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AimsIdiopathic 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 resultsPatients 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.ConclusionImplantable 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.

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.

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.

Sudden cardiac arrest (SCA) and sudden cardiac death (SCD) are disastrous outcomes of various predominant cardiac diseases. The leading cause of SCA and SCD is coronary artery disease.1 However, SCA/SCD in young patients is mainly caused by congenital disorders of primary arrhythmic or structural origin.2 SCD is defined as death from an unexpected circulatory arrest, usually because of a cardiac arrhythmia occurring within an hour of the onset of symptoms. The definition of SCA is similar, with the addition that a medical intervention (eg, defibrillation) reverses the event.3 Idiopathic ventricular fibrillation (IVF) is a rare cause of SCA. Patients with IVF present with a sudden onset of ventricular fibrillation (VF) of unknown origin that is not identified even after extensive diagnostic testing. The exact incidence of IVF is unknown but is declining with the advance of diagnostic testing and the discovery of primary arrhythmia syndromes, such as the Brugada syndrome (BrS), catecholaminergic polymorphic ventricular tachycardia (CPVT), long-QT syndrome (LQTS), short-QT syndrome, and early repolarization syndrome (ERS). Although the exact definition of IVF has changed during the years and although new diagnostic tools are available, no specific guidelines have been developed for the definition and diagnosis of IVF, as well as a protocol for exclusion of specific cardiac diseases that cause SCA and SCD. In this review, we discuss the definition of IVF, overlap with other primary arrhythmia syndromes, the diagnosis, and follow-up of patients with IVF. Two different consensus statements about IVF have been published, and proposed 2 different definitions of IVF. The first is from the 1997 Consensus Statement of the Joint Steering Committees of the Unexplained Cardiac Arrest Registry of Europe and the United States that describes IVF as the terminology that best acknowledges our current inability to identify a causal relationship between the clinical …

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 which 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 IVF patients. METHODS: A total of 33 patients initially diagnosed with IVF were included (mean age 53±15; 42% male). In all included patients NGS of 33 genes + the DPP6 haplotype were screened and normal in a previous stage. Genetic screening comprised NGS of a panel of 179 additional genes. Variants with a minor allele frequency of