Causes

History

Vasovagal syncope (the common faint) is the most common cause of syncope. It is associated with peripheral vasodilatation and a vagally mediated slowing of the heart rate. It may be precipitated by situations such as fear, emotion, prolonged standing or pain. The patient may complain of nausea, weakness and blurred vision, and appear pale with bradycardia on examination. Palpitations (p. 370) preceding collapse may suggest an arrhythmia. Situational syncope are faints classified according to the precipitating factors and are often due to an excessive vagal response to the offending stimuli.