A comparative analysis of printing techniques by using an active concentric ring electrode for bioelectrical recording

The electrocardiogram (ECG) provides useful global temporal assessment of the cardiac activity, but has limited spatial capabilities. The Laplacian electrocardiogram (LECG), an improvement over the ECG, provides high spatiotemporal distributed information about cardiac electrical activation. We designed and developed LECG tripolar concentric ring electrode active sensors based on the finite element algorithm 'nine-point method' (NPM). The active sensors were used in an array of 6 by 12 (72) locations to record bipolar and tripolar LECG from the body surface over the anterolateral chest. Compared to bipolar LECG, tripolar LECG showed significantly higher spatial selectivity which may be helpful in inferring information about cardiac activations detected on the body surface. In this study the moment of activation (MOA), an indicator of a depolarization wave passing below the active sensors, was used to surmise possible timing information of the cardiac electrical activation below the active sensors' recording sites. The MOA on the body surface was used to generate isochronal maps that may some day be used by clinicians in diagnosing arrhythmias and assessing the efficacy of therapies.

Potentials recorded on the body surface from the heart are of a spatial and temporal function. The 12-lead electrocardiogram (ECG) provides a useful means of global temporal assessment; however, it yields limited spatial information due to the smoothing effect caused by the volume conductor. In an attempt to circumvent the smoothing problem, researchers have used the five-point method (FPM) to numerically estimate the analytical solution of the Laplacian with an array of monopolar electrodes. Researchers have also developed a bipolar concentric ring electrode system to estimate the analytical Laplacian, and others have used a quasi-bipolar electrode configuration. In a search to find an electrode configuration with a close approximation to the analytical Laplacian, development of a tri-polar concentric ring electrode based on the nine-point method (NPM) was conducted. A comparison of the NPM, FPM, and discrete form of the quasi-bipolar configuration was performed over a 400 x 400 mesh with 1/400 spacing by computer modeling. Different properties of bipolar, quasi-bipolar and tri-polar concentric ring electrodes were evaluated and compared, and verified with tank experiments. One-way analysis of variance (ANOVA) with post hoc t-test and Bonferroni corrections were performed to compare the performance of the various methods and electrode configurations. It was found that the tri-polar electrode has significantly improved accuracy and local sensitivity. This paper also discusses the development of an active sensor using the tri-polar electrode configuration. A 1-cm active Laplacian tri-polar sensor based on the NPM was tested and deemed feasible for acquiring Laplacian cardiac surface potentials.