Mitral valve prolapse (MVP) is commonly benign, but an arrhythmic phenotype (AMVP) with increased risk for sudden cardiac death has been described. A prolonged Tpeak-Tend interval has been association with increased arrhythmic risk in different clinical settings. The aim of this study was to investigate a possible correlation between prolonged Tpeak-Tend interval and ventricular tachycardia (VT) inducibility in MVP. Sixty-five patients fulfilling the EHRA criteria of AMVP syndrome underwent programmed ventricular stimulation between 2016 and 2024. Sustained polymorphic VT was induced in 19 patients (29.2

Mitral valve prolapse (MVP) is commonly benign, but an arrhythmic phenotype (AMVP) with increased risk for sudden cardiac death has been described. Current risk stratification is mainly based on clinical data and imaging markers, while the role of programmed ventricular stimulation (PVS) remains uncertain. In this prospective single-center cohort study, 42 patients fulfilling the EHRA consensus criteria for AMVP underwent an electrophysiological study with programmed ventricular stimulation between 2016 and 2025. Stimulation was performed from the right ventricular apex and outflow tract using up to two extra stimuli. Following shared decision-making, patients received either an implantable cardioverter-defibrillator (ICD) or an implantable loop recorder (ILR). The endpoint was the occurrence of clinically significant ventricular arrhythmias (VAs), defined as appropriate ICD therapies, ILR-documented sustained VT, or arrhythmic syncope. Sustained ventricular arrhythmias were inducible in 20 patients (47.6

Background: Takotsubo syndrome (TTS) is an acute cardiac condition characterized by transient left ventricular dysfunction. Although generally considered reversible, early arrhythmias are a dreaded complication and their prognostic significance remains incompletely understood. Methods: In this study, 104 consecutive patients diagnosed with TTS (January 2007 to September 2024) were examined for the prognostic relevance of in-hospital arrhythmias during monitoring at the time of diagnosis. The median follow-up was 2.1 years. The primary combined endpoint included cardiac death, TTS recurrence, occurrence of arrhythmias, and rehospitalization for cardiac causes. Results: In-hospital arrhythmias occurred in 35.6% of the patients. Ventricular arrhythmias were significantly associated with an increased risk of adverse cardiac events (odds ratio 3.94, 95% confidence interval 1.22–12.69; p = 0.021). Reduced left ventricular ejection fraction and QTc prolongation, while frequently observed, were not independently associated with adverse outcomes when analyzed separately from arrhythmic events. Supraventricular arrhythmias exhibited a non-significant trend (p = 0.145). Conclusions: In a large registry of consecutive TTS patients, in-hospital ventricular arrhythmias at diagnosis were significantly associated with adverse outcomes, underscoring the importance of early rhythm monitoring.

Outflow tract tachycardia (OT) is the most common form of idiopathic ventricular tachycardia (VT) in children. It is usually an incidental finding and presents only with mild symptoms. If affected patients have impaired left ventricular (LV) function, recovery usually progresses quickly after termination of the VT. To the best of the authors’ knowledge, this is the first description of a 9-year-old female patient who presented with incessant right ventricular OT and LV dysfunction that was initially assumed to be tachycardiomyopathy and later diagnosed to be related to underlying laminopathy. The VT was successfully treated by radiofrequency ablation, and electroanatomical mapping demonstrated no signs of endocardial scarring. The VT had most likely been present for a prolonged period since the patient and initially presented with only mild symptoms of cardiac congestion despite severely impaired LV function. It seems probable that the laminopathy somehow influenced the unusual course of impaired LV function in this patient, who had either idiopathic VT combined with incidentally proven laminopathy or, less likely, outflow tract VT related to the laminopathy mimicking idiopathic VT.

BACKGROUND:The subcutaneous implantable defibrillator (S-ICD) is an alternative to transvenous implantable defibrillators. The present analysis presents real-world data from patients with S-ICD and a follow-up duration of 10 years or more. METHODS AND RESULTS:Between July 2010 and November 2013 76 S-ICD systems were implanted. After a follow-up duration of 10 years, data from 67 patients (88.1%) was available. Mean follow-up duration was 10.7 ± 1.3 years. Forty-seven patients (70.2%) were still alive with active S-ICD therapy. Eight patients (11.9%) died during follow-up. In eight patients (11.9%), conversion to a transvenous ICD system was necessary. This was either due to heart failure with indication for biventricular pacing (n = 2), bradycardia (n = 3), oversensing that could not be solved (n = 2), or pocket infection (n = 1). In four patients (6%), the S-ICD system was explanted without replacement for individual reasons. Sixteen patients already underwent two generator replacements, while one generator replacement was performed in the rest of the cohort. Therefore, generator longevity was documented to be within the predicted values. In 10 patients (14.9%), appropriate therapy delivery for ventricular arrhythmias was delivered. In 12 patients (17.9%), inappropriate shock delivery due to oversensing occurred. Of note, this could be resolved in all but two patients. Furthermore, the majority of these episodes occurred in the early years before the implementation of the Smart Pass algorithm. CONCLUSION:S-ICD therapy can be successfully maintained over a long time. Incidence of oversensing significantly decreased with the implementation of novel algorithms and the new S-ICD generation. However, the present data also points out that in selected individuals conversion to transvenous systems is required.

Background and Objective: Implantable Cardioverter Defibrillators (ICDs) are crucial in treating ventricular tachyarrhythmias (VTs) and preventing sudden cardiac death. However, ICD shocks are linked to higher mortality and a lower quality of life. Many patients suffer from recurrent VTs despite concomitant antiarrhythmic drug (AAD) therapy with amiodarone, and it is unclear if changing the AAD while on chronic amiodarone therapy is beneficial. Hence, we investigated the impact of changing the AAD on the incidence of appropriate ICD shocks in patients on chronic amiodarone, impaired LV function, and at least one previous VT ablation. Methods and Results: We retrospectively analyzed 131 ICD patients (LVEF < 40%) from a single-center registry. All were on chronic amiodarone and had undergone VT ablation. The mean age was 66.0 ± 12.8 years; 82.4% were male; and the follow-up period averaged 5.8 ± 0.6 years. Ischemic cardiomyopathy was present in 52.7% of patients. AAD therapy was changed in 49 patients (37.4%), primarily due to inefficacy (40.8%), intolerance (16.3%), or other reasons (42.9%). Of those, 8 received flecainide (≥200 mg) and 41 sotalol (≥240 mg); 82 (62.6%) continued amiodarone. VT re-ablation was performed in 23.7%. During follow-up, 11 patients (8.4%) died and 18 (13.7%) received appropriate ICD shocks—17 with changed AAD vs. 1 with continued amiodarone (p ≤ 0.01). A multivariate regression showed that switching from amiodarone to flecainide or sotalol was significantly associated with increased ICD shock risk (OR 34.9; 95% CI 4.3–283.8; p < 0.01). Conclusions: In patients on chronic amiodarone with severely impaired LV function and at least one previous VT ablation, changing AAD therapy to flecainide or sotalol is associated with an increased incidence of appropriate ICD shocks.

BACKGROUND:Antiarrhythmic drug therapy is a cornerstone in managing electrical storm (ES). Data on the safety and efficacy of antiarrhythmic drugs besides beta-blockers and amiodarone are limited. OBJECTIVE:This retrospective observational study aimed to assess the potential role of ajmaline in patients with ES refractory to guideline-recommended care. METHODS:Adult patients admitted to the intensive care unit owing to ES between 2013 and 2023 who received ajmaline for therapy-refractory ES were retrospectively analyzed. RESULTS:46 of 332 patients with recurrent ventricular tachycardia/ventricular fibrillation (mean age 64 ± 11 years; 93% male; mean left ventricular ejection fraction 33% ± 12%; 78% with implanted implantable cardioverter-defibrillator) were treated with intravenous ajmaline. Most patients (98%) had known structural heart disease. Serious adverse events requiring discontinuation were not observed. Minor adverse events occurred in 3 patients (7%). Complete arrhythmia suppression was achieved in 34 patients (74%), partial suppression in 2 (4%), and ventricular tachycardia slowing in 5 (11%). In 5 patients (11%), ajmaline showed no effect. During hospitalization, 5 patients (11%) died: 2 (4%) because of multiorgan failure and 3 (7%) because of a combined septic and cardiogenic shock despite complete or partial arrhythmia suppression by ajmaline. 28 patients (61%) underwent catheter ablation, and 41 patients (89%) were discharged in stable rhythm. After a 6-month follow-up, 15 patients were lost to follow-up and 24 of the 26 remaining patients were still alive. CONCLUSION:In selected patients with refractory ES, intravenous ajmaline treatment was associated with a reduction in ventricular arrhythmias and a favorable safety profile. Ajmaline may serve as a valuable bridge to definitive treatment in life-threatening ES.

BACKGROUND:Smartwatches are increasingly used for screening of tachyarrhythmias and for ECG recording. We therefore investigated possible mechanisms of magnet-mode induction of smartwatches in cardiac implantable electronic devices (CIED). METHODS:Fifteen CIED (5 pacemakers, 10 implantable cardioverter-defibrillators) from all manufacturers were implanted in a subcutaneous and submuscular location in an isolated porcine thorax and connected to an interactive heart simulator. Eight different smartwatches (3 Apple, 3 Samsung, 1 Huawei, 1 Withings) were placed on top of the implantation site in 3 different configurations, and signs of magnet mode induction were recorded. RESULTS:When the faces of smartwatches were placed on top of subcutaneously implanted CIED, only 1 instance of magnet mode induction was recorded in 120 measurements (<1%). When turning around the smartwatches and placing the backs on the implantation site, signs of magnet mode were recorded in 36 of 120 measured instances (30%). Smartwatches connected to respective chargers induced magnet mode in 28 of 120 measurements (23%). Magnet mode induction in submuscularly implanted CIED was seen in 5 of 360 measurements (1%). The smartwatch with physical charging connectors was the only one not to induce magnet mode in any CIED, resulting from a lower-than-average magnetic field strength likely due to its different charging mechanism. CONCLUSIONS:ECG-capable smartwatches can induce magnet mode in CIED. Although the risk for patients wearing smartwatches on their wrist is low, patients should be discouraged from placing their watch close to their CIED. Smartwatch charging mechanism and CIED implantation depth influence the risk of magnet mode induction.

Background/Objectives: Electrocardiographic (ECG) findings such as sinus tachycardia and right bundle branch block are commonly associated with acute pulmonary embolism (PE). This study aimed to investigate the prevalence of advanced interatrial block (IAB) in patients with acute PE and its association with atrial fibrillation (AF) and hemodynamic changes. Methods: This retrospective, single-center study included patients diagnosed with acute PE (42% female, 58% male) between January 2014 and September 2024 at University Hospital Münster. A control group of individuals without manifest heart disease (45% female, 55% male) served as a control group. All patients underwent clinical, laboratory, ECG, and echocardiographic evaluations. Results: A total of 351 patients with acute PE and 120 control patients were included. The PE group had a mean age of 62.5 years. Advanced IAB was detected in 35% of PE patients, significantly higher than in controls (2%). In contrast, typical ECG signs of PE such as sinus tachycardia (23%), right bundle branch block (8%), and S1Q3 pattern (20%) were less frequent. A subgroup analysis demonstrated that patients with IAB were older, had a higher CHA2DS2-VA score, and were more likely to have pre-existing and new-onset AF. IAB was not associated with right heart dysfunction on echocardiography. Conclusion: For the first time, this study revealed that advanced IAB was present in many patients with acute PE. IAB was associated with a higher risk of AF and greater thromboembolic risk but not with hemodynamic changes typical of PE. Detecting an advanced IAB at the initial presentation in the emergency department could provide an important indication of PE.

Background: Previous studies suggest a direct effect of sacubitril on cardiac electrophysiology and indicate potential arrhythmic interactions between sacubitril and antiarrhythmic drugs. Therefore, the aim of this study was to explore the electrophysiologic effects of combining sacubitril with the antiarrhythmic drugs d,l-sotalol and mexiletine in isolated hearts. Methods and results: A total of 25 rabbit hearts were perfused using a Langendorff setup. Following baseline data collection, hearts were treated with mexiletine (25 µM, 13 hearts) or d,l-sotalol (100 µM, 12 hearts). Monophasic action potential demonstrated an abbreviation of action potential duration (APD90) after administration of mexiletine. Spatial dispersion of repolarization remained unchanged after mexiletine treatment, whereas effective refractory periods (ERP) were significantly prolonged. D,l-sotalol prolonged cardiac repolarization and amplified spatial dispersion. Further infusion of sacubitril (5 µM) led to a significant reduction in APD90 and ERP in the mexiletine group. In the d,l-sotalol group, additional administration of sacubitril shortened cardiac repolarization duration without affecting spatial dispersion. No proarrhythmic effect was observed after mexiletine treatment as assessed by a predefined pacing protocol. Additional sacubitril treatment did not increase ventricular vulnerability. When potassium concentration was reduced, 30 episodes of torsade de pointes tachycardia occurred after d,l-sotalol treatment. Additional sacubitril treatment significantly suppressed torsade de pointes tachycardia (eight episodes) in the d,l-sotalol-group. Conclusions: In class IB- and class III-pretreated hearts, sacubitril shortened refractory periods and cardiac repolarization duration. The combination of sacubitril with the antiarrhythmic drugs d,l-sotalol and mexiletine demonstrates a safe electrophysiologic profile and sacubitril reduces the occurrence of class III-related proarrhythmia, i.e., torsade de pointes tachycardia.

BACKGROUND:In about 8% of survivors of sudden cardiac death, no structural or electrical heart disease can be identified. Some of these patients with idiopathic ventricular fibrillation (IVF) present ECG markers of early repolarization (Early Repolarization Syndrome, ERS). The Tpeak-Tend interval has been linked to increased arrhythmic risk in different clinical settings, such as Brugada syndrome or hypertrophic cardiomyopathy. As there is limited data about the relationship of Tpeak-Tend and arrhythmogenesis in IVF, respectively, its significance in risk stratification in ERS, the aim of this study was to investigate a possible correlation between sustained ventricular arrhythmia (VA) recurrences in these patients and the Tpeak-Tend interval. METHODS AND RESULTS:We retrospectively investigated 56 consecutive IVF patients (64.3% male, mean age 37.8 ± 12.9 years) who received an implantable cardioverter-defibrillator for secondary prevention. Markers of early repolarization were present in 32.1% of cases. During a mean follow-up of 41.2 ± 35.8 months, 11 patients (19.6%) received in total 18 adequate ICD-therapies. Patients with VA recurrence showed longer Tpeak-Tend compared to arrhythmia-free patients (105 ± 14 ms vs. 91 ± 14 ms, p = 0.03). The combination of prolonged Tpeak-Tend (> 90 ms) and an early repolarization pattern was associated with a 12-fold increased risk of recurrent VA (p = 0.002). CONCLUSION:Prolonged Tpeak-Tend was associated with VA recurrence in patients with survived IVF. This correlation was even more pronounced in IVF patients with early repolarization pattern. The Tpeak-Tend interval might play a future role in risk stratification of patients with ERS.

OBJECTIVE AND BACKGROUND:Data on incidence of in-hospital pulmonary embolisms (PE) after catheter ablation (CA) are scarce. To gain further insights, we sought to provide new findings through case-based analyses of administrative data. METHODS:Incidences of PE after CA of supraventricular tachycardias (SVT), atrial fibrillation (AF), atrial flutter (AFlu), and ventricular tachycardias (VT) in three German tertiary centers between 2005 and 2020 were determined and coded by the G-DRG (German Diagnosis Related Groups System) and OPS (German Operation and Procedure Classification) systems. An administrative search was performed with a consecutive case-based analysis. RESULTS:Overall, 47,344 ablations were analyzed (10,037 SVT; 28,048 AF; 6,252 AFlu; 3,007 VT). PE occurred in 14 (0.03%) predominantly female (n = 9; 64.3%) patients with a mean age of 55.3 ± 16.9 years, body mass index 26.2 ± 5.1 kg/m2, and left ventricular ejection fraction of 56 ± 13.6%. PE incidences were 0.05% (n = 5) for SVT, 0.02% (n = 5) for AF, and 0.13% (n = 4) for VT ablations. No patient suffered PE after AFlu ablation. Five patients (35.7%) with PE after CA had no prior indication for oral anticoagulation (OAC). Preprocedural international normalized ratio in PE patients was 1.2 ± 0.5. Most patients with PE following CA presented with symptoms the day after the procedure (n = 9) after intraprocedural heparin application of 12,943.2 ± 5,415.5 IU. PE treatment included anticoagulation with either phenprocoumon (n = 5) or non-vitamin K-dependent OAC (n = 9). Two patients with PE died after VT/AF ablation, respectively. The remaining patients were discharged without sequels. CONCLUSION:Over a 15-year period, incidence of PE after ablation is low, particularly low in patients with ablation for AF/AFlu. This is most likely due to stricter anticoagulation management in these patients compared with those receiving SVT/VT ablation procedures and could argue for continuation of OAC prior to ablation. Optimizing periprocedural anticoagulation management should be subject of further prospective trials.

Background: Noninferiority of omitting intraoperative defibrillation threshold (DFT) testing has been documented for transvenous implantable cardioverter defibrillators (ICD) whereas data for the subcutaneous-ICD (S-ICD) regarding the need for DFT testing, especially during S-ICD generator replacement, is not available. Methods: A total of 112 consecutive patients who underwent S-ICD generator replacement and routine testing were included in this retrospective single-center study and analyzed regarding the outcome of intraoperative DFT. Results: The majority of patients (87.3%) were successfully tested during generator replacement with no major adverse events. PREATORIAN score was generally lower, while high voltage (HV) impedance increased compared to first implantation. The risk of conversion failure increased with the PRAETORIAN risk class, whereas patient characteristics did not impact conversion rates. PRAETORIAN score and HV impedance were shown to be the most accurate factors when predicting conversion failure. In all patients with an HV impedance <70 Ohm and a PREATORIAN score < 90 at the time of initial implantation DFT was successfully performed during generator replacement. Conclusion: General omittance of DFT in S-ICD generator replacement is not advisable. New algorithms for low impedance DFT measurements during S-ICD query and PREATORIAN score at first implantation can be used to predict conversion failure. An impedance <70 Ohm and a PRAETORIAN score < 90 show a very low risk of conversion failure. In patients with a PRAETORIAN score > 150 DFT testing should be performed when the S-ICD generator is replaced until randomized data is available.

Despite impressive developments in the field of ventricular arrhythmias, there is still a relevant number of patients with ventricular arrhythmias who require antiarrhythmic drug therapy and may, e.g., in otherwise drug and/or ablation refractory situations, benefit from agents known for decades, such as mexiletine. Through its capability of blocking fast sodium channels in cardiomyocytes, it has played a minor to moderate antiarrhythmic role throughout the recent decades. Nevertheless, certain patients with structural heart disease suffering from drug-refractory, i.e., mainly amiodarone refractory ventricular arrhythmias, as well as those with selected forms of congenital long QT syndrome (LQTS) may nowadays still benefit from mexiletine. Here, we outline mexiletine's cellular and clinical electrophysiological properties. In addition, the application of mexiletine may be accompanied by various potential side effects, e.g., nausea and tremor, and is limited by several drug-drug interactions. Thus, we shed light on the current therapeutic role of mexiletine for therapy of ventricular arrhythmias and discuss clinically relevant aspects of its indications based on current evidence.

Background Cryoballoon ablation is a widely used single-shot technique for pulmonary vein isolation (PVI) in the treatment of paroxysmal atrial fibrillation (AF). Procedural endpoints ensuring maximal PVI durability are important. Objective To assess the performance of cryoablation procedural markers to predict long-term PVI. Methods In a single center, consecutive patients who underwent redo ablation with high-density mapping for symptomatic AF recurrence after cryoballoon ablation were included and cryoballoon procedural data were collected, including temperature values at 30 and 60 s, time to isolation, nadir temperature and the velocity of temperature decline estimated with the temperature/time catch-up point (T2T-Catch-Up) defined as positive when the freeze temperature in minus degree equals the time in seconds after cryoablation initiation (e.g. − 15 °C in the first 15 s of the ablation impulse). Results 47 patients (62% male; 58.3 ± 11.2 years) were included. Overall, 38 (80.9%) patients had ≥ 1 reconnected PV. Among 186 PVs, 56 (30.1%; 1.2 per patient on average) were reconnected. Univariate analysis revealed T2T-Catch-Up in 103 (56%) and more frequent in durably isolated than in reconnected PVs (93 [72%] vs 10 [19%], p < 0.0001). Among binary endpoints, T2T-Catch-Up had the highest specificity (82%) and predictive value for durable PVI at redo ablation (90%). In multivariable analyses, absence of T2T-Catch-Up (Odds-ratio 0.12, 95% CI [0.05–0.31], p < 0.0001) and right superior PV (Odds-ratio 3.14, 95% CI [1.27–7.74], p = 0.01) were the only variables independently associated with PV reconnection. Conclusion T2T-Catch-Up, a new and simple cryoballoon procedural endpoint demonstrated excellent predictive value and strong statistical association with durable PVI. Graphical abstract

Catheter-based treatment of patients with ventricular arrhythmias (VA) reduces VA and mortality in selected patients. With regard to potential risks of catheter ablation, a benefit–risk assessment should be carried out. This can be performed with risk scores such as the recently published “Risk in Ventricular Ablation (RIVA) Score”. We sought to validate this score and to test for possible additional predictors in a large database of VT ablations. We analyzed 1964 catheter ablations for VA in patients with (1069; 54.4

Abstract Aims The incidence of in-hospital post-interventional complications and mortality after ablation of supraventricular tachycardia (SVT) vary among the type of procedure and most likely the experience of the centre. As ablation therapy of SVT is progressively being established as first-line therapy, further assessment of post-procedural complication rates is crucial for health care quality. Methods and results We aimed at determining the incidence of in-hospital mortality and bleeding complications from SVT ablations in German high-volume electrophysiological centres between 2005 and 2020. All cases were registered by the German Diagnosis Related Groups—and the German Operation and Procedure Classification (OPS) system. A uniform search for SVT ablations from 2005 to 2020 with the same OPS codes defining the type of ablation/arrhythmia as well as the presence of a vascular complication, cardiac tamponade, and/or in-hospital death was performed. An overall of 47 610 ablations with 10 037 SVT ablations were registered from 2005 to 2020 among three high-volume centres. An overall complication rate of 0.5% (n = 38) was found [median age, 64; ±15 years; female n = 26 (68%)]. All-cause mortality was 0.02% (n = 2) and both patients had major prior co-morbidities precipitating a lethal outcome irrespective of the ablation procedure. Vascular complications occurred in 10 patients (0.1%), and cardiac tamponade was detected in 26 cases (0.3%). Conclusion The present case-based analysis shows an overall low incidence of in-hospital complications after SVT ablation highlighting the overall very good safety profile of SVT ablations in high-volume centres. Further prospective analysis is still warranted to guarantee continuous quality control and optimal patient care.

Aim COVID-19 has been associated with cardiovascular complications including ventricular arrhythmias (VA) and an increased number of out-of-hospital cardiac arrests. Nevertheless, several authors described a decrease of VA burden in patients with an implantable defibrillator (ICD) during the first wave of the COVID-19 pandemic. The objective of this study was to determine if these observations could be transferred to later periods of the pandemic as well. Methods We retrospectively analyzed a total of 1674 patients with an ICD presenting in our outpatient clinic during the second wave of the COVID-19 pandemic and during a control period for the occurrence of VA requiring ICD interventions. Results Seven hundred ninety-five patients with an ICD had a device interrogation in our ambulatory clinic during the second wave of the COVID-19 pandemic compared to eight hundred seventy-nine patients in the control period. There was significant higher amount of adequate ICD therapies in the course of the COVID-19 period. Thirty-six patients (4.5%) received in total eighty-five appropriate ICD interventions during COVID-19, whereas only sixteen patients (1.8%) had sustained VA in the control period ( p = 0.01). Conclusion In contrast to the first wave of COVID-19, which was characterized by a decrease or least stable number of ICD therapies in several centers, we found a significant increase of VA in ICD patients during the second wave of COVID-19. Possible explanations for this observation include higher infectious rates, potential cardiac side effects of the vaccination as well as personal behavioral changes, or reduced utilization of medical services.