Assessment of the Mechanism of Non-cardiac Syncope

Inclusion Criteria:

• severe recurrent non-cardiac syncope referred for assessment of the mechanism ofsyncope. Non-cardiac syncope is diagnosed when the clinical features are consistentwith reflex syncope and orthostatic hypotension, and cardiac syncope is ruled out .

Exclusion Criteria:

1. Non-syncopal causes of real or apparent loss of consciousness that may beincorrectly diagnosed as syncope (eg, unexplained falls, epilepsy, psychogenicpseudosyncope and other rare causes)

2. Established or suspected cardiac syncope in complying with the criteria of theEuropean Society of Cardiology (ESC) syncope guidelines (1). Specifically, thesewere the patients with: (i) suspected cardiac arrhythmic syncope [inadequate sinusbradycardia (<50 b.p.m.) or sinoatrial block, second-degree Mobitz Iatrioventricular block, second-degree Mobitz II or third-degree atrioventricularblock, paroxysmal tachyarrhythmia or ventricular tachycardia, bundle branch block]; (ii) severe structural heart disease and/or significant ECG abnormalities, asdefined in Table 2 of those guidelines (1).

3. Classical orthostatic hypotension diagnosed at the initial evaluation by ActiveStanding test

4. Constitutional or drug-induced persistent hypotension already diagnosed at theinitial evaluation by office BP measurement or previous historical features

5. Non-severe forms of non-cardiac syncope, i.e., patients with rare and mild episodesoccurring in low-risk situations. In these patients the investigation of theunderlying mechanism of syncope is not necessary and treatment strategies are mainlybased on education on preventive measures, lifestyle modification, and reassuranceregarding the benign nature of the condition.