Spatiotemporally controlled cardiac conduction block using high-frequency electrical stimulation

Area of Science:

• Cardiovascular Electrophysiology
• Biomedical Engineering
• Cardiac Excitation Control

Background:

• Electrical inhibition of cardiac excitation is crucial for controlling excitability and conduction.
• Existing methods using alternating current (AC) stimulation have limitations, including entrainment and potential for arrhythmias.
• A method avoiding entrainment, irrespective of stimulation amplitude, is highly desirable for safe in vivo applications.

Purpose of the Study:

• To investigate the effects of broad amplitude and frequency ranges of extracellular AC stimulation on cardiac tissue.
• To determine if high-frequency AC stimulation can inhibit cardiac excitation without causing entrainment.
• To demonstrate the ability to create controlled, reversible conduction blocks.

Main Methods:

• Utilized HL-1 cardiomyocytes cultured on microelectrode arrays.
• Applied sinusoidal and square waveform AC stimulation across various amplitude and frequency ranges.
• Investigated spatiotemporal control of conduction blocks using electrode geometry and stimulus duration.

Main Results:

• Cardiac tissue exhibits a binary response (prolonged action potentials or no effect) to stimulus amplitude at sufficiently high frequencies, avoiding entrainment.
• Demonstrated precise, reversible local conduction block formation without affecting surrounding tissue.
• Conduction blocks were spatiotemporally controlled and sustainable for up to 300 seconds.

Conclusions:

• High-frequency AC stimulation provides a binary amplitude response, enabling reversible conduction blocks without entrainment risks.
• This method offers a promising approach for in vitro arrhythmia modeling.
• Potential for safer and more effective in vivo cardiac mapping and radio-frequency ablation guidance.