Detection of microbubble formation during radiofrequency ablation using phonocardiography

Area of Science:

• Biomedical Engineering
• Acoustics
• Medical Devices

Background:

• Microbubble (MB) formation during radiofrequency (RF) ablation signals excessive tissue heating and potential explosive pops.
• Current detection of MB formation relies on echocardiography, limiting real-time monitoring during procedures.

Purpose of the Study:

• To detect and characterize acoustic energy from MB formation in an isolated tissue preparation.
• To investigate the feasibility of using high-sensitivity phonocardiography for MB detection during RF ablation.

Main Methods:

• RF lesions were created in porcine left ventricle tissue in a saline bath.
• A high-sensitivity computerized phonocardiography system was used to record acoustic signals.
• Echocardiography visualized MB formation, correlating acoustic signals with MB events.

Main Results:

• Acoustic signatures corresponding to MB formation were detected in 75% of preparations before audible pops.
• These characteristic signals occurred within the 600-2000 Hz range and 10-40 dB intensity.
• Acoustic signals preceded MB formation by an average of 51.3 seconds.

Conclusions:

• Acoustic energy from MB formation is detectable using a computer-based phonocardiography system.
• Characteristic acoustic signatures reliably indicate MB formation prior to pops.
• Phonocardiography offers a potential alternative to echocardiography for monitoring MB formation and titrating RF ablation.