Risk stratification key in patients with syncope.

Many conditions may mimic syncope, including epilepsy, TIA, coma, hypoxia, hypoglycaemia, hyperventilation, falls, drop attacks, and psychogenic pseudosyncope. An episode of loss of consciousness is highly likely to be syncope if it is complete, transient, has rapid onset and short duration, with associated loss of postural tone and is followed by a spontaneous and complete recovery without sequelae. Reflex syncope has a more favourable, benign prognosis but structural and primary electrical heart diseases are major risk factors for sudden cardiac death. The initial assessment in patients with suspected syncope should aim to confirm the syncopal nature of the episode, identify the most likely cause of syncope and stratify the risk of major cardiovascular events or sudden arrhythmic death. Vasovagal syncope represents the most common cause of syncope, irrespective of age, sex and comorbidity. Cardiac syncope is the second most common cause. A detailed history should be taken, and a thorough physical examination and an ECG performed as initial assessment in suspected syncope. A detailed account of the episode should be obtained from the patient, and any witnesses, as well as a drug history. Treatment of reflex syncope and orthostatic hypotension is based on lifestyle modifications. It is important first of all to identify and treat the potential secondary causes of arrhythmic syncope. Cardiac pacing is indicated in patients with bradycardia-induced syncope. For patients with tachycardia-induced syncope, drug therapy, catheter ablation or ICD implantation are potential options. Because of its high efficacy, catheter ablation is the first choice in most supraventricular tachycardias and in patients with ventricular tachycardia and a normal heart.