Insertable cardiac monitor detection of silent atrial fibrillation in candidates for percutaneous patent foramen ovale closure

Background. An underlying atrial vulnerability or a pre-existing misdiagnosed atrial fibrillation (AF) in some patients (pts) candidates to PFO closure may lead to an unnecessary percutaneous intervention. The ischaemic recurrences after device implantation affect mainly over 55 years old pts, usually in the absence of a significant residual shunt. An improvement in AF detection algorithms may lead to a more accurate clinical selection of pts candidates to PFO closure. Aim. To define the additional rate of paroxysmal AF detection, through a 6-months prolonged insertable cardiac “loop-recorder” monitoring (ICM), in patients over 55 years old with cryptogenic stroke and candidates to percutaneous PFO closure. Methods. Pts were candidates to PFO closure in presence of significant right-to-left shunt and one or more of the following high-risk features: permanent right-to-left shunt, atrial septal aneurysm, prominent Eustachian valve, recurrent brain ischemia, previous deep vein thrombosis, thrombophilia. ICM inclusion criteria: previous cryptogenic stroke (CS), more than 55 y and one or more of the following AF risk factors: heart failure, hypertension, age older than 65years, diabetes, atrial runs, left atrium dilatation, left ventricle hypertrophy, pulmonary disease, thyroid disease, obesity. ICM-detected AF threshold: AF duration of more than 5 minutes was considered clinically meaningful, indicating oral anticoagulation and excluding a percutaneous treatment. Results. From January 2008 to March 2017, 195 pts older than 55 years and suffering from CS underwent to ICM monitoring. Seventy (36%) pts of this cohort presented a high-risk PFO and were considered candidates to closure. In this group, the 6-months paroxysmal AF detection rate was 11,4% (8/70 pts). In the remaining AF-free cohort, 28 pts (45,2%) underwent to a percutaneous PFO closure (group A) and 34 (54,8%) were medically treated (group B). The following AF detection rate was 14,3% in group A and 0% in group B. The 36-months cumulative AF-free survival was 76%. Conclusion. An occult pre-existing AF may lead to an unnecessary percutaneous intervention in a significant proportion of pts over 55 years old suffering from a CS. Strict preoperative AF rule-out protocols should systematically be applied in this group of pts. A 6-months prolonged ICM monitoring is advisable, allowing a more appropriate selection of pts.