Pacing-induced spatiotemporal dynamics can be exploited to improve reentry termination efficacy

Area of Science:

• Cardiac Electrophysiology
• Computational Cardiology

Background:

• Cardiac arrhythmias, such as monomorphic ventricular tachycardia, can be life-threatening.
• Reentrant arrhythmias, like ventricular tachycardia, can be modeled as a circulating excitation wave.
• Premature stimuli are a potential mechanism for terminating cardiac arrhythmias.

Purpose of the Study:

• To investigate the mechanisms and requirements for terminating reentrant arrhythmias using an ionic cardiac ring model.
• To determine the critical conditions for conduction block induced by premature stimuli.
• To explore novel pacing strategies for enhancing arrhythmia termination.

Main Methods:

• Utilized an ionic cardiac ring model to simulate cardiac tissue.
• Analyzed the effects of premature stimuli on reentrant wave dynamics.
• Investigated the role of spatial dispersion in repolarization and recovery time.
• Derived analytical conditions for stimulus-induced wave dynamics.

Main Results:

• Termination of reentrant arrhythmias requires conduction block, facilitated by spatial dispersion in recovery time.
• A critical spatial gradient of 20 ms/cm in recovery time is necessary for robust conduction block.
• Pacing-induced wave dynamics can create the required spatial gradients in a homogeneous system.
• An "aggressive ramp" pacing protocol enhances termination efficacy by exploiting pacing-induced heterogeneities.

Conclusions:

• Conduction block is essential for terminating reentrant ventricular tachycardia.
• Spatial gradients in recovery time, inducible by pacing, are crucial for effective termination.
• The "aggressive ramp" pacing protocol offers a promising, clinically relevant strategy for arrhythmia management.