title: Electrophysiological changes correlated with temperature increases induced by high-intensity focused ultrasound ablation.
abstract: To gain better understanding of the detailed mechanisms of high-intensity focused ultrasound (HIFU) ablation for cardiac arrhythmias, we investigated how the cellular electrophysiological (EP) changes were correlated with temperature increases and thermal dose (cumulative equivalent minutes [CEM43]) during HIFU application using Langendorff-perfused rabbit hearts. Employing voltage-sensitive dye di-4-ANEPPS, we measured the EP and temperature during HIFU using simultaneous optical mapping and infrared imaging. Both action potential amplitude (APA) and action potential duration at 50% repolarization (APD50) decreased with temperature increases, and APD50 was more thermally sensitive than APA. EP and tissue changes were irreversible when HIFU-induced temperature increased above 52.3 ± 1.4°C and log10(CEM43) above 2.16 ± 0.51 (n = 5), but were reversible when temperature was below 50.1 ± 0.8°C and log10(CEM43) below -0.9 ± 0.3 (n = 9). EP and temperature/thermal dose changes were spatially correlated with HIFU-induced tissue necrosis surrounded by a transition zone.
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Ziqi
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Kumon
authors.affiliation: Department of Biomedical Engineering, Washington University at Saint Louis, MO, USA.
authors.forename: Jacob I
authors.initials: JI
authors.lastname: Laughner
authors.affiliation: Department of Biomedical Engineering, Washington University at Saint Louis, MO, USA.
authors.forename: Igor R
authors.initials: IR
authors.lastname: Efimov
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA. Electronic address: xdeng@umich.edu.
authors.forename: Cheri X
authors.initials: CX
authors.lastname: Deng
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000601:surgery*; D004195:Disease Models, Animal; D055724:Electrophysiological Phenomena / Q000502:physiology*; D057086:High-Intensity Focused Ultrasound Ablation / Q000379:methods*; D006358:Hot Temperature; D011817:Rabbits
keywords: Bioeffects; Cellular electrophysiology; High-intensity focused ultrasound; Infrared imaging; Langendorff-perfused rabbit hearts; Optical mapping