Triggers of Ventricular Fibrillation in Patients With Inferolateral J-Wave Syndrome

BACKGROUND There are few data on ventricular fibrillation (VF) initiation in patients with inferolateral J waves. OBJECTIVES This multicenter study investigated the characteristics of triggers initiating spontaneous VF in inferolateral J -wave syndrome. METHODS A total of 31 patients (age 37 +/- 14 years, 24 male) with spontaneous VF episodes associated with inferolateral J waves were evaluated to determine the origin and characteristics of triggers. The J -wave pattern was recorded in inferior leads in 11 patients, lateral leads in 3, and inferolateral leads in 17. RESULTS The VF triggers (n = 37) exhibited varying QRS durations (176 +/- 21 milliseconds, range 119-219 milliseconds) and coupling intervals (339 +/- 46 milliseconds, range 250-508 milliseconds) with a right (70%) or left (30%) bundle branch block (BBB) pattern. Trigger patterns were associated with J -wave location: left BBB triggers with inferior J waves and right BBB triggers with lateral J waves. Electrophysiologic study was performed for 22 VF triggers in 19 patients. They originated from the left or right Purkinje system in 6 and from the ventricular myocardium in 10 and were undetermined in 6. Purkinje vs myocardial triggers showed distinct electrocardiographic characteristics in coupling interval and QRS-complex duration and morphology. Abnormal epicardial substrate associated with fragmented electrograms was identified in 9 patients, with triggers originating from the same region in 7 patients. Catheter ablation resulted in VF suppression in 15 patients (79%). CONCLUSIONS VF initiation in inferolateral J -wave syndrome is associated with significant individual heterogeneity in trigger characteristics. Myocardial triggers have electrocardiographic features distinct from Purkinje triggers, and their origin often colocalizes with an abnormal epicardial substrate. (J Am Coll Cardiol EP 2024;10:1-12) (c) 2024 by the American College of Cardiology Foundation.