Design, Fabrication and Modelling of Intracardiac Catheter for Electrical Mapping of Atrial Fibrillation

Atrial Fibrillation (AF) is the most common heart rhythm disturbance affecting one quarter of people older than 40 years old. It is predicted to affect 6 – 12 M people in the USA by 2050 and 17.9 M in Europe by 2060 (Schnabel et al. 2015). Catheter ablation is a treatment for patients with recurring AF where areas of heart are ablated in an attempt to restore natural rhythm. The success of this treatment is highly dependent on the accurate location of AF sources using 3D electro-anatomic mapping systems (EAMS). Current EAMS lack the needed spatial-temporal resolution to perform panoramic mapping while doing ablation. Various types of catheters are commercially available to perform mapping. However, they have limited resolution and most required contact between the electrodes and the atrial endocardial surface. This is difficult to achieve resulting in half of the recordings being discarded during mapping. Ideally, data is obtained with sampling over a maximum volume and with the highest density of electrodes. Inverse mapping techniques can use this data and avoid the reliance on the need for contact mapping. This thesis is focused on developing an improved accuracy representation of atrial electrical activation by solving the inverse problem supporting the use of non-contacting electrodes. The tools developed are able to be applied to designing a better multi-electrode basket catheter (MBC) for AF mapping A multi-electrode basket catheter (MBC) with spatially uniform electrode distribution and having 96 electrodes based on flexible splines was developed. The use of flexible splines based on commercially available printed circuit board technology made the assembly of the catheter prototype feasible. The prototype was used in animal experiments to test the advantages of optimised electrode distribution. The experiment showed that the 96 electrodes were able to record precise representation of atrial signal characteristics resulting to higher spatial temporal resolution compared to using an equivalent Constellation catheter. The use of non-contacting electrodes in our prototype may provide a more robust approach to AF inverse mapping because all electrode information can be used to accurately locate sources of macroentry. A novel in-silico test bed using the method of fundamental solutions (MFS) approach was used to test various MBC designs in inverse mapping. This is novel in a way that it provided a more realistic representation of the physiological makeup of atria accounting for the presence of inlet and outlet valves. The approach used was proven to be more computationally efficient and superior than the conventional boundary based numerical solution such as finite element method (FEM). Inverse mapping was performed using the MFS forward interpolated potentials for the electrodes of various MBC designs. A dual-spline catheter model having 128 electrodes spatially uniform on 16 splines was found to accurately recover the rotor potential field and locate the macro-reentry for global mapping. Interestingly, for region of interest mapping (ROI) where ROI is specified near the LAA, a 38 mm diameter 64-electrode spatially uniform on 16 splines MBC placed at LAA was able to achieve the same quality indices as the 42 mm dual-spline model placed at the center of the atrial cavity. The result of this thesis showed great promise for improving mapping results to support more reliable guidance of AF ablation therapy. Further, the computational test bed has shown promise for evaluating the performance of new catheter designs.

Name thesis:degree_name

PhD

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Bioengineering

Grantor dc:publisher

ResearchSpace@Auckland

Year dc:date.issued

2022

Author dc:creator

• Ordono, Emma Evangelista

Advisors dc:contributor.advisor

• Budgett, David
• Smaill, Bruce

Statement dc:rights

• Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Licence dc:rights.uri

• https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm

Handle dc:identifier.uri

https://hdl.handle.net/2292/58290

OAI identifier oai:identifier

oai:researchspace.auckland.ac.nz:2292/58290