Background: Sudden cardiac death (SCD) is generally associated with life-threatening ventricular arrhythmias. Supraventricular arrhythmias are an accepted cause of SCD in Wolff-Parkinson-White syndrome and complex congenital heart disease. However, the role of atrial tachyarrhythmias (ATA) in SCD in patients with structurally normal hearts is unclear.

Objectives: To present data on resuscitated patients without structural heart disease (SHD), suffering from recurrent ICD shocks, that share common clinical and electrical features suggesting that ATAs can cause SCD.

Methods: We describe the clinical characteristics and ICD analysis of syncopal events terminated with shock delivery in 5 young SCD survivors without SHD. Furthermore, we report the follow-up after ablation of the arrhythmia causing the syncopal episode.

Results: In all patients (4 male/1 female, median age 23 years, range 15-47), a surface-ECG recording in the resuscitation setting suggested ventricular fibrillation. Following the index event, all patients showed recurrent arrhythmic syncopal episodes in a setting of elevated adrenergic tone, treated with ICD shocks. ICD interrogation suggested ATAs (atrial fibrillation in 4 patients, atrial tachycardia in 1 patient), conducting to the ventricles at rates approaching 300 bpm, as the underlying arrhythmia leading to the syncopal events. ATA ablation abolished episodes of arrhythmic syncope and shock delivery in all patients after a median follow-up of 34 months. No patient died suddenly during follow-up.

Conclusions: Common clinical and electrical features define a distinct entity of SCD caused by ATAs with ultra-rapid ventricular response in otherwise healthy patients. Catheter ablation of the ATA is an effective treatment in these patients.

Editor-in-Chief
Kalyanam Shivkumar, MD, PhD, FACC
 
CME Editor
Kenneth A. Ellenbogen, MD, FACC

Author
Kelvin N.V. Bush, MD


Important Dates
Date of Release: March 24, 2025
Term of Approval/Date of CME/MOC Expiration: March 23, 2026