Incidence and Predictive Factors of Hidden Atrial Fibrillation Detected by Implantable Loop Recorder After an Embolic Stroke of Undetermined Source

The term embolic stroke of undetermined source (ESUS) has been defined for patients with ischemic strokes, where neither a cardioembolic nor a non-cardiac source can be detected. These patients may have asymptomatic episodes of atrial fibrillation (AF). Prolonged monitoring with implantable loop recorder (ILR) and daily remote interrogation in patients after an ESUS has shown an incidence of AF of about 25%. The main objective of this study was to analyze the incidence and predictive factors of atrial fibrillation in patients with ESUS who underwent an ILR implantation. It was a single center study. From June 2013 to January 2017 all consecutive patients with an ESUS, who underwent an ILR implantation searching for hidden AF, were included. Possible predictive factors of AF were also analyzed. 65 patients were included (mean age 65.4±13.8 years, 55.4% males, mean CHA2DS2VASc score 2.3± 1.5). After a median follow-up of 17.1±10.7 months, AF was detected in 19 (29.2%) of patients. Variables associated with AF were: age > 65 years (HR 9.45 (CI 95% 1.25-71.34); p= 0.02), CHA2DS2VASC score≥2 (HR 4.09 (CI 95% 0.93-17.87); p=0,06), left atrial enlargement (HR 2.29 (CI 95% 0.89-5.91); p=0.08) and presence of Supraventricular premature complex(SVC) on 24-hour Holter (HR 4.05 (CI 95% 1.55-10.57); p = 0.004) A cut-point of 0.15% for SVC was identified to predict AF with a sensitivity and specificity of 88.9 and 90%, respectively. A CHA2DS2VASc score