TY - JOUR
T1 - Cardiac activation mapping using ultrasound current source density imaging (UCSDI)
AU - Olafsson, Ragnar
AU - Witte, Russell
AU - Jia, Congxian
AU - Huang, Sheng Wen
AU - Kim, Kang
AU - O'Donnell, Matthew
N1 - Funding Information:
Manuscript received april 13, 2008; accepted october 1, 2008. We gratefully acknowledge the support of the nIh through grants hl67647, EB003451, and hl082640; the department of Biomedical Engineering at the University of Michigan; and the Fulbright Fellowship Program, U.s. department of state. r. olafsson, c. Jia, s.-W. huang, K, Kim, and M. o’donnell are with the Biomedical Engineering department, University of Michigan, ann arbor, MI. r. s. Witte is with the department of radiology, University of arizona, Tucson, aZ.
PY - 2009/3
Y1 - 2009/3
N2 - 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.
AB - 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.
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U2 - 10.1109/TUFFC.2009.1073
DO - 10.1109/TUFFC.2009.1073
M3 - Article
C2 - 19411215
AN - SCOPUS:65149085287
SN - 0885-3010
VL - 56
SP - 565
EP - 574
JO - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
JF - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
IS - 3
M1 - 4816064
ER -