The Spectrum of Idiopathic Ventricular Fibrillation and J-Wave Syndromes

Abstract

Idiopathic ventricular fibrillation (IVF) is defined as unexplained sudden cardiac death due to ventricular fibrillation (VF) without any identifiable structural or electrical cause after extensive investigations (no phenotype). Recent data show that the use of high-density electrophysiologic mapping may ultimately offer subclinical diagnoses of cardiac disease in about 90% of individuals with IVF. Two major conditions underlie the occurrence of VF: the presence of either depolarization abnormalities due to microstructural myocardial alteration or Purkinje abnormalities manifesting as triggering ectopy or reentry in the peripheral network. J-wave syndromes are defined as a distinct electrocardiographic phenotype (slurring/notch) affecting the junction between the QRS complex and the ST segment in inferolateral leads. Recent data provide evidence for heterogeneous substrates, related to either delayed depolarization due to microstructural alterations or early repolarization abnormalities. IVF and J-wave syndromes are the result of a wide spectrum of pathophysiologic processes. The individual phenotypic characterization is essential given its implications in therapy, genetic testing, and risk stratification.

Early Repolarization Pattern and Idiopatic Sustained Monomorphic Ventricular Tachycardia: an Infrequent Combination

“…Recent evidence shows, through high density electrogram mapping, a wide spectrum of heterogeneous substrates, which may be a consequence of late depolarization or caused by abnormalities in the ER: the first one due to microstructural changes not visible on CMR, and in the second due to a voltage gradient across the ventricular wall, in which case the Purkinje system has an important triggering role 6 . In both cases, the resulting substrate could be the cause of SMVT with a focal mechanism.…”

“…In both cases, the resulting substrate could be the cause of SMVT with a focal mechanism. Current evidence shows ablation as a therapeutic option with favorable results 6 .…”

Echocardiographic deformation imaging unmasks global and regional mechanical dysfunction in patients with idiopathic ventricular fibrillation: A multicenter case-control study

“…These results suggest that "idiopathic VF" may be less associated with a completely structurally normal heart than previously appreciated, which is compatible with the significant subset of IVF patients having localized structural alterations demonstrated by detailed endocardial and epicardial mapping. 4,17…”

Ablation of premature ventricular contraction triggering ventricular fibrillation in a patient with early repolarization syndrome

“…To the best of our knowledge, we firstly report a case that radiofrequency ablation for VF‐triggering PVCs originating from the tricuspid annular area successfully suppressed the recurrence of VF in a patient with ER syndrome. Recent studies demonstrated that J wave is related to ER abnormalities or delayed depolarization owing to microstructural alterations (Haissaguerre, Nademanee, Hocini, Duchateau, et al., 2019). In this case, the abnormal electrograms related to microstructural alterations were not recorded in the endocardium of the right ventricle.…”