Wearable devices are described herein including a housing and a mount configured to mount the housing to a wrist of a wearer. The wearable devices further include first and second electrical contacts configured such that the first electrical contact is in contact with skin proximate of the wrist when the wearable device is so mounted. The second electrical contact is disposed on a surface of the wearable device away from the wrist such that, when the wearer contacts the second electrical contact with a finger or other element of the arm opposite the wrist, an electrocardiographic waveform of the wearer can be extracted from voltage fluctuations between the first and second electrodes. Such wearable devices can be used for periodic logging or other applications of the electrocardiographic waveforms of the wearer. Such logged electrocardiographic waveforms could be used to determine a medical or health state of the wearer.
