A smart-technology wearable wristband may be able to automatically detect cardiac arrest, potentially leading to faster medical assistance and improved survival rates when cardiac arrest occurs outside of a hospital, according to new research published today in Circulation: Arrhythmia and Electrophysiology, a peer-reviewed scientific journal of the American Heart Association.
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 the procedure, pulseless ventricular tachycardia (pVT) or ventricular fibrillation (VF) was induced—both of which are dangerous rhythms that can lead to sudden cardiac death. The algorithm-based wristband detected cardiac arrest 92% of the time.
“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 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 (photoplethysmography algorithm) to continuously monitor changes in blood flow in the wrist. This approach differs from previous methods because it allows continuous and unobtrusive monitoring in daily life, said 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.
A total of 59 shockable cardiac arrest events were recorded. The device accurately detected cardiac arrest in 92% of cases, including 100% of ventricular fibrillation and 90% of pulseless ventricular tachycardia. Nine events were classified as false positives during 125 hours of recording. In the per-patient analysis, considering only the first event per person, the accuracy for detecting the irregular rhythms was 92%.
“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.
Cameron Dezfulian, M.D., FAHA, chair of the American Heart Association’s Resuscitation Science Symposium Program Committee, who was not involved in the study, noted the low frequency of false positives as particularly impressive. “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.”
However, Dezfulian cautioned that pulseless electrical activity remains the most common presenting rhythm in all cardiac arrest, but it accounts for only a small number of the validation data for such wearable sensors. “Further research will be important,” he said.
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. In a future application, the algorithm could be used to alert nearby lay rescuers, emergency services, or both. “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.
The DETECT-1b study involved 49 adults with a median age of 66 years, and 41 (84%) were men. Participants wore the smart technology wristband while undergoing ventricular tachycardia ablation or subcutaneous implantable cardioverter defibrillator implantation. The research is part of the broader DETECT project, a collaboration of several hospitals and a company in the Netherlands.
