Abstract: A wrist-worn device heart-monitoring device is presented. The wrist-worn heart-monitoring device includes a radial tonometer configured to output a pressure signal indicating a pulse pressure wave at a user's wrist, two or more electrodes configured to output an electrical signal indicating a user's heart has been commanded to contract, and a microphone configured to output an audio signal indicating a closing of a user's aortic valve. The wrist-worn heart-monitoring device further includes a pulse transit time monitor configured to calculate a pre-ejection period of the user's heart based on at least the pressure, electrical, and audio signals, and calculate a pulse transit time based on at least the pre-ejection period, the pressure signal, and the electrical signal.

Abstract: A wrist-worn pressure sensing device includes a pressure sensor. The wrist-worn pressure sensing device also includes a first strap that sets the position of the pressure sensor on a wearer's wrist and a second strap that engages with the first strap to adjust the overall length of the strap without moving the set position of the pressure sensor on the wearer's wrist.

Abstract: An arterial pulse wave may be determined via a system that includes a pressure transducing pad configured to temporarily attach to skin of a user and to deflect outwards from the skin proportionate to pressure applied by an artery. A sensor is configured to measure outward deflection of the pressure transducing pad. A plurality of electrodes are coupled to the pressure transducing pad and configured to interface with the skin of the user when the pressure transducing pad is attached to the skin of the user. The plurality of electrodes include electrodes configured to apply a current to the skin of the user, and electrodes configured to measure a voltage differential across the skin of the user. An arterial pulse wave may be determined based on at least the measured outward deflection and the measured voltage differential.

Abstract: A wrist-worn pressure sensing device includes a pressure sensor. The wrist-worn pressure sensing device also includes a first strap that sets the position of the pressure sensor on a wearer's wrist and a second strap that engages with the first strap to adjust the overall length of the strap without moving the set position of the pressure sensor on the wearer's wrist.

Abstract: A wrist-worn device heart-monitoring device is presented. The wrist-worn heart-monitoring device includes a radial tonometer configured to output a pressure signal indicating a pulse pressure wave at a user's wrist, two or more electrodes configured to output an electrical signal indicating a user's heart has been commanded to contract, and a microphone configured to output an audio signal indicating a closing of a user's aortic valve. The wrist-worn heart-monitoring device further includes a pulse transit time monitor configured to calculate a pre-ejection period of the user's heart based on at least the pressure, electrical, and audio signals, and calculate a pulse transit time based on at least the pre-ejection period, the pressure signal, and the electrical signal.