PhD defence J.M.E. (Lisette) van der Does

The mechanism underlying atrial fibrillation is still mainly unknown causing therapies to often fail. There is still not enough knowledge about the persistence of atrial fibrillation and mapping techniques in clinical practice are not detailed enough. We used new techniques to map electrical conduction of the heart atria in great detail. This way, we observed that even during the normal heart rhythm differences in conduction disorders occur between patients with different valvular heart diseases and mainly between patients with and without atrial fibrillation. Next, we discovered by measuring from both sides of the heart simultaneously that during atrial fibrillation the layers of the heart are asynchronously excited. Thereby creating opportunity for the emergence of new atrial fibrillation waves that maintain atrial fibrillation. Asynchrony also occurs more frequently during extra atrial beats than during normal heart beats. In some patients, extra atrial beats start atrial fibrillation and perhaps asynchrony could be involved. Finally, we investigated a way to measure asynchronous activation of the atrial wall from only one side of the wall making it easier to detect in clinical practice. We discovered that the additional, mostly unused, signals on the electrogram also originate from asynchronous activation. The best sensitivity can be achieved by using the unprocessed (unipolar) signals. Detailed mapping of conduction disorders will help us to better understand atrial fibrillation and to develop treatment strategies that are better tailored to each individual patient.

Due to corona, the PhD defences do not take place publicly in the usual way in the Senate Hall or in the Professor Andries Querido Room. The candidates will defend their dissertation either in a small group or online.