Syncope (fainting) accounts for 160,000 emergency visits annually across Canada. <10% of these patients will have serious underlying conditions that cause syncope with arrhythmia (abnormal heart rhythm) being the most common (48.5%). About half to one-third of patients with serious underlying conditions will be discharged home and some will even die. Concerns about hidden serious conditions (particularly arrhythmia) has led to prolonged monitoring of patients in emergency or in specialized syncope units (in the US and Europe) or excessive hospitalization (admission to hospital wards). We derived and validated the Canadian Syncope Risk Score (CSRS) to predict the possibility of serious outcomes including arrhythmia within 30-days of emergency discharge. The total scores range from -3 to +11; higher scores indicating greater risk. 

In our study: 46.5% of all hospitalizations (admitted for an average of 7 days) were for cardiac rhythm monitoring, of whom 71.2% had no abnormalities identified in-hospital; and among those who suffered arrhythmias, the majority (99.4%) suffered non-lethal arrhythmias. Additionally, only a fraction (11.8%) of the high-risk (score≥4) patients discharged home had 2-day heart (Holter) monitoring applied and that too a few days later. In our study, the risk of arrhythmia/death within 30-days for scores ≥3 and ≥4 was 19.5% and 24.7% respectively with >90% occurring within 15-days (the probability of detection decreased over time). New innovative technology can now monitor rhythm remotely (outside the hospital) for prolonged periods (15 days).

Aim: We will conduct a randomized-controlled study at 21 Canadian emergency departments to compare serious arrhythmia detection in two study arms among medium and high-risk syncope patients (score ≥3) discharged home after obtaining written informed consent. Analysis will compare arrhythmia detection using 15-day versus 48-hour holter monitoring. All patients will be monitored for 15-days using an event monitor and continuous holter monitor. If serious arrhythmia is detected, patients will be transported to the emergency and if non-serious arrhythmias are detected, an interim report will be issued to the cardiologist for appropriate follow-up. We plan to recruit 566 patients (283 per arm) to prove the usefulness of prolonged cardiac monitoring. We anticipate that prolonged home monitoring will lead to improved patient safety and healthcare efficiency (better syncope care at lower cost).