Two further common clinical pitfalls are worth noting. One is assuming that the cause of syncope in older patients is orthostatic syncope in those that have an orthostatic drop.¹⁹ This may lead to failure to search further for cardiac causes. Orthostatic vital signs do not predict 30-day serious outcomes in older emergency department patients with syncope.²⁰ Many older patients will have an orthostatic drop at baseline, and some patients with orthostatic symptoms will not have an orthostatic drop; orthostatic vitals are non-specific and may lead to premature closure. The other common pitfall is assuming that presyncope alone is less morbid than syncope. The differentials for patients with presyncope and syncope are similar.²¹ Older patients with syncope or pre-syncope have comparable one-month risk of major adverse cardiac events.^22,23

Clinical factors that are more often associated with a noncardiac cause of syncope include syncope only following position change from sitting or lying to standing position, presence of a prodrome of nausea, vomiting or feeling warm, presence of a specific trigger such as pain, stressful stimulus or blood draw, and presence of a situational trigger such as coughing, laughing, micturition, defecation, or deglutition.^19,24

Do Clinical Decision Tools Perform Better Than Physician Gestalt for Determining Low Risk Syncope for Safe Discharge?

Decision tools, despite their varying levels of external validation, can be used to reassure clinicians and assist in shared decision-making when considering safe discharge of patients who have presented to the ED after a syncopal episode. The problem with these decision tools is that they include laboratory tests that are generally not useful in the evaluation of isolated syncope.⁵ For example, the San Francisco Syncope Rule (SFSR) requires a hematocrit. The SFSR’s sensitivity for adverse events was poor in external validation studies and a meta-analysis (86 percent and 87 percent, respectively).^25,26

The Canadian Syncope Risk Score (CSRS) requires a troponin level which, alone, has questionable value in the evaluation of syncope. The CSRS has shown excellent sensitivities in internal validation studies. Scores of negative two or higher were found to have a sensitivity of 99 percent and on secondary internal validation in Canada, patients with “very low” and “low” risk scores had 0.3 percent and 0.7 percent risks of a serious outcome, respectively.^27,28 However, a 2021 external validation in Italy demonstrated that the CSRS is no better than physician gestalt at predicting outcomes for patients with syncope. Additionally, physician gestalt had a lower rate of adverse events compared to low-risk patients on the CSRS.²⁹ Physician gestalt is incorporated into the score, which may limit its usefulness.