Age-Dependent Detection of Atrial Fibrillation with Implantable Cardiac Monitors in Patients with Cryptogenic Stroke

Abstract

Background Continuous monitoring using implantable cardiac monitors (ICMs) results in atrial fibrillation (AF) detection rates of up to 30% in patients with cryptogenic stroke (CS). Although higher age is an independent risk factor for AF, there are no age-specific recommendations for the implantation of ICM. Objective The aim of this study was to analyze age-related AF rates in patients with CS and continuous rhythm monitoring, to determine the rates of oral anticoagulation (OAC) and recurrent cerebrovascular events (stroke or transient ischemic attack) in patients with ICM-detected AF, and to describe the temporal relationship of AF detection and recurrent cerebrovascular events. Methods In this observational study, patients with CS provided with ICMs were systematically followed. All patients underwent 72-hour electrocardiography monitoring, transcranial Doppler ultrasound, and transthoracic echocardiography prior to ICM insertion. Follow-up included a regular outpatient presentation every 3 months with medical history, physical examination, and interrogation of the ICM. Results One-hundred eighty-six patients (mean age: 65 ± 12 years, 54% female) were included in this analysis. AF was detected in 6, 27, 56, and 65% ( p < 0.001) of patients aged less than 60, 60 to 69, 70 to 79, and more than or equal to 80 years, respectively. All patients with AF under 60 years had an impaired left ventricular systolic function. OAC was initiated in 85% of the patients with AF. Recurrent cerebrovascular events occurred in 34 patients of whom 14 had a diagnosis of AF. In nine patients, AF was diagnosed before the occurrence of a recurrent cerebrovascular event. Conclusion AF prevalence increased with age and was absent in CS patients younger than 60 years and with preserved left ventricular ejection fraction. The temporal relationship of AF and recurrent cerebrovascular events was weak.

Keywords: atrial fibrillation; cryptogenic stroke; implantable cardiac monitors.

Fig. 1

Absolute and relative AF detection in patients aged less than 60 years, 60 to 69 years, 70 to 79 years, and more than or equal to 80 years, respectively. AF, atrial fibrillation; ICM, implantable cardiac monitor.

Fig. 2

Time to first detection of atrial fibrillation in patients aged less than 60 years, 60 to 69 years, 70 to 79 years, and more than or equal to 80 years, respectively.

Fig. 3

Temporal relationship of first detected atrial fibrillation (AF) and recurrent cerebrovascular events in patients with cryptogenic stroke. Black arrows indicate recurrent cerebrovascular events, white arrows first diagnosed AF, and the gray arrow indicates coincidence of recurrent stroke and first diagnosed AF, respectively. Light gray timelines indicate the time before any of both events, while dark gray lines indicate the time after occurrence of AF and recurrent cerebrovascular event. Timelines are depicted in green in case of AF detection before recurrent cerebrovascular events and in brown in case of recurrent cerebrovascular events before AF detection. Asterisks indicate patients without sufficient anticoagulation after AF detection. Daggers indicate transient ischemic attacks (TIAs)..