Left Ventricular Mechanical Insights Into Left Bundle Branch Pacing and Left Ventricular Septal Pacing

Area of Science:

• Cardiology
• Electrophysiology
• Cardiac Mechanics

Background:

• The relationship between left ventricular (LV) mechanical efficiency and left bundle branch area pacing (LBBAP) modalities requires further investigation.
• Understanding these dynamics is crucial for optimizing pacing strategies in patients with cardiac conduction abnormalities.

Purpose of the Study:

• To evaluate the correlation between left bundle branch pacing (LBBP) and LV septal pacing (LVSP) and myocardial work (MW).
• To compare MW during spontaneous rhythm versus LBBAP in patients with normal or moderately reduced LV ejection fraction.

Main Methods:

• Analysis of data from the TREEBEARD prospective study (NCT06324682).
• Patients were categorized into LBBP or LVSP groups.
• Myocardial work indices, including global work index, global constructive work, global wasted work, and global work efficiency, were assessed.

Main Results:

• 155 patients were included (102 LBBP, 53 LVSP).
• LBBP group showed strong correlations for all MW indices between spontaneous rhythm and pacing.
• LVSP group demonstrated moderate correlations for global work index, global constructive work, and global work efficiency, with no significant correlation for global wasted work.

Conclusions:

• LBBP preserves LV mechanical efficiency, comparable to spontaneous LV activation in patients with preserved or moderately reduced ejection fraction.
• LVSP is a viable pacing option, but it is associated with impaired LV mechanics and reduced global work efficiency.