Implantable loop recorder versus conventional diagnostic workup for unexplained recurrent syncope

Value of Extended Arrhythmia Screening in Adult Congenital Heart Disease Patients

The European Society of Cardiology guidelines for the management of adult congenital heart disease patients recommend screening for arrhythmias and bradycardias in symptomatic patients, often being done by means of an ambulatory 24-48-hour Holter or implantable loop recorder (ILR). However, nowadays non-invasive instruments, such as patches, smartwatches and smartphones based on single-lead ECGs that perform extended monitoring, are also available. The aim of this narrative review was to assess whether these instruments, when they detect arrhythmias and bradycardias in patients with adult congenital heart disease, will lead to meaningful changes in clinical care. Clinically meaningful changes include adjustment of medication, cardioversion, electrophysiology study, ablation or implantation of a cardiovascular implantable electronic device. The following monitoring instruments are discussed: cumulative Holter, 2-week continuous monitor, smartwatchand smartphone-based single-lead ECG, and ILR. The diagnostic yield of extended rhythm monitoring is high, and varies between 18% (smartphone-based single-lead ECG) and 41% with ILR. In conclusion, contemporary arrhythmia screening includes various new non-invasive technologies that are promising new tools as an alternative to Holter monitoring or ILR. However, the optimal mode of detection is still unclear due to the lack of head-to-head comparisons.

Vasospasm in the First Septal Perforator Branch and Late High-Grade Atrioventricular Block Following Successful Primary Percutaneous Coronary Intervention for the Proximal Left Anterior Descending Coronary Artery: A Case Report

We present a case of a high-degree advanced atrioventricular block (AVB), which occurred 24 hours after successful primary percutaneous coronary intervention (PCI) in the proximal left anterior descending coronary artery (LAD), the culprit of ST-segment elevation myocardial infarction (STEMI). The methylergometrine provocation test for coronary vasospasms, which was performed on the eighth hospital day, revealed transient total occlusion of the first septal perforator branch. After prescribing a calcium channel blocker to the patient, AVB did not recur for three years, as confirmed using an implantable loop recorder (ILR). In this patient, delayed high-grade AVB following primary PCI in the proximal LAD might be caused by the spasm of the first septal perforator branch. Documented cases of spasms in this branch are rare.

Multicentre open label randomised controlled trial of immediate enhanced ambulatory ECG monitoring versus standard monitoring in acute unexplained syncope patients: the ASPIRED study

INTRODUCTION

Diagnosing underlying arrhythmia in emergency department (ED) syncope patients is difficult. There is a evidence that diagnostic yield for detecting underlying arrhythmia is highest when cardiac monitoring devices are applied early, ideally at the index visit. This strategy has the potential to change current syncope management from low diagnostic yield Holter to higher yield ambulatory monitoring, reduce episodes of syncope, reduce risk of recurrence and its potential serious consequences, reduce hospital admissions, reduce overall health costs and increase quality of life by allowing earlier diagnosis, treatment and exclusion of clinically important arrhythmias.

METHODS AND ANALYSES

This is a UK open prospective parallel group multicentre randomised controlled trial of an immediate 14-day ambulatory patch heart monitor vs standard care in 2234 patients presenting acutely with unexplained syncope. Our patient focused primary endpoint will be number of episodes of syncope at 1 year. Health economic evaluation will estimate the incremental cost per syncope episode avoided and quality-adjusted life year gained.

ETHICS AND DISSEMINATION

Informed consent for participation will be sought. The ASPIRED trial received a favourable ethical opinion from South East Scotland Research Ethics Committee 01 (21/SS/0073). Results will be disseminated via scientific publication, lay summary and visual abstract.

TRIAL REGISTRATION NUMBER

ISRCTN 10278811.

Remote Monitoring of Cardiac Implantable Electronic Devices: What is the Evidence?

PURPOSE OF REVIEW

This review offers an overview of the evidence in diagnostic and therapeutic applications of remote monitoring implantable devices.

RECENT FINDINGS

Remote monitoring of cardiac implantable devices has become more and more popular in recent years as healthcare is moving towards a more patient centralized system. For heart failure patients with an ICD or pacemaker, there is controversial evidence regarding improvements in the clinical outcome, e.g., reduction of hospitalization rates or overall mortality. New developments as hemodynamic remote monitoring via measurement of the pulmonary artery pressure are promising technical achievements showing encouraging results. In cardiac remote monitoring of syncope and arrhythmias, implantable loop recorder plays an important role in diagnostic algorithms. Although there is controversial evidence according to remote monitoring of implantable devices, its use is rapidly expanding, giving healthcare providers the opportunity to react promptly to worsening of their patients. Adequate evaluation of the data created by remote monitoring systems remains an unsolved challenge of contemporary healthcare services.

An implantable loop recorder or smartphone based single-lead electrocardiogram to detect arrhythmia in adults with congenital heart disease?

Background

The European Society of Cardiology (ESC) guidelines for the management of adult congenital heart disease (ACHD) recommend screening in patients at risk for arrhythmic events. However, the optimal mode of detection is unknown.

Methods

Baseline and follow-up data of symptomatic ACHD patients who received an implantable loop recorder (ILR) or who participated in a smartphone based single-lead electrocardiogram study were collected. The primary endpoint was time to first detected arrhythmia.

Results

In total 116 ACHD patients (mean age 42 years, 44% male) were studied. The ILR group (n = 23) differed from the smartphone based single-lead electrocardiogram group (n = 93) in having a greater part of males and had more severe CHD and (near) syncope as qualifying diagnosis. In the smartphone based single-lead electrocardiogram group history of arrhythmia and palpitations were more frequent (all p < 0.05). Monitoring was performed for 40 and 79 patient-years for the ILR- and smartphone based single-lead electrocardiogram group, respectively. Arrhythmias occurred in 33 patients with an equal median time for both groups to first arrhythmia of 3 months (HR of 0.7, p = 0.81). Furthermore, atrial fibrillation occurred most often (n = 16) and common therapy changes included medication changes (n = 7) and implantation of pacemaker or Implantable Cardioverter Defibrillator (ICD) (N = 4). Symptoms or mode of detection were not a determinant of the first event.

Conclusion

Non-invasive smartphone based single-lead electrocardiogram monitoring could be an acceptable alternative for ILR implantation in detecting arrhythmia in symptomatic ACHD patients in respect to diagnostic yield, safety and management decisions, especially in those without syncope.

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.

Diagnostic value of implantable loop recorders in patients with unexplained syncope or palpitations

Background

The implantable loop recorder (ILR) is a small cardiac rhythm‐monitoring device. Our aim was to determine ILR diagnostic value in patients with unexplained syncope, presyncope, or palpitations suggesting cardiac arrhythmias.

Methods

This has been a retrospective, observational, single‐center study. We included 181 patients in whom ILR was implanted at the Clinical Center of Serbia between January 2006 and July 2019. An event was marked as diagnostic if it led to a diagnosis and ILR was considered diagnostic if it verified or excluded an arrhythmia as the cause of syncope or palpitations.

Results

The mean age was 51.8 ± 17.8 years and 94 (51.9%) were male. The mean follow‐up period was 20.2 ± 15.8 months. ILR was diagnostic in 98 patients (54.1%). There was no significant difference in diagnostic value of ILR in regard to the baseline patients’ characteristics. The mean time to occurrence of the diagnostic event was 11.1 ± 9.6 months. The time to occurrence of a diagnostic event did not differ significantly between patients who underwent basic as compared to extended diagnostics before ILR implantation.

Conclusions

ILR was able to achieve an etiological diagnosis in 54.1% of patients with unexplained syncope, presyncope, or palpitations suggesting cardiac arrhythmias. In a subgroup of patients with recurrent palpitations, ILR was significantly less diagnostic than in patients with syncope or presyncope. ILR should be implanted beforehand in syncope evaluation process.

Cardiac Implantable Electronic Miniaturized and Micro Devices

Advancement in the miniaturization of high-density power sources, electronic circuits, and communication technologies enabled the construction of miniaturized electronic devices, implanted directly in the heart. These include pacing devices to prevent low heart rates or terminate heart rhythm abnormalities ('arrhythmias'), long-term rhythm monitoring devices for arrhythmia detection in unexplained syncope cases, and heart failure (HF) hemodynamic monitoring devices, enabling the real-time monitoring of cardiac pressures to detect and alert for early fluid overload. These devices were shown to prevent HF hospitalizations and improve HF patients' life quality. Pacing devices include permanent pacemakers (PPM) that maintain normal heart rates, defibrillators that are capable of fast detection and the termination of life-threatening arrhythmias, and cardiac re-synchronization devices that improve cardiac function and the survival of HF patients. Traditionally, these devices are implanted via the venous system ('endovascular') using conductors ('endovascular leads/electrodes') that connect the subcutaneous device battery to the appropriate cardiac chamber. These leads are a potential source of multiple problems, including lead-failure and systemic infection resulting from the lifelong exposure of these leads to bacteria within the venous system. One of the important cardiac innovations in the last decade was the development of a leadless PPM functioning without venous leads, thus circumventing most endovascular PPM-related problems. Leadless PPM's consist of a single device, including a miniaturized power source, electronic chips, and fixating mechanism, directly implanted into the cardiac muscle. Only rare device-related problems and almost no systemic infections occur with these devices. Current leadless PPM's sense and pace only the ventricle. However, a novel leadless device that is capable of sensing both atrium and ventricle was recently FDA approved and miniaturized devices that are designed to synchronize right and left ventricles, using novel intra-body inner-device communication technologies, are under final experiments. This review will cover these novel implantable miniaturized cardiac devices and the basic algorithms and technologies that underlie their development. Advancement in the miniaturization of high-density power sources, electronic circuits, and communication technologies enabled the construction of miniaturized electronic devices, implanted directly in the heart. These include pacing devices to prevent low heart rates or terminate heart rhythm abnormalities ('arrhythmias'), long-term rhythm monitoring devices for arrhythmia detection in unexplained syncope cases, and heart failure (HF) hemodynamic monitoring devices, enabling the real-time monitoring of cardiac pressures to detect and alert early fluid overload. These devices were shown to prevent HF hospitalizations and improve HF patients' life quality. Pacing devices include permanent pacemakers (PPM) that maintain normal heart rates, defibrillators that are capable of fast detection and termination of life-threatening arrhythmias, and cardiac re-synchronization devices that improve cardiac function and survival of HF patients. Traditionally, these devices are implanted via the venous system ('endovascular') using conductors ('endovascular leads/electrodes') that connect the subcutaneous device battery to the appropriate cardiac chamber. These leads are a potential source of multiple problems, including lead-failure and systemic infection that result from the lifelong exposure of these leads to bacteria within the venous system. The development of a leadless PPM functioning without venous leads was one of the important cardiac innovations in the last decade, thus circumventing most endovascular PPM-related problems. Leadless PPM's consist of a single device, including a miniaturized power source, electronic chips, and fixating mechanism, implanted directly into the cardiac muscle. Only rare device-related problems and almost no systemic infections occur with these devices. Current leadless PPM's sense and pace only the ventricle. However, a novel leadless device that is capable of sensing both atrium and ventricle was recently FDA approved and miniaturized devices designed to synchronize right and left ventricles, using novel intra-body inner-device communication technologies, are under final experiments. This review will cover these novel implantable miniaturized cardiac devices and the basic algorithms and technologies that underlie their development.

Implantable loop recorder in clinical practice

The implantable loop recorder (ILR), also known as insertable cardiac monitor (ICM) is a subcutaneous device used for diagnosing heart rhythm disorders. These devices have been strongly improved and miniaturized during the last years showing several reliable features along with the availability of remote monitoring which improves the diagnostic timing and the follow-up strategy with a potential reduction of costs for health care. The recent advent of injectable ILRs makes the procedure even easier and more tolerated by patients. ILR allows the investigation of unexplained recurrent syncope with uncertain diagnosis, revealing a possible relationship with cardiac arrhythmias. In addition, it has recently been equipped with sophisticated algorithms able to detect atrial fibrillation episodes. This new opportunity may provide to the physicians systematic heart rhythm screening with possible effects on patient antiarrhythmic and anticoagulant therapy management. The use of such devices will surely increase, since they may be helpful to diagnose a wide range of disorders and pathologies. Indeed, further studies should be performed in order to identify all the potentialities of these tools.

[Indications for loop recorder implantation for syncope]

Implantable loop recorder with discontinuous ECG recording enables monitoring of heart rhythm over several years. Consequently, in patients with recurrent syncope it is possible to record an ECG during the next syncopal event to obtain symptom-ECG correlations. In patients with recurrent syncope of unknown origin, the implantation of a loop recorder leads to an earlier diagnosis and an asystole is more often detected as the cause of the recurrent syncope. In addition, the loop recorder identifies patients who will benefit from pacemaker implantation. An established indication for early implantation of a loop recorder is given in patients with recurrent syncope and no high-risk marker, e. g., reduced left ventricular function, valve disease, history of myocardial infarction or ECG findings such as bifascicular block, pre-excitation, long QT syndrome or an epsilon wave. These patients should receive a complete cardiological work-up with the aim of detecting the underlying heart disease. Patients with no conclusive findings should also receive a loop recorder. A relative indication is given for patients with recurrent syncope and injuries in order to predict the effect of pacemaker implantation. Possible indication is given for patients with transient loss of consciousness to rule out an arrhythmogenic origin.

Use of implantable and external loop recorders in syncope with unknown causes

The gold standard for diagnosing syncope is to elucidate the symptom-electrocardiogram (ECG) correlation. The ECG recordings during syncope allow physicians to either confirm or exclude an arrhythmia as the mechanism of syncope. Many studies have investigated the use of internal loop recorder (ILR), while few studies have used external loop recorder (ELR) for patients with unexplained syncope. The aim of this review is to clarify the clinical usefulness of ILR and ELR in the diagnosis and management of patients with unexplained syncope. Many observational and four randomized control studies have shown that ILR for patients with unknown syncope is a useful tool for early diagnosis and improving diagnosis rate. ILR also provides important information on the mechanism of syncope and treatment strategy. However, there is no evidence of total mortality or quality of life improvements with ILR. The diagnostic yield of ELR in patients with syncope was similar to that with ILR within the same timeframe. Therefore, ELR could be considered for long-term ECG monitoring before a patient switches to using ILR. A systematic approach and selection of ECG monitoring tools reduces health care costs and improves the selection of patients for optimal treatment possibilities.

Management of Bradyarrhythmias in Heart Failure: A Tailored Approach

Patients with heart failure (HF) may develop a range of bradyarrhythmias including sinus node dysfunction, various degrees of atrioventricular block, and ventricular conduction delay. Device implantation has been recommended in these patients, but the specific etiology should be sought as it may influence the choice of the type of device required (pacemaker vs. implantable cardiac defibrillator). Also, pacing mode must be carefully set in patients with heart failure (HF) and left ventricular systolic dysfunction.In this chapter, we summarize the knowledge required for a tailored approach to bradyarrhythmias in patients with heart failure.

[Implantable loop recorders in the diagnosis of syncope]

In syncope patients, it is essential to make the right diagnosis with respect to underlying etiology. Cardiac (arrhythmic and structural) syncopal episodes carry untoward prognostic implication compared with reflex syncope. While rhythm-symptom correlation of a spontaneous syncopal episode is key to making the correct diagnosis, in case of unclear syncope the early implantation of a loop recorder leads to faster, more efficacious, and more cost-effective diagnosis. This review article summarizes the current data regarding diagnostic accuracy and clinical role of implantable loop recorders. It outlines the superiority of loop recorders in the management of unclear syncope according to present knowledge.

[Implantable loop recorder BioMonitor 2 (Biotronik)]

The implantable loop recorder BioMonitor 2 is available with an emphasis on syncope and one on detection of atrial tachycardias. The BioMonitor 2 can be easily implanted. The BioMonitor 2 pilot study showed a high and over time stable signal and the telemetric performance was above average.