Blackout and collapse

‘Collapse?cause’ is a common acute medical presentation, and there are many different causes. This article focuses on syncope, which is caused by transient global cerebral hypoperfusion. There are four main sub-types of syncope, with neurally mediated and orthostatic syncope being by far the most common. Cardiac arrhythmias account for only 20% of all syncope. The initial evaluation is extremely important and leads to a diagnosis in around half of cases. Only some patients need tests. The tests to request depend on the history, whether the person has structural heart disease or not, and whether the syncope is frequent or severe. The evaluation of syncope is often unstructured and varies considerably among doctors. The European Society of Cardiology guidelines on syncope are the standard for syncope specialists and are outlined here.