Relating spatial heterogeneities to rotor formation in studying human ventricular fibrillation

Area of Science:

• Cardiovascular Electrophysiology
• Cardiac Arrhythmias
• Medical Physics

Background:

• Ventricular fibrillation (VF) is a life-threatening arrhythmia characterized by disorganized electrical activity in the ventricles, leading to sudden cardiac death.
• The precise mechanisms initiating and sustaining VF remain incompletely understood, though theories like the mother rotor model propose high-frequency sources maintain the arrhythmia.

Purpose of the Study:

• To investigate the relationship between the location of rotors and myocardial scar boundaries and dominant frequency gradients in human VF.
• To elucidate the substrate supporting rotor formation in human ventricular fibrillation.

Main Methods:

• Correlation analysis of rotor locations with scar boundary maps and dominant frequency maps.
• Utilized spatio-temporal electrical mapping of human VF data acquired from isolated human hearts.

Main Results:

• In 6 human hearts, 14 rotors were identified and all co-localized to boundary zones of scar tissue.
• Rotors were also found at locations exhibiting low-to-high dominant frequency transitions.
• The mean variance of dominant frequency within rotor locations was 0.55 Hz, with frequencies ranging from 4.15 Hz to 5.71 Hz.

Conclusions:

• The findings strongly suggest that boundaries between healthy and non-healthy myocardial tissue, alongside gradients in dominant frequencies, create a favorable substrate for rotor formation in human VF.
• Understanding these substrates could inform targeted therapies for ventricular fibrillation.