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A 24-year-old man was resuscitated successfully after ventricular fibrillation. Structural heart disease and a primary channelopathy could not be identified despite extensive work-up, including molecular genetic testing. Three years after the initial event, ventricular fibrillation recurred and recording of the induction mechanism opened additional therapeutic options., (© 2021. Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: Brugada Syndrome is a genetic arrhythmogenic disease with a variable clinical spectrum. The role of clinical and ECG parameters in the risk stratification is still uncertain., Aims: In a large cohort of Brugada patients we analysed clinical and ECG features to determine the variables with prognostic value for the occurrence of a first documented arrhythmic event and for recurrences., Methods: We enrolled 614 patients, subdivided into 3 groups according to their clinical presentation: 531 (88%) asymptomatic, 69 (10%) with previous unexplained syncope and 14 (2%) with aborted sudden death. We also compared the ECG characteristics of patients with a single documented arrhythmic event (either at presentation or at follow-up, 17 patients), with those of patients with arrhythmic recurrences (13 patients)., Results: The event rate was 1.3% in the asymptomatic patients and 15% among patients with unexplained syncope (median follow-up 6 years), p < 0.0001. In both groups a QRS duration ≥110 ms in lead II and/or V6 and/or S wave duration ≥40 ms in lead I and/or II were significant risk factors for the occurrence and timing of events at follow-up. The same ECG risk factors were also significantly associated with arrhythmic recurrences., Conclusions: The arrhythmic risk of Brugada patients is related not only to the symptoms at presentation, but also to the presence of a ventricular conduction delay (QRS duration ≥ 110 ms and/or S wave duration ≥ 40 ms). The ECG conduction parameters also affect the timing of events and recurrences., Competing Interests: Declaration of competing interest The authors report no relationships that could be construed as a conflict of interest., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Defibrillation threshold (DFT) testing is commonly performed in patients undergoing subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation. Growing evidence indicates that successful DFT testing correlates with the technique used for implantation of the defibrillation lead and pulse generator. However, evidence on whether DFT testing should be performed in patients undergoing S-ICD pulse generator replacement is lacking., Objective: The purpose of this study was to determine the outcome of DFT testing in patients undergoing replacement of an S-ICD pulse generator., Methods: A total of 357 S-ICD implantations were performed between November 2010 and July 2019. Twenty-five consecutive patients underwent S-ICD replacement between 2015 and 2019. Clinical data, perioperative medication, technical measurements, and PRAETORIAN score were assessed and grouped according to the outcome of DFT testing., Results: In 5 of 25 patients (20%), induced ventricular fibrillation was not successfully terminated after the first or second 65-J shock after pulse generator replacement with need for external defibrillation. Repositioning of the pulse generator and/or capsulectomy at the pocket site were necessary to achieve effective DFT with 65 J in all cases. Shock impedance increased in all patients at the time of pulse generator replacement compared to first implantation and was significantly higher in patients with ineffective DFT (119 ± 17 Ω vs 93 ± 26 Ω; P = .03). Otherwise, no differences in clinical characteristics, comorbidities, body mass index, intraoperative medication, or PRAETORIAN score were predictive of defibrillation failure., Conclusion: The high proportion of patients with DFT failure after S-ICD pulse generator replacement indicates that DFT testing is mandatory to ensure safe function of the S-ICD., (Copyright © 2019 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: For years early repolarization (ER) has been considered as a benign electrocardiographic finding. However, recent reports show that ER is associated with a higher incidence of ventricular fibrillation (VF) and sudden cardiac death in patients without structural heart disease. Sporadic case studies have pointed out that ER might be related to an adverse outcome in patients with stable coronary artery disease., Objective: To evaluate the incidence of ER in patients with acute myocardial infarction complicated by VF., Methods: The study population consisted of 60 patients (80% men; mean age 61.8 ± 13.1 years) with acute myocardial infarction. Thirty consecutive patients (80% men; mean age 63.3 ± 12 years) admitted to our hospital had documented VF during myocardial infarction and were successfully resuscitated before hospital admission. A matched control group consisted of 30 patients (80% men; mean age 60.2 ± 14.2 years) with myocardial infarction without ventricular tachyarrhythmias. Twelve-lead electrocardiograms were analyzed for ER defined as J-point elevation ≥ 0.1 mV and "notching" and "slurring" of the terminal part of the QRS complex in at least 2 lateral or inferior leads., Results: The ER pattern was observed in 18 of the 60 patients with acute myocardial infarction. Mean elevation of the J point was 0.151 ± 0.46 mV. Notching of the J wave was observed in 14 of the 18 patients and slurring in 4 of the 18 patients. ER was more common in patients with myocardial infarction complicated by VF than in patients with myocardial infarction without ventricular tachyarrhythmias (47% vs 13%; P = .005). There have been no statistical differences in the distribution of ER in the 12-lead electrocardiogram (inferior 39% vs lateral 33% vs inferolateral 28%; P >.05)., Conclusion: Early repolarization pattern seems to be associated with ventricular tachyarrhythmias in the setting of acute myocardial infarction., (Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: Inappropriate shocks (IAS) remain a challenge for patients and physicians after implantation of the subcutaneous implantable cardioverter-defibrillator (S-ICD). The aims were to assess and characterize different patterns of IAS.Methods and Results: Two hundred and thirty-nine patients were implanted with an S-ICD between 2010 and 2018 for primary and secondary prevention. Follow-up data of at least 6 months were analysed. During a mean follow-up of 34.9 ± 16.0 months, a total of 73 shocks occurred in 38 patients (6%). Forty-three (59%) shocks were considered appropriate due to ventricular tachycardia/ventricular fibrillation, while 30 (41%) were inappropriate and occurred in 19 patients (8%). Myopotentials/noise was the most frequent cause of inappropriate shocks (n = 8), followed by T-wave oversensing (n = 6) and undersensing of the QRS, resulting in adaptation of the automatic gain control and inappropriate shock (n = 5). Seventy-four percent of all IAS occurred on the primary vector, while no IAS occurred on the alternate vector. In seven of eight patients (88%), IAS related to myopotentials have occurred on the primary sensing vector. Multivariate analysis identified taller patients, primary sensing vector and first-generation S-ICD device as predictors for IAS. SMART pass effectively reduced the occurrence of IAS in the second-generation S-ICD system.Conclusion: Inappropriate therapies are less frequently observed on the alternate vector. The primary vector seems to be unfavourable with regard to oversensing caused by myopotentials. Inappropriate shocks were associated with an increased rate of rehospitalization but not mortality. These observations have implications for the prevention of inappropriate S-ICD shocks. [ABSTRACT FROM AUTHOR]

Brugada syndrome (BrS) is a rare channelopathy associated with sudden cardiac death (SCD). Although outcome data of adult cohorts are well known, information on children are lacking. The aim of the present study was to analyze the clinical profile, treatment approach and long-term outcome of children affected with BrS. After a systematic review of the literature compiled from a thorough database search (PubMed, Web of Science, Cochrane Libary, Cinahl), data from a total of 4 studies which included 262 BrS patients were identified. The mean age of patients was 12.1 ± 5.5, 53.8% males and 19.8% spontaneous BrS type I. 80.2% of patients presented BrS ECG I after receiving sodium channel blockers. 76% of these patients were asymptomatic while only 17.9% suffered from recurrent syncope. Around 1.5% of the patients were admitted due to aborted SCD, and 3% suffered from atrial arrhythmias. Electrophysiological work-up was performed in 132 patients. Induction of ventricular tachycardia/ventricular fibrillation using programmed ventricular stimulation was inducible in 16 patients. 56 children received an ICD. 11 patients received quinidine. An electrical storm was documented in 1 patient. Appropriate shocks occured in 16% of the patients over a median follow-up period of 62.2 (54–64). ICD-related complications were observed in 11 patients (19.6%) with a predominance of inappropriate shocks and lead failure and/or fracture. Although BrS in the childhood is rare, diagnosis and management continues to be challenging. ICD therapy is an effective therapy in high-risk children with BrS, however, with relevant ICD-related complications. [ABSTRACT FROM AUTHOR]

Aims: The purpose of the this study was to evaluate a possible genotype-phenotype correlation in BrS patients and to analyze possible associations with clinical events in affected patients. SCN5A gene encodes the alpha-subunit of the voltage-gated sodium channel NaV1.5. Its mutations are associated with a broad spectrum of hereditary arrhythmias such as long-QT syndrome, cardiac conduction diseases, and Brugada syndrome (BrS). Experimental studies have shown an interaction between SCN5A and cellular cytoskeleton, explaining its functional role in cellular integrity of heart cells.Methods and Results: Cardiovascular magnetic resonance was performed on 81 consecutive genetically screened BrS patients and 30 healthy controls. Left ventricular (LV) and right ventricular (RV) volumes and dimensions were assessed and compared with respect to the genotype. Brugada syndrome patients with an SCN5A mutation (16 patients; 20%) revealed significantly larger RV volumes, along with lower RV ejection fraction, than patients without a mutation or controls, indicating a more severe phenotype in patients with a mutation. Furthermore, patients with an SCN5A mutation showed significantly more often a spontaneous type 1 BrS-electrocardiogram (ECG). In multivariate analysis, the presence of a spontaneous type 1 BrS-ECG showed the strongest association with cardiac events. Receiver-operating characteristic curve analysis indicated good predictive performance of RV end-diastolic volume, RV end-systolic, and LV cardiac output (area under the curve = 0.81, 0.81, and 0.2), with respect to the presence of an SCN5A mutation.Conclusion: Brugada syndrome patients with an SCN5A mutation reveal distinct changes in RV volumes and function when compared with those without an SCN5A mutation. Furthermore, mutation-positive patients have a higher likelihood of a spontaneous type 1 BrS-ECG, which is associated with a higher incidence of clinical events. Cardiovascular magnetic resonance may provide additional insight to distinguish between SCN5A mutation-positive and -negative BrS patients. [ABSTRACT FROM AUTHOR]

Inherited arrhythmia syndromes and genetic cardiomyopathies attribute in a significant proportion to sudden cardiac death. Implantable cardioverter defibrillators (ICDs) are the cornerstone in the prevention of sudden death in high-risk patients. However, ICD therapy is also associated with high rates of inappropriate shocks and/or device-related complications especially in young patients. To determine the outcome of high-risk patients with inherited arrhythmia syndromes and genetic cardiomyopathies comparing two defibrillator technologies. Between 2010 and 2018, 183 consecutive patients from two large German tertiary care centers were enrolled in the study. The majority of patients (83%) had either cardiac channelopathies or idiopathic ventricular fibrillation without cardiac structural abnormalities, while the remaining 17% had a genetic cardiomyopathy (HCM/ARVC). Eighty-six patients (47%) received a transvenous ICD (TV-ICD), while a subcutaneous ICD (S-ICD) was implanted in another 97 patients (53%). During a mean follow-up of 4.3 years, 30 patients had an appropriate ICD therapy (annual rate 3.8%). Fifteen patients experienced an inappropriate shock (annual rate 1.9%). Lead failure occurred in 17 (9%) patients and was less frequent in the S-ICD group (OR 0.48, 95%CI 0.38–0.62). Adverse defibrillator events, defined as a composite of inappropriate shocks and lead failure requiring surgical revision were significantly lower in the S-ICD group as compared to the TV-ICD group (OR 0.55, 95%CI 0.41–0.72). There was a non-significant trend towards lower appropriate shocks in the S-ICD group, that in combination with all-cause shocks yielded in a significantly higher freedom of any shock in the S-ICD group (RR 39%, p = 0.003). No deaths occurred during follow-up. The present data favor the use of the subcutaneous ICD for patients with inherited arrhythmia syndromes and genetic cardiomyopathies who do not need anti-bradycardia pacing. • High rates of appropriate shocks were observed in patients with inherited arrythmia syndromes and genetic cardiomyopathies. • Appropriate therapies were mainly offset by inappropriate therapies and lead failures in transvenous ICDs. • Subcutaneous ICD may help lowering the rate of appropriate and inappropriate shocks and thereby improve patient outcomes. [ABSTRACT FROM AUTHOR]