An advanced TWIPAD system: Wireless instant-power driven passive implantable defibrillator for the treatment of atrial fibrillation.
Atrial fibrillation (AF) is certainly the most commonly encountered cardiac arrhythmia. The overall prevalence of AF in the population is close to 0.5%. The incidence and prevalence of AF rise markedly with age. When atrial fibrillation occurs, there is certainly a significantly increased risk of stroke for the majority of patients. The haemodynamic consequences of AF occur with loss of atrial contraction, which normally contributes 15-30% of ventricular filling, due to the irregular ventricular response and the rapid ventricular rate. Several options are available to treat AF. These include pharmacological cardioversion, electrical cardioversion, pacemaker based therapies and atrial ablation techniques. Over the past two decades, much energy has been spent researching the field of transvenous defibrillation. Generally speaking, internal atrial defibrillation is a safe and highly effective procedure. The concept of transferring RF energy through the body surface via an inductive link has been investigated for over 20 years. This technology can be used to power implanted devices. In simple terms, these devices use an external coil to transmit sufficient instant power to an internalised coil that induces electric current (dc) directly to the heart, without using an internalised large capacitor.
A Transdermal Wireless Instant Powered Atrial Defibrillator (TWIPAD) could be operating at low radio frequency (RF) in order to reduce the size and hardware complexity of the device. However the aim is to achieve high reliability and energy efficiency (> 50%). The first human prototype for the assessment of the TWIPAD in transvenous atrial cardioversion, would be completed in the first 18 months. Then, the subcutaneous implantable device will be adequately engineered and encapsulated according to standards for implantable devices, including the leads to be connected to the heart. Medical device certification and ethical approval for the advanced TWIPAD system will be enquired. During the third year, the complete system, integrating the implantable device and the external handheld and battery operated power transmitter, will be tested by different methods: in-vitro, in-silico and possibly with in-vivo models.
References
[1] - “Transdermal atrial defibrillation with bipolar low-tilt pulses”. Santos, J.A., Walsh, S., Evans, N.E., Escalona, O., Manoharan, G., Anderson, J. McC, Allen, J.D., Adgey, A.A.J.. Electronics Letters, Vol. 39, No. 25, pp. 1789-1790, 2003.
[2] - “Comparing the Efficacy and Safety of a Novel Monophasic Waveform Delivered by the Passive Implantable Atrial Defibrillator With Biphasic Waveforms in Cardioversion of Atrial Fibrillation”. Ganesh Manoharan, MD; Noel Evans, PhD; Desmond Allen, MD; John Anderson, DPhil; Jennifer Adgey, MD. Circulation. 109:1686-1692, 2004.
[3] -“Radio-frequency powered atrial defibrillation with a biphasic rectangular pulse waveform: a safety study at 3 and 5 Jouls”. Escalona, O.J., Walsh, S.J., Allen, J.D., Anderson, J. McC., Adgey, A.A.J. Proceedings of the Fifth IEEE International Caracas Conference on Devices Circuits and Systems, Dominican Republic, pp. 309-314, ISBN: 0-7803-8777-5, Nov 3-5, 2004.
[4] -“NovelRectangular Biphasic and Monophasic Waveforms Delivered by a RadiofrequencyPowered Defibrillator Compared with Conventional Capacitor Based Waveforms inTransvenous Cardioversion of Atrial Fibrillation”.Walsh SJ, Manoharan G, Escalona OJ, Santos J, Evans N, Anderson JMcC, Stevenson M, Allen JD, Adgey J. EUROPACE, Vol. 8, pp. 873-880, 2006.
[5] - “Transcutaneous Dual Tuned RF Coil System Voltage Gain and Efficiency Evaluation for a Passive Implantable Atrial Defibrillator”; OJ Escalona, JJ Velasquez, N Waterman, L Chirwa, J Anderson. Computing in Cardiology, Vol. 37:569−572, 2010.
[6] - “Waveform Optimisation for internal cardioversion of atrial fibrillation”. Kodoth V, Castro NC, Glover BM, Anderson JMcC, Escalona OJ, Lau E, Manoharan G. J Electrocardiology; 44:689–693, 2011.
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[8] - “Clinical correlates of immediate success and outcome at 1-year follow-up of real-world cardioversion of atrial fibrillation: the Euro Heart Survey”. Pisters R, Nieuwlaat R, Prins MH, Heuzey J, Maggioni AP, Camm J, Crijns H. Europace, doi:10.1093/europace/eur406, 2012.
Personnel Involved
First Supervisor: Escalona, OJ Prof
Second Supervisor: McLaughlin, JAD Prof
Collaborator: Dr Rebecca Di Maio, Dr David McEneaney
Collaboration: - Heartsine Technologies Ltd.
- Craigavon Area Hospital.Synopsis:
The development and evaluation, both in-vitro and in-silico, and possibly with in-vivo models of an advanced versatile and compact TWIPAD system for transdermal wireless transmission of instant power for reliable internal atrial defibrillation, by means of resonant inductive coupling, for highly energy efficient performance, and a feedback communication control link.