Build Your Own ECG-EKG Unit | Nuts & Volts Magazine
Electrocardiography for Cheap: DIY ECG Uses One LM741 Op-Amp, Five Resistors, and 'Penny Electrodes' « Adafruit Industries – Makers, hackers, artists, designers and engineers!
DIY Propeller-based ECG | Hackaday
Electrocardiogram (ECG) circuit diagram for oscilloscopes
Build your own Electrocardiogram Device | ECG Reader | Getting Started! - YouTube