Predictors of ventricular tachyarrhythmia in patients with a wearable cardioverter defibrillator: an international multicenter registry.

BACKGROUND AND AIMS: Wearable cardioverter defibrillator (WCD) can protect patients from sudden cardiac death due to ventricular tachyarrhythmias and serve as a bridge to decision of definite defibrillator implantation. The aim of this analysis from an international, multicenter WCD registry was to identify predictors of sustained ventricular tachycardia (VT) and/or ventricular fibrillation (VF) in this population. METHODS: One thousand six hundred seventy-five patients with WCD were included in a multicenter registry from 9 European centers, with a median follow-up of 440 days (IQR 120-893). The primary study end point was the occurrence of sustained VT/VF. RESULTS: Sustained VT was detected by WCD in 5.4% and VF in 0.9% of all patients. Of the 30.3% of patients receiving ICD implantation during follow-up, sustained VT was recorded in 9.3% and VF in 2.6%. Non-ischemic cardiomyopathy (HR 0.5, p < 0.001), and medication with angiotensin-converting enzyme inhibitors (HR 0.7, p = 0.027) and aldosterone antagonists (HR 0.7, p = 0.005) were associated with a significantly lower risk of VT/VF. CONCLUSIONS: Patients who received WCD due to a transient increased risk of sudden cardiac death have a comparatively lower risk of VT/VF in the presence of non-ischemic cardiomyopathy. Of note, optimal medical treatment for heart failure not only results in an improvement in left ventricular ejection fraction but also in a reduction in the risk for VT/VF.

Use of the Wearable Cardioverter-Defibrillator Among Patients With Myocarditis and Reduced Ejection Fraction or Ventricular Tachyarrhythmia: Data From a Multicenter Registry.

Background Data on the use of the wearable cardioverter-defibrillator (WCD) among patients with myocarditis remain sparse. Consequently, evidence for guideline recommendations in this patient population is lacking. Methods and Results In total, 1596 consecutive patients were included in a multicenter registry from 8 European centers, with 124 patients (8%) having received the WCD due to myocarditis and reduced left ventricular ejection fraction or prior ventricular tachyarrhythmia. The mean age was 51.6±16.3 years, with 74% being male. Patients were discharged after index hospitalization on heart failure medication: Angiotensin-converting enzyme inhibitors (62.5%), angiotensin-receptor-neprilysin inhibitor (22.9%), aldosterone-antagonists (51%), or beta blockers (91.4%). The initial median left ventricular ejection fraction was 30% (22%-45%) and increased to 48% (39%-55%) over long-term follow-up (P<0.001). The median BNP (brain natriuretic peptide) level at baseline was 1702 pg/mL (565-3748) and decreased to 188 pg/mL (26-348) over long-term follow-up (P=0.022). The mean wear time was 79.7±52.1 days and 21.0±4.9 hours per day. Arrhythmic event rates documented by the WCD were 9.7% for nonsustained ventricular tachycardia, 6.5% for sustained ventricular tachycardia, and 0% for ventricular fibrillation. Subsequently, 2.4% of patients experienced an appropriate WCD shock. The rate of inappropriate WCD shocks was 0.8%. All 3 patients with appropriate WCD shock had experienced ventricular tachycardia/ventricular fibrillation before WCD prescription, with only 1 patient showing a left ventricular ejection fraction <35%. Conclusions Patients with myocarditis and risk for occurrence of ventricular tachyarrhythmia may benefit from WCD use. Prior ventricular arrhythmia might appear as a better risk predictor than a reduced left ventricular ejection fraction <35% in this population.

A worldwide survey on incidence, management, and prognosis of oesophageal fistula formation following atrial fibrillation catheter ablation: the POTTER-AF study.

AIMS: Oesophageal fistula represents a rare but dreadful complication of atrial fibrillation catheter ablation. Data on its incidence, management, and outcome are sparse. METHODS AND RESULTS: This international multicentre registry investigates the characteristics of oesophageal fistulae after treatment of atrial fibrillation by catheter ablation. A total of 553 729 catheter ablation procedures (radiofrequency: 62.9%, cryoballoon: 36.2%, other modalities: 0.9%) were performed, at 214 centres in 35 countries. In 78 centres 138 patients [0.025%, radiofrequency: 0.038%, cryoballoon: 0.0015% (P < 0.0001)] were diagnosed with an oesophageal fistula. Peri-procedural data were available for 118 patients (85.5%). Following catheter ablation, the median time to symptoms and the median time to diagnosis were 18 (7.75, 25; range: 0-60) days and 21 (15, 29.5; range: 2-63) days, respectively. The median time from symptom onset to oesophageal fistula diagnosis was 3 (1, 9; range: 0-42) days. The most common initial symptom was fever (59.3%). The diagnosis was established by chest computed tomography in 80.2% of patients. Oesophageal surgery was performed in 47.4% and direct endoscopic treatment in 19.8% and conservative treatment in 32.8% of patients. The overall mortality was 65.8%. Mortality following surgical (51.9%) or endoscopic treatment (56.5%) was significantly lower as compared to conservative management (89.5%) [odds ratio 7.463 (2.414, 23.072) P < 0.001]. CONCLUSION: Oesophageal fistula after catheter ablation of atrial fibrillation is rare and occurs mostly with the use of radiofrequency energy rather than cryoenergy. Mortality without surgical or endoscopic intervention is exceedingly high.

Age differences of patients treated with wearable cardioverter defibrillator: Data from a multicentre registry.

BACKGROUND: Wearable cardioverter defibrillators (WCD) are used as a 'bridging' technology in patients, who are temporarily at high risk for sudden cardiac death (SCD). Several factors should be taken into consideration, for example patient selection, compliance and optimal drug treatment, when WCD is prescribed. We aimed to present real-world data from seven centres from Germany and Switzerland according to age differences regarding the outcome, prognosis, WCD data and compliance. MATERIALS AND METHODS: Between 04/2012 and 03/2021, 1105 patients were included in this registry. Outcome data according to age differences (old ≥45 years compared to young <45 years) were analysed. At young age, WCDs were more often prescribed due to congenital heart disease and myocarditis. On the other hand, ischaemic cardiomyopathy (ICM) was more present in older patients. Wear days of WCD were similar between both groups (p = .115). In addition, during the WCD use, documented arrhythmic life-threatening events were comparable [sustained ventricular tachycardia: 5.8% vs. 7.7%, ventricular fibrillation (VF) .5% vs. .6%] and consequently the rate of appropriate shocks was similar between both groups. Left ventricular ejection fraction improvement was documented over follow-up with a better improvement in younger patients as compared to older patients (77% vs. 63%, p = .002). In addition, at baseline, the rate of atrial fibrillation was significantly higher in the older age group (23% vs. 8%; p = .001). The rate of permanent cardiac implantable electronic device implantation (CiED) was lower in the younger group (25% vs. 36%, p = .05). The compliance rate defined as wearing WCD at least 20 h per day was significantly lower in young patients compared to old patients (68.9% vs. 80.9%, p < .001). During the follow-up, no significant difference regarding all-cause mortality or arrhythmic death was documented in both groups. A low compliance rate of wearing WCD is predicted by young patients and patients suffering from non-ischaemic cardiomyopathies. CONCLUSION: Although the compliance rate in different age groups is high, the average wear hours tended to be lower in young patients compared to older patients. The clinical events were similar in younger patients compared to older patients.

EASY-WPW: a novel ECG-algorithm for easy and reliable localization of manifest accessory pathways in children and adults.

AIMS: Accessory pathway (AP) ablation is a standard procedure for the treatment of Wolff-Parkinson-White syndrome (WPW). Twelve-lead electrocardiogram (ECG)-based delta wave analysis is essential for predicting ablation sites. Previous algorithms have shown to be complex, time-consuming, and unprecise. We aimed to retrospectively develop and prospectively validate a new, simple ECG-based algorithm considering the patients' heart axis allowing for exact localization of APs in patients undergoing ablation for WPW. METHODS AND RESULTS: Our multicentre study included 211 patients undergoing ablation of a single manifest AP due to WPW between 2013 and 2021. The algorithm was developed retrospectively and validated prospectively by comparing its efficacy to two established ones (Pambrun and Arruda). All patients (32 ± 19 years old, 47% female) underwent successful pathway ablation. Prediction of AP-localization was correct in 197 patients (93%) (sensitivity 92%, specificity 99%, PPV 96%, and NPV 99%). Our algorithm was particularly useful in correctly localizing antero-septal/-lateral (sensitivity and specificity 100%) and posteroseptal (sensitivity 98%, specificity 92%) AP in proximity to the tricuspid valve. The accuracy of EASY-WPW was superior compared to the Pambrun (93% vs. 84%, P = 0.003*) and the Arruda algorithm (94% vs. 75%, P < 0.001*). A subgroup analysis of children (n = 58, 12 ± 4 years old, 55% female) revealed superiority to the Arruda algorithm (P < 0.001*). The reproducibility of our algorithm was excellent (Ï°>0.8; P < 0.001*). CONCLUSION: The novel EASY-WPW algorithm provides reliable and accurate pre-interventional ablation site determination in WPW patients. Only two steps are necessary to locate left-sided AP, and three steps to determine right-sided AP.

Pulsed field ablation for pulmonary vein isolation: real-world experience and characterization of the antral lesion size compared with cryoballoon ablation.

BACKGROUND: Pulsed field ablation (PFA) is a new, non-thermal technology in the treatment of atrial fibrillation (AF). Early investigations have shown a promising safety profile with durable pulmonary vein isolation (PVI) and large antral lesions. However, clinical data remains scarce. METHODS: We investigated a cohort of 43 patients. Twenty-three patients underwent PVI with PFA in our hospital and we analyzed them with regard to procedural characteristics and with regard to the size of acute antral lesion which was estimated by using an electroanatomical map of the left atrium (LA). We compared these data with data of 20 patients who had undergone cryoballon (CB) PVI in our hospital. RESULTS: We could show acute isolation of all veins in all patients (100% PFA, 100% CB). Post-ablation high-density mapping revealed no early reconnection (0%). The acute antral lesion size of PFA was significantly higher compared to the CB (67.03 ± 12.69% vs. 57.39 ± 10.91%, p = 0.01). In the PFA group, we found no acute phrenic nerve injury, no major or minor bleeding, and no tamponade but one (4.34%) patient suffered from a stroke. Transient hypotension was observed frequently as well as transient bradycardia or asystole episodes requiring right ventricular pacing. In the CB group, no complications occurred. Furthermore, we discuss practical issues on PFA procedures. CONCLUSIONS: PFA is a promising technology with high acute PV isolation rate and large antral lesions compared to CB. However, larger trials with more patients and data on long-term freedom of AF but also complications are needed.

[Focal atrial tachycardias: diagnostics and therapy]. / Fokale atriale Tachykardien: Diagnostik und Therapie.

In this article, typical characteristics of focal atrial tachycardias are described and a systematic approach regarding diagnostics and treatment options in the field of invasive cardiac electrophysiology (EP) is presented. Subjects of this article include the definition of focal atrial tachycardias, knowledge about localizing the origin of such, and guidance on how to approach an invasive EP study (e.g., administration of medication during the EP study to provoke tachycardias). Further, descriptions will be found on how to localize the origin of focal atrial tachycardias with the help of the 12-lead ECG and invasive three-dimensional mapping to successfully treat focal atrial tachycardias with catheter ablation.

[Atypical atrial fibrillation : Diagnostics and therapy]. / Atypisches Vorhofflattern : Diagnostik und Therapie.

In contrast to typical atrial flutter, atypical atrial flutter is a heterogeneous group of right and left atrial macro- or localized reentry tachycardias whose critical component for maintaining tachycardia is not the cavotricuspid isthmus. Atypical atrial flutter occurs more frequently after previous catheter ablation and after cardiac surgery. The intraprocedural success rate during ablation is high, although the recurrence rate depends on structural changes in the atria as well as the underlying mechanism. This article provides an overview of the mechanisms as well as mapping and ablation strategies of the most common forms of right and left atrial atypical atrial flutter. This article is part of the "EP Basics" series for targeted continuing education in invasive electrophysiology. Basics, clinic and therapy of atypical atrial flutter are presented with focus on clinically relevant aspects. Procedures and findings of invasive electrophysiological diagnostics and ablation treatment are the focus of this article.

Percolated Plasmonic Superlattices of Nanospheres with 1 nm-Level Gap as High-Index Metamaterials.

Nanophotonics relies on precise control of refractive index (RI) which can be designed with metamaterials. Plasmonic superstructures of nanoparticles (NPs) can suggest a versatile way of tuning RI. However, the plasmonic effects in the superstructures demand 1 nm-level exquisite control over the interparticle gap, which is challenging in a sub-wavelength NPs. Thus far, a large-area demonstration has been mostly discouraged. Here, heteroligand AuNPs are prepared, which are stable in oil but become Janus particles at the oil-water interface, called "adaptive Janus particles." NPs are bound at the interface and assembled into 2D arrays over square centimeters as toluene evaporates, which distinctively exhibits the RI tunability. In visible and NIR light, the 2D superstructures exhibit the highest-ever RI (≈7.8) with varying the size and interparticle gap of NPs, which is successfully explained by a plasmonic percolation model. Furthermore, fully solution-processable 2D plasmonic superstructures are proved to be advantageous in flexible photonic devices such as distributed Bragg reflectors.

Telemonitoring Potential of Wearable Cardioverter-Defibrillators during the Follow-Up of Patients with Heart Failure.

BACKGROUND: Wearable cardioverter-defibrillators (WCDs) are a well-established tool to bridge the recovery time of left ventricular ejection fraction (LVEF) until the implantation of an implantable cardioverter defibrillator (ICD), as recommended by the current guidelines. Besides their function to detect and treat malignant arrhythmias, WCDs may be used as a telemonitoring system. In this study, we sought to illustrate and discuss the telemonitoring potential of WCDs and to analyze physical activity in specific patient cohorts. METHODS AND RESULTS: We retrospectively included 140 patients with reduced LVEF who were prescribed WCDs in our clinic. We analyzed the patients' physical activity (n = 105 with a WCD compliance above 21 h/day), body position and resting position. We found a reduced physical activity in women and in patients over the age of 65 compared to younger patients. Furthermore, the patients who were overweight or obese showed significantly reduced physical activity compared to the patients with a normal weight (6365 ± 3572 vs. 4972 ± 2476 vs. 7045 ± 3521, p = 0.02). CONCLUSION: WCDs may be used as a telemonitoring and intervention tool in patients with reduced LVEF. Specific patient groups may benefit from guidance from their treating physician regarding physical activity.

Transesophageal echocardiography guided transseptal puncture and nadir temperatures in cryoballoon pulmonary vein isolation.

Introduction: Cryoballoon (CB) guided pulmonary vein isolation (PVI) is an established procedure in the treatment of atrial fibrillation (AF). Transseptal access is an indispensable step during PVI and may be associated with severe complications. For specific interventions, specific puncture sites of the fossa ovalis are advantageous. Here, we analyzed the potential impact of a transesophageal echocardiography (TOE) guided transseptal puncture on nadir temperatures in CB PVI. Methods and Results: We retrospectively analyzed 209 patients undergoing CB PVI in our hospital. The use of TOE had been at the operator's discretion. No TOE-related complications such as perforation of the pharynx or esophagus or loss of teeth were noted. Concerning the applied freezes, we found significantly lower nadir temperatures in all PVs in the TOE group than in the non-TOE group. Procedure time and fluoroscopy time and complications were similar in both groups. Conclusion: TOE-guided TSP in CB PVI is safe and feasible. Our study found significantly lower nadir temperatures of CB freezes after TOE-guided TSP which potentially underscores the value of a more infero-anterior puncture site.

[Catheter ablation of ventricular tachycardias in patients with ischemic cardiomyopathy]. / Katheterablation ventrikulärer Tachykardien bei Patienten mit ischämischer Kardiomyopathie.

Radiofrequency (RF) ablation is an effective treatment option of scar-related ventricular tachycardias (VT) in patients with ischemic cardiomyopathy. Several studies proved the benefit of VT catheter ablation, which has become routine in most electrophysiology laboratories. This article provides practical instructions to perform a VT catheter ablation. The authors describe conventional and substrate-based mapping and ablation strategies as well as concepts for image integration. This article continues a series of publications created for education in advanced electrophysiology.

Reduction of Radiation Exposure in Atrioventricular Nodal Reentrant Tachycardia Ablations Using an Electroanatomical Mapping System With Fluoroscopy Integration Module.

Introduction: Atrioventricular nodal reentrant tachycardia (AVNRT) is a common supraventricular tachycardia. Current guidelines recommend electrophysiology study (EPS) and ablation, which have been proven to show high success rates with very low complication rates. Usually, ablation of AVNRT is performed conventionally using only fluoroscopy. Electroanatomical mapping systems (EMS) are widely used in complex arrhythmias. One of their advantages is their potential in decreasing the need of fluoroscopy time (FT). In this study we analyzed patients undergoing either conventional AVNRT ablation or by using an EMS with a fluoroscopy integrating system (FIS). Materials and Methods: We included 119 patients who underwent AVNRT ablation in our study. Eighty-nine patients were ablated conventionally using only fluoroscopy, 30 patients were ablated using EMS + FIS. Results: We found that the use of EMS + FIS led to a significant reduction of FT (449.90 ± 217.21 vs. 136.93 ± 109.28 sec., p < 0.001) and dose-area-product (DAP, 268.27 ± 265.20 vs. 41.07 ± 27.89 µGym2, p < 0.001) without affecting the procedure time (PT, 66.55 ± 13.3 vs. 67.33 ± 13.81 min, p = 0.783). Furthermore, we found no significance with regard to complications. Conclusion: The use of EMS+FIS is safe and feasible. It leads to a significant reduction of both FT and DAP without affecting PT and safety. Hence, EMS + FIS is beneficial for both the operator and the patients by reducing the radiation exposure.

[Practical guide for safe and efficient cryoballoon ablation for atrial fibrillation : Practical procedure, tips and tricks]. / Leitfaden zur sicheren und effizienten Kryoballon-Vorhofflimmerablation : Praktisches Vorgehen, Tipps und Tricks.

In the current guidelines on treatment of atrial fibrillation, cryoballoon-based catheter ablation of atrial fibrillation is recommended in addition to radiofrequency ablation and has become established as a standard procedure in the clinical routine of many centers for index pulmonary vein isolation. A safe, simplified and often durable pulmonary vein isolation can be achieved by a systematic approach. This review article provides a practical guide for all steps of cryoballoon-based pulmonary vein isolation, including preprocedural preparation and postinterventional follow-up. Both cryoballoon systems currently available on the market are considered.

Wearable Cardioverter-Defibrillator Used as a Telemonitoring System in a Real-Life Heart Failure Unit Setting.

BACKGROUND: In patients with reduced left ventricular ejection fraction (LVEF) who are at risk of sudden cardiac death, a wearable cardioverter-defibrillator (WCD) is recommended as a bridge to the recovery of LVEF or as a bridge to the implantation of a device. In addition to its function to detect and treat malignant arrhythmia, WCD can be used via an online platform as a telemonitoring system to supervise patients' physical activity, compliance, and heart rate. METHODS: We retrospectively analyzed 173 patients with regard to compliance and heart rate after discharge. RESULTS: Mean WCD wearing time was 59.75 ± 35.6 days; the daily wearing time was 21.19 ± 4.65 h. We found significant differences concerning the patients' compliance. Men showed less compliance than women, and younger patients showed less compliance than patients who were older. Furthermore, we analyzed the heart rate from discharge until the end of WCD prescription and found a significant decrease from discharge to 4, 8, or 12 weeks. CONCLUSION: WCD can be used as a telemonitoring system to help the involved heart failure unit or physicians attend to and adjust the medical therapy. Furthermore, specific patient groups should be educated more intensively with respect to compliance.

Fast anatomical mapping of the carina and its implications for acute pulmonary vein isolation.

BACKGROUND: Fast anatomical mapping (FAM) of the left atrium and pulmonary veins (PV) during PV isolation (PVI) generates anatomical information about the carina region additionally. We aimed to investigate the utility of these data in relation to conduction abilities of the intervenous carina. METHODS: We investigated 71 patients with drug-refractory atrial fibrillation (AF) who underwent first-time circumferential PVI using an electroanatomical mapping system. Carina width between ipsilateral PV was measured using FAM and an integrated distance measurement tool. Encirclings were divided into carina ablation and noncarina ablation groups based on the necessity of carina ablation to achieve PVI. RESULTS: In total, 142 encirclings were analyzed and first-pass isolation was observed in 102 (72%) encirclings. Nonfirst-pass PVI solely due to a gap on the line or persistent carina conduction was observed in 10 (7%) and 30 (21%) encirclings, respectively. Encirclings were classified into a carina ablation group (n = 30, 21%) and noncarina ablation group (n = 112, 79%). Carina width was significantly larger in the carina ablation vs nonarina ablation group (right: 11.9 ± 1.5 mm vs 8 ± 1.4 mm, P < .001/left: 12.1 ± 1.3 mm vs 8.1 ± 1.1 mm, P < .001) requiring additional carina ablation. CONCLUSION: Carina-related PV conduction is a common finding after the first-pass ablation during PVI. Measurement of carina width using FAM is feasible and its value correlates with the necessity of carina ablation to achieve PVI.

Influence of excess weight and obesity on performance and outcome of pulmonary vein isolation with the cryoballoon.

Pulmonary vein isolation (PVI) has become a cornerstone therapy in the treatment of atrial fibrillation (AF). Patients with overweight or obesity suffer more often from AF, and studies investigating the safety and feasibility of PVI in these patients have shown varying results. In this study we analyzed PVI performed with the 2nd generation cryoballoon (CB) with regard to safety, procedure and fluoroscopy time in patients with normal weight, overweight and obesity. We analyzed 228 consecutive patients treated with CB PVI in our hospital in 2018 and 2019. Fifty nine (25.88%) patients presented with normal weight (body mass index (BMI) of <25), 115 (50.44%) patients with overweight (BMI between 25 and 29.9) and 54 (23.68%) were obese patients (BMI >30). All pulmonary veins (PV) were isolated successfully. Concerning procedural parameters, neither complications, procedural time, nor fluoroscopy time differed significantly. There was a significant increase of dose area product (DAP) in obese patients compared to normal weight and overweight patients (2035.5 ± 1930.1 µGym2 vs. 975.3 ± 814.9 vs. 1325.1 ± 2081.3, p = 0.001) but no significant difference between overweight and normal weight patients (p = 0.611). Our follow-up data of 168 patients (73.68%) observed for 12 months showed no differences in the recurrence of AF in the three BMI groups [80.9% vs. 83.3% (p = 0.733) vs. 86.55% (p = 0.460)]. In conclusion, CB PVI in overweight and obese patients is safe with similar levels of complications and recurrence of AF as patients of normal weight. However, obese patients and operators are exposed to higher radiation doses.

[Pulmonary vein isolation using radiofrequency ablation]. / Pulmonalvenenisolation mittels Radiofrequenzablation.

Catheter ablation represents the primary treatment for most arrhythmias. The effectiveness of catheter ablation for the treatment of atrial fibrillation is superior to drug therapy. Therefore, catheter ablation has been established as an increasingly common procedure in clinical routine. In this context, the electrical isolation of the pulmonary veins (PVI) constitutes the cornerstone of the interventional therapy of paroxysmal and persistent atrial fibrillation. This article describes the procedure of pulmonary vein isolation utilizing radiofrequency point-by-point ablation. It shall be a practical guide for the staff in the electrophysiological laboratory. This article continues a series of manuscripts focusing on interventional electrophysiology topics in the course of EP (electrophysiology) training.This article describes the procedure of pulmonary vein isolation utilizing radiofrequency point-by-point ablation. It shall be a practical guide for the staff in the electrophysiological laboratory. This article continues a series of manuscripts dealing with topics of interventional electrophysiology in the course of EP training.