Why is a broad approach that works with iPSC-derived cardiomyocytes so important to understanding molecular mechanisms underlying calcium homeostasis and arrhythmias? In this episode, Associate Editor Dr. Petra Kleinbongard (University of Duisburg-Essen) interviews author Dr. Katrin Streckfuss-Bömeke (University Medical Center Göttingen) and expert Dr. Melanie Paillard (Université Claude Bernard Lyon 1) about the new study by Ajmail et al. While arrhythmias in calcium transients are easy to detect by human perception, quantifying arrhythmias in a computer-readable manner is often difficult. To tackle the challenge, the authors developed an open-source program called Arrhythpy that quantifies and classifies confocal microscopy-based Fluo-4 Ca2+ transients to generate a measure of arrhythmia. What is unique about Arrhythpy is that it directly measures the shape and frequency of transients. The program includes two parts: frequency profiling using a method called wavelet transformation, and measuring transient peak shape using a method called autocorrelation function. After combining these measurements, Arrhythpy classifies each transient into one of 6 different subgroups. No specialty training is needed, and no specialized platforms are required to use Arrhythpy. The program can be used with different microscopes, cell types, and calcium dyes. What is the utility of Arrhythpy beyond the arrhythmia field? Listen now to find out.

Karim Ajmail, Charlotte Brand, Thomas Borchert, Benjamin Meder, Sabine Rebs, Katrin Streckfuss-Bömeke Arrhythpy: An Automated Tool to Quantify and Classify Arrhythmias in Ca2+ Transients of iPSC-Cardiomyocytes Am J Physiol Heart Circ Physiol, published September 15, 2025. DOI: 10.1152/ajpheart.00414.2025