Immediate ambulatory electrocardiographic monitoring in syncope

Background

In patients with syncope who present to the emergency department for evaluation, diagnosing an underlying cardiac arrhythmia remains difficult.

Methods

We conducted an open-label, randomized, controlled trial at 45 hospitals in the United Kingdom to assess the effects of 14-day cardiac monitoring on diagnosis, treatment, and outcomes among patients with syncope. Adults with syncope that remained unexplained after an evaluation in the emergency department were assigned in a 1:1 ratio to undergo 14-day ambulatory electrocardiographic (ECG) monitoring (the intervention group) or to receive the standard care provided for patients with unexplained syncope at each participating site (the standard-care group). The primary outcome was the mean number of patient-reported episodes of syncope at 1 year.

Results

A total of 2234 patients underwent randomization: 1123 were assigned to the intervention group and 1111 to the standard-care group. The mean age of the patients was 58.3 years, and 52.1% were male. After the exclusion of patients who did not complete any follow-up, a total of 1970 patients (1004 in the intervention group and 966 in the standard-care group) were included in the primary analysis. The mean (±SD) number of patient-reported syncope episodes at 1 year was 1.37±5.10 in the intervention group and 1.58±8.56 in the standard-care group (incidence rate ratio, 0.89; 95% confidence interval, 0.68 to 1.18; P=0.42). A total of 49 adverse events were reported in the intervention group, and 8 adverse events were reported in the standard-care group, with 1 serious adverse event in each group.

Conclusions

Among patients with syncope that remained unexplained after evaluation in the emergency department, the use of 14-day ambulatory ECG monitoring did not result in significantly fewer patient-reported syncope episodes at 1 year than standard care. (Funded by the British Heart Foundation and National Health Service Research Scotland; ASPIRED ISRCTN Registry number, ISRCTN10278811.)