Optimal Duration of Cardiac Monitoring Following Syncope

A prospective Canadian cohort study suggested that serious underlying arrhythmia was often identified within the first 2-hours of emergency department (ED) arrival for low-risk patients, and within 6-hours for medium- and high-risk patients. Outpatient cardiac rhythm monitoring for 15-days for selected medium-risk patients and all high-risk patients discharged from the hospital should also be considered. There were 5,581 patients (mean age 53.4 years, 54.5% females, 11.6% hospitalized) available for analysis, including 346 (6.2%) censored due to incomplete 30-day follow-up. 417 (7.5%) patients suffered serious outcomes of which 207 (3.7%) were arrhythmic (161 arrhythmias, 30 cardiac device implantations, 16 unexplained death). Overall, 4123 (73.9%) were classified as Canadian Syncope Risk Score low-risk, 1062 (19.0%) medium and 396 (7.1%) high-risk. The score accurately stratified subjects as low (0.4% risk for 30-day arrhythmic outcome), medium (8.7% risk) and high-risk (25.3% risk). One-half of arrhythmic outcomes were identified within 2-hours of ED arrival in low-risk and within 6-hours in medium and high-risk patients and the residual risk after these cut-points were 0.2% for low-risk, 5.0% medium and 18.1% high-risk patients. Overall, 91.7% of arrhythmic outcomes among medium and high-risk patients including all ventricular arrhythmias were identified within 15-days. None of the low-risk patients suffered ventricular arrhythmia or unexplained death while 0.9% medium-risk and 6.3% of high-risk patients suffered them. Source: https://www.ahajournals.org/