Incidence, implications, and management of sense-B-noise failure in subcutaneous cardioverter-defibrillator patients: insights from a large multicentre registry.

AIMS: Subcutaneous implantable cardioverter-defibrillators (S-ICDs) offer potentially distinct advantages over transvenous defibrillator systems. Recent randomized trials showed significantly lower lead failure rates than transvenous ICD. Still, S-ICDs remain associated with the risk of inappropriate shocks (IAS). While previous studies have reported varying causes of IAS, this study explores a rare cause of IAS, referred to as 'sense-B-noise.' It was recently described in case series, but its incidence has not been studied in a large cohort of S-ICD patients. METHODS AND RESULTS: We retrospectively reviewed data from patients implanted with S-ICD models 1010, A209, and A219 between October 2009 and July 2023 across nine centres in Europe and the USA. The analysis concentrated on determining the incidence and understanding the implications of sense-B-noise events. Sense-B-noise represents a rare manifestation of distinct electrogram abnormalities within the primary and alternate sensing vectors. Data were collected from medical records, device telemetry, and manufacturer reports for investigation. This registry is registered on clinicaltrials.gov (NCT05713708). Subcutaneous implantable cardioverter-defibrillator devices of the 1158 patients were analysed. The median follow-up time for all patients was 46 (IQR 23-64) months. In 107 patients (9.2%) ≥1 IAS was observed during follow-up. Sense-B-noise failure was diagnosed in six (0.5 and 5.6% of all IAS) patients, in all patients, the diagnosis was made after an IAS episode. Median lead dwell time in the affected patients was 23 (2-70) months. To resolve the sense-B-noise defect, in three patients reprogramming to the secondary vector was undertaken, and two patients underwent system removal with subsequent S-ICD reimplantation due to low amplitude in the secondary vector. In one patient, the secondary vector was initially programmed, and subsequently, an S-ICD system exchange was performed due to T-wave-oversensing IAS episodes. CONCLUSION: This multicentre analysis' findings shed light on a rare but clinically highly significant adverse event in S-ICD therapy. To our knowledge, we provide the first systematic multicentre analysis investigating the incidence of sense-B-noise. Due to being difficult to diagnose and limited options for resolution, management of sense-B-noise is challenging. Complete system exchange may be the only option for some patients. Educating healthcare providers involved in S-ICD patient care is crucial for ensuring accurate diagnosis and effective management of sense-B-noise issues.

Occurrence of premature battery depletion in a large multicentre registry of subcutaneous cardioverter-defibrillator patients.

AIMS: Subcutaneous implantable cardioverter-defibrillators (S-ICDs) have become established in preventing sudden cardiac death, with some advantages over transvenous defibrillator systems, including a lower incidence of lead failures. Despite technological advancements, S-ICD carriers may suffer from significant complications, such as premature battery depletion (PBD), that led to an advisory for nearly 40 000 patients. This multicentre study evaluated the incidence of PBD in a large set of S-ICD patients. METHODS AND RESULTS: Data from patients implanted with S-ICD models A209 and A219 between October 2012 and July 2023 across nine centres in Europe and the USA were reviewed. Incidence and implications of PBD, defined as clinically observed sudden drop in battery longevity, were analysed and compared to PBD with the definition of battery depletion within 60 months. Prospectively collected clinical data were obtained retrospectively from medical records, device telemetry, and manufacturer reports. This registry is listed on ClinicalTrials.gov (NCT05713708). Of the 1112 S-ICD devices analysed, 547 (49.2%) were equipped with a potentially affected capacitor linked to PBD occurrence, currently under Food and Drug Administration advisory. The median follow-up time for all patients was 46 [inter-quartile range (IQR) 24-63] months. Clinically suspected PBD was observed in 159 (29.1%) of cases, with a median time to generator removal or replacement of 65 (IQR 55-72) months, indicative of significant deviations from expected battery lifespan. Manufacturer confirmation of PBD was made in 91.7% of devices returned for analysis. No cases of PBD were observed in devices that were not under advisory. CONCLUSION: This manufacturer-independent analysis highlights a notable incidence of PBD in patients equipped with S-ICD models under advisory, and the rate of PBD in this study corresponds to the rate currently estimated by the manufacturer. To the best of our knowledge, this provides the largest contemporary peer-reviewed study cohort investigating the actual incidence of PBD in S-ICD patients. These findings emphasize the importance of post-market registries in collaboration between clinicians and the manufacturer to optimize safety and efficacy in S-ICD treatment.

Ventricular pacing burden in patients with left bundle branch block after transcatheter aortic valve replacement therapy.

INTRODUCTION: Electrophysiological testing has been proposed in the latest European Society of Cardiology (ESC) guidelines for cardiac pacing to identify left bundle branch block (LBBB) patients with infrahisian conduction delay (IHCD) after transcatheter aortic valve replacement (TAVR). While in general IHCD is defined by a His-ventricular (HV) interval of >55 ms, a cut-off of ≥70 ms to trigger pacemaker (PM) implantation has been proposed in the latest ESC guidelines. The ventricular pacing (VP) burden during follow-up in such patients is largely unknown. As such, we aimed to assess the VP burden during follow-up of patients receiving PM therapy for LBBB after TAVR based on an HV interval > 55 ms and ≥70 ms. METHODS: All patients with new-onset or pre-existing LBBB after undergoing TAVR at a tertiary referral center underwent EP testing the day after TAVR. In patients with a prolonged HV interval (>55 ms), PM implantation was performed by a trained electrophysiologist in a standardized fashion. All devices were programmed to avoid unnecessary VP by specific algorithms (e.g., AAI-DDD). RESULTS: 701 patients underwent TAVR at the University Hospital of Basel. One hundred seventy-seven patients presented with new-onset or pre-existing LBBB the day following TAVR and underwent EP testing. An HV interval > 55 ms was found in 58 patients (33%) and an HV interval ≥ 70 ms in 21 patients (12%). 51 patients (mean age 84 ± 6.2 years, 45% women) agreed to receive a PM, out of which 20 (39%) patients had an HV Interval over 70 ms. Atrial fibrillation was present in 53% of the patients. A dual chamber PM was implanted in 39 (77%), and a single chamber PC in 12 (23%) patients, respectively. Median follow-up was 21 months. The median VP burden overall was 3%. The median VP burden was not significantly different between patients with an HV ≥ 70 ms (6.5 [0.8-52]) and those with an HV between 55 and 69 ms (2 [0-17], p = .23). 31% of patients demonstrated a VP burden < 1%, 27% 1%-5% and 41% > 5%. The median HV intervals in patients with VP burdens < 1%, 1%-5% and >5% were 66 (IQR 62-70) ms, 66 (IQR 63-74) ms and 68 (IQR 60-72) ms, respectively, p = .52. When only assessing patients with an HV interval 55-69 ms, 36% demonstrated a VP burden of <1%, 29% of 1%-5% and 35% of >5%. In patients with an HV Interval ≥ 70 ms, 25% demonstrated a VP burden < 1%, 25% of 1%-5% and 50% of >5% %, p = .64 (Figure). CONCLUSION: In patients with LBBB after TAVR and IHCD defined by an HV interval > 55 ms, VP burden is relevant in a non-negligible amount of patients during follow-up. Further studies are warranted to define the optimal cut-off value for the HV interval or to develop risk models incorporating HV measurements and other risk factors to trigger PM implantation in patients with LBBB after TAVR.

Sense-B-noise: an enigmatic cause for inappropriate shocks in subcutaneous implantable cardioverter defibrillators.

AIMS: Subcutaneous implantable cardioverter defibrillators (S-ICDs) are well established. However, inappropriate shocks (IAS) remain a source of concern since S-ICDs offer very limited troubleshooting options. In our multicentre case series, we describe several patients who experienced IAS due to a previously unknown S-ICD system issue. METHODS AND RESULTS: We observed six patients suffering from this novel IAS entity. The IAS occurred exclusively in primary or alternate S-ICD sensing vector configuration (therefore called 'Sense-B-noise'). IAS were caused by non-physiologic oversensing episodes characterized by intermittent signal saturation, diminished QRS amplitudes, and disappearance of the artefacts after the IAS. Noise/oversensing could not be provoked by manipulation, X-ray did not show evidence for lead/header issues and impedance measurements were within normal limits. The pooled experience of our centres implies that up to ∼5% of S-ICDs may be affected. The underlying root cause was discussed extensively with the manufacturer but remains unknown and is under further investigation. CONCLUSION: Sense-B-noise is a novel cause for IAS due to non-physiologic signal oversensing, arising from a previously unknown S-ICD system issue. Sense-B-noise may be suspected if episodes of signal saturation in primary or alternate vector configuration are present, oversensing cannot be provoked, and X-ray and electrical measurements appear normal. The issue can be resolved by reprogramming the device to secondary sensing vector.

Atrial substrate characterization based on bipolar voltage electrograms acquired with multipolar, focal and mini-electrode catheters.

BACKGROUND: Bipolar voltage (BV) electrograms for left atrial (LA) substrate characterization depend on catheter design and electrode configuration. AIMS: The aim of the study was to investigate the relationship between the BV amplitude (BVA) using four catheters with different electrode design and to identify their specific LA cutoffs for scar and healthy tissue. METHODS AND RESULTS: Consecutive high-resolution electroanatomic mapping was performed using a multipolar-minielectrode Orion catheter (Orion-map), a duo-decapolar circular mapping catheter (Lasso-map), and an irrigated focal ablation catheter with minielectrodes (Mifi-map). Virtual remapping using the Mifi-map was performed with a 4.5 mm tip-size electrode configuration (Nav-map). BVAs were compared in voxels of 3 × 3 × 3 mm3. The equivalent BVA cutoff for every catheter was calculated for established reference cutoff values of 0.1, 0.2, 0.5, 1.0, and 1.5 mV. We analyzed 25 patients (72% men, age 68 ± 15 years). For scar tissue, a 0.5 mV cutoff using the Nav corresponds to a lower cutoff of 0.35 mV for the Orion and of 0.48 mV for the Lasso. Accordingly, a 0.2 mV cutoff corresponds to a cutoff of 0.09 mV for the Orion and of 0.14 mV for the Lasso. For healthy tissue cutoff at 1.5 mV, a larger BVA cutoff for the small electrodes of the Orion and the Lasso was determined of 1.68 and 2.21 mV, respectively. CONCLUSION: When measuring LA BVA, significant differences were seen between focal, multielectrode, and minielectrode catheters. Adapted cutoffs for scar and healthy tissue are required for different catheters.

Reassessment of clinical variables in cardiac resynchronization defibrillator patients at the time of first replacement: Death after replacement of CRT (DARC) score.

INTRODUCTION: Cardiac resynchronization defibrillator (CRT-D) as primary prevention is known to reduce mortality. At the time of replacement, higher age and comorbidities may attenuate the benefit of implantable cardioverter-defibrillator (ICD) therapy. The purpose of this study was to evaluate the progression of comorbidities after implantation and their association with mortality following CRT-D generator replacement. In addition, a risk score was developed to identify patients at high risk for mortality after replacement. METHODS AND RESULTS: We identified patients implanted with a primary prevention CRT-D (n = 648) who subsequently underwent elective generator replacement (n = 218) from two prospective ICD registries. The cohort consisted of 218 patients (median age: 70 years, male gender: 73%, mean left ventricular ejection fraction [LVEF]: 36 ± 11% at replacement). Median follow-up after the replacement was 4.2 years during which 64 patients (29%) died and 11 patients (5%) received appropriate ICD shocks. An increase in comorbidities was observed in 77 patients (35%). The 5-year mortality rate was 41% in patients with ≥2 comorbidities at the time of replacement. A risk score incorporating age, gender, LVEF, atrial fibrillation, anemia, chronic kidney disease, and history of appropriate ICD shocks at time of replacement accurately predicted 5-year mortality (C-statistic 0.829). Patients with a risk score of greater than 2.5 had excess mortality at 5-year postreplacement compared with patients with a risk score less than 1.5 (57% vs. 6%; p < .001). CONCLUSION: A simple risk score accurately predicts 5-year mortality after replacement in CRT-D patients, as patients with a risk score of greater than 2.5 are at high risk of dying despite ICD protection.

Man vs machine: Performance of manual vs automated electrocardiogram analysis for predicting the chamber of origin of idiopathic ventricular arrhythmia.

BACKGROUND: Radiofrequency catheter ablation of idiopathic ventricular arrhythmias (VAs) is performed to eliminate symptoms and to prevent or reverse arrhythmia-induced cardiomyopathy. Preprocedural prediction of the chamber of VA origin is critical for patient counseling, procedure planning, and guidance of invasive mapping. OBJECTIVE: We aimed to assess the performance of manual expert versus automated 12-lead electrocardiogram (ECG) analysis in the prediction of VA origin. METHODS: Patients with ablation of idiopathic VA and sustained success were included. The VA origin was defined as the site where ablation caused arrhythmia suppression. Standard baseline 12-lead ECGs with documentation of the VA were analyzed manually in a blinded fashion by three electrophysiologists and three electrophysiology (EP) fellows. In addition, the same standard 12-lead ECG was analyzed by an automated computer algorithm using a vectorcardiographic approach. RESULTS: Thirty-eight patients (median age, 47 [interquartile range, 37-58]; 68% female) were enrolled. The VA originated from the right ventricle in 24 (63%) and the left ventricle in 14 (37%) patients. The electrophysiologists and EP fellows identified the VA chamber of origin with a similar accuracy of 73% and 72% (P = .72). The automated algorithm showed a higher accuracy of 89% (P = .03 compared with electrophysiologists and EP fellows). This resulted in a sensitivity of 95% and specificity of 86%. CONCLUSION: While the manual ECG analysis of the standard 12-lead ECG by both electrophysiologists and EP fellows correctly identified the chamber of VA origin in around 75% of cases, an automated vectorcardiographic computer algorithm achieved an accuracy of 89% with clinically acceptable diagnostic parameters.

Leadless pacemaker implantation quality: importance of the operator's experience.

AIMS: Leadless cardiac pacemaker (PM) implantation differs from conventional PM implantation. While the procedure has been considered safe, recent real-world data raised concerns about the learning curve of new operators and their implantation quality. The goal of this study was to investigate the influence of the first operator's experience on leadless PM implantation quality and procedural efficiency. METHODS AND RESULTS: We performed a bicentric analysis of all Micra TPS™ implantations in two large tertiary referral hospitals. We assessed both leadless PM implantation quality based on the absence of complications (requiring intervention or prolonged hospitalization), good electrical performance (pacing threshold ≤ 1.5 V/0.24 ms, R-wave amplitude > 5 mV), and acceptable fluoroscopy duration (<10 min) as well as procedural efficiency in relation to the operator's experience. Univariate and multivariate logistic regression analyses were performed to identify predictors for implantation quality and procedural efficiency. Leadless PM implantation was successful in 106/111 cases (95.5%). Three patients (2.7%) experienced acute complications (one cardiac tamponade, one femoral bleeding, one posture-related PM exit block). Multivariate analysis showed that implantation quality of more experienced first operators was higher [odds ratio 1.09 (95% confidence interval 1.00-1.19), P = 0.05]. Procedural efficiency increased with operator experience as evidenced by an inverse correlation of procedure time, time to the first deployment, fluoroscopy time, and the number of procedures performed (all P < 0.05). CONCLUSION: The operator's learning curve is a critical factor for leadless PM implantation quality and procedural efficiency.

Predicting Early Mortality Among Implantable Defibrillator Patients Treated With Cardiac Resynchronization Therapy.

BACKGROUND: The beneficial effects of a cardiac resynchronization defibrillator (CRT-D) in patients with heart failure, low left ventricular ejection fraction (LVEF), and wide QRS have clearly been established. Nevertheless, mortality remains high in some patients. The aim of this study was to develop and validate a risk score to identify patients at high risk for early mortality who are implanted with a CRT-D. METHODS AND RESULTS: For predictive modelling, 1282 consecutive patients from 5 centers (74% male; median age 66 years; median LVEF 25%; New York Heart Association class III-IV 60%; median QRS-width 160 ms) were randomly divided into a derivation and validation cohort. The primary endpoint is mortality at 3 years. Model development was performed using multivariate logistic regression by checking log likelihood, Akaike information criterion, and Bayesian information criterion. Model performance was validated using C statistics and calibration plots. The risk score included 7 independent mortality predictors, including myocardial infarction, LVEF, QRS duration, chronic obstructive pulmonary disease, chronic kidney disease, hyponatremia, and anemia. Calibration-in-the-large was suboptimal, reflected by a lower observed mortality (44%) than predicted (50%). The validated C statistic was 0.71 indicating modest performance. CONCLUSION: A risk score based on routine, readily available clinical variables can assist in identifying patients at high risk for early mortality within 3 years after CRT-D implantation.

Ablation of typical atrial flutter guided by the paced PR interval on the surface electrocardiogram: a proof of concept study.

AIMS: We aimed to assess the novel concept of using the paced PR interval (PRI) on the surface electrocardiogram (ECG) to prove trans-isthmus block after cavotricuspid isthmus (CTI) ablation for typical atrial flutter (AFl). METHODS AND RESULTS: Consecutive patients with AFl underwent linear radiofrequency ablation of the inferior CTI (6 o'clock). After AFl termination and/or presumed completion of the CTI line, CTI block was proven by atrial pacing by the ablation catheter medial (5 o'clock) and lateral to the line (7 and 9 o'clock). Corresponding PRIs were measured on the surface ECG. CTI block was assumed, if a sudden increase in the PRI was observed by moving the pacing site from 5 to 7 o'clock, and if the latter was longer than at 9 o'clock. Afterwards, bidirectional CTI block was confirmed by differential pacing. Thirty-one patients (mean age 67 ± 16 years, 81% male) underwent CTI ablation, and 18/31 (58%) were in AFl at the time of ablation (cycle length 249 ± 31 ms). Successful CTI block as defined by the PRI method was achieved in 31/31 (100%), and the mean PRIs during pacing at 5, 7, and 9 o'clock were 203 ± 56 ms, 329 ± 70 ms, and 296 ± 66 ms, respectively. Cavotricuspid isthmus block was confirmed in all patients (100%) by coronary sinus pacing with a reversal of the local activation sequence lateral to the isthmus line. CONCLUSION: The method of PRI analysis on the surface ECG to guide CTI ablation is easy to apply and highly accurate in confirming CTI block. This simple technique enables the novel concept of CTI ablation and proof of block with a single catheter.

Out-of-hospital cardiac arrest due to idiopathic ventricular fibrillation in patients with normal electrocardiograms: results from a multicentre long-term registry.

AIMS: To define the clinical characteristics and long-term clinical outcomes of a large cohort of patients with idiopathic ventricular fibrillation (IVF) and normal 12-lead electrocardiograms (ECGs). METHODS AND RESULTS: Patients with ventricular fibrillation as the presenting rhythm, normal baseline, and follow-up ECGs with no signs of cardiac channelopathy including early repolarization or atrioventricular conduction abnormalities, and without structural heart disease were included in a registry. A total of 245 patients (median age: 38 years; males 59%) were recruited from 25 centres. An implantable cardioverter-defibrillator (ICD) was implanted in 226 patients (92%), while 18 patients (8%) were treated with drug therapy only. Over a median follow-up of 63 months (interquartile range: 25-110 months), 12 patients died (5%); in four of them (1.6%) the lethal event was of cardiac origin. Patients treated with antiarrhythmic drugs only had a higher rate of cardiovascular death compared to patients who received an ICD (16% vs. 0.4%, P = 0.001). Fifty-two patients (21%) experienced an arrhythmic recurrence. Age ≤16 years at the time of the first ventricular arrhythmia was the only predictor of arrhythmic recurrence on multivariable analysis [hazard ratio (HR) 0.41, 95% confidence interval (CI) 0.18-0.92; P = 0.03]. CONCLUSION: Patients with IVF and persistently normal ECGs frequently have arrhythmic recurrences, but a good prognosis when treated with an ICD. Children are a category of IVF patients at higher risk of arrhythmic recurrences.

Arrhythmic episodes in patients implanted with a cardioverter-defibrillator - results from the Prospective Study on Predictive Quality with Preferencing PainFree ATP therapies (4P).

BACKGROUND: Little is known about the ICD performance using enhanced detection algorithms in unselected, non-trial patients. Performance of recent generation ICD equipped with SmartShock™ technology (SST) for detection and conversion of ventricular tachyarrhythmias (VTA) was investigated. METHODS: 4P was a prospective, multicenter, observational study conducted in 10 Swiss implanting centers. Patients with a Class I indication according to international guidelines were included and received an ICD with SST. ICD discrimination capability was assessed by evaluating SST performance; therapy efficacy was assessed by rate of VTA conversions by ATP and by rescue shocks. RESULTS: Overall, 196 patients were included in the analysis with a mean duration of follow-up of 27.7 months (452 patient-years of observation). Patient-specific rather than recommended programming was preferred. Device-detected episodes were frequent (5147 episodes in 146 patients, 74.5%). In 44 patients (22.4%), 1274 episodes were categorized as VTA; only 215 episodes were symptomatic. ATP was the first-line therapy and highly effective (99.9% success rate at the episode level, 100.0% at the patient level). Rescue shocks were rare (66 episodes in 28 patients); 7 shocks in 5 patients (2.6%) were inappropriate. Death and hospitalization rates were low. CONCLUSIONS: In a cohort of non-trial, unselected ICD patients, VTA episodes were frequent. The 4P results confirm the robustness of VTA detection by SST and the effectiveness of ATP treatment, hence limiting overall ICD shock burden.

The Medtronic Sprint Fidelis® lead history revisited-Extended follow-up of passive leads.

BACKGROUND: Due to high failure rates, Medtronic withdrew the Sprint Fidelis lead (SFL) from the market. Passive fixation lead models exhibited better survival than active models, but most studies have limited follow-up. Aim of this study was to give insights into passive lead survival with a follow-up of 10 years. METHODS: In two large Swiss centers, patients with passive SFLs were identified and data from routine implantable cardioverter defibrillator (ICD) follow-ups were collected. Patients were censored at time of death, last device interrogation (if lost to follow-up), time of lead revision (in non-SFL-related problems), or at database closure (31th December 2017). We defined lead failure as any of the following: lead fracture with inappropriate discharge; sudden increase in low-voltage impedance to >1500 or high-voltage impedance to >100 Ω; >300 nonphysiological short VV-intervals. RESULTS: We identified 145 patients. Age at implant was 60 ± 12 years with a median follow-up of 10.2 (interquartile range [IQR]: 5.0-11.2) years. Thirty-five percent of patients died after 5.4 ± 2.7 years. A total of 19 leads (13%) failed after 6.7 ± 3.2 years (range: 1.2-12.0). Overt malfunction with shocks existed in four patients (3%). Cumulative lead survival was 93.1% at 6, 88.2% at 8, 83.8% at 10, and 77.6% at 11 years, respectively, with 35% of implanted leads under monitoring at 10 years. Lead survival fits best a Weibull distribution with accelerating failure rates (k = 1.95, 95% CI 1.32-2.87, P < 0.001). CONCLUSIONS: During very long-term follow-up, failure rate of the passive SFL shows an increase resulting in an impaired lead survival of 84% at 10 years.

Battery longevity of implantable cardioverter-defibrillators and cardiac resynchronization therapy defibrillators: technical, clinical and economic aspects. An expert review paper from EHRA.

In recent years an extension of devices longevity has been obtained for implantable cardioverter-defibrillators (ICDs), including ICDs for cardiac resynchronization therapy (CRT-D) through improved battery chemistry and device technology and this implies important clinical benefits (reduced need for device replacements and associated complications, particularly infections), as well as economic benefits, in line with patient preferences and needs. From a clinical point of view, the availability of this improvement in technology allows to better tune the choice of the device to be implanted, taking into account that the reasons supporting the value of an extended device longevity as a clinical priority may differ according to the clinical setting (purely electrical diseases or left ventricular dysfunction/heart failure, respectively). From an economic point of view, extension of device longevity may have an important impact in reducing long-term costs of device therapy, with substantial daily savings in favour of devices with extended longevity, up to 30%, depending on clinical scenarios. In studies based on projections, an extension of device longevity allowed to calculate that the cost per day of ICDs may be substantially reduced, and this allows to overcome the frequent perception of ICD and CRT-D devices as treatments with unaffordable costs and to overturn the misconception that up-front costs are the only metric with which to value device treatments. In view of its clinical and economic value, device longevity should be a determining factor in device choice by physicians and healthcare commissioners and should be appropriately considered and valued in comparative tenders.

Sex differences in outcomes of primary prevention implantable cardioverter-defibrillator therapy: combined registry data from eleven European countries.

Aims: Therapy with an implantable cardioverter defibrillator (ICD) is established for the prevention of sudden cardiac death (SCD) in high risk patients. We aimed to determine the effectiveness of primary prevention ICD therapy by analysing registry data from 14 centres in 11 European countries compiled between 2002 and 2014, with emphasis on outcomes in women who have been underrepresented in all trials. Methods and results: Retrospective data of 14 local registries of primary prevention ICD implantations between 2002 and 2014 were compiled in a central database. Predefined primary outcome measures were overall mortality and first appropriate and first inappropriate shocks. A multivariable model enforcing a common hazard ratio for sex category across the centres, but allowing for centre-specific baseline hazards and centre specific effects of other covariates, was adjusted for age, the presence of ischaemic cardiomyopathy or a CRT-D, and left ventricular ejection fraction ≤25%. Of the 5033 patients, 957 (19%) were women. During a median follow-up of 33 months (IQR 16-55 months) 129 women (13%) and 807 men (20%) died (HR 0.65; 95% CI: [0.53, 0.79], P-value < 0.0001). An appropriate ICD shock occurred in 66 women (8%) and 514 men (14%; HR 0.61; 95% CI: 0.47-0.79; P = 0.0002). Conclusion: Our retrospective analysis of 14 local registries in 11 European countries demonstrates that fewer women than men undergo ICD implantation for primary prevention. After multivariate adjustment, women have a significantly lower mortality and receive fewer appropriate ICD shocks.

Atrial electrogram quality in single-pass defibrillator leads with floating atrial bipole in patients with permanent atrial fibrillation and cardiac resynchronization therapy.

Many patients receiving cardiac resynchronization therapy (CRT) suffer from permanent atrial fibrillation (AF). Knowledge of the atrial rhythm is important to direct pharmacological or interventional treatment as well as maintaining AV-synchronous biventricular pacing if sinus rhythm can be restored. A single pass single-coil defibrillator lead with a floating atrial bipole has been shown to obtain reliable information about the atrial rhythm but has never been employed in a CRT-system. The purpose of this study was to assess the feasibility of implanting a single coil right ventricular ICD lead with a floating atrial bipole and the signal quality of atrial electrograms (AEGM) in CRT-defibrillator recipients with permanent AF. METHODS AND RESULTS: Seventeen patients (16 males, mean age 73 ±â€¯6 years, mean EF 25 ±â€¯5%) with permanent AF and an indication for CRT-defibrillator placement were implanted with a designated CRT-D system comprising a single pass defibrillator lead with a atrial floating bipole. They were followed-up for 103 ±â€¯22 days using remote monitoring for AEGM transmission. All patients had at last one AEGM suitable for atrial rhythm diagnosis and of 100 AEGM 99% were suitable for visual atrial rhythm assessment. Four patients were discharged in sinus rhythm and one reverted to AF during follow-up. CONCLUSION: Atrial electrograms retrieved from a single-pass defibrillator lead with a floating atrial bipole can be reliably used for atrial rhythm diagnosis in CRT recipients with permanent AF. Hence, a single pass ventricular defibrillator lead with a floating bipole can be considered in this population.

Reliability of luminal oesophageal temperature monitoring during radiofrequency ablation of atrial fibrillation: insights from probe visualization and oesophageal reconstruction using magnetic resonance imaging.

AIMS: A current concept to prevent atrio-oesophageal fistula during radiofrequency (RF) catheter ablation of atrial fibrillation is to monitor luminal oesophageal temperature (LET). The objective of this study was to describe the temporal course of LET and to assess the reliability of monitoring the maximal LET during pulmonary vein isolation (PVI) using irrigated multi-electrode (IMEA, nMARQTM) and focal ablation catheters. METHODS AND RESULTS: We studied 40 patients with LET monitoring during PVI (20 patients using the IMEA and 20 patients using the focal catheter). A linear probe was used and visualized in the 3D mapping system. Left atrial and oesophageal reconstructions from delayed enhanced magnetic resonance imaging were integrated. Analysing 745 temperature profiles, LET >38°C was observed in 48 of 296 (17%) and 44 of 449 (10%) ablations for the IMEA and the focal catheter, respectively (P = 0.012). Temporal latency after interruption of RF energy delivery was observed for both catheters. Time until LET baseline temperature was restored after an increase of >1°C was 100 and 86 s for the IMEA and the focal catheter, respectively (P = 0.183). Imprecise representation of the maximal LET was observed in 24 (60%) and 28 patients (70%) for the left and right PVs, respectively. CONCLUSION: Due to the unknown exact lateral position of the LET probe within the oesophagus, the measured temperature does not necessarily reflect the maximal LET. The absence of LET increase does not rule out significant temperature increase within the oesophagus. Consequently, the temperature information of the linear multipolar probe should be used with caution.

Case report: electrical storm during induced hypothermia in a patient with early repolarization.

BACKGROUND: Population based studies showed an association of early repolarization in the electrocardiogram (ECG) and a higher rate of sudden cardiac death presumably due to ventricular fibrillation. The triggers for ventricular fibrillation in patients with early repolarization are not fully understood. CASE PRESENTATION: We describe the case of a young patient with a survived ventricular fibrillation arrest while asleep followed by multiple episodes of recurrent ventricular fibrillation. The admission ECG showed an early repolarization pattern with substantial J-point elevation in most of the ECG-leads. After initiation of a hypothermia protocol, the patient developed an electrical storm with multiple ventricular fibrillation episodes requiring multiple cardioversions. Intravenous isoproterenol infusion successfully suppressed the malignant arrhythmia. CONCLUSION: Hypothermia appears proarrhythmic in patients with early repolarization and may trigger ventricular fibrillation. This knowledge is particularly important when initiating temperature management protocols in patients after a survived cardiac arrest. During the acute phase of an early repolarization associated electrical storm, isoproterenol is the most effective treatment suppressing the ventricular fibrillation-inducing premature ventricular complexes at higher heart rates.

The patient perspective on remote monitoring of patients with an implantable cardioverter defibrillator: Narrative review and future directions.

BACKGROUND: Studies have shown that remote patient monitoring (RPM) of implantable cardioverter defibrillators (ICDs) is at least comparable to in-clinic follow-up with regard to clinical outcomes and might be cost-effective, yet RPM is not standard clinical practice within Europe. Better insight into the patient perspective on RPM may aid in its acceptance, implementation, and reimbursement. This narrative review (1) summarizes existing evidence on the impact of RPM on patient-reported outcomes and (2) discusses future directions in examining the patient perspective. METHODS AND RESULTS: Literature review indicated that only five randomized trials on RPM in ICD patients included patient-reported outcomes, with inconclusive results. Observational studies show a trend toward good patient satisfaction and acceptation of RPM. Yet, results should be interpreted with caution due to a number of limitations including a potential selection bias, use of generic/nonvalidated questionnaires, relatively short follow-up durations, and a lack of subgroup identification. CONCLUSION: Although RPM seems to be safe, effective, timely, and efficient, the patient perspective has received little attention so far. The scarce evidence on patient-reported outcomes in RPM studies seems to be positive, but future trials with a follow-up of ≥12 months and validated patient-reported outcome measures are needed. The REMOTE-CIED study from our group is the first prospective randomized controlled trial primarily designed to examine the patient perspective on RPM, and is powered to identify characteristics associated with RPM satisfaction and benefit. Results are expected in 2018 and will add valuable information to the current evidence.

Incidence of and predictors for appropriate implantable cardioverter-defibrillator therapy in patients with a secondary preventive implantable cardioverter-defibrillator indication.

AIMS: Incidence of implantable cardioverter-defibrillator (ICD) therapy in secondary prevention has been assessed in randomized trials and registries. However, results are considerably limited by short follow-up and hazy definition of treated arrhythmias. This study aimed to determine appropriate ICD therapy and to define predictors based on registry patients followed for up to 20 years. METHODS AND RESULTS: All patients with a secondary prevention indication and ischaemic or dilated cardiomyopathy were identified. Arrhythmic endpoints were appropriate ICD therapies for any ventricular tachycardia (VT) >175 b.p.m. and appropriate ICD therapies in the ventricular fibrillation (VF) zone of >220 b.p.m. (potentially life-threatening). Predictors were determined by analysing 19 baseline characteristics. We included 357 patients, age 65 ± 11 years, predominantly male (89%) with ischaemic cardiomyopathy (83%). During follow-up of 82 ± 53 months, 156 (44%) patients died and 208 received any form of ICD therapies (59%), 71 of them (34%) in the VF zone. Forty-four patients (28%) died without experiencing any form of appropriate ICD therapy. Cumulative incidence of any form of ICD therapy at 10 years was 65%. Predictors for any form of ICD therapy were implantation for VT and age [VT: hazard ratio (HR) 1.45, 95% confidence interval (95% CI) 1.05-2.01, P = 0.03; age (per year): HR 1.02, 95% CI 1.01-1.04, P = 0.001]. For therapy in the VF zone, univariate analysis determined male gender (29 vs. 5%, P = 0.01) as predictor. CONCLUSION: The rate of appropriate ICD therapies in secondary prevention is high. No useful predictors for them, especially not for life-threatening arrhythmias could be identified.