investigated without loop recorder implantation). Data were compared with Group C, including patients assessed prior to syncope unit establishment.

RESULTS

There was no difference between Group A (n = 133) and Group B (n = 63) in the diagnostic yield (74% vs. 76%, p = 0.22). There were significant differences between Groups A and B regarding age (67.3 ± 16.9 years vs. 48.3 ± 19.1 years, p < 0.001) and cause of syncope (cardiogenic in 69% of Group A, reflex syncope in 77% of Group B, p < 0.001). Electrocardiography-based diagnosis occurred in 55% and 19% of Groups A and B, respectively (p < 0.001). The time to diagnosis was 4.2 ± 2.7 months in Group A and 7.5 ± 5.6 months in Group B (p < 0.001). In Group C, the diagnostic yield was 57.9% and the electrocardiography-based diagnostic yield was 18.3%.

CONCLUSIONS

A selective use of loop recorders according to clinical and electrocardiographic characteristics increases the effectiveness of the structured syncope unit approach and further preserves financial resources.

False-positive alarms in patients with implantable loop recorder followed by remote monitoring: A systematic review

Remote Monitoring (RM) has been shown to provide useful information about arrhythmic events in patients with implantable loop recorders (ILRs), however there is few and conflicting data about the false positive (FP) alarms burden and characteristics among ILR recipients. The aim of the present systematic review was to evaluate incidence and characteristics of FP alarms among ILR patients followed by RM. We developed a systematic research in Embase, MEDLINE and PubMed databases and selected all papers focused on false positive ILR transmissions published from June 1, 2013 to June 1, 2023. Case reports, meeting summaries, posters and simple reviews were excluded. Twelve reports were finally selected, including five prospective and seven retrospective studies. Information about population characteristics, device type and setting, overall transmissions and FP alarms and any adopted strategies to reduce them were extracted from an overall population of 3.305 patients. FP alarms were 59.7% of the overall remote transmissions and were found in 1/5 of the analyzed population. FP alarms for atrial fibrillation were the most common cause of false transmissions and were mainly due to premature atrial and ventricular complexes. No clinical predictors of FP alarms were identified, except for nonparasternal ILR implantation site. Since the overload work due to FP alarms might reduce the benefit of remote monitoring of ILR patients, the device optimization is an important step until an help from machine-learning algorithms is available.

Remote monitoring of implantable cardiac monitors in patients with unexplained syncope: Predictors of false-positive alert episodes

BACKGROUND

Remote monitoring is recommended for patients with implantable cardiac monitors (ICMs), but compared to other cardiac implantable devices, ICMs are less accurate and transmit a higher number of alerts.

OBJECTIVE

The aim of this study was to investigate the predictors of false-positive (FP) arrhythmic alerts in patients with unexplained syncope who were implanted with ICM and followed by an automatic remote monitoring system.

METHODS

We retrospectively evaluated all consecutive patients who received a long-sensing vector ICM for unexplained syncope between January 2019 to September 2021 at our Syncope Unit. The primary endpoint was the incidence of the first FP episode. The secondary endpoints included assessing the incidence of FP episodes for all types of algorhythms and indentifying the reasons for the misdetection of these episodes.

RESULTS

Among 105 patients (44.8% males, median age 51 years), 51 (48.6%) transmitted at least one FP alert during a median follow-up of 301 days. The presence of pre-ventricular complexes (PVCs) on the resting electrocardiogram was the only clinical characteristic associated with an increased risk of FP alerts (adjusted Hazard ratio [HR] 5.76 [2.66-12.4], p = 0.010). The other significant device-related variables were a low-frequency filter at 0.05 Hz versus the default 0.5 Hz (adjusted HR 3.82 [1.38-10.5], p = 0.010) and the R-wave amplitude (adjusted HR 0.35 [0.13-0.99], p = 0.049).

CONCLUSION

Patients who have PVCs are at higher risk of inappropriate ICM activations. To reduce the occurrence of FP alerts, it may be beneficial to target a large R-wave amplitude during device insertion and avoid programming a low-frequency filter at 0.05 Hz.