Harvard Heart Letter

Heart Beat: Little support for that sinking feeling

Heart Beat

Little support for that sinking feeling

Fainting is frightening. Fortunately, it's a one-time thing for most people, brought on by standing too long, dehydration, an injection, or other triggers. Some people, though, faint repeatedly. If the culprit is a slow heartbeat, a pacemaker can halt fainting spells. If it isn't — a condition that doctors call neurocardiogenic syncope (SING-cuh-pee) — several "may help" options are available. A clinical trial casts doubt on one of these: the use of a beta blocker.

In the Prevention of Syncope Trial (POST), more than 200 people with recurrent fainting spells took the beta blocker metoprolol or a placebo. After a year, fainting episodes were equally common in both groups.

The standard recommendation for preventing fainting is to drink more fluid and get more salt. Physical maneuvers can also help. If you feel like you are going to faint, sitting down or lying down can nip it in the bud. Tensing the muscles in your legs and abdomen can ward off a fainting spell by pushing blood back toward your heart. Another technique involves grabbing one hand with the other and pulling. Other drugs that are used to prevent fainting — midodrine, fludrocortisone, and selective serotonin reuptake inhibitors such as Prozac — may work, although they haven't been rigorously tested.

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