DIAGNOSTIC ACCURACY OF A NOVEL CUFFLESS BLOOD PRESSURE MONITOR FOR ATRIAL FIBRILLATION SCREENING IN THE ELDERLY

Abstract

Objective: Screening for atrial fibrillation (AF) during routine automated blood pressure (BP) monitoring in asymptomatic elderly subjects is an attractive tool. This study validated a novel cuffless BP monitor (Freescan, Maisense) for AF detection during BP measurement in elderly subjects versus reference continuous electrocardiography (ECG). Design and method: Subjects recruited from a hypertension outpatient clinic were instructed to self-measure their BP in the clinic setting using the Freescan cuffless BP monitor (up to 15 attempts until 5 valid BP readings were obtained), with simultaneous ECG monitoring using a Holter device. Data from the device were transferred via Bluetooth to an online data management system, where for each BP measurement an ‘AF’ indication was displayed in case of detected AF and ‘Arrhythmia’ in other arrhythmias. Results: 1,223 Freescan BP measurements with simultaneous automated AF detection were obtained from 132 subjects. Readings reported by the device as ‘unstable’ (uncertainty of displayed rhythm result: 31%) and those reporting error (19%) were discarded. Thus, data of 108 subjects who had 5 valid Freescan BP measurements were analyzed (age 73.9 ± 7.3 years, males 65%, treated for hypertension 85%, AF in ECG 19%). In reading-to-reading analysis (N = 540 valid Freescan readings) the sensitivity, specificity and accuracy of the Freescan device in detecting AF were 70%, 99% and 94%, respectively. In subjects’ analysis (N = 108) and by considering AF diagnosis if > = 3 of 5 Freescan readings indicated AF, the sensitivity, specificity and accuracy of Freescan in detecting AF were 76%, 100%, and 95%, respectively. When the indication ‘Arrhythmia’ was regarded as AF indication, in reading-to-reading analysis the sensitivity, specificity, and accuracy were 95%, 91%, and 92%, respectively, while when using the >=3 of 5 readings for AF diagnosis rule the sensitivity, specificity and accuracy were 100%, 92% and 94%, respectively. Conclusions: The Freescan device appears to have satisfactory diagnostic accuracy for AF screening during routine self-measurement of BP in the elderly, particularly when >=3 of 5 valid readings are considered for diagnosis.