Study Shows Presyncope Carries Same 30-Day Cardiac Risk as Syncope

The Deceptive Reassurance of a Near Miss

Syncope is a frequent and challenging presentation in the emergency department, requiring clinicians to rapidly distinguish benign episodes from life-threatening cardiovascular conditions [1, 2]. While risk stratification tools and cardiac biomarkers help predict short-term adverse events, identifying high-risk patients remains an imperfect science, even though markers like high-sensitivity troponin T above 50 nanograms per liter correlate with a 29 percent risk of severe outcomes [3, 4]. Historically, medical training and clinical decision rules have heavily emphasized the complete loss of consciousness as a primary red flag for serious underlying pathology, a practice supported by systematic reviews of 4,317 patients showing that specific clinical features strongly predict cardiac causes [5, 1]. However, patients frequently present with presyncope, reporting a sensation of an impending blackout without an actual loss of consciousness, which often leads to variable triage and admission decisions. A new multicenter study now offers fresh insights into whether these near-miss events carry the same prognostic weight for serious cardiac outcomes as true syncope [6].

Evaluating the Near-Miss Cohort

Emergency department physicians often face a clinical dilemma when evaluating patients who feel faint but never actually lose consciousness. Previous research suggests that the short-term incidence of adverse events is similar in emergency department patients with presyncope and syncope. However, admission rates for presyncope are lower than for syncope, a discrepancy that implies clinicians might underestimate the risk of a near miss. To address this gap, researchers sought to compare physician risk estimates and the 30-day rate of serious cardiac outcomes between patients with syncope and presyncope. The investigators conducted a secondary analysis (an approach that re-examines existing data from a prior large-scale study to answer a new clinical question) of a prospective, observational, multicenter registry. The study included patients aged 40 years or older presenting to the emergency department with either presyncope or syncope. To ensure the focus remained on undifferentiated cases where the underlying pathology was not immediately obvious, patients with serious emergency department diagnoses already established at the time of triage were excluded. The final analysis included a total of 1,263 patients. Within this cohort, 721 patients (57 percent) had syncope and 542 patients (43 percent) had presyncope. Importantly, baseline characteristics were similar between the two groups, providing a balanced foundation for comparing clinical trajectories without significant confounding from underlying health differences. To rigorously evaluate how these patients were triaged and how they fared after their initial evaluation, the researchers used descriptive statistics and multivariable regression analyses (statistical models that adjust for multiple patient variables simultaneously to isolate the true effect of the symptom presentation). This methodology allowed the investigators to determine whether the subjective clinical impression of presyncope matched its objective cardiovascular danger.

Identical Rates of Serious Cardiac Events

Despite the historical emphasis on a complete loss of consciousness as a primary indicator of cardiovascular danger, objective clinical data reveal nearly identical short-term risks for both presentations. The researchers found that at 30 days, 34 syncope patients (4.7 percent) experienced a serious cardiac outcome. Strikingly, the near-miss cohort faced an equivalent threat, as at 30 days, 28 presyncope patients (5.2 percent) experienced a serious cardiac outcome. To ensure these raw event rates were not skewed by confounding variables, the researchers utilized multivariable analysis. Logistic regression showed no difference in the odds of serious cardiac outcomes between syncope and presyncope patients (odds ratio 1.13; 95 percent confidence interval 0.66 to 1.79). Ultimately, the findings demonstrate that patients with unexplained presyncope and syncope had similar rates of 30-day serious cardiac outcomes after their emergency department visit. For practicing physicians, this underscores a critical clinical reality: a patient who feels like they might pass out requires the exact same diagnostic rigor, cardiac monitoring, and risk stratification as a patient who actually loses consciousness.

The Perception Gap in Triage and Admission

While the objective data show identical 30-day cardiac risks, the study revealed a significant disconnect in how clinicians perceive and manage these two presentations. Overall, patients with presyncope had a lower mean physician-estimated risk of adverse outcomes compared to those with syncope. Specifically, the mean physician-estimated risk of serious cardiac outcomes was 7.6 percent in syncope patients, whereas the mean physician-estimated risk was 5.3 percent in presyncope patients. This discrepancy yielded a risk difference of 2.3 percent (95 percent confidence interval 0.89 percent to 3.7 percent). Furthermore, this difference in physician-estimated risk remained significant after adjustment for clinical characteristics, indicating a systemic bias in how near-miss events are evaluated regardless of the patient's underlying health profile. This perception gap directly influenced clinical decision-making, as patients with presyncope were less likely to be admitted than those with syncope. The researchers found that the admission rate was 49.5 percent for syncope patients, while the admission rate was 38.2 percent for presyncope patients. This translates to a substantial risk difference in admission rates of 11.3 percent (95 percent confidence interval 1.2 percent to 21.5 percent). For practicing emergency physicians and hospitalists, these findings highlight a critical vulnerability in triage protocols. Even though presyncope carries the exact same short-term threat of severe cardiac events, such as arrhythmias or myocardial infarction, these patients are systematically viewed as lower risk and are consequently discharged at higher rates. Recognizing this cognitive bias is the first step toward ensuring that presyncope patients receive appropriate observation and follow-up care, preventing potentially fatal cardiovascular emergencies from slipping through the cracks.

References

1. Sutton R, Ricci F, Fedorowski A. Risk stratification of syncope: Current syncope guidelines and beyond.. Autonomic Neuroscience: Basic & Clinical. 2021. doi:10.1016/j.autneu.2021.102929

2. Alsaidiani AA, Allehaimeed IS, Almansour A, et al. Assessment of the San Francisco syncope rule in detecting high-risk cardiac and neurological causes of syncope. International Journal of Community Medicine and Public Health. 2026. doi:10.18203/2394-6040.ijcmph20260060

3. Probst MA, Gibson T, Weiss RE, et al. Risk Stratification of Older Adults Who Present to the Emergency Department With Syncope: The FAINT Score.. Annals of emergency medicine. 2020. doi:10.1016/j.annemergmed.2019.08.429

4. Clark CL, Gibson TA, Weiss RE, et al. Do High-sensitivity Troponin and Natriuretic Peptide Predict Death or Serious Cardiac Outcomes After Syncope?. Academic emergency medicine : official journal of the Society for Academic Emergency Medicine. 2019. doi:10.1111/acem.13709

5. Albassam O, Redelmeier RJ, Shadowitz S, Husain A, Simel D, Etchells E. Did This Patient Have Cardiac Syncope?: The Rational Clinical Examination Systematic Review.. 2019. doi:10.1001/jama.2019.8001

6. Suh EH, Sacco DL, Winskill C, et al. Serious Cardiac Outcomes and Physician Estimation of Risk in Emergency Department Patients With Presyncope Versus Syncope.. Annals of emergency medicine. 2026. doi:10.1016/j.annemergmed.2025.08.014