Arrhythmias

The arrhythmia research is clustered around the two most common arrhythmias: ventricular arrhythmias and atrial fibrillation.

Ventricular arrhythmia research

At present the Hartcentrum is the largest center for treatment of ventricular arrhythmias (VA) in the Netherlands and one of the largest centers in Europe. The Hartcentrum is integrated in a network of the leading ventricular arrhythmia research centers worldwide. Electrophysiologists, Cardiothoracic Surgeons and the department of Experimental Cardiology focus in a joint effort on the substrate and mechanisms of ventricular arrhythmias and on new treatment modalities in the growing number of patients with heart failure and repaired congenital heart disease. Furthermore, a close collaboration is established with the departments of Radiology and Image processing. Research projects focus on the underlying substrate and mechanisms of ventricular arrhythmia, the development of new mapping and ablation technologies and risk stratification to improve treatment and prognosis in patients with ventricular arrhythmias.

Three large interdisciplinary research projects focusing on the arrhythmogenic substrate in different stages and types of underlying heart disease are currently being conducted. (1) In a large prospective study we focus on the substrate and mechanisms of ventricular arrhythmia in patients with nonischemic cardiomyopathy which affect >1/2500 children and adults. In this study, basic and clinical researchers closely collaborate to evaluate the substrate from the subcellular to the tissue and organ level. Understanding of the substrate is the first step to individualized treatment and risk stratification. (2) In cooperation with the department of Radiology and image processing tissue imaging data are integrated during ablation procedures for complex ventricular arrhythmias and analyzed after the procedure in order to improve the understanding and visualization of the underlying arrhythmogenic substrate. Finally (3), the mechanism of ventricular arrhythmias in patients with Congenital Heart Disease is under evaluation to improve risk stratification and potential preventive intraoperative treatment strategies in patients who undergo repair or re-operation.

State-of-the-art techniques are employed during ablation procedures for complex ventricular arrhythmias, integrating CT- and contrast-enhanced MRI-derived data in order to improve procedural safety and efficacy. Integration of pre-acquired 3D CE-MRI data with real-time electroanatomical mapping data is likely to provide supplementary substrate characterization and can facilitate catheter ablation. Novel substrate-based treatment strategies are under development in order to even prevent the occurrence of ventricular arrhythmia.

To gain more insights in the limitation and potential risks of ablation in particular if performed from the epicardium we are currently developing advanced techniques to visualize not only the VA substrate but also factors with impact on procedure safety and outcome like coronary arteries and epicardial fat.

To further improve ablation results new ablation techniques such as bipolar two-irrigated-tip catheter ablation are applied in complex cases.

Modern treatment strategies for ventricular arrhythmias concomitant with reconstructive left ventricular surgery in patients after myocardial infarction are under evaluation and we currently develop new electroanatomical mapping technologies to facilitate intraoperative mapping and ablation of ventricular arrhythmia.

Atrial fibrillation research

Atrial fibrillation (AF) is the most widespread supraventricular arrhythmia, with a prevalence of 9.5 per 1000 people, which increases with age; ranging from 1 per 1000 below 55 years to 90 per 1000 above 80 years. Clinical research is directed at the various aspects of catheter and surgical ablation to improve safety and efficacy. In catheter ablation, a trial is being conducted comparing the effect of three different ablation techniques on procoagulation, cerebral micro-emboli and neuropsychological functioning. In surgical ablation, new ablation methods have been developed for both stand-alone ablation (mini-MAZE) as well as for concomitant ablation during valvular or coronary bypass surgery. Emphasis is both on outcome of this new methods as well as on atrial function after ablation. In addition, various experimental cellular models of AF are being developed to further improve our understanding of the underlying tissue substrate and mechanisms of AF. These novel insights are used to develop new treatment strategies aiming to effectively treat or prevent AF occurrence.

The evolving expertise and integration of basic and clinical research results in clinical practice ensures ongoing improvement of our understanding of arrhythmias but is also likely to improve safety and success of treatment.