CytoCypher BV 1 article published in JoVE Biology Real-Time Measurements of Calcium and Contractility Parameters in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes Rafeeh Dinani1,2, Emmy Manders1,2,3, Michiel Helmes1,2,3, Lili Wang4, Bjorn C. Knollmann4, Diederik W. D. Kuster1,2, Jolanda van der Velden1,2 1Division of Physiology, Amsterdam UMC, Vrije University, 2Heart Failure & Arrhythmias, Amsterdam Cardiovascular Sciences, 3CytoCypher BV, 4Division of Clinical Pharmacology, Vanderbilt School of Medicine Here, an established method is described to perform contractility and calcium measurements in human induced pluripotent stem cell-derived cardiomyocytes using an optics-based platform. This platform enables researchers to study the effect of mutations and the response to various stimuli in a rapid and reproducible manner.