A team of researchers, led by Professor Daniel Franklin (BME) at U of T Engineering, and Dr. Andreas Tzavelis and Professor John Rogers at Northwestern University, has unveiled a new wearable medical device system designed to transform cardiovascular monitoring.
This device integrates multiple sensory modalities to provide a comprehensive assessment of hemodynamic status — the measurement of cardiovascular functioning, including how blood flows through blood vessels — surpassing conventional blood pressure monitoring. The findings were published in Nature Biomedical Engineering.
The wearable system’s core innovation lies in its ability to measure not only blood pressure, but also correlates for cardiac output and vascular resistance, which are key indicators of the body’s regulatory processes for maintaining blood pressure. This addresses a critical gap in current monitoring methods, where underlying cardiovascular issues may go unnoticed despite normal blood pressure readings.
“Your body goes through great lengths to regulate and maintain blood pressure. If the ability of your heart to pump blood declines, say due to progression of disease, your body may compensate by constricting blood vessels to maintain blood pressure,” says Tzavelis, who is an MD/PhD candidate at The Feinburg School of Medicine.
The wearable system also enables remote monitoring, allowing patients to record data throughout their everyday activities. This continuous stream of data provides a holistic view of an individual’s cardiovascular health, allowing for early detection and intervention from health care providers.
“This system offers a more comprehensive approach to quantifying an individual’s risk for heart failure and disease,” says Franklin. “Instead of periodic clinic visits, patients can now record data daily, providing invaluable insights into how their hemodynamic vital signs evolve over time.”
The system consists of two parts: a chest patch and a peripheral device, which work in tandem. The chest patch, measuring approximately 44 centimetres by 70 centimetres, is attached using medical-grade adhesive. The peripheral device can be worn on the wrist or finger, allowing for versatile and personalized monitoring.
The device advances technology found within some commercial smart watches for non-invasive blood pressure measurements. Pulse arrival time, a well-established metric for estimating blood pressure, is used in conjunction with miniature spectrometers in the peripheral device. This enables the measurement of pulse wave dynamics as they propagate through the large arteries and the skin simultaneously, offering a deeper understanding of blood pressure and its regulation.
The system is constructed using flexible printed circuit boards, encapsulated in medical-grade silicone. Its flexible design allows for various form factors, making it adaptable to different wearables, including wristbands, rings and compact patches.
Moreover, the wearables are hermetically sealed, ensuring water resistance and enabling them to be sterilized for medical use. They are wirelessly charged, eliminating the need for cumbersome connectors or charging ports.
Franklin acknowledges the collaborative effort that made this breakthrough possible.
“It’s been a large team effort, with each member contributing their expertise in various aspects of the project,” he says.
The project received support from the Ted Rogers Centre for Heart Research and was funded in part by TRANSFORM HF, a program aimed at advancing heart failure research.