The genetic basis of apparently idiopathic ventricular fibrillation:A retrospective overview

Aims: During the diagnostic work-up of patients with idiopathic ventricular fibrillation (VF), next-generation sequencing panels can be considered to identify genotypes associated with arrhythmias. However, consensus for gene panel testing is still lacking, and variants of uncertain significance (VUS) are often identified. The aim of this study was to evaluate genetic testing and its results in idiopathic VF patients. Methods and results: We investigated 419 patients with available medical records from the Dutch Idiopathic VF Registry. Genetic testing was performed in 379 (91%) patients [median age at event 39 years (27-51), 60% male]. Single-gene testing was performed in 87 patients (23%) and was initiated more often in patients with idiopathic VF before 2010. Panel testing was performed in 292 patients (77%). The majority of causal (likely) pathogenic variants (LP/P, n = 56, 15%) entailed the DPP6 risk haplotype (n = 39, 70%). Moreover, 10 LP/P variants were found in cardiomyopathy genes (FLNC, MYL2, MYH7, PLN (two), TTN (four), RBM20), and 7 LP/P variants were identified in genes associated with cardiac arrhythmias (KCNQ1, SCN5A (2), RYR2 (four)). For eight patients (2%), identification of an LP/P variant resulted in a change of diagnosis. In 113 patients (30%), a VUS was identified. Broad panel testing resulted in a higher incidence of VUS in comparison to single-gene testing (38% vs. 3%, P &lt; 0.001). Conclusion: Almost all patients from the registry underwent, albeit not broad, genetic testing. The genetic yield of causal LP/P variants in idiopathic VF patients is 5%, increasing to 15% when including DPP6. In specific cases, the LP/P variant is the underlying diagnosis. A gene panel specifically for idiopathic VF patients is proposed.</p

Re-visiting Meltsner: Policy Advice Systems and the Multi-Dimensional Nature of Professional Policy Analysis

10.2139/ssrn.15462511-2

Catheter ablation in highly symptomatic Brugada patients: a Dutch case series

Aims: In the past few years, promising results were described in targeting the arrhythmogenic substrate of the epicardial right ventricular outflow tract (RVOT) region in patients with Brugada syndrome (BrS). In this report, we describe our experience with endo- and epicardial substrate mapping and ablation in a series of highly symptomatic BrS patients. Methods: This case series consists of seven patients with clinical BrS diagnosis who underwent catheter ablation in two Dutch hospitals (Isala hospital Zwolle; and Amsterdam University Medical Centre, location AMC, Amsterdam) and Hamad Heart Hospital in Qatar between 2013 and 2017. All patients had an ICD and recurrent ventricular arrhythmia (VA) episodes. All patients underwent endo-and epicardial mapping of the RVOT region. Elimination of all abnormal potentials and disappearance of BrS ECG pattern during the ablation procedure was the aimed endpoint. Results: The study group consisted of seven patients with mean age 45.6 ± 16.9 years. Five patients had SCN5A mutations. One patient was excluded from analysis, since ablation could not be performed due to a very large low-voltage area and was later diagnosed with arrhythmogenic right ventricular cardiomyopathy, associated with an SCN5A mutation. One patient underwent both endo- and epicardial ablation to eliminate VA. During a mean follow-up of 3.6 ± 1.5 years, 5/6 patients remained VA free with two patients continuing quinidine. Conclusion: In patients with BrS and drug-refractory VA, ablation of the arrhythmogenic substrate in the RVOT region was associated with excellent long-term VA-free survival. The majority of these highly symptomatic BrS patients had an SCN5A mutation and also low-voltage areas epicardially. Graphic abstract: [Figure not available: see fulltext.]

Left Bundle Branch Area Pacing and Atrioventricular Node Ablation in a Single-Procedure Approach for Elderly Patients with Symptomatic Atrial Fibrillation

Background: Implantation of a permanent pacemaker and atrioventricular (AV) node ablation (pace-and-ablate) is an established approach for rate and symptom control in elderly patients with symptomatic atrial fibrillation (AF). Left bundle branch area pacing (LBBAP) is a physiological pacing strategy that might overcome right ventricular pacing-induced dyssynchrony. In this study, the feasibility and safety of performing LBBAP and AV node ablation in a single procedure in the elderly was investigated. Methods: Consecutive patients with symptomatic AF referred for pace-and-ablate underwent the treatment in a single procedure. Data on procedure-related complications and lead stability were collected at regular follow-up at one day, ten days and six weeks after the procedure and continued every six months thereafter. Results: 25 patients (mean age 79.2 &amp; PLUSMN; 4.2 years) were included and underwent successful LBBAP. In 22 (88%) patients, AV node ablation and LBBAP were performed in the same procedure. AV node ablation was postponed in two patients due to lead-stability concerns and in one patient on their own request. No complications related to the single-procedure approach were observed with no lead-stability issues at follow-up. Conclusions: LBBAP combined with AV node ablation in a single procedure is feasible and safe in elderly patients with symptomatic AF

Heritability in a SCN5A-mutation founder population with increased female susceptibility to non-nocturnal ventricular tachyarrhythmia and sudden cardiac death

BACKGROUND: Heritable cardiac-sodium channel dysfunction is associated with various arrhythmia syndromes, some predisposing to ventricular fibrillation. Phenotypic diversity among carriers of identical-by-descent mutations is often remarkable, suggesting influences of genetic modifiers. OBJECTIVE: The purpose of this study was to identify a unique SCN5A-mutation founder population with mixed clinical phenotypes and sudden cardiac death, and to investigate the heritability of electromechanical traits besides the SCN5A-mutation effect. METHODS: The 16-generation founder population segregating SCN5A c.4850_4852delTCT, p.(Phe1617del), was comprehensively phenotyped. Variance component analysis was used to evaluate the mutation's effects and assess heritability. RESULTS: In 45 p.(Phe1617del) positives, the mutation associated strongly with QTc prolongation (472 ± 60 ms vs 423 ± 35 ms in 26 mutation negatives; P <.001; odds ratio for long-QT syndrome22.4; 95% confidence interval 4.5–224.2; P <.001) and electromechanical window (EMW) negativity (−29 ± 47 ms vs 34 ± 26 ms; P <.001). Overlapping phenotypes including conduction delay and Brugada syndrome were noted in 19. Polymorphic ventricular tachyarrhythmias occurred mostly in the daytime, after arousal-evoked heart-rate acceleration and repolarization prolongation. Cox proportional hazards regression analysis revealed female gender as an independent risk factor for cardiac events (hazard ratio 5.1; 95% confidence interval 1.6–16.3; P = .006). p.(Phe1617del) was an important determinant of QTcbaseline, QTcmax, and EMW, explaining 18%, 28%, and 37%, respectively, of the trait’s variance. Significant heritability was observed for PQ interval (P = .003) after accounting for the p.(Phe1617del) effect. CONCLUSION: This SCN5A-p.(Phe1617del) founder population with phenotypic divergence and overlap reveals long-QT syndrome-related and arousal-evoked ventricular tachyarrhythmias with a female preponderance. Variance component analysis indicates additional genetic variance for PQ interval hidden in the genome, besides a dominant p. .(Phe1617del) effect on QTc and EMW

The genetic basis of apparently idiopathic ventricular fibrillation:a retrospective overview

AIMS: During the diagnostic work-up of patients with idiopathic ventricular fibrillation (VF), next-generation sequencing panels can be considered to identify genotypes associated with arrhythmias. However, consensus for gene panel testing is still lacking, and variants of uncertain significance (VUS) are often identified. The aim of this study was to evaluate genetic testing and its results in idiopathic VF patients. METHODS AND RESULTS: We investigated 419 patients with available medical records from the Dutch Idiopathic VF Registry. Genetic testing was performed in 379 (91%) patients [median age at event 39 years (27-51), 60% male]. Single-gene testing was performed in 87 patients (23%) and was initiated more often in patients with idiopathic VF before 2010. Panel testing was performed in 292 patients (77%). The majority of causal (likely) pathogenic variants (LP/P, n = 56, 15%) entailed the DPP6 risk haplotype (n = 39, 70%). Moreover, 10 LP/P variants were found in cardiomyopathy genes (FLNC, MYL2, MYH7, PLN (two), TTN (four), RBM20), and 7 LP/P variants were identified in genes associated with cardiac arrhythmias (KCNQ1, SCN5A (2), RYR2 (four)). For eight patients (2%), identification of an LP/P variant resulted in a change of diagnosis. In 113 patients (30%), a VUS was identified. Broad panel testing resulted in a higher incidence of VUS in comparison to single-gene testing (38% vs. 3%, P &lt; 0.001). CONCLUSION: Almost all patients from the registry underwent, albeit not broad, genetic testing. The genetic yield of causal LP/P variants in idiopathic VF patients is 5%, increasing to 15% when including DPP6. In specific cases, the LP/P variant is the underlying diagnosis. A gene panel specifically for idiopathic VF patients is proposed