The European Society of Cardiology (ESC) guidelines on syncope say that the challenge for doctors is to identify the small number of patients in whom syncope is caused by a potentially life-threatening heart problem. ESC also recommends that intermediate or high risk patients should be evaluated in the emergency department or an outpatient syncope clinic. These guidelines were released in March 2018.

Syncope has been defined in the guidelines as “transient loss of consciousness (TLOC) due to cerebral hypoperfusion, characterized by a rapid onset, short duration, and spontaneous complete recovery”.

TLOC has been defined as “a state of real or apparent LOC with loss of awareness, characterized by amnesia for the period of unconsciousness, abnormal motor control, loss of responsiveness, and a short duration”.

The initial evaluation of syncope should answer four key questions.

• Was the event TLOC?
• In it is a TLOC, is it syncopal or non-syncopal?
• In case of suspected syncope, is there a clear etiological diagnosis?
• Is there evidence to suggest a high risk of cardiovascular events or death?

The initial diagnostic evaluation should comprise of careful history taking, physical examination (BP, both supine and standing) and standard ECG. The findings from the initial evaluation will direct further diagnostic evaluation via echocardiography, immediate ECG monitoring, head-up tilt testing, carotid sinus massage, electrophysiology studies.

Blood tests should be performed when clinically indicated such as,

• Hematocrit or hemoglobin when hemorrhage is suspected
• Oxygen saturation and blood gas analysis when hypoxia is suspected
• Troponin when cardiac ischemia-related syncope is suspected
• D-dimer when pulmonary embolism is suspected

Management depends on evaluation of the patient in the emergency department, which should address the following questions:

• Is there a serious underlying cause that can be identified?   
• If the cause is uncertain, what is the risk of a serious outcome?   
• Should the patient be hospitalized? 

High risk patients are more likely to have cardiac syncope and need urgent hospital admission and comprehensive evaluation. Whereas, syncope in low risk patients is likely to be reflex, situational, or orthostatic; hence, they do not need further evaluation.

The guideline also recommends that friends and relatives use their smartphones to film the attack and recovery.

The following treatments are recommended based on the clinical severity:

• Education regarding lifestyle maneuvers
• Adequate hydration and salt intake
• Discontinuation/reduction of hypotensive therapy
• Counter-pressure maneuvers
• Abdominal binders and/or support stockings
• Head-up tilt sleeping
• Midodrine or fludrocortisone

An implantable cardioverter-defibrillator (ICD) should be considered in patients with unexplained syncope at high risk of sudden cardiac death.

(Source: ESC Press release, Eur Heart J. 2018 Jun 1;39(21):1883-1948)

Dr KK Aggarwal

Padma Shri Awardee

President Elect Confederation of Medical Associations in Asia and Oceania   (CMAAO)

Group Editor-in-Chief IJCP Publications

President Heart Care Foundation of India

Past National President IMA