The exising technologies used to capture Electrocardiograms (ECGs) pose a number of challenges, including bulky hardware, slow processing times, and inadequate built-in support for ensuring the quality of collected data. We worked with a major healthcare organization to develop mobile, tablet-based ECG hardware and software. In this work, we describe requirements gathering, design, development activities for our mobile ECG data collection solutions, followed by an initial user testing. The results of this research show the potential of mobile device-based ECGs in the clinical domain, and point to types of automation that the healthcare industry may resist and a need for care in automating the collection of ECGs.