Diagnostic Yield of an Ambulatory Patch Monitor in Unexplained Emergency Department Syncope: A Pilot Study (PATCH-ED)

Syncope is a common Emergency Department (ED) presentation but the underlying diagnosis is not apparent in 60% of patients after assessment and serious adverse event rate is 7% at one month with most having acute cardiovascular events, also more likely to be unexplained after ED assessment. Many cardiovascular events are due to arrhythmia, difficult for clinicians to diagnose, as examination and Electrocardiogram (ECG) findings may both be normal and symptoms have resolved by the time the patient gets to the ED. Currently establishing a cardiac arrhythmia as the cause of syncope rests on correlating the arrhythmia with symptoms using monitoring devices such as Holter but these all have significant drawbacks. The clinical challenge in the ED is therefore to identify the moderate and high-risk patients and refer them for further investigation and monitoring if appropriate. The logistics of arranging follow up within a timely period of the patient's ED visit is often problematic for a variety of reasons including availability of timely specialty outpatient appointments, a lack of consensus of the specialty to whom the syncope patient should be referred (cardiology, medicine, neurology, general practice) and availability of Holter and other monitoring devices. For this reason most high and medium risk patients are admitted to hospital. Previous syncope clinical decision rules have not been well adopted due to their lack of sensitivity and specificity probably due to the varied and heterogeneous nature of potentially serious causes. However, the majority of patients with syncope have no serious underlying pathology and do not require hospitalisation. Rather than continued attempts at risk stratification of outcome based on presentation, more research is required into how we can better improve diagnosis and therefore treatment in order to provide improved patient benefit. We believe that ambulatory patch monitoring will allow better and earlier arrhythmia detection and plan to assess the ability of a 14-day ambulatory patch to detect serious arrhythmic outcomes at 90 days.