The first prospective, single-blinded, phase I study to evaluate a novel, watch-based pulse detection device was published in Heart Rhythm this week. Wriskwatch by Emergency Medical Technologies is a watch-like device that serves as both a motion sensor and a pulse sensor (via a piezoelectric disk enabling detection of the radial pulse rate) designed to identify a patient in cardiac arrest. The rationale behind the device is once the watch detects pulselessness and lack of movement, an emergency medical system is immediately activated with hopes of decreasing the time a patient is in cardiac arrest and potentially improving the chance of survival.
This study was designed to simulate cardiac arrest and assess the device’s ability to correctly identify pulse status. 24 hospitalized patients and 10 patients planned for implantable cardioverter defibrillator (ICD) testing were enrolled in the trial. Pulselessness was simulated in the hospitalized patients via inflation of a blood pressure cuff on the same arm as the watch while they held still. Ventricular fibrillation was induced in the 10 ICD patients as part of normal protocol to test the ICDs – essentially creating a pulseless, motionless state. Of the 34 subjects, 5 had unusable signals, device ejection, or too much motion artifact. Of the 29 remaining, the device correctly identified a pulse state in 3 of 4 patients and the time of pulselessness in 23 of 25 patients. The device’s sensitivity and specificity to detect pulse status (based on 15 second intervals) was 99.9% and 90.3%, respectively.
Approximately 250,000 to 500,000 people die from sudden cardiac death each year in the United States. Time to electrical defibrillation directly links to survival in patients suffering from cardiac arrest due to ventricular fibrillation.
Article abstract in Heart Rhythm: The Utility of a Novel Watch-based Pulse Detection System to Detect Pulselessness in Human Subjects.