Sammanfattning - Medicinsk teknik

Examensarbete Kristina Willner
730503-7124
Abstract
Postoperative atrial fibrillation is a complication occurring in patients during the first
few days after cardiac surgery. For patients with a limited heart function this may
cause serious complications like thrombemolism and homodynamic instability.
Treatment strategies may vary between different hospitals but most often include use
of antiarrythmic drugs and temporary atrial pacing with electrodes sewn into the atrial
wall.
Due to the fact that medications/drugs are partially ineffective and often cause side
effects and atrial electrodes often cause complications because they perforate the
myocardium, Doc. Jan van der Linden has developed a new type of electrode. The
main advantage of the new developed electrode is that by pinching it onto the atrial
wall bleeding is prevented. Besides the ability to pace the heart, the electrode
maypossibly be used for defibrillation if atrial fibrillation occurs.
Tests in vivo have shown that the electrode can be futher improved. The threshold
values tend to raise or have a high starting value. Another risk factor is that high
current densities during defibrillating may cause tissue damage by burning.
The goal of this thesis is to develop, to evaluate and to describe the working principle
of this new type of electrode. It is shown that titanium, the material that the electrodes
are made of, is not responsible for the raise of the threshold. Tests showed that
defibrillation may work satisfactory. Studies on the atrial myocardium showed that the
rise of the threshold may be caused by circulatory disturbances. The thesis
recommends further studies to examine this phenomenon.
In case the results of such studies confirm this assumption, a slightly different design
of the electrodes is suggested to minimize these problems. Another modification of the
design makes the removal of the connecting cable of the electrodes easier.
In a field trip to the producer of the electrodes these modifications and the possibilities
to fabricate them were discussed. Other electrode designs are also presented.
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