Some people are prone to fainting.
They may have a history of fainting going on their whole lives but rarely have any serious consequences from it. These fainting spells often occur when they are upset or nervous about something. These swoons also frequently occur when they undergo medical procedures, have a blood test drawn or simply at the site of blood and needles. These nervous faints have been portrayed to great dramatic effect in the old movies of the 1930s and 1940s. Such people will often appear to have perfectly normal hearts by most tests.