In collaboration with researchers of 14 centers throughout Europe, the United States and Canada, we have developed an online app that makes it possible to predict the risk of life-threatening cardiac arrhythmias. This app is now available for free at arvcrisk.com. Cardiologists can use this app to calculate the risk of individual patients with ACM. The predicted risk from this app can then be used to aid the physician and his or her patient with the (often difficult) decision to place an ICD. We would like to thank all patients who have joined the ACM Registry, without whom developing this app would not have been possible!