Underwent Implantable Loop Recorders Implantation Research Articles

THE CASE OF THE MIGRATING LOOP RECORDER

Implantable loop recorders (ILR) have been increasingly utilized for the evaluation as well as the diagnosis of unexplained palpitations or syncope. A 36 year old male underwent ILR implantation by his cardiologist one week prior to presenting to the ED complaining of left chest and flank pain. The

Efficacy And Safety Of Implantable Loop Recorder: Experience Of A Center.

Introduction: Symptoms like syncope or palpitations frequently present a diagnostic challenge. An implantable loop recorder (ILR) is an important aid in the management of these patients. Methods: A retrospective study of patients that underwent ILR implantation from November 2007 to 2014. For each patient the indication for implantation, baseline characteristics, previous study, complications, recorded tracing and interventions were evaluated. Results: A total of 62 patients were included, 50% men, with a mean age of 62.5±18.8 years old. Previously to ILR implantation 88.7% of patients had performed Holter, 17.7% external events recorder, 33.9% Tilt test and 29% an electrophysiological study. The implantation indications were recurrent syncope in 90.3%, palpitations 8.1% and ischemic stroke in one patient. Mean follow-up time was 17.1±16.3 months. Symptoms were reported in 66.1% of the patients, 46.8% of those yielding a diagnostic finding. In all cases of palpitation complaints with diagnosis we found atrial fibrillation (AF). In patients with syncope atrioventricular conduction disturbance was demonstrated in 19.6%, sinus node dysfunction in 16.1%, paroxysmal supra-ventricular tachycardia 7.1% and AF in 1.8%. These finding resulted in 19 pacemaker and one CRT-D implantation, introduction of anticoagulation in five patients and one ablation of accessory pathway. There were no major complications. Conclusion: ILR proved to be safe and efficient. It has enabled the identification or exclusion of serious rhythm disturbances in more than half of patients and provided a targeted therapeutic intervention.

Implantable loop recorder versus conventional diagnostic workup for unexplained recurrent syncope.

The most recent syncope guideline recommends that implantable loop recorders (ILRs) are implanted in the early phase of evaluation of people with recurrent syncope of uncertain origin in the absence of high-risk criteria, and in high-risk patients after a negative evaluation. Observational and case-control studies have shown that loop recorders lead to earlier diagnosis and reduce the rate of unexplained syncopes, justifying their use in clinical practice. However, only randomised clinical trials with an emphasis on a primary outcome of specific ILR-guided diagnosis and therapy, rather than simply electrocardiogram (ECG) diagnosis, might change clinical practice. To assess the incidence of mortality, quality of life, adverse events and costs of ILRs versus conventional diagnostic workup in people with unexplained syncope. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 3, 2015), MEDLINE, EMBASE, ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) Search Portal in April 2015. No language restriction was applied. We included all randomised controlled trials of adult participants (i.e. ≥ 18 years old) with a diagnosis of unexplained syncope comparing ILR with standard diagnostic workup. Two independent review authors screened titles and abstracts of all potential studies we identified as a result of the literature search, extracted study characteristics and outcome data from included studies and assessed risk of bias for each study using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions. We contacted authors of trials for missing data. We analysed dichotomous data (all-cause mortality and aetiologic diagnosis) as risk ratios (RR) with 95% confidence intervals (CI). We used the Chi(2) test to assess statistical heterogeneity (with P < 0.1) and the I² statistic to measure heterogeneity among the trials. We created a 'Summary of findings' table using the five GRADE considerations (study limitations, consistency of effect, imprecision, indirectness and publication bias) to assess the quality of a body of evidence as it relates to the studies which contribute data to the meta-analyses for the prespecified outcomes. We included four trials involving a total of 579 participants. With the limitation that only two studies reported data on mortality and none of them had considered death as a primary endpoint, the meta-analysis showed no evidence of a difference in the risk of long-term mortality between participants who received ILR and those who were managed conventionally at follow-up (RR 0.97, 95% CI 0.41 to 2.30; participants = 255; studies = 2; very low quality evidence) with no evidence of heterogeneity. No data on short term mortality were available. Two studies reported data on adverse events after ILR implant. Due to the lack of data on adverse events in one of the studies' arms, a formal meta-analysis was not performed for this outcome.Data from two trials seemed to show no difference in quality of life, although this finding was not supported by a formal analysis due to the differences in both the scores used and the way the data were reported. Data from two studies seemed to show a trend towards a reduction in syncope relapses after diagnosis in participants implanted with ILR. Cost analyses from two studies showed higher overall mean costs in the ILR group, if the costs incurred by the ILR implant were counted. The mean cost per diagnosis and the mean cost per arrhythmic diagnosis were lower for participants randomised to ILR implant.Participants who underwent ILR implantation experienced higher rates of diagnosis (RR (in favour of ILR) 0.61, 95% CI 0.54 to 0.68; participants = 579; studies = 4; moderate quality evidence), as compared to participants in the standard assessment group, with no evidence of heterogeneity. Our systematic review shows that there is no evidence that an ILR-based diagnostic strategy reduces long-term mortality as compared to a standard diagnostic assessment (very low quality evidence). No data were available for short-term all-cause mortality. Moderate quality evidence shows that an ILR-based diagnostic strategy increases the rate of aetiologic diagnosis as compared to a standard diagnostic pathway. No conclusive data were available on the other end-points analysed.Further trials evaluating the effect of ILRs in the diagnostic strategy of people with recurrent unexplained syncope are warranted. Future research should focus on the assessment of the ability of ILRs to change clinically relevant outcomes, such as quality of life, syncope relapse and costs.

Evolución a largo plazo de pacientes ancianos con síncope de etiología desconocida: utilidad de los registradores de eventos implantables

BackgroundSyncope in older people remains a diagnostic challenge due to its high prevalence and recurrence rate. Implantable loop recorders (ILR) have been established in recent guidelines as the cornerstone of unexplained syncope diagnosis, but its usefulness in older people, where syncope tends to be multifactorial in origin, remains poorly defined. Herein we review our experience with ILR in identifying the etiology of recurrent unexplained syncope in older patients after conventional management in a Syncope Unit. MethodsConsecutive patients >75years who underwent ILR implantation in our center due to unexplained syncope after complete evaluation were included. Results75 patients (26 male, mean age 79.8±3.2years) with unexplained syncope (3.7±2.3 mean syncope episodes) were included. After mean implant period of 15.5±11.6 months, 32 patients (42.6%) experienced syncope recurrence with diagnostic ILR registry. Arrhythmic causes were identified in 20 cases (AV block 8, sinus pauses/ventricular asystole 10, tachyarrhythmia 2). There were no sudden deaths during monitorization time nor in long term follow up after ILR explantation (median 48.4months, IC rank 17.9-62.5); 2 patients underwent pacemaker implantation due to complete AV block after non-diagnostic ILR. ConclusionOur results confirm usefulness and safety of ILR in diagnosis of unexplained syncope in elderly people. A significant proportion of patients had arrhythmic cause, mostly bradycardias, although neuromediated origin counts for up to 37.5%.

Demographic and Clinical Characteristics to Predict Paroxysmal Atrial Fibrillation: Insights from an Implantable Loop Recorder Population.

There is growing interest in detecting paroxysmal atrial fibrillation (PAF) to identify patients at high risk of thromboembolic stroke. The implantable loop recorder (ILR) is emerging as a powerful new tool in the diagnosis of PAF. Widespread implantation has significant cost implications and their use must be targeted at those patients at most risk. We retrospectively studied a population of 200 adult patients who underwent ILR implantation for the investigation of syncope or palpitations. Clinical data, baseline electrocardiogram (ECG) characteristics, and echocardiographic data were collected. All ECGs and electrograms (EGMs) were scrutinized by two blinded investigators. PAF incidence was defined as episodes lasting >30 seconds on EGMs recorded in ILR memory. Our ILR population consists of 200 patients, 111 (56%) male, with a mean age of 61.4 years (range 19-95). PAF was detected in 42 patients. The following factors were significant predictors of PAF by multivariate logistic regression analysis: cigarette smoking (odds ratio [OR] = 3.73, 95% confidence interval [CI] = 1.40-10.24, P = 0.009) and incomplete right bundle branch block (IRBBB; OR = 9.04, 95% CI = 2.51-34.64, P = 0.00088). Significant differences included incidence of IRBBB (P = 0.012), cigarette smoking (P = 0.026), hypercholesterolemia (P = 0.015), age (P = 0.002), estimated glomerular filtration rate (P = 0.031), left atrial volume (P = 0.019), and PR interval (P = 0.031). The PAF group had significantly higher CHA2 DS2 -VASc scores (P = 0.01). Our study reports predictive factors for PAF in an ILR population. We suggest that cigarette smoking and IRBBB are independently associated with paroxysmal AF in patients presenting with palpitations or syncope.

Clinical Predictors of Pacemaker Implantation in Patients with Syncope Receiving Implantable Loop Recorder with or without ECG Conduction Abnormalities

Implantable loop recorders (ILR) allow prolonged cardiac rhythm monitoring and improved diagnostic yield in syncope patients. Predictive factors for pacemaker (PM) implantation in the ILR population with unexplained syncope have not been adequately investigated. In this single center, retrospective, observational study we investigated factors that predict PM implantation in this population. We retrospectively analyzed our ILR database of patients aged over 18 years who underwent ILR implantation for unexplained syncope between January 2009 and June 2013. Patient case notes were examined for demographics, history, electrocardiogram (ECG) abnormalities, investigations, and events during follow-up. The primary end-point was the detection of a symptomatic or asymptomatic bradycardia requiring PM implantation. During a period of 4.5 years, 200 patients were implanted with ILR for unexplained syncope, of who n = 33 (16.5%) had clinically significant bradycardia requiring PM implantation. After multivariable analysis, history of injury secondary to syncope was found to be the strongest independent predictor for PM implantation (odds ratio [OR]:9.1; P < 0.001; 95% confidence interval [CI]: (3.26-26.81). Other significant predictors included female sex, PR interval > 200msec, and age >75 years. In patients without conduction abnormalities on the ECG, history of injury secondary to syncope was found to be the strongest independent predictor for PM implantation (OR: 8.16; P = 0.00027; 95% [CI]: (2.67-26.27). A history of injury secondary to syncope and female sex were independent predictive factors for bradycardia necessitating PM implantation in patients receiving an ILR for syncope with or without ECG conduction abnormalities.

Initial real world experience with a novel insertable (Reveal LinQ™@Medtronic) compared to the conventional (Reveal XT™@Medtronic) implantable loop recorder at a tertiary care center — Points to ponder!

IntroductionLimited data is available regarding the novel Reveal LinQ™ (LinQ) which is a new generation implantable loop recorders (ILRs). MethodsWe performed a prospective, observational study of all consecutive patients undergoing conventional (Reveal XT™; XT) and LinQ devices at our institution between January 2012 and December 2014. ResultsA total of 217 patients underwent ILR implantation. XT was implanted in 105 and LinQ in 112 patients. There were no significant differences in baseline characteristics between the two groups. LinQ implantation using the manufacturer's technique termed, “manufacturer's method” group had significantly higher incidence of pocket infection compared to XT (6/50, 12% vs 3/105, 3%, p=0.032). With modifications to the LinQ implantation technique (using a conventional scalpel and placing a suture when needed to the incision) termed “modified method” group, the rate of infection has decreased significantly compared to “manufacturer's method group” (0/62, 0% vs 6/50, 12%, p=0.004) (Table 3). In multivariate regression analysis, the only independent predictors of infection were younger age (OR 0.95; p=0.04), insertion of LinQ device (OR 30.02; p=0.006) and procedure time (OR 1.07; p=0.03). ConclusionIn our single-center, prospective, observational study we found that with the current implantable techniques, the novel insertable LinQ device is associated with increased risk of complications.

Predictive factors for pacemaker implantation in patients receiving an implantable loop recorder for syncope remained unexplained after an extensive cardiac and neurological workup

Several previous implantable loop recorder (ILR) studies have shown bradyarrhythmic events requiring a pacemaker implantation in a significant proportion of patients with unexplained syncope (US). The aim of this observational, two-centre, study was to identify the predictive factors for pacemaker implantation in a population of patients receiving an ILR for US with suspected arrhythmic aetiology. Fifty-six patients (mean age 68 years, 61% male) with a history of US and negative cardiac and neurological workup, who underwent ILR implantation, were enrolled. After the implantation, a follow-up visit was undertaken after symptomatic events or every 3 months in asymptomatic subjects. The end-point of the study was the detection of a bradyarrhythmia (with or without a syncopal recurrence) requiring pacemaker implantation. After a median ILR observation of 22 months, a clinically significant bradyarrhythmia was detected in 11 patients (20%), of which 9 cases related to syncopal relapses. In the multivariable analysis, three independent predictive factors for pacemaker implantation were identified: an age >75 years (odd ratio [OR]: 29.9; p=0.035); a history of trauma secondary to syncope (OR: 26.8; p=0.039); and the detection of periods of asymptomatic bradycardia, not sufficient to explain the mechanism of syncope, during conventional ECG monitoring (through 24 h Holter or in hospital telemetry), performed before ILR implantation (OR: 24.7; p=0.045). An advanced age, a history of trauma secondary to syncope, and the detection of periods of asymptomatic bradycardia during conventional ECG monitoring were independent predictive factors for bradyarrhythmias requiring pacemaker implantation in patients receiving an ILR for US.

Diagnostic Yield of Implantable Loop Recorders in Patients with Unexplained Syncope

of patients in sinus rhythm at one and two year follow up. These results are comparable to international reports. Follow up at 12 months Follow up at ≥24 months Total (n= 65) Paroxysmal AF (n= 37) Nonparoxysmal AF (n= 28) Total (n= 36) Paroxysmal AF (n= 20) Nonparoxysmal AF (n= 16) Success without drugs Single procedure (%) 53.8 56.8 50.0 50.0 55.0 43.8 Success with or without drugs Single procedure (%) 58.5 59.5 57.1 50.0 55.0 43.8 Success without drugs ≥1 procedure (%) 69.2 67.6 71.4 69.4 70.0 68.8 Success with or without drugs ≥1 procedure (%) 89.2 91.9 85.7 86.1 90.0 81.3 http://dx.doi.org/10.1016/j.hlc.2012.03.098 Diagnostic Yield of Implantable Loop Recorders in Patients with Unexplained Syncope J. Swampillai ∗, R.F. Allen, S. Levings, M.R.Webber, C.M. Wade, M.K. Stiles, S.C. Heald Department of Cardiology, Waikato Hospital, Hamilton, New Zealand Background: The implantable loop recorder (ILR) is a subcutaneous, electrocardiographic monitoring device used for diagnosis in patients with recurrent, infrequent Use of Exercise Tolerance Test in Intermediate Risk nonST Elevation Acute Coronary Syndrome P. Tamuno ∗, J. Mazhar, J. Swampillai, V. Pera, A. Kerr, G. Devlin Department of Cardiology, Waikato Hospital, Hamilton, New Zealand Background: Exercise tolerance test (ETT) is recommended for initial risk stratification in patients with Non ST Elevation Acute Coronary Syndrome (NSTEACS) in the absence of high risk features. We reviewed current practice at Waikato Hospital, the regional tertiary centre. Methods:FromtheACUTEPREDICTregistrywe identified 716 patients admitted with NSTEACS and TIMI score 0–4 between January 2008 and January 2010. After excluding143patientswhoweremanagedmedically (20%)due to co-morbidities, the remaining 573 patients were analysed in two groups: Group A had ETT prior to angiography; Group B had angiography without ETT. Results: There were 244 (43%) patients in Group A (mean age 64± 12 years, 72% males) and 329 (57%) in Group B (mean age 64± 13 years, 66% males). Compared togroupA,GroupBhadmorepatientswithTIMI score 3–4 (63%vs. 53%,P= 0.02) andNSTEMI (66%vs. 44%,P≤ 0.01). Results are summarised in the tables below. Only 20% of patients risk-stratified by ETT did not undergo inpatient angiography (Tables 1 and 2). symptoms with a suspected arrhythmic aetiology. We aimed to establish the diagnostic yield of ILR in patients with unexplained syncope. Methods: We identified all patients who had an ILR implanted at Waikato Hospital from March 2007 to November 2011. Previous investigations, arrhythmias detected by the device and outcomes were recorded. Results: Thirty-one patients (17 men; mean age 46± 24 years) underwent ILR implantation. The mean number of cardiac investigations prior to ILR was 4± 1; duration of implant 16± 12 months. Arrhythmias were detected in 13 patients; eight tachycardias, five bradycardias. Time to diagnosis was 7± 6 months and specific treatment was guided by ILR analysis in these patients. Pacemakers were implanted in four patients, two received implantable cardioverter defibrillators, two were given anti-arrhythmic drugs, four had an electrophysiological study (two were normal and two underwent catheter ablation). Neurocardiogenic syncope was diagnosed in one patient and symptoms resolved. Sinus rhythm was documented during syncope in five patients. Death from non-arrhythmic causes occurred in twopatients (onemyocardial infarction and cardiogenic shock, one stroke). No arrhythmias have been detected so far in 11 patients remaining under follow up (mean implant duration 9± 7 months). Conclusion: More than half of patients had an arrhythmic causeof syncopediagnosed (13) or excluded (5) by ILR. This confirms their usefulness in selected patients with unexplained syncope despite normal preliminary investigations. http://dx.doi.org/10.1016/j.hlc.2012.03.099 Table 1. Summary of coronary interventions and outcomes. Group A N= 244 Group B N= 329 P value Inpatient angiogram 195 (80%) 329 (100%) <0.01 PCI 109 (45%) 180 (55%) 0.02 CABG 23 (9%) 24 (7%) NS Length of stay in days (mean±SD) 6.8± 6 6.1± 5 0.09 Stroke/TIA (in-hospital) 0 3 Death (in-hospital) 1 1 Table 2. Angiograms performed in relation to ETT results. Positive ETT N= 167 (68%) Negative ETT N= 42 (18%) Inconclusive ETT N= 35 (14%) In-patient angiogram, N (%) 159 (95%) 10 (24%) 26 (74%) Angiogram in 6-month F/U, N (%) 6 (4%) 7 (17%) 2 (6%) Conclusions: The majority of patients admitted with NSTEACS and TIMI score ≤4 underwent inpatient angiography regardless of the use of ETT as a risk stratification tool for intermediate risk scores. No difference was evident in early events. http://dx.doi.org/10.1016/j.hlc.2012.03.100

A retrospective study of the clinical experience of the implantable loop recorder in a paediatric setting

The implantable loop recorder (ILR) has proved highly efficacious in the management of syncope, presyncope and palpitations in selected populations. Limited information regarding patient selection and diagnostic yield exists in the paediatric setting. A retrospective evaluation of patients who underwent ILR implantation over a 66-month period, in a tertiary paediatric cardiology unit was conducted. Twenty-three patients (10 male, 13 female) following initial assessment and investigation, were referred for device implantation. The mean age at time of ILR insertion was 11.39 +/- 4.34 (range, 2.0-16.8) years. The indications for ILR were recurrent syncope (n = 11), presyncope (n = 3) or palpitations (n = 9). Four (17.4%) patients had structural heart disease, three (13%) had a positive family history of sudden cardiac death and one (4%) had perinatal arrhythmia. One patient required ILR repositioning, and pocket infection necessitated explantation in one further patient. Minimum follow-up was 7.8 months during which symptoms were reported in 15 (65.2%) patients post-ILR insertion. Eight (34.7%) remained asymptomatic. Of the 15 who experienced symptom recurrence, eight (53.3%) had an arrhythmia recorded. Tachycardias recorded were polymorphic ventricular tachycardia (n = 1) and supraventricular tachycardia (n = 5). Clinically significant bradycardias documented, included sinus arrest (n = 1) and Mobitz type II second degree atrioventricular block (n = 1). The ILR had a high diagnostic yield, enabling an arrhythmic or non-arrhythmic diagnosis in 65.2% of patients with recurrent syncope, presyncope or palpitations in a selected paediatric population.

Comparison of automatic and patient-activated arrhythmia recordings by implantable loop recorders in the evaluation of syncope

The implantable loop recorder (ILR) has become an important tool for evaluating patients with recurrent syncope. Second generation ILRs have the ability to record events either automatically (auto activated) or by manual activation (patient activated). In an attempt to evaluate the relative utility of the auto-activation feature, this study stratified ILR events based on a grading system designed to classify detected arrhythmias in terms of the likelihood that they provide a diagnostic basis for syncope. Data from 50 patients (27 men, mean age 64 ± 22 years) who underwent ILR implantation for investigation of recurrent syncope were assessed. The arrhythmia syncope grading system used 5 levels, ranging from grade 0 (rhythm recorded during syncope) to grade IV (rhythm unlikely to provide a diagnostic basis for syncope). Thirty-six patients (72%) demonstrated ≥1 auto-activated or patient-activated recording during a follow-up of 14.3 ± 7.9 months. Of the total of 529 recordings, 223 (194 after auto activation [86.9%]) from 30 patients showed a rhythm abnormality. Auto activation was more effective for documenting arrhythmias that were recorded during syncope or those with highest probability of providing a syncope diagnosis (grade 0 or I arrhythmias: auto activated, 19 patients, patient activated, 3 patients). Times from ILR implantation to first grade 0 and grade I arrhythmias were 13.4 and 7.8 months, respectively. The ILR auto-activation feature proved effective in providing a high probability basis for syncope (196 arrhythmia recordings [87.1%] in 27 patients) and enhanced the diagnostic effectiveness of the device compared with patient activation alone (29 arrhythmia recordings [12.9%] in 6 patients).