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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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Device patients may require upgrade interventions from simpler to more complex cardiac implantable electronic devices. Prior to upgrading interventions, clinicians need to balance the risks and benefits of transvenous lead extraction (TLE), additional lead implantation or lead abandonment. However, evidence on procedural outcomes of TLE at the time of device upgrade is scarce. Methods: This is a post hoc analysis of the investigator-initiated multicenter Swiss TLE registry. The objectives were to assess patient and procedural factors influencing TLE outcomes at the time of device upgrades. Results: 941 patients were included, whereof 83 (8.8%) had TLE due to a device upgrade. Rotational mechanical sheaths were more often used in upgraded patients (59% vs. 42.7%, p = 0.015) and total median procedure time was longer in these patients (160 min vs. 105 min, p < 0.001). Clinical success rates of upgraded patients compared to those who received TLE due to other reasons were not different (97.6% vs. 93.0%, p = 0.569). Moreover, multivariable analysis showed that upgrade procedures were not associated with a greater risk for complications (HR 0.48, 95% confidence interval 0.14–1.57, p = 0.224; intraprocedural complication rate of upgraded patients 7.2% vs. 5.5%). Intraprocedural complications of upgraded patients were mostly associated with the implantation and not the extraction procedure (67% vs. 33% of complications). Conclusions: TLE during device upgrade is effective and does not attribute a disproportionate risk to the upgrade procedure. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: A pace and ablate strategy may be performed in refractory atrial fibrillation with rapid ventricular response. Objective: We aimed to assess sex-related differences in patient selection and clinical outcomes after pace and ablate. Methods: In a retrospective multicentre study, patients undergoing AV junction ablation were studied. Sex-related differences in baseline characteristics, all-cause mortality, heart failure (HF) hospitalizations, and device-related complications were assessed. Results: Overall, 513 patients underwent AV junction ablation (median age 75 years, 50% men). At baseline, men were younger (72 vs. 78 years, p < 0.001), more frequently had non-paroxysmal AF (82% vs. 72%, p = 0.006), had a lower LVEF (35% vs. 55%, p < 0.001) and more frequently had cardiac resynchronization therapy (75% vs. 25%, p < 0.001). Interventional complications were rare in both groups (1.2% vs. 1.6%, p = 0.72). Patients were followed for a median of 42 months in survivors (IQR 22–62). After 4 years of follow-up, the combined endpoint of all-cause death or HF hospitalization occurred more often in men (38% vs. 27%, p = 0.008). The same was observed for HF hospitalizations (22% vs. 11%, p = 0.021) and all-cause death (28% vs. 21%, p = 0.017). Sex category remained an independent predictor of death or HF hospitalization after adjustment for age, LVEF and type of stimulation. Lead-related complications, infections, and upgrade to ICD or CRT occurred in 2.1%, 0.2% and 3.5% of patients, respectively. Conclusions: Pace and ablate is safe with a need for subsequent device-related re-interventions in 5.8% over 4 years. We found significant sex-related differences in patient selection, and women had a more favourable clinical course after AV junction ablation. [ABSTRACT FROM AUTHOR]

A new approach for the design of electronic beam steering arrays with reactive parasitic elements is introduced. The method is demonstrated at the example of a circular array formed by capacitively tuned monopoles. The related capacitances are determined straightforwardly and without any need for optimization techniques. The resulting beams are rotatable and maintain their gain and beamwidth within tight margins. Comparisons with NEC2 verify the pattern calculation. Index Terms--Beam steering, circular arrays, parasitic antennas, phased arrays.