Incidence and predictors of implantable cardioverter-defibrillator therapy and its complications in idiopathic ventricular fibrillation patients.

AIMS: Idiopathic ventricular fibrillation (IVF) is a rare cause of sudden cardiac arrest. Implantable cardioverter-defibrillator (ICD) implantation is currently the only treatment option. Limited data are available on the prevalence and complications of ICD therapy in these patients. We sought to investigate ICD therapy and its complications in patients with IVF. METHODS AND RESULTS: Patients were selected from a national registry of IVF patients. Patients in whom no underlying diagnosis was found during follow-up were eligible for inclusion. Recurrence of ventricular arrhythmia (VA) was derived from medical and ICD records, electrogram records of ICD therapies were used to differentiate between appropriate or inappropriate interventions. Independent predictors for appropriate ICD shock were calculated using cox regression. In 217 IVF patients, recurrence of sustained VAs occurred in 66 patients (30%) during a median follow-up period of 6.1 years. Ten patients died (4.6%). Thirty-eight patients (17.5%) experienced inappropriate ICD therapy, and 32 patients (14.7%) had device-related complications. Symptoms before cardiac arrest [hazard ratio (HR): 2.51, 95% confidence interval (CI): 1.48-4.24], signs of conduction disease (HR: 2.27, 95% CI: 1.15-4.47), and carrier of the DPP6 risk haplotype (HR: 3.24, 1.70-6.17) were identified as independent predictors of appropriate shock occurrence. CONCLUSION: Implantable cardioverter-defibrillator therapy is an effective treatment in IVF, treating recurrences of potentially lethal VAs in approximately one-third of patients during long-term follow-up. However, device-related complications and inappropriate shocks were also frequent. We found significant predictors for appropriate ICD therapy. This may imply that these patients require additional management to prevent recurrent events.

Impaired Mental Health-Related Quality of Life in Patients with Idiopathic Ventricular Fibrillation.

BACKGROUND: Idiopathic ventricular fibrillation (iVF) is diagnosed in cardiac arrest survivors without an identifiable cause. Data regarding the health-related quality of life (HRQoL) in iVF patients are lacking. The purpose of this study was to investigate the HRQoL of iVF patients and to compare it to patients with an implantable cardioverter defibrillator (ICD) diagnosed with an underlying disease and healthy subjects. METHODS: In 61 iVF patients with an ICD (iVF-ICD) and 59 ICD patients with a diagnosis (diagnosis-ICD), HRQoL was assessed using the 12-item Short-Form Health Survey (SF-12), the EuroQoL-5 dimensions (EQ-5D), the 9-item Patient Health Questionnaire, and the ICD Patient Concerns (ICDC) Questionnaire. In addition, 860 healthy subjects completed the SF-12. RESULTS: IVF-ICD showed similar SF-12 physical summary scores compared with diagnosis-ICD patients (50.8 [interquartile range (IQR) = 42.1-53.9] vs 54.1 [IQR = 46.5-58.3]; P = 0.080) and healthy subjects (51.8 [IQR = 45.9-54.1]; P = 0.691). The mental summary score was impaired in iVF-ICD patients compared with diagnosis-ICD patients (45.9 [IQR = 40.7-49.4] vs 54.6 [IQR = 46.0-57.9]; P < 0.001) and healthy subjects (47.7 [IQR = 43.0-50.4]; P = 0.027). Scores on all five EQ-5D domains were similar between iVF-ICD patients and diagnosis-ICD patients, as well as symptoms of severe depression (19% vs 12%; P = 0.101). ICD concerns were similar between iVF-ICD and diagnosis-ICD patients (ICDC-scores 2 vs 2; P = 0.494). CONCLUSIONS: Data suggest that there is a reduced mental HRQoL in patients with iVF compared to other cardiac arrest survivors. Screening and treatment of psychological distress should therefore be considered in iVF patients.

Next-generation sequencing of a large gene panel in patients initially diagnosed with idiopathic ventricular fibrillation.

BACKGROUND: Idiopathic ventricular fibrillation (IVF) is a rare primary cardiac arrhythmia syndrome that is diagnosed in a resuscitated cardiac arrest victim, with documented ventricular fibrillation, in whom no underlying cause is identified after comprehensive clinical evaluation. In some patients, causative genetic mutations are detected that facilitate patient treatment and follow-up. The feasibility of next-generation sequencing (NGS) has increased with its greater availability and decreasing costs. OBJECTIVE: The aim of this study was to assess the diagnostic yield of NGS in patients with IVF. METHODS: A total of 33 patients initially diagnosed with IVF were included (mean age 53 ± 15 years; 14(42%) men). In all included patients, NGS of 33 genes and the DPP6 haplotype revealed no pathogenic mutations. Genetic screening comprised NGS of a panel of 179 additional genes. Variants with a minor allele frequency of <0.05% were assessed for pathogenicity by using existing mutation databases and in silico predictive algorithms. RESULTS: In 1 of 33 patients, a likely pathogenic mutation was detected. The added yield of genetic testing with NGS of 179 additional genes is 3% in patients with IVF. In 15% of patients, 1 or multiple variants of uncertain clinical significance were detected. CONCLUSION: The added yield of genetic screening of extended NGS panels in patients initially diagnosed with IVF is minimal. Routine analysis of large diagnostic NGS panels is therefore not recommended.

Long-Term Outcome of Patients Initially Diagnosed With Idiopathic Ventricular Fibrillation: A Descriptive Study.

BACKGROUND: Idiopathic ventricular fibrillation (IVF) is a rare cause of sudden cardiac arrest. Limited data are available on the long-term outcome of IVF patients. METHODS AND RESULTS: In this retrospective cohort study, 107 consecutive patients with an initial diagnosis of IVF were analyzed (age at index event 40.4 years, 60% male). Missing diagnostic data were acquired during follow-up, including genetic testing, to exclude underlying disease. A specific diagnosis was revealed in 22 of 107 patients (21%) during a median follow-up of 10.2 years. Mortality rate was 9% in IVF patients (8/85). Appropriate implantable cardioverter-defibrillator therapy was delivered in 23 patients (29%) of 78 IVF patients with an implantable cardioverter-defibrillator, with a median of 3 appropriate shocks per patient. CONCLUSIONS: One fifth of the patients initially diagnosed with IVF reveal a specific diagnosis during long-term follow-up. Additional diagnostic testing, including genetic testing, contributes to the detection of specific diseases. The recurrence rate of ventricular arrhythmias in IVF patients is high. Our data show the importance of thorough follow-up and reassessment of diagnosis in IVF patients.

Functional defecation disorders in children with lower urinary tract symptoms.

PURPOSE: We assessed the prevalence of functional defecation disorders, such as functional constipation and functional nonretentive fecal incontinence, in children referred to a tertiary pediatric urology outpatient clinic for lower urinary tract symptoms. MATERIALS AND METHODS: We reviewed the charts of 4 to 17-year-old patients evaluated due to lower urinary tract symptoms. All patients received a standardized bowel questionnaire and physical examination. We assessed the prevalence of pediatric functional defecation disorders according to Rome III criteria. Transabdominal ultrasound was performed to measure rectal diameter with a diameter of greater than 3 cm considered to indicate a rectal fecal mass. RESULTS: We analyzed the records of 113 patients, including 50 boys, with a median age of 8 years (IQR 6-10) who had lower urinary tract symptoms. Of the patients 46 had dysfunctional voiding and 38 had urge incontinence/overactive bladder. Rome III criteria for functional constipation and functional nonretentive fecal incontinence were fulfilled by 47% and 11% of patients with lower urinary tract symptoms, respectively. Children with dysfunctional voiding were more likely to fulfill the criteria for functional constipation than those with urge incontinence and other urological disorders (63% vs 42% and 28%, respectively, p = 0.009). Children with urge incontinence more likely fulfilled the criteria for functional nonretentive fecal incontinence than those with dysfunctional voiding and other urological disorders (21% vs 2.2% and 10%, respectively, p = 0.02). CONCLUSIONS: More than 50% of children with lower urinary tract symptoms evaluated at a tertiary referral center fulfilled the diagnostic criteria for functional defecation disorders. We recommend evaluating bowel habits as part of the initial assessment of a child who presents with urological symptoms. Future studies of the effect on urological symptoms of treating functional defecation disorders are justified.