Distinct patterns of ventricular fibrillation onset in primary electrical diseases: insights from a retrospective...

Ventricular fibrillation (VF) initiation is influenced by the underlying arrhythmia mechanism. Long QT syndrome (LQTS), catecholaminergic polymorphic ventricular tachycardia (CPVT), Brugada syndrome (BS), and idiopathic ventricular fibrillation (IVF) share overlapping clinical features that often hamper their diagnosis. This study aims to identify distinctive features of VF pattern that may provide additional diagnostic tools to discriminate them.

We included consecutive patients affected by LQTS, CPVT, BS, or IVF with recurrent VF episodes. The evaluation of VF episodes documented on electrocardiogram or implantable cardioverter-defibrillator recordings allowed us to assess different features of VF episodes including sinus rhythm preceding VF, the trigger's coupling interval (CI) initiating VF, and the mean cycle length of VF (VFCL) of the 10 first VF beats. Among 2399 patients with LQTS (n = 1587), CPVT (n = 155), BS (n = 584), or IVF (n = 62), 76 episodes of VF were identified in 30 patients. Catecholaminergic polymorphic ventricular tachycardia patients presented higher heart rate preceding VF (CL = 359 ± 26 ms; P < 0.001) and shorter trigger's CI initiating VF (256 ± 21 ms; P < 0.001). Short-long-short sequence and very long CI (>450 ms) of trigger initiating VF were mostly observed in LQTS (54%; P < 0.001 and 68%, respectively). The VFCL was shorter in CPVT patients (168 ± 15 ms; P < 0.001). Based on these results, we created a discrimination algorithm to support the diagnostic process in clinical practice.

Primary electrical diseases display distinct VF patterns. The comprehensive analysis of VF pattern, rather than of isolated VF features, holds then a major potential to support diagnostic accuracy and consequently refine therapeutic strategies in patients and in their relatives.