Advances in electrical and mechanical cardiac mapping

Abstract

Cardiac mapping--recording cardiac activity during electrophysiological testing--has evolved into an indispensable tool in studying the cardiac excitation process, analysing activation patterns, and identifying arrhythmogenic tissue. Cardiac mapping is a broad term that is used here to encompass applications that record electrical or mechanical activity of the heart or both. In recent years, simultaneous and sequential electrical mapping methods have been combined with direct mechanical measurements or imaging techniques to acquire information regarding both the electrical and mechanical activity of the heart (electromechanical mapping) during normal and irregular cardiac behavior. This paper reviews the emerging area of electromechanical mapping from the point of view of the applicable technology, including its history and application.

Electric current mapping using the acousto-electric effect

“…With the electrodes out of the way of the ultrasound and with the ultrasound passing through a homogenous saline solution we can be fairly confident that this has been accomplished. Figure 9 demonstrates that the data the amplitude of the measured signal is roughly proportional to pressure amplitude when the current amplitude is fixed as expected from relationship (4). Similarly in Figure 10, for a fixed pressure amplitude, the measured signal is proportional to current amplitude as predicted by relationship (3).…”

“…Combined electromechanical data are difficult to obtain at present and would potentially allow the diagnoses of a broader range of disorders than what current systems allow. 4 .…”

Optimizing frequency and pulse shape for ultrasound current source density imaging

“…To succeed at these interventional surgeries, accurate and rapid imaging the electric current activities is critical to localize the abnormalities and guide therapy. Conventional mapping techniques are generally invasive and require a large number of electrodes to reconstruct the current field distribution [2][3][4]. To overcome these limitations, we have developed ultrasound current source density imaging (UCSDI) [5][6][7][8][9], which potentially facilitates electrical imaging procedures and improves spatial resolution.…”

Silicon cantilever sensor for micro-/nanoscale dimension and force metrology

“…Commercial stylus instruments, which can be found in most IC fabrication facilities, offer an adjustable static force setting typically within 1 lN and 10 mN. Periodical re-calibration of the probing force is necessary for quantitative measurements (Pratt et al 2005;Malkin et al 2005) as it is common practice for the vertical position read-out of stylus instruments using thickness artifacts.…”