Cardiac activation mapping using ultrasound current source density imaging (UCSDI)

Ragnar Olafsson, Russell Witte, Congxian Jia, Sheng Wen Huang, Kang Kim, Matthew O'Donnell

Research output: Contribution to journalArticle

34 Scopus citations

Abstract

We describe the first mapping of biological current in a live heart using ultrasound current source density imaging (UCSDI). Ablation procedures that treat severe heart arrhythmias require detailed maps of the cardiac activation wave. The conventional procedure is time-consuming and limited by its poor spatial resolution (5-10 mm). UCSDI can potentially improve on existing mapping procedures. It is based on a pressure-induced change in resistivity known as the acousto-electric (AE) effect, which is spatially confined to the ultrasound focus. Data from 2 experiments are presented. A 540 kHz ultrasonic transducer (f/# = 1, focal length = 90 mm, pulse repetition frequency = 1600 Hz) was scanned over an isolated rabbit heart perfused with an excitation-contraction decoupler to reduce motion significantly while retaining electric function. Tungsten electrodes inserted in the left ventricle recorded simultaneously the AE signal and the low-frequency electrocardiogram (ECG). UCSDI displayed spatial and temporal patterns consistent with the spreading activation wave. The propagation velocity estimated from UCSDI was 0.25 ± 0.05 mm/ms, comparable to the values obtained with the ECG signals. The maximum AE signal-to-noise ratio after filtering was 18 dB, with an equivalent detection threshold of 0.1 mA/ cm2. This study demonstrates that UCSDI is a potentially powerful technique for mapping current flow and biopotentials in the heart.

Original languageEnglish (US)
Article number4816064
Pages (from-to)565-574
Number of pages10
JournalIEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Volume56
Issue number3
DOIs
StatePublished - Mar 1 2009

ASJC Scopus subject areas

  • Instrumentation
  • Acoustics and Ultrasonics
  • Electrical and Electronic Engineering

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