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Wrist and arm sensing technologies for cardiac arrhythmias detection

Periodic Reporting for period 1 - WASTCArD (Wrist and arm sensing technologies for cardiac arrhythmias detection)

Reporting period: 2015-05-01 to 2017-04-30

Title: Wrist and arm sensing technologies for cardiac arrhythmias detection in long term monitoring

Summary
Abnormal heart rhythms are a major cause of cardiovascular disease and death in Europe. Sudden cardiac death accounts for 50% of cardiac mortality in developed countries; ventricular tachycardia or ventricular fibrillation is the commonest underlying arrhythmia. In the ambulatory population, atrial fibrillation is the commonest one, and is associated with increased risk of stroke and heart failure, particularly in the aged population. If arrhythmias are detected at an early stage of heart disease, appropriate treatment can be effective, reducing disability and death. However, in the early stages of disease these may be transient, lasting only a few seconds, and thus difficult to detect. Current approaches to cardiac rhythm monitoring include: a) non-invasive external recording devices; which are suitable for short term (<24 hours) recording, and b) implantable loop recorders, which are inserted subcutaneously beneath the chest wall; capable of monitoring heart rhythm for extended periods, but there is considerable expense associated with the device, hospitalisation costs and risk of infection.
The proposed joint research project through staff exchange activities, will investigate enabling technologies for non-invasive recording heart rhythm during long periods of time (>36 hours), using a wrist or arm wearable device with novel ECG sensing techniques and embedded real-time cardiac arrhythmia detection processes. The problem of extracting the far-field heart electrogram signal from noise components will be addressed using smart denoising algorithms.
The project will impact by establishing a successful international and intersectoral partnership for the development of new technologies addressing a significant cardiovascular healthcare problem. These technologies will be suitable for integration into current e-Health and cardiac information systems, and will impact on healthcare costs reduction by improved efficiency in the diagnosis and early treatment of cardiac disease.
For patient comfort and compliance, a long-term ECG recording system technique for a body surface location which is remote from the heart (eg. a wearable band on the wrist or positioned along arm), it has been investigated that, if possible, it is best to use dry electrodes as patients will either lose the gel or the gel-electrode interface impedance degrades. Also, to avoid the use of skin adhesives for attachment onto the body, a wearable band on the wrist or upper arm, is a feasible and practical solution.

The project has addressed the related technological challenges through a multidisciplinary, multi-sectoral and international Consortium joint effort.
In the 1st Period, the project has advanced: 65% of the Project tasks and deliverable. Currently, the clinical study to evaluate the potential solutions, which will address the clinical needs, is being implemented.

The joint research and innovation action, through a multiple of short ( < 2 months ) staff exchange activities enabling knowledge transfer; targeted to deliver integrated technological solutions and to induce long-term collaboration between the participant organisation.

The project has focused on the completion of the following specific objectives:

1) An advanced dry-electrode based monitoring system, which will enable continuous long-term, comfortable, non-invasive ECG recordings of cardiac patients presenting sporadic abnormalities of heart rate or rhythm, or for preventive long-term ECG screening schemes of healthy subjects, with cardiac related risks, for early detection and diagnosis of heart disease.
2) An advanced real-time signal processing technique for effective ECG denoising. .

Through various secondment activities in the project, an integrated technological solution in a system prototype has enabled the clinical assessment of the combined performance of the ECG denoising technique applied to the far-field ECG signal with an adjacent pair of dry-electrode wearable system device.
Technological advancement that will enable a new clinical practice by allowing continuous, long-term, non-invasive cardiac rhythm and rate monitoring (not just the heart rate) using an “adjacent” pair of ECG dry-electrodes conveniently placed, on a wearable band along the arm or wrist; thus, no surgical procedure would be required (which is the case for using an implantable “loop recorder”). The challenges of this approach lie in the difficulty of detecting an adequate cardiac electrocardiographic signal due to the low amplitude and excessive muscle artefact in these so called “far field ECG” locations. Of particular interest in solving the ECG denoising problem in this project is the proposed software applications based on smart filtering techniques, the empirical mode decomposition (EMD), the application of an advanced cardiac ECG linear estimator method and the wavelet assessed moving-averaging method.

A functionalised advanced dry-electrode material/technique, which will enable long-term, comfortable, non-invasive ECG recordings, will be developed and assessed through this joint multidisciplinary research and innovation through staff exchange actions. Key to the successful delivery of these dry electrodes is their optimised surface structure, enabling comfortable skin contact, encouraging optimal sweat/skin contact and minimising the electrode/skin contact impedance. The overall design of the electrodes, and that of the wearable sleeve platform, will be able to minimise skin deformation potentials, which give rise to the motion artefacts which have hitherto plagued such measurements. Therefore this aspect of the Project will focus on the development of more appropriate materials for electrode/skin interface electrical performance. The innovative dry-electrode technology will then be integrated into a wearable arm/wrist band system.
Photos of WASTCArD Main Representatives