His bundle pacing insights from electroanatomical mapping: Topography and pacing targets

Area of Science:

• Electrophysiology
• Cardiac Anatomy
• Medical Imaging

Background:

• 3D electroanatomical mapping (EAM) of the His bundle (HB) region for His bundle pacing (HBP) is not well-described.
• Visualizing selective (S) and nonselective (NS) HB capture areas may optimize HBP lead placement.

Purpose of the Study:

• To characterize the 3D electroanatomical mapping (EAM) of the His bundle (HB) region.
• To visualize and describe selective (S) and nonselective (NS) HB capture areas during His bundle pacing (HBP).

Main Methods:

• Performed 3D electroanatomical mapping (EAM) using the NavX system in 17 patients undergoing His bundle pacing (HBP).
• Mapped the His bundle (HB) anatomical region, including selective (S-HB), nonselective (NS-HB), and right bundle (RB) capture areas.

Main Results:

• Identified S-HB capture in 11 patients, NS-HB in 14, and RB in 11. Two distinct NS-HB areas (upper and lower) were observed.
• Measured S-HB area at 1.1 cm², upper NS-HB at -1.2 cm², lower NS-HB at -1.2 cm², RB at -1.7 cm², and total His cloud at -4.1 cm².
• Observed distinct electrocardiogram (ECG) pacemap morphologies between upper and lower NS-HBP areas in 13/14 patients (p=0.006).

Conclusions:

• Pacemapping can identify distinct regions corresponding to HB anatomy.
• A linear S-HB area is typically surrounded by two separate NS areas.
• Distinct ECG morphologies from upper and lower NS-HB areas suggest these mapped features can aid implanters in His bundle pacing lead placement.