Archive | 2019
The Role of Medical Therapy in Idiopathic Ventricular Fibrillation
Abstract
Idiopathic ventricular fibrillation (VF) is a diagnosis of exclusion following a resuscitated cardiac arrest which remain unexplained after comprehensive cardiac, respiratory, metabolic and toxicological evaluation. However, idiopathic VF patients may share electrophysiological and clinical features. Polymorphic ventricular tachycardia, rapidly degenerating in VF, is often triggered by short-coupled premature ventricular contractions originating from the Purkinje system or localised areas of the inferior left or right ventricular wall. Secondary prevention with an automated implantable cardiac defibrillator is a cornerstone in idiopathic VF treatment. Ablation strategies may also play a role where a substrate is identified. The role of medical therapy in idiopathic VF is, however, poorly defined, mainly due to the lack of exploratory studies and the absence of randomised clinical trials. Use of IV calcium channel antagonists and isoprenaline for the acute management of VF has proven effective in idiopathic VF associated with short-coupled Torsades de Pointes and early repolarisation, respectively. Despite the lack of large-scale data, long-term prophylaxis with quinidine seems to be effective in suppressing VF recurrence, regardless of the associated electrocardiogram phenotype. Further understanding of the underlying mechanisms of idiopathic VF, including genetic studies, will play a role in the development of targeted pharmacological therapies.