Projects:2018s1-119 Design of Calibration Platform for Medical Sensing

Supervisors

Principal Supervisor:

. Dr. Said Al-Sarawi [1]

Co-Supervisors:

. Dr. Rajiv Mahajan (RAH) [2]

. Prof. Jagan Mazumdar [3]

Project Members

. Bowen SHI

. Roziana Abdullah

Introduction

The aim of this research is to provide a platform that can be used to test the sensing sensitivity of the catheter ablation in determining its performance level. The platform that will be produced shall mimics the heart biological pulse to ensure the reliability of the test. This determination of the device performance level can be used as a guideline in proving the accuracy of the catheter ablation being used in surgery operation nowadays.

This project is intended for use of Cardiology Department of Royal Adelaide Hospital in testing their device, known as 'catheter ablation' used in performing heart surgery. The knowledge of the near and far field sensitivity of the catheter may benefit future clinicians to have a better understanding of their device and improve the accuracy of the heart surgery.

Background

Atrial fibrillation is heart-related disease that affects the upper chambers of the heart (the atria) and causes them to quiver (fibrillate). This result in affect in an abnormal heart rhythm (arrhythmia) affecting the pumping action of the blood around the body. Based on the literature published in 2015 [1] more than 33 million individuals worldwide have Atrial fibrillation (AF), and there are approximately 5 million new cases each year.AF incidence and prevalence increase with age; the prevalence of AF increase 3-fold for individuals in their 60s to 80s.

If this disease is untreated, it can increase risk of stroke by 5-fold, risk of dementia by 2-fold, as well as increased risk of myocardial infarction, heart failure (HF), and death. Hence the significant interest in treating and managing this disease [2].

One of the different techniques to treat AF is Surgical ablation (SA). In this approach normal sinus rhythm is restored, resulting in improving the long-term quality of life [3]. In most cases, more than 50%, the ablation is applied to the left atrium, followed by biatrial, then right atrium. The ablation techniques used can vary from on clinic to another. Example of these techniques are can vary from RF based, cryoablation, cut-and-sew lesions, or a combination of these techniques

In the RF technique, it is very significant to know the properties of the catheter's near and far fields sensitivity. The project will demonstrate the feasibility of building a hardware prototype that can be used to investigate the catheter's near and far fields sensitivity. The hardware should interface to a large size micro-pad array.

Project Equipment

1. Electrode signal source: DAC60096 EVM;

2. Device Under Test: 96 Electrode Array with different electrode size;

3. Catheter (Provided by Dr. Rajiv Mahajan);

4. DC Power Supply;

5. Oscilloscope;

6. Signal Generator;

7. Arduino UNO.

DAC60096 and DAC60096 EVM

DAC60096 is a 96-channel, 12-bit, low-power, serial-input, high-voltage, output digital-to-analogue convertor with conversion trigger. In other words, it is the signal source of 96 electrode array.

The evaluation model of this DAC chip was produced by Texas Instruments and it could be controlled by:

1. SPI Interface: /CS, SCLK, SDI and SDO;

2. Control logic: /LDAC, /CLEAR, STATS and TRIGG.

Microelectrode Array

Platform designed for determining the sensitivity of sensing the near field and far field of the catheter is Printed Circuit Board (PCB). The main part of the PCB is microelectrode array which will models the sensing area. Circle shaped electrodes are used where only the electrodes are left visible on the top layer and the routing is done on the bottom layer. This is to create a point-of-voltage and each of the electrodes will be individually programmed. Independently programmed electrode provide control over the activation of the individual electrodes. All the electrode will be covered with an insulation layer and the via connecting the bottom layer and the top layer will be "tented". A wall container is placed encircling the array. The container will be able to hold saline solution that represents human blood to mimic the ablation operating state.

The platform will be mounted on the DAC 60096 EVM board using the 4 headers as board-to-board connectors. DAC EVM board is a 96 channel Digital Analog Converter (DAC) which converts the digital programmed voltage to an analog output.