Thermal effects on cardiac alternans onset and development: A spatiotemporal correlation analysis

Area of Science:

• Cardiac Electrophysiology
• Nonlinear Dynamics
• Computational Biology

Background:

• Cardiac action potential duration alternans are critical precursors for life-threatening arrhythmias and sudden cardiac death.
• The thermal state of the cardiac system significantly impacts these electrical disorders, necessitating improved patient-specific clinical understanding.
• Existing theoretical and experimental frameworks require further development to fully address the influence of temperature on cardiac electrical activity.

Purpose of the Study:

• To generalize and extend previous work on cardiac alternans by conducting an in-depth spatiotemporal correlation study.
• To evaluate the characteristic length extracted from optical mapping recordings as a potential predictive index for cardiac alternans onset and evolution.
• To investigate the impact of temperature and pacing frequency on cardiac electrical dynamics and alternans development.

Main Methods:

• Utilized high-resolution optical mapping recordings of canine ventricular wedges' electrical activity.
• Analyzed data across a range of temperatures and pacing frequencies to assess spatiotemporal correlations.
• Performed theoretical investigations to evaluate the proposed characteristic length as a predictive index for alternans regimes.

Main Results:

• Demonstrated that a reduction in temperature leads to a significant drop in the characteristic length, confirming the influence of thermal instabilities.
• Showcased the characteristic length's potential as a predictive index for cardiac alternans onset and progression under various system states.
• Identified different alternans regimes through theoretical analysis using the characteristic length index.

Conclusions:

• The characteristic length is a valuable metric for predicting cardiac alternans and understanding the impact of thermal variations on cardiac dynamics.
• Thermal instabilities play a crucial role in cardiac alternans, and the characteristic length effectively captures this relationship.
• Proposed a phenomenological law linking conduction velocity, characteristic length, and temperature for future numerical modeling and clinical applications.