High-density epicardial mapping in Brugada syndrome: Depolarization and repolarization abnormalities

Area of Science:

• Cardiology
• Electrophysiology
• Medical Imaging

Background:

• The exact cause of Brugada syndrome (BrS) and abnormal electrograms (aEGMs) in the right ventricular outflow tract epicardium (RVOT-EPI) remains unclear.
• Investigating these aEGMs is crucial for understanding BrS pathogenesis.

Purpose of the Study:

• To analyze aEGMs from high-density RVOT-EPI electroanatomic mapping (EAM) in patients with BrS.
• To characterize different types of aEGMs and their relationship with cardiac activation.

Main Methods:

• Retrospective analysis of 15 BrS patients undergoing RVOT-EPI EAM with a HD-Grid catheter.
• Acquisition of electroanatomic maps before and after ajmaline administration.
• Correlation of EAM data with noninvasive electrocardiographic imaging, defining high-frequency potentials (HFPs) and low-frequency potentials (LFPs).

Main Results:

• All patients exhibited HFPs before and after ajmaline; LFPs were observed in 7 patients pre-ajmaline and all post-ajmaline.
• Ajmaline significantly increased mean activation times for HFPs, LFPs, and RVOT-EPI latest activation time (RVOTat).
• RVOTat correlated with HFPat, and was shorter than LFPat, with longer aEGMs observed in BrS patients with a history of sudden cardiac death.

Conclusions:

• High-density epicardial mapping in BrS reveals two distinct types of aEGMs.
• These findings suggest a potential correlation between these aEGMs and underlying depolarization and repolarization abnormalities in BrS.