University of Twente Student Theses


Electro-mechanical resynchronisation therapy with a smart material in patients with heart failure: an experimental study

Aarnink, K.M. (2017) Electro-mechanical resynchronisation therapy with a smart material in patients with heart failure: an experimental study.

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Abstract:Introduction: Heart failure (HF), a clinical syndrome, is increasingly prevalent in West-European countries. The purpose of treatment in patients with HF is to improve their clinical condition, quality of life, prevent hospital admission and reduce mortality. A select group of HF patients with reduced ejection fraction (HFrEF) are eligible for cardiac resynchronisation therapy (CRT), which can improve refilling and contraction pattern of both ventricles. However, 30 - 40% of patients who are treated with CRT remain non-responders. The aim of this study is to investigate if a shape memory alloy (SMA) is able to support and strengthen the pump function of the heart and create an improvement in ejection fraction (EF) of 5%. Method: A paediatric ventilation balloon was used as a heart model. Flexinol®, an SMA, was placed around the heart model and activated by using pulse width modulation (PWM) technique to determine the influence of diameter, configuration, insulation and variables of PWM on volume displacement. Furthermore, temperature of the SMA and pressure within the heart model was measured with a thermal image camera and a fabricated pressure sensor, respectively. Results: An SMA with a diameter of 0.38 mm, which was placed in a spiral shape and activated with a duty cycle of 80% and a frequency of 50/min gave the highest volume displacement. A silicone tube insulated the SMA-wire well. Maximum achieved EF was 3.5%. Conclusion: This study confirmed that volume displacement was successfully demonstrated in a static heart model by activation of SMA-wires around the model. It gave furthermore insight in the influence of several factors (i.e. configuration, duty cycle, frequency, pulse intervals, diameter and insulation) on the activation of SMA-wires and corresponding volume displacement. Recommendations for further optimisation of experiments were made.
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Subject:44 medicine, 50 technical science in general, 51 materials science
Programme:Technical Medicine MSc (60033)
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