Immediate Ambulatory Electrocardiographic Monitoring in Syncope

Syncope, or fainting, is a common reason for emergency department (ED) visits. While many cases are benign, identifying underlying cardiac arrhythmias is critical for preventing future events. However, diagnosing these arrhythmias is difficult because they are often intermittent. This study, the ASPIRED trial, investigated whether providing patients with a 14-day ambulatory ECG monitor immediately after an ED visit for unexplained syncope would improve long-term outcomes compared to standard care.

Researchers conducted an open-label, randomized controlled trial across 45 hospitals in the United Kingdom. They enrolled 2,234 adults who had experienced unexplained syncope. Participants were assigned in a 1:1 ratio to either receive a 14-day ambulatory heart monitor (the intervention group) or to receive standard care, which typically involves various diagnostic tests based on local clinical guidelines. The primary outcome was the mean number of patient-reported syncope episodes at 1 year. Secondary outcomes included the detection of clinically significant cardiac arrhythmias, hospital admissions, and mortality.

At the 1-year follow-up, there was no significant difference in the mean number of patient-reported syncope episodes between the intervention group (1.37) and the standard-care group (1.58). While the intervention group had a higher rate of detecting clinically significant cardiac arrhythmias (22.0% vs. 9.0%) and a corresponding increase in therapeutic interventions like pacemaker implantation, this did not translate into a reduction in the primary outcome of recurrent syncope. Interestingly, the intervention group showed lower all-cause mortality at 1 year, though the authors note this finding should be interpreted with caution as it was a secondary outcome.

This study suggests that while extended ambulatory monitoring increases the detection of arrhythmias and leads to more clinical interventions, it does not necessarily reduce the frequency of patient-reported fainting episodes. These results provide important evidence for clinicians balancing the use of advanced diagnostic technology against standard care practices for patients with unexplained syncope.