Non-thermal ablation technology for arrhythmia therapy: Acute and chronic electrical conduction block with photosensitization reaction

Arisa Ito, Hiroki Matsuo, Tsukasa Suenari, Takuro Kajihara, Takehiro Kimura, Shunichiro Miyoshi, Tsunenori Arai

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)


We have examined the possibility of non-thermal ablation technology for arrhythmia therapy with photosensitization reaction, in which photochemically generated singlet molecular oxygen may induce myocardial electrical conduction block. In the most popular energy source for arrhythmia catheter ablation; radiofrequency current, the thermal tissue injury causes electrophysiological disruption resulting in electrical isolation of ectopic beats. The temperature-mediated tissue disruption is difficult to control because the tissue temperature is determined by the heating and thermal conduction process, so that severe complications due to excessive heat generation have been the problem in this ablation. We demonstrated the electrical conduction block of surgically exposed porcine heart tissue in vivo with photosensitization reaction. The acute myocardial electrical conduction block was examined by the stimulation and propagation set-up consisting of a stimulation electrode and two bipolar measurement electrodes. Fifteen to thirty minutes after the injection of 5-10 mg/kg water-soluble chlorine photosensitizer, Talaporfin sodium (NPe6, LS11), the laser light at the wavelength of 663 nm with the total energy density of 50-200 J/cm2 was irradiated several times with 3- 7 mm in spot-size to make electrical block line in myocardial tissue across the conduction pathway between the bipolar measurement electrodes. The propagation delay time of the potential waveform increased with increasing the irradiated line length. The observation of Azan-stained specimens in the irradiated area two weeks after the procedure showed that the normal tissue was replaced to the scar tissue, which might become to be permanent tissue insulation. These results demonstrated the possibility of non-thermal electrical conduction block for arrhythmia therapy by the photosensitization reaction.

Original languageEnglish
Title of host publicationPhotonic Therapeutics and Diagnostics VI
Publication statusPublished - 2010
EventPhotonic Therapeutics and Diagnostics VI - San Francisco, CA, United States
Duration: 2010 Jan 232010 Jan 25

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


OtherPhotonic Therapeutics and Diagnostics VI
Country/TerritoryUnited States
CitySan Francisco, CA


  • Arrhythmia
  • Talaporfin sodium
  • cardiac ablation
  • chlorin photosensitizer
  • electrical conduction block
  • myocardial tissue
  • photodynamic therapy
  • photosensitization reaction

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


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