Syncope is a major health problem. In the emergency department (ED), the management of patients with syncope still remains a clinical challenge because underlying diseases and prognosis can be extremely various. Structural heart disease and primary electrical disorders are major risk factors for sudden cardiac death and mortality in patients with syncope. In contrast, patients with reflex syncope and exclusion of structural heart disease have an excellent prognosis.

Therefore The investigators test the hypothesis that the use of a meticulous patient history, clinical examination and novel biomarkers can improve the rapid and accurate diagnosis of cardiac syncope in patients presenting to the ED and is able to improve risk stratification regarding adverse outcomes.

The prospective multicenter cohort study is designed to enroll 720 patients presenting with transient loss of consciousness within the last 12 hours to the ED. Blood samples for the measurement of novel biomarkers will be obtained at presentation.

All patients will be contacted by phone at 6, 12 and 24 months to determine major adverse events (death, resuscitation, recurrence of syncope, hospitalization for syncope).

Background: Management of patients with syncope is a serious problem concerning 1-2% of emergency department (ED) visits. In 6-20% of these, syncope will be due to a cardiac origin. The rapid and accurate identification of these patients is an important unmet clinical need.

Aim: The aim of the study is to evaluate the diagnostic value of patient's history, clinical judgement and novel biomarkers, alone or in combination, in the diagnosis and risk stratification of patients > 40 years of age presenting with syncope to the ED.

Patients and Methods: This prospective, observational, international multicenter study is initially designed to enroll 720 adult patients > 40 years presenting to the ED with syncope within the last twelve hours. Patient history will be standardized using a predefined form. Treating physicians will be asked to quantify their clinical judgment regarding the presence of cardiac syncope. Digital 12-lead ECG will be recorded at presentation and stored electronically. Blood samples for the measurement of novel cardiovascular biomarkers (including copeptin, pro-endothelin-1, pro-adrenomedullin, natriuretic peptides and high-sensitive cardiac troponins) will be obtained at presentation and stored anonymized. Patients will be contacted by phone at 6, 12 and 24 months to determine major adverse events (death, resuscitation, recurrence of syncope, hospitalization for syncope) and results of follow-up examinations. The final diagnosis will be adjudicated by two independent experts after review of all documents pertaining to the individual patient after 6 months. The primary endpoint is to assess the performance of a standardized form of patient's history, clinical judgment and biomarkers, alone and in combination, in the diagnosis of a cardiac syncope, as adjudicated by two independent experts. Secondary endpoints include the accuracy of the above cited items in prognostic stratification and the determination of the cost-effectiveness of the best approach.

Clinical significance: A more accurate and more rapid diagnosis and risk stratification of cardiac syncope can significantly improve patient management and therefore reduce patient morbidity and treatment cost. Overall, we expect this study to provide novel insights, holding important scientific, clinical and economic implications.

Inclusion Criteria:

• Patients presenting to the emergency department
• Age > 40 years
• Syncope within the last 12 hours
• Written informed consent

Exclusion Criteria:

• Age < 40 years
• Patients without loss of consciousness and with certain neurological causes (e.g. recurrent epilepsy, hemiplegia at presentation)
• No written informed consent

Patients presenting to the emergency department with syncope within the last 12 hours.