Background: About half of ED patients with syncope of unknown etiology are admitted for telemetry monitoring. No consensus exists regarding the optimal duration of telemetry monitoring in these patients to detect underlying arrhythmia.
Study design: Prospective cohort study.
Setting: Six EDs in Canada during September 2010–March 2015.
Synopsis: Using the Canadian Syncope Risk Score, 5,581 adults who presented to the ED within 24 hours of a syncopal event were risk stratified as low, medium, or high risk for serious adverse events (arrhythmic vs. nonarrhythmic) and then followed for 30 days. Approximately half of arrhythmias were identified among low-risk patients within 2 hours of telemetry monitoring and within 6 hours of monitoring among medium- and high-risk patients. In the low-risk group, none experienced death or ventricular arrhythmia within 30 days. In the medium- and high-risk group, 91.7% of underlying arrhythmias were identified within 15 days. The study was limited by the lack of standardized approach in the use of outpatient cardiac rhythm monitoring, which may have resulted in arrhythmia underdetection.
Bottom line: Among ED patients with syncope of unknown etiology, approximately 47% of arrhythmias were detected after 2-6 hours of telemetry monitoring. Among medium- and high-risk patients, the majority of serious arrhythmias were identified within 15 days. Based on these results, the authors recommend the use of 15-day outpatient cardiac monitoring for medium- and high-risk patients.
Citation: Thiruganasambandamoorthy V et al. Duration of electrocardiographic monitoring of emergency department patients with syncope.
Dr. Roy is a hospitalist at Beth Israel Deaconess Medical Center and instructor in medicine at Harvard Medical School.