How ischaemic region shape affects ST potentials in models of cardiac tissue

Area of Science:

• Biophysics
• Computational Biology
• Cardiovascular Physiology

Background:

• Myocardial ischemia significantly alters cardiac electrical activity.
• Extracellular potentials during the ST segment are crucial indicators of ischemic events.
• Understanding the impact of ischemic region geometry on these potentials is vital for diagnosis.

Purpose of the Study:

• To numerically investigate the influence of ischemic region geometry on extracellular epicardial potentials during the ST segment.
• To compare the effects of rectangular, cylindrical, and semi-ellipsoidal ischemic shapes.
• To explore the impact of heterogeneous conductivities and border zone widths on these potentials.

Main Methods:

• A simple bidomain model of cardiac tissue was employed.
• Anisotropic conductivities derived from experimental data were used.
• The model was modified to incorporate heterogeneous conductivities and varying border zone widths.

Main Results:

• Rectangular and cylindrical ischemic shapes showed central depressions that evolved into three depressions with increasing thickness.
• Semi-ellipsoidal shapes exhibited a central depression that separated into two depressions.
• Ischemic region conductivity heterogeneity significantly altered potential distributions, maintaining depression up to 90% thickness.

Conclusions:

• Ischemic region geometry critically influences ST segment epicardial potential patterns.
• Conductivity heterogeneity within the ischemic region plays a substantial role in shaping these potentials.
• The findings provide insights into the electrophysiological consequences of varying myocardial infarction morphologies.