Feasibility of Extended Ambulatory Electrocardiogram Monitoring to Identify Silent Atrial Fibrillation in High‐risk Patients: The Screening Study for Undiagnosed Atrial Fibrillation ( STUDY‐AF )

ABSTRACT Background Identification of silent atrial fibrillation ( AF ) could prevent stroke and other sequelae. Hypothesis Screening for AF using continuous ambulatory electrocardiographic ( ECG ) monitoring can detect silent AF in asymptomatic in patients with known risk factors. Methods We performed a single‐center prospective screening study using a wearable patch‐based device that provides up to 2 weeks of continuous ambulatory ECG monitoring ( iRhythm Technologies, Inc.). Inclusion criteria were age ≥55 years and ≥2 of the following risk factors: coronary disease, heart failure, hypertension, diabetes, sleep apnea. We excluded patients with prior AF , stroke, transient ischemic attack, implantable pacemaker or defibrillator, or with palpitations or syncope in the prior year. Results Out of 75 subjects (all male, age 69 ± 8.0 years; ejection fraction 57% ± 8.7%), AF was detected in 4 subjects (5.3%; AF burden 28% ± 48%). Atrial tachycardia ( AT ) was present in 67% (≥4 beats), 44% (≥8 beats), and 6.7% (≥60 seconds) of subjects. The combined diagnostic yield of sustained AT / AF was 11%. In subjects without sustained AT / AF , 11 (16%) had ≥30 supraventricular ectopic complexes per hour. Conclusions Outpatient extended ECG screening for asymptomatic AF is feasible, with AF identified in 1 in 20 subjects and sustained AT / AF identified in 1 in 9 subjects, respectively. We also found a high prevalence of asymptomatic AT and frequent supraventricular ectopic complexes, which may be relevant to development of AF or stroke. If confirmed in a larger study, primary screening for AF could have a significant impact on public health.