Out-of-hospital cardiac arrest due to idiopathic ventricular fibrillation in patients with normal electrocardiograms: results from a multicentre long-term registry

Abstract

Aims To define the clinical characteristics and long-term clinical outcomes of a large cohort of patients with idiopathic ventricular fibrillation (IVF) and normal 12-lead electrocardiograms (ECGs). Methods and results Patients with ventricular fibrillation as the presenting rhythm, normal baseline, and follow-up ECGs with no signs of cardiac channelopathy including early repolarization or atrioventricular conduction abnormalities, and without structural heart disease were included in a registry. A total of 245 patients (median age: 38 years; males 59%) were recruited from 25 centres. An implantable cardioverter-defibrillator (ICD) was implanted in 226 patients (92%), while 18 patients (8%) were treated with drug therapy only. Over a median follow-up of 63 months (interquartile range: 25–110 months), 12 patients died (5%); in four of them (1.6%) the lethal event was of cardiac origin. Patients treated with antiarrhythmic drugs only had a higher rate of cardiovascular death compared to patients who received an ICD (16% vs. 0.4%, P = 0.001). Fifty-two patients (21%) experienced an arrhythmic recurrence. Age ≤16 years at the time of the first ventricular arrhythmia was the only predictor of arrhythmic recurrence on multivariable analysis [hazard ratio (HR) 0.41, 95% confidence interval (CI) 0.18–0.92; P = 0.03]. Conclusion Patients with IVF and persistently normal ECGs frequently have arrhythmic recurrences, but a good prognosis when treated with an ICD. Children are a category of IVF patients at higher risk of arrhythmic recurrences.

Clinical characteristics and risk factors of arrhythmia during follow‐up of patients with idiopathic ventricular fibrillation

“…We identified that repeated cardiac arrest at index SCA increases the risk of appropriate ICD therapy and ERP in baseline ECG was not associated with an increased risk of appropriate ICD therapy. With only one traumatic noncardiological death in the follow‐up period the long‐term prognosis of IVF is good, which is consistent with other studies 5–7 …”

“…In a recent study by Blom et al, 3 all conduction disturbances among IVF patients was pooled, and was found to increase risk of appropriate ICD therapy. Currently most studies include patients with LBBB in the IVF cohort, 3,5,9 however, this might change in the future 3,7 . Yet, in the present study we did not find any associations between conduction disturbances (neither individually or pooled) and the primary outcome, appropriate ICD therapy.…”

“…As expected, younger patients seemed to be tested more thoroughly (Figure 2). However, the overall diagnostic work‐up of all patients is comparable to similar studies 3,7 . Age was not a risk factor of receiving appropriate ICD therapy ( P = .718), suggesting clinicians should be careful of age discrimination when treating and assessing IVF patients clinically.…”

“…The recurrence of ventricular arrhythmias is high in IVF patients ranging between 21% and 32%, 2,3,5–7 and the only (Class I) recommended treatment of IVF is an implantable cardioverter defibrillator (ICD) implantation 8 . Recommendations regarding management of IVF patients have been published, 1,8 and studies describing predictors of arrhythmia recurrence among IVF patients are emerging 3,7,9 . To date, IVF is a diagnosis of exclusion with numerous diagnostic tests that do not fulfil any diagnostic criteria for other diseases.…”

“…1 The initial clinical assessment of SCA patients is essential, and reassessment and further diagnostic testing of patients with SCA due to initially unidentified causes may reveal an underlying diagnosis in 7%-56% of cases. [2][3][4][5] The recurrence of ventricular arrhythmias is high in IVF patients ranging between 21% and 32%, 2,3,[5][6][7] and the only (Class I) recommended treatment of IVF is an implantable cardioverter defibrillator (ICD) implantation. 8 Recommendations regarding management of IVF patients have been published, 1,8 and studies describing predictors of arrhythmia recurrence among IVF patients are emerging.…”