Typically an attack occurs without warning, leading to sudden loss of consciousness. Prior to an attack, a patient may be pale with hypoperfusion. Abnormal movements may be present, typically consisting of twitching after 15–20 seconds of unconsciousness. (These movements, which are not seizures, occur because of brainstem hypoxia and not due to cortical discharge as is the case for epileptiform seizures). Breathing typically continues normally throughout the attack, and, upon recovery, the patient becomes flushed as the heart rapidly pumps the oxygenated blood from the pulmonary beds into the systemic circulation, which has become dilated due to hypoxia. As with any syncopal episode that results from a cardiac dysrhythmia, the fainting does not depend on the patient's position. If it occurs during sleep, the presenting symptom may simply be feeling hot and flushed on waking.
Adams–Stokes syndrome
Hopkins syndrome
SUNCT syndrome
Michels Caskey syndrome
PHACE syndrome
Hennekam syndrome
Dressler syndrome
Wunderlich syndrome