Atrial fibrillation (AF) is an irregular heart rhythm due to disorganized atrial electrical activity, often sustained by rotational drivers called rotors. In the present work, we sought to characterize and discriminate whether simulated single stable rotors are located in the pulmonary veins (PVs) or not, only by using non-invasive signals (i.e., the 12-lead ECG). Several features have been extracted from the signals, such as Hjort descriptors, recurrence quantification analysis (RQA), and principal component analysis. All the extracted features have shown significant discriminatory power, with particular emphasis to the RQA parameters. A decision tree classifier achieved 98.48% accuracy, 83.33% sensitivity, and 100% specificity on simulated data. Clinical relevance— This study might guide ablation proce- dures, suggesting doctors to proceed directly in some patients with a pulmonary veins isolation, and avoiding the prior use of an invasive atrial mapping system.
Student Theses (1)
S. Sassi. Mechanische Modellierung und Kalibrierung von Muskelfaser-Schichten im menschlichen Herzen. Institut für Biomedizinische Technik, Karlsruher Institut für Technologie (KIT). Bachelorarbeit. 2015
Accurately describing and understanding the myocardial structure as well as the me- chanic cardiac properties would provide crucial knowledge about normal and abnormal cardiac electro-mechanics. Several studies have quantified the cardiac fiber orientation using a local coordinate system with which the helix angles were determined. The most used approaches to fulfill this task include rule-based and image-based methods.First, fiber orientations were assessed by using a novel global coordinate system. The aim of establishing such a new coordinate system is to compare it to the local coordinate system defined by Bayer. The results demonstrate that the greatest difference between the two coordinate systems is 23.2◦. The lowest fiber angle deviation has a value of 6.94◦.Second, the hyperelastic material law of Costa, which takes into account the fully three dimensional architecture of the myocardium, was implemented and then compared to the material law of Guccione. These laws have been using anisotropic strain energy functions that best fit the stress-strain behavior of the myocardium obtained from uniaxial tests. Hence the theory of continuum mechanics is used in conjunction with simulations of uni- axial tests in order to generate stress-strain curves of respectively the Costa and Guccione law. This yielded further insights into the mechanical features of the heart muscle and allowed a comparison between the two material laws mentioned above.