Idiopathic short-coupled ventricular tachyarrhythmias: Systematic review and validation of electrocardiographic indices

Abstract

Introduction: Idiopathic short-coupled ventricular tachyarrhythmias make up a considerable proportion of ventricular tachyarrhythmias in structurally normal hearts and are the cause of 5–10% of unexpected sudden cardiac deaths. There is disparity in the literature regarding their description and a lack of formal diagnostic criteria to define them. Objective: To validate ECG indices for the diagnosis of these ventricular tachyarrythmias and to subsequently unify their differing descriptions in the literature under a new terminology: Idiopathic Short-Coupled Ventricular Tachyarrhythmias. Methods: We conducted a systematic review of all published studies describing short-coupled torsades de pointes, idiopathic ventricular fibrillation and polymorphic ventricular tachycardia. Published tracings were analysed using a standard set of criteria to define the different ECG intervals. Previously proposed diagnostic indices were validated using a control group of previously published long-coupled torsades de pointes cases. Results: Validation of the ECG indices revealed that a coupling interval < 400 ms was the most reliable measurement (sensitivity 100%, specificity 97%), followed by a coupling interval/QT < 1 (sensitivity 96%, specificity 100%). Conclusion: Idiopathic short-coupled ventricular tachyarrhythmias encompass all previous descriptions of this tachyarrhythmia including idiopathic ventricular fibrillation, short-coupled torsades de pointes, Purkinje-related torsades de pointes and idiopathic polymorphic ventricular tachycardia. This arrhythmia can be diagnosed by newly proposed criteria with high sensitivity and specificity. Keywords: Ventricular tachyarrhythmia, Purkinje fibres, Reentry, Delayed afterdepolarization, Electrocardiography, Sudden cardiac death