Effects of Purkinje Fiber Conduction Block on Cardiac Pump Function: Computational Modeling Study

Area of Science:

• Cardiovascular Physiology
• Computational Biology
• Biomedical Engineering

Background:

• Cardiac conditions can disrupt the Purkinje fiber network, affecting left ventricular (LV) pump function.
• Understanding these disruptions is crucial for diagnosing and treating heart dysfunction.

Purpose of the Study:

• To develop and utilize a computational framework analyzing the impact of Purkinje fiber network conduction abnormalities on LV electromechanics and pump function.
• To investigate the relationship between conduction block location and cardiac performance metrics.

Main Methods:

• Coupling electrical propagation in a Purkinje fiber network with LV electromechanics.
• Simulating conduction blocks at various locations within the Purkinje fiber network.
• Analyzing changes in ejection fraction (EF), peak pressure, myocardial activation delay, and systolic dyssynchrony index (SDI).

Main Results:

• Left bundle branch block (LBBB) caused the most significant reduction in EF (59% to 46%) and peak pressure.
• Left anterior fascicle block resulted in smaller functional changes compared to LBBB.
• A nonlinear relationship was observed between activation delay/SDI and EF/myocardial strain, with a threshold identified around 240 ms activation duration and 8.4% SDI.

Conclusions:

• LV pump function is highly sensitive to the location of conduction blocks within the Purkinje fiber network.
• The study provides a mechanistic framework for understanding how Purkinje fiber conduction abnormalities lead to LV pump dysfunction.
• Identified thresholds for activation delay and SDI predict significant decreases in cardiac performance.