Anisotropic Cardiac Conduction.

Area of Science:

• Cardiovascular Physiology
• Biophysics of Cardiac Conduction
• Medical Imaging in Cardiology

Background:

• Cardiac conduction velocity exhibits anisotropy, primarily determined by the orientation of cardiac myocytes.
• Factors influencing anisotropic conduction include cell size, excitability, fibrosis, and gap junction properties.
• Enhanced anisotropy in disease states is linked to pathological arrhythmias, but its underlying mechanisms are not fully understood.

Purpose of the Study:

• To explore the contributing factors to enhanced anisotropic conduction in cardiac tissue during disease.
• To investigate potential mechanisms such as altered cellular excitability, gap junction function, or fibrosis.
• To highlight novel imaging and pacing techniques for assessing myocyte orientation and anisotropic conduction in vivo.

Main Methods:

• Review of existing literature on factors affecting cardiac anisotropy.
• Discussion of diffusion tensor magnetic resonance imaging (DT-MRI) for identifying myocyte orientation in explanted hearts.
• Consideration of multisite pacing protocols for in vivo estimation of myocyte orientation and anisotropic conduction.

Main Results:

• Anisotropic conduction is a fundamental property of cardiac tissue, influenced by myocyte alignment.
• Disease states can enhance cardiac anisotropy, potentially leading to arrhythmias.
• Diffusion tensor magnetic resonance imaging and multisite pacing show promise in quantifying myocyte orientation and anisotropic conduction.

Conclusions:

• The precise mechanisms driving enhanced cardiac anisotropy in disease require further investigation.
• Myocyte disarray and altered anisotropic conduction are implicated in the genesis of arrhythmias.
• Advanced imaging and pacing techniques offer new avenues for understanding the role of anisotropy in cardiac electrophysiology and disease.