Spiral defect chaos with intermittency increases mean termination time.

Area of Science:

• Computational Biology
• Nonlinear Dynamics
• Cardiac Electrophysiology

Background:

• Cardiac models exhibit stable spiral waves, but parameter changes can lead to spiral defect chaos (SDC).
• SDC is characterized by fluctuating spiral wave numbers and is implicated in atrial fibrillation.
• Atrial fibrillation often displays intermittent dynamics, switching between fibrillation and normal sinus rhythm.

Purpose of the Study:

• To investigate the transition from spiral defect chaos (SDC) to stable spiral waves in cardiac models.
• To characterize the intermittent dynamics observed during this transition.
• To explore the implications of these findings for understanding clinical atrial fibrillation.

Main Methods:

• Utilized computational cardiac models to simulate excitable systems.
• Varied a single system parameter to observe transitions in spiral wave behavior.
• Quantified intermittency and analyzed spiral wave dynamics and termination times.

Main Results:

• Demonstrated a transition from SDC to a single stable spiral wave by adjusting one parameter.
• Identified an intermediate regime of intermittency with alternating SDC and non-SDC intervals.
• Observed that mean termination time increases as the system approaches stability, with intermittent quasi-stable waves also noted.

Conclusions:

• A single parameter can control the transition between SDC and stable spiral waves, mediated by intermittency.
• The observed intermittent dynamics in models may mirror the complex behavior seen in clinical atrial fibrillation.
• These findings contribute to understanding the mechanisms underlying atrial fibrillation and its intermittent nature.