LAUSR

Study purpose Routine transthoracic echocardiography (TTE) in patients with syncope or presyncope is resource-intensive. We assessed if risk thresholds defined by a validated risk score may identify patients at low risk of cardiac abnormality in whom TTE is unnecessary. Study design We conducted a retrospective study of all general medicine patients with syncope/presyncope presenting to a tertiary hospital between July 2016 and September 2020 and who underwent TTE. The Canadian Syncope Risk Score (CSRS) was used to categorise patients as low to very low risk (score −3 to 0) or moderate to high risk (score ≥1) for serious adverse events at 30 days. A cut-point of 0 was used to calculate the sensitivity, specificity, positive and negative predictive values (PPV and NPV) for CSRS and the odds ratio (OR) of a clinically significant finding on TTE in patients with CSRS ≥1 compared with all patients. Results Among 157 patients, the CSRS categorised 69 (44%) as very low to low risk in whom TTE was normal. In 88 patients deemed moderate to high risk, TTE detected a cardiac abnormality in 24 (27%). A CSRS ≥1 yielded a sensitivity of 100% (95% CI 85.7% to 100%), specificity of 51.1% (95% CI 42.3% to 59.8%), PPV of 26.5% (95% CI 26.3% to 30.1%) and NPV of 100% (95% CI 92.5% to 100%) for cardiac abnormalities and doubled the odds of an abnormality (OR=2.05, 95% CI 1.08 to 3.87, p=0.028). Conclusion In general medicine patients with syncope/presyncope, using the CSRS to stratify risk of a cardiac abnormality on TTE can almost halve TTE use.