Comparative analysis of body surface potential distribution during cardiac pacing

Abstract

Body surface potential map (BSPM) pace-mapping is a system and method that can be used in medicine to localize with precision the site of origin of abnormal cardiac electrical activity and to guide the positioning of a catheter over this site of origin, such as the site of ventricular preexcitation in patients with the Wolff-Parkinson-White syndrome or the focus of ectopic activity in patients with tachycardia. Body surface potential distributions are measured with a large number of electrodes, e.g. 24 to 128, distributed over the entire torso surface. The electrical signals are first amplified, converted into digital data and treated to remove electrical or muscle artifacts. Data recorded during abnormal activation (reference beat) are aligned with data recorded during cardiac pacing (paced beat) so as to maximize the average value of the correlation coefficient between the reference and the paced potential distributions during a preset time interval following the beginning of the QRS complex. Reference and paced maps showing color-coded isopotential contour lines are displayed side by side for the same time instant. Visual analysis of these maps according to previously published criteria determines the relative position of the pacing catheter with respect to the focus of abnormal activation, and gives information so as to guide the catheter toward the focus.

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