A small study published today in Circulation: Arrhythmia and Electrophysiology, a peer-reviewed journal of the American Heart Association, suggests that a smart technology wristband may be able to automatically detect cardiac arrest, which could lead to faster medical assistance and increased survival odds when cardiac arrest occurs outside of a hospital.
The DETECT‑1b study analyzed data from 49 adults in the Netherlands with abnormal heart rhythms who underwent a medical procedure in which a life-threatening heart rhythm was briefly induced during routine treatment to correct the irregular rhythm. Pulseless ventricular tachycardia (pVT) or ventricular fibrillation (VF) was induced during the procedure. Ventricular fibrillation is considered the most serious abnormal heart rhythm and can lead to sudden cardiac death.
The algorithm‑based wearable wristband detected cardiac arrest 92% of the time. Specifically, it detected 100% of ventricular fibrillation cases and 90% of pulseless ventricular tachycardia cases. A total of 59 shockable cardiac arrest events were recorded, with nine false positives during 125 hours of recording.
“Our findings are important because many out-of-hospital cardiac arrests are unwitnessed. A smart technology wristband capable of automatically detecting cardiac arrest and triggering an alert could function as a digital witness,” said study senior author Judith Bonnes, M.D., Ph.D., a cardiologist at the Radboud University Medical Center in Nijmegen, Netherlands. “With the device automatically notifying emergency services or nearby trained responders, help could arrive sooner, which may significantly improve survival chances.”
The device uses a light-based technique, known as a photoplethysmography algorithm, to continuously monitor changes in blood flow in the wrist. Unlike previous approaches, this method allows continuous and unobtrusive monitoring in daily life, according to lead study author Roos Edgar, M.Sc., a technical physician at Radboud University Medical Center. Many commercially available smart watches use similar sensors, but most are not designed to detect cardiac arrest.
“This is the first study to externally validate such an algorithm using patient data, which is an important step toward developing a reliable detection system for real-world use,” Edgar said.
In a future application, the algorithm could be used to alert nearby lay rescuers, emergency services, or both when someone having a cardiac arrest is detected. “The goal is to connect the wristband to emergency dispatch centers and volunteer responder networks in the Netherlands so that nearby rescuers and ambulance services can be alerted immediately when cardiac arrest is detected,” Bonnes said.
Cameron Dezfulian, M.D., FAHA, chair of the American Heart Association’s Resuscitation Science Symposium Program Committee, who was not involved in the study, called the results exciting. “What is more impressive than the ability of this technology to detect cardiac arrest is the fairly low frequency of false positives it detected,” said Dezfulian, senior faculty in pediatrics and critical care at Baylor College of Medicine in Houston. “This study parallels findings from a study in Canada and one in the U.S. that shows this technology has great potential.” He noted that further research is important, as pulseless electrical activity remains the most common presenting rhythm in all cardiac arrest but accounts for a small number of the validation data for such wearable sensors.
The research was conducted in a controlled clinical setting, which is a limitation. The system’s effectiveness and reliability in real-world conditions still need to be evaluated in future studies, Bonnes said.
Study participants had a median age of 66 years, and 41 (84%) were men. Seven people underwent a procedure for an implantable defibrillator and 43 had ablation, a procedure to destroy a small area of heart tissue causing rapid and irregular heartbeats. Researchers assessed more than 125 hours of the algorithm’s data for cardiac arrest alerts. The research is part of the broader DETECT project, a collaboration of several hospitals and a company in the Netherlands conducting studies to develop a smart wristband for the automated detection of cardiac arrest and alerting emergency services.
Additional information on cardiac arrest can be found on the American Heart Association website at heart.org. The full manuscript is available at Circulation: Arrhythmia and Electrophysiology.
