Abstract Background Radiofrequency catheter ablation (RFCA) has good acute and long-term success rates in idiopathic and ischemic ventricular arrhythmia (VA). Drawbacks of the RFCA are reversibility of the edema and limited penetration of the RF energy into the tissue which explain a worse effectiveness in midmyocardial substrates. In comparison to RFCA, the lesions produced by ultra-low temperature cryoablation (ULTC) which uses near-critical nitrogen cryogen at -1960C can be both deeper and irreversible, depending on the duration of the freeze. Purpose We aimed to evaluate the acute effectiveness of a new ULTC technology for VA by examining post-interventional cardiac magnetic resonance images (CMR) with late gadolinium enhancement (LGE), as a part of multi-center Cryocure-VT study. Methods Between December 2022 and May 2023, we ablated 6 patients (age 63±16%; 5 male) with sustained VA and structural heart disease. Three patients had previous myocardial infarction; 1 cardiac sarcoidosis, 1 LMNA/C dilated cardiomyopathy and 1 post-myocarditis VA. LGE-CMR was available in all patients before the ULTC. At first, electro-anatomical mapping and VA induction were performed followed by ULTC using transseptal access. Each application consisted of freeze-thaw-freeze cycle with freeze duration at operator’s discretion based on manufacturer-recommended duration-depth curve. At the end, induction protocol was repeated to assess the acute success. Additionally, LGE-CMR was performed after ablation as an attempt to visualize the cryo-lesions. Results Median of 6 applications (IQR 4.75-7.5) of cryo-energy were applied per patient. Median procedure time was 180 min (IQR 97-180), and median fluoroscopy time of 20 min (IQR 15-26). Septal VA exits were detected in 3/6 patients; in 1 the exit was at aorto-mitral continuity; in 2 – basal inferior. After ablation, no VAs were inducible in 5/6 (83%) patients. The only patient with failure to ablate all VAs had fewer applications (n=4) and shorter freeze duration of 30 sec., as compared to the rest. Post-procedural CMR revealed new LGE with up to 75% transmurality in 5/6 patients; microvascular obstruction in 4/6 patients. Only LV edema, but no LGE was observed in the patient with shortest freeze time, who also had intra-hospital recurrence. No complications occurred. Conclusions Cryoablation of VA using a new ultra-low temperature technology is effective and safe to ablate VT even in patients with mid-septal substrates. New LGE in result of ULTCA can be observed in CMR and the lesions depth depends on the duration of application.

BACKGROUND:Catheter ablation has become one of the main treatment strategies in patients with premature ventricular complexes (PVC). The successful mapping and ablation can be performed with an ablation catheter without additional diagnostic catheters.HYPOTHESIS:We hypothesize that using a single catheter for PVC ablation may decrease complications, procedure time, and fluoroscopy exposure while maintaining comparable success rates.METHODS:Sixty-nine consecutive patients with PVC were treated with a single catheter approach compared to a historical cohort, in which a conventional setup was used. Propensity score matching was conducted with a 1:1 ratio. Outcome parameters included acute procedural success with elimination of all premature ventricular contractions after catheter ablation, procedural data as well as complication rates.RESULTS:Patients treated with a single catheter approach had shorter total procedure (60 minutes [IQR: 47,5-69,0 minutes] vs. 90 minutes [IQR 60-120 minutes]; p = 0.001) and fluoroscopy times (218 seconds [IQR: 110,5-446 seconds] vs. 310 seconds [IQR 190-640 seconds]; p = 0.012), which consecutively leads to a reduction of radiation exposure signified by a lower dose area product (155 cGycm² [IQR 74.4-334.5 cGycm²] vs. 368.4 cGycm² [IQR: 126-905.4 cGycm²]; p value 0.009). Acute procedural success rates were comparable in both groups (54 [84.3%] in the single catheter approach group and 58 [90.6%] in the conventional group; p: 0.287).CONCLUSION:A single catheter approach for the treatment of PVC is associated with a reduction of procedure- and fluoroscopy time, as well as a lesser radiation exposure, while maintaining equivalent acute success and complication rates compared with a conventionally used catheter setup.

Abstract Introduction Atrioventricular Node Reentry Tachycardia (AVNRT) is commonly treated with catheter ablation, with high success and low complication rates. However a small risk of complete AV block still remains. Recent studies could show that using collision map is a feasible approach in mapping the slow pathway. The aim of the current study is to show a reduction of the total ablation points needed to modify/ablate the slow pathway using the collision mapping compared to conventional 3D mapping guided slow pathway modulation/ablation and therefore minimize the risk of a complete heart block. Methods Patients diagnosed with AVNRT (n = 24) underwent collision mapping for slow pathway identification, compared to a historical cohort (n=76) using conventional mapping. For collision mapping a dynamic visualization of atrial propagation during sinus rhythm was condcted. Two propagation fronts were observed to collide at the triangle of Koch, one propagation through the slow and one through the fast pathway. The designated collision zone was considered ideal for catheter ablation (Figure 1). The endpoint after ablation in both groups was non-inducibility of AVNRTs. Results After propensity score matching the collision mapping group needed significantly fewer ablation impulses (2 (IQR 1 - 5) vs. 6 (IQR 2,5 - 11,5) p = 0.002) and shorter ablation time (p < 0.001) compared to the conventional group (Table 1). No significant differences were observed in procedure time (p = 0.209), fluoroscopy time (p = 0.296), or dose area product (p = 0.391). Conclusion Collision Mapping in AVNRT ablation showed a notable reduction in ablation points, suggesting enhanced procedural efficiency and safety.Figure 1Table1

BackgroundCardiac arrhythmias have markedly increased in recent decades, highlighting the urgent need for appropriate test systems to evaluate the efficacy and safety of new pharmaceuticals and the potential side effects of established drugs.MethodsThe Microelectrode Array (MEA) system may be a suitable option, as it provides both real-time and non-invasive monitoring of cellular networks of spontaneously active cells. However, there is currently no commercially available cell source to apply this technology in the context of the cardiac conduction system (CCS). In response to this problem, our group has previously developed a protocol for the generation of pure functional cardiac pacemaker cells from mouse embryonic stem cells (ESCs). In addition, we compared the hanging drop method, which was previously utilized, with spherical plate-derived embryoid bodies (EBs) and the pacemaker cells that are differentiated from these.ResultsWe described the application of these pacemaker cells on the MEA platform, which required a number of crucial optimization steps in terms of coating, dissociation, and cell density. As a result, we were able to generate a monolayer of pure pacemaker cells on an MEA surface that is viable and electromechanically active for weeks. Furthermore, we introduced spherical plates as a convenient and scalable method to be applied for the production of induced sinoatrial bodies.ConclusionWe provide a tool to transfer modeling and analysis of cardiac rhythm diseases to the cell culture dish. Our system allows answering CCS-related queries within a cellular network, both under baseline conditions and post-drug exposure in a reliable and affordable manner. Ultimately, our approach may provide valuable guidance not only for cardiac pacemaker cells but also for the generation of an MEA test platform using other sensitive non-proliferating cell types.

Abstract Introduction Ischemic stroke-risk has been associated with clinical characteristics, atrial remodeling and P- wave changes, like P-wave duration (PWD) or interatrial block (IAB). Despite the increasing evidence though, their use in risk-stratification remains limited. Purpose The aim of this review and meta-analysis was to examine the predictive value of PWD/IAB for stroke and offer practical implications. Methods Publication databases were systematically searched and studies reporting PWD and/or morphology at baseline and thromboembolic events (TEs) during follow-up (FUP) were included. IAB was defined as partial (pIAB) if PWD≥120 ms or advanced (aIAB) if the P-wave was biphasic in the inferior leads. After quality assessment and data extraction, random-effects analysis calculated odds ratio (OR) and confidence intervals (CI). Subgroup-analysis was performed to address heterogeneity. Results Among 180.997 patients (17 studies, mean 66 years old), including primary care patients (n=152.759), 15.578 (9%) had a new TE during 4 years of FUP. The pIAB was significant TE-risk predictor for non-primary care patients (OR:1.7; 95% CI:1.4-2.1) and those with prior TE (OR:1.8; 95% CI:1.4-2.2), but not for primary-care (OR:1.0) or those without prior TE (OR:1.3). The aIAB was significant TE-risk predictor both for primary (OR:1.6; 95% CI:1.4-1.9) and nonprimary care (OR:2.5; 95% CI:1.8-3.4) as well as those without (OR:2.2; 95% CI:1.1-4.4) or with prior TE (OR:2.6; 95% CI:1.4-4.7). There was heterogeneity but no publication bias in the subgroup-analysis. Conclusion Interatrial block is an independent predictor of TE-risk. The association is stronger for non-primary care patients or those with prior TE. Thus, PWD and IAB could be used as selection criteria for intensive screening, follow-up or interventions.

Abstract Background Atrial fibrillation (AF) is a common cardiac arrhythmia associated with morbidity and mortality. One of the mainstays of AF treatment is the interventional isolation of the pulmonary veins. However, the presence of low voltage areas (LVAs) in the left atrium is associated with a worse outcome after catheter ablation. Therefore, identifying LVAs prior to intervention is important for tailoring individualized treatment approaches. Although several prediction models for LVAs exist, none of them incorporate electrocardiographical parameters. Therefore, this study aimed to develop and evaluate the predictive value of a novel LVAs prediction score that incorporates a novel ECG parameter, prospectively validate the score, and compare it with existing prediction scores. Methods The study enrolled 264 patients with AF undergoing catheter ablation. LVAs were determined using high-density maps, which were defined as areas of low voltage amplitude (<0.5 mV). Before intervention, all patients underwent cardiovascular magnetic resonance imaging to measure left atrial dimensions. A novel LVAs prediction score (TAG P²) was established, which included a parameter of cumulative atrial electrical forces in relation to left atrial area (PWAi<0.478 msec * mV * m²/cm² – 2pts), along with type of AF (persistent – 1pt.), age (>70 years - apt.), and gender (female – 1pt.). The score was prospectively validated in a cohort of 126 patients. Results The TAG P² score was effective in predicting LVAs in the study population (AUC: 0.918; 95%CI [0.884 to 0.951]; p<0.001) and the results were confirmed in the validation cohort (AUC: 0.884; 95%CI [0.826 to 0.943]; p<0.001). The TAG P² score outperformed existing prediction scores, such as the DR-FLASH (AUC: 0.788; 95%CI [0.685 to 0.891]) and APPLE scores (AUC: 0.764; 95%CI [0.671 to 0.856]). Conclusion The TAG P² score, which incorporates a novel ECG parameter (PWAi) effectively predicts LVAs in patients undergoing catheter ablation for AF.

Key Teaching Points•Cryoablation is a safe and effective treatment option for nonischemic cardiomyopathy patients suffering from ventricular tachycardia.•Preprocedural cardiac magnetic resonance imaging allows the estimation of the desired lesion depth and titration of the ablation duration, which is correlated with the postprocedural depth of the lesion based on cardiac magnetic resonance imaging and late gadolinium enhancement (LGE).•Cryothermal ablation with an ultra-low-temperature cryoablation catheter resulted in microvascular obstruction at the ablation site, with subendocardial LGE. •Cryoablation is a safe and effective treatment option for nonischemic cardiomyopathy patients suffering from ventricular tachycardia.•Preprocedural cardiac magnetic resonance imaging allows the estimation of the desired lesion depth and titration of the ablation duration, which is correlated with the postprocedural depth of the lesion based on cardiac magnetic resonance imaging and late gadolinium enhancement (LGE).•Cryothermal ablation with an ultra-low-temperature cryoablation catheter resulted in microvascular obstruction at the ablation site, with subendocardial LGE.

Abstract Introduction Presence of low voltage areas (LVA) mirrors progression of atrial fibrillation (AF) and is associated with an impaired rhythm outcome after AF ablation. P-wave indices can predict LVA, however accuracy is depending on myocardial mass, therefore the P Wave area was indexed for the left atrial area. The aim of current analysis was to investigate the association between the novel P-Wave Area Index (PWAi) and the presence of LVA. Methods Patients undergoing first AF ablation were included into analysis. LVA were determined using high-density maps and defined as <0.5 mV. All patients underwent CMR imaging (Ingenia 1.5T Philips) and received 12 lead ecg in sinusrhythm before intervention. CMR data (LA area) and P-Wave Area in Leads I ( PWA(I)) and II (PWA(II)) were measured in all patients. Afterwards the P-Wave Area was indexed for LA area to create the PWAi. Results A total of 264 consecutive patients were included in the analysis (65 years, 41% females, 57% persistent AF, 30.6% LVAs). Of all analyzed P-Wave indices, P Wave Area in lead II could effectively identify LVA (AUC: 0.813, p<0.001). In patients with LVA, PWAi below 0.4781 msec*mV*m²/cm² identified patients with LVA with an accuracy of 81% (81% sensitivity, 81% specificity, 65% pos. predictive value and 91% neg. predictive value) and was the strongest predictor among all analyzed parameters (OR: 20,578, AUC; 0.860) Conclusion The PWAi is a highly significant tool to identify potential LVA before AF Ablation. This findings help to further individualize AF treatment.Multivariate AnalysisROC analysis

Despite the advances in technologies and techniques in the field of catheter ablation for cardiac arrhythmias, it is estimated that the prevalence of atrial fibrillation (AF) will further increase in the nearest future. The latest trials have proven the beneficial effect on mortality after pulmonary vein isolation in patients with impaired left ventricular function, while no such effect has been seen in patients without left ventricular dysfunction. This raises the question of whether catheter ablation for AF is still suited for the latter patient cohort or whether the endpoint of mortality is not adequate enough. Not only does pulmonary vein isolation reduce the burden of atrial fibrillation, but it also somehow alters the patients’ perception of it in the case of recurrence. Independent of the presence of ventricular dysfunction, patients experience a relief of AF-related symptoms, which is accompanied by an increase in quality of life based on the available patient-reported outcome measures, despite AF recurrence. Trials that are currently recruiting patients seek to unveil the accountable circumstances for these remaining uncertainties and help expand our understanding of a procedure that has been routinely performed for two decades.

Der plötzliche Herztod (PHT) stellt ein sehr großes, bisher ungelöstes Problem der öffentlichen Gesundheit dar. Die Prävention des PHT wird in 2 Hauptkategorien unterteilt, und zwar zum einen in die Primär- (Prävention eines ersten Ereignisses von PHT) und zum anderen in die Sekundärprävention (Prävention von Wiederholungsereignissen bei Überlebenden eines Herzstillstands). In diesem Übersichtsartikel wird der aktuelle Wissensstand über die Primär- und Sekundärprävention des PHT in verschiedenen klinischen Situationen zusammengefasst.