(a) The seismocardiogram (SCG) signal represents the vibrations of the chest wall in response to the movement of the heart and blood with each heartbeat. SCG is measured using a miniature, three-axis accelerometer, typically positioned on the mid-sternum. (b) The SCG signal consists of vibrations in three-axes: head-to-foot, dorso-ventral, and lateral. (c) A custom, small, wearable patch for measuring SCG and electrocardiogram signals was designed. The patch is placed on the chest using three gel adhesive electrodes, and stores data locally on a micro secure digital (microSD) card. The low power design allows for > 50 hours of continuous recording and use without recharging the battery.