Jessica Zègre-Hemsey, PhD ’11, RN : Saving Minutes in Cardiac Emergencies

The Ambulance Starts the Clock

Before a patient experiencing a heart attack reaches the emergency room, the clock is already running — and critical data are already streaming from the field. A monitor can transmit an electrocardiogram (ECG) from a speeding ambulance, giving clinicians an earlier view of the heart in distress. Those minutes — when time can make a life-or-death difference — are the focus of Jessica Zègre-Hemsey’s work. “Cardiovascular systems of care start the moment someone calls 911,” she says. “We can’t wait until they’re through the ER doors to start [treatment].”

As an emergency department nurse at UCSF, Zègre-Hemsey began asking urgent questions: “Why weren’t warning signs recognized earlier? Why did some patients delay calling 911? What could be done before irreversible damage occurred?” She didn’t know nurses could earn PhDs until she met Barbara Drew, PhD, a nurse scientist whose pioneering research in ECG monitoring reshaped her career. In Drew’s lab, her clinical questions became research questions. A master’s degree led to a PhD life devoted to detecting cardiac emergencies sooner.

Using Machine Learning to Recognize the Unseen

Now an associate professor at the University of North Carolina at Chapel Hill, she leads an interdisciplinary research program focused on emergency cardiac care. Her NIH-funded work uses machine learning to analyze data collected before patients reach the hospital, helping clinicians spot warning signs they might otherwise miss. By studying ECGs, symptoms, and other physiological data gathered in ambulances, her team identifies patterns linked to worse outcomes – and opportunities to intervene sooner. She is also developing algorithms that analyze 911 call audio to detect vocal changes that may signal a heart attack in progress.

Drones for Faster Defibrillation

Zègre-Hemsey is also tackling cardiac arrest’s most stubborn obstacle: access to life-saving equipment. Every minute without CPR or defibrillation decreases survival by about 10%. In her National Science Foundation-sponsored research, she studies how drones equipped with automated external defibrillators (AEDs) could augment emergency response, with simulations showing dramatically faster response times. Collaborating with researchers in Sweden and Canada, she is determined to bring drone-deployed AEDs into U.S. emergency systems. From ambulance-based diagnostics to AEDs in the sky, her work pushes lifesaving care into the community — closer to where emergencies begin, and the moments when rapid action matters most. “The ultimate goal is better outcomes,” she says. “Earlier detection. Faster intervention. Preserving quality of life.”