Non-invasive Blood Pressure monitoring integrated in a smart watch form factor

Blood pressure (BP) has always been one of the most important parameters in monitoring cardiovascular system conditions and coronary artery diseases (CAD), such as angina and myocardial infarction (commonly known as a heart attack). This is due to the fact that many of the changes within the cardiovascular system, like clogged arteries for example, are reflected by changes in BP. A number of methods and devices that can measure BP are available on the market for both clinical and consumer use. However, being able to measure one's own BP non-invasively, with the required frequency (even continuously) in a comfortable fashion remains an unsolved problem using currently available systems as these are often based on inflatable cuff technology. The purpose of this work is the development of a new wearable sensing system able to monitor ambulatory BP in a non-invasive and seamless manner. The method chosen to calculate BP is based on Pulse Transient Time (PTT) [1] measurements in combination with other vital signs information such as pulse, activity, environmental parameters and lifestyle [9]. PTT is derived from calculating the delay between the electrocardiograph (ECG) R wave (highest ECG spike) that identifies the hearts pump action and the highest and lowest peaks of Photoplethysmography (PPG) signal, when the wrist pulse is detected. The novel smart system being developed there for contains both PPG and ECG sensors as well as traditional inertial measurement sensors. The output of ECG and PPG can be easily visualized on a user interface [Fig. 2] to enable algorithm development based on these parameters. The device will also provide constant readings of heart rate (HR) and arterial blood oxygen saturation (SpO2).