It is estimated that 60,000 out-of-hospital sudden cardiac arrests (SCAs) occur each year in Canada. Only about 10% of these cases survive to return home, meaning that there more than 150 deaths every day attributed to SCA.
The faster a person experiencing a SCA receives medical attention, the more favourable their outcomes will be. As a result, whether a SCA is witnessed or not is a key determinant of survival. Unfortunately, in over three-quarters of out-of-hospital SCAs, no one is there to witness the event. In many cases, minutes, hours, or days pass before the emergency is recognized.
According to Drs. Katie Dainty and Brian Grunau, immediate recognition of SCAs could triple survival rates and save over 3,400 lives in Canada per year. They believe that this can be done through remote monitoring.
TRANSFORM HF is pleased to present a 2024 Seed Grant to Drs. Dainty, Grunau, and their team for their proposal to build the first ever sensor to detect cardiac arrest – the ultimate heart failure.
Sudden Cardiac Arrest, or SCA, is when the heart unexpectedly stops pumping blood, often due to a malfunctioning cardiac electrical system.
People living with heart failure are 6 to 9 times more likely to have ventricular arrhythmias that can lead to SCA.
Dr. Dainty, Research Chair in Patient-Centred Outcomes at North York General Hospital, first met Emergency Physician and UBC Assistant Professor Dr. Grunau through CanSAVE, a research network dedicated to transforming the response to SCA. Now, with support from TRANSFORM HF, they’re working on developing a wearable sensor system to instantly recognize a SCA and alert 9-1-1.
This Seed Grant will support the team in fabricating and testing the sensor, assessing its usability, and building a software application for it to communicate with a computing system.
“It’s not often that a social scientist and sensor technology development team come together on a project,” said Dr. Dainty. “This grant is perfect for us, because it allows us to ask two kinds of questions and supports true multi-disciplinary collaboration.”
Keeping a finger on the pulse – or pulselessness – of SCA
Although it seems like wearable technologies are continually providing us with an ever-growing range of health data with increasing accuracy, they are in fact not calibrated to detect pulselessness – a key measurement for Drs. Dainty and Grunau.
“When a smart watch is giving you your heart rate measurements, its actually running a complex formula using waveforms showing the amount of light transmitted in the finger tissue,” explains Dr. Grunau. “But these formulas require a pulsatile nature of the waveforms. If there is no pulse, it can’t produce data. It will read nothing, or sometimes leave you with the last value that it measured.”
Essentially, the team needs to create a totally new algorithm to detect pulselessness consistent with an SCA – and a population to create these models from. “An individual’s risk of cardiac arrest is quite small,” explains Dr. Grunau. “We could deploy a watch on 100,000 people and maybe we’d catch 50-100 cardiac arrests – but that is a huge number of people to enroll in the study.”
“We’re in a unique position where we’re trying to find a population with a heartbeat, and then reliably without a heartbeat in the next moment,” says Dr. Dainty.
However, this hasn’t deterred Drs. Dainty and Grunau. Instead, they’ve turned to an alternate patient cohort – individuals undergoing Medical Assistance in Dying (MAiD).
Working with MAiD programs at Vancouver Coastal Health and Sunnybrook Health Science Centre, the team will test their prototype and train, evaluate, and improve a machine learning algorithm to identify features which identify an SCA. They will also investigate the impacts of sex, age, and race on these features to ensure their system works across a diverse population.
The human side of research
While the most severe heart failure patients are treated with implantable defibrillators, others living with the condition remain at increased risk of SCA. An inexpensive, unobtrusive cardiac sensor could significantly improve outcomes among this population should an arrest occur. However, such a device must be acceptable for people living with heart failure to integrate into their day-to-day life – this is where the project’s patient collaborators play an invaluable role.
“People with lived experience have been instrumental in helping us design this project,” says Dr. Dainty, who considers her patient partner as co-investigators. “Really, at the end of the day, this is all about improving life for them.”
Specifically, patient collaborators will be involved in helping the team assess the acceptance and value of wearable sensors in the heart failure population. This includes framing the research for other patient partners, formulating questions for qualitative interviews, and testing the ‘wearability’ of device prototypes.
But it’s not just the specific research activities that patient collaborators have been helpful with: “Cardiac arrest is an abstract thought for most people, but working with patients and family members brings a realistic lens. Having not lived that experience, I really need their help to see through that lens,” says Dr. Dainty. “They inform everything we do.”
Getting from here to there
The team has big hopes for their sensor once it has been fabricated, validated, tested, assessed, and connected to a cloud-based computing system. Dr. Grunau dreams of the day when users can visit the App Store, find their wearable SCA detection app, and download it on an existing smartwatch. “Boom! That’s the eventual goal.”
The team acknowledges that there are many steps from where they are now, and where they want to be. “Everyone says it’s possible… But without the little bit of cash and someone having a bit of faith in you, it’s difficult,” says Dr. Grunau.
“But that’s what’s so great about this Seed Grant!” responds an excited Dr. Dainty. “We need funding like this to get off the ground and take care of the middle steps where the challenging questions are.”
TRANSFORM HF is excited to support this important work. Stay tuned for updates on the team’s work as it unfolds!
