We use openCARP, the open-source cardiac electrophysiology simulator, to perform our simulations and in-silico studies for various cardiac arrhythmia applications. This free academic research tool offers single cell as well as multiscale simulations from ion channel to organ level. In addition, data pre- and post-processing functions as well as visualization are also included in openCARP. The package also provides a python-based framework called CARPutils that enables the user to develop and share simulation pipelines to automate the modeling and simulation steps of in-silico experiments. Our team is part of the openCARP collaboration and one of the leading contributors in the development of these simulation tools.