Education: Individuals prone to this kind of syncope need to know five facts:
- Vasovagal syncope is produced by a reflex that causes sudden dilation of the blood vessels in the legs, causing the blood to pool there.
- Any condition that causes a bit of dehydration will make you more prone to have a syncopal episode.
- Most people will have a brief “prodrome” (i.e., a set of characteristic symptoms) that precedes the loss of consciousness. That is, there is usually a warning.
- If you lie down and elevate your legs when you experience the prodrome, you can prevent the syncopal episode.
- Patients will often have occasional periods of days or weeks in which they are particularly prone to vasovagal episodes.
First, avoid dehydration. Dehydration (and therefore syncope) most commonly occurs after exercise, after any kind of illness, and early in the morning after an overnight fast. Coffee, tea, and diuretic drugs can also produce dehydration. If dehydrated, you should take pains to rehydrate yourself. Drink plenty of fluids, and avoid prolonged standing while you are dehydrated.
Pay close attention to any prodromal symptoms you may have. Syncope is usually preceded by at least a few seconds of symptoms that may consist of visual disturbances, buzzing in the ears, lightheadedness, sweating, nausea, or other symptoms. Individuals who have had syncopal episodes usually have an excellent idea of what prodromal symptoms to expect. It is important to recognize these symptoms, because if you do, syncope can be averted virtually 100% of the time by lying down and elevating your legs. If instead, you choose to fight the episode, you’re likely to pass out in the frozen foods section, and the store manager will insist (for well-founded legal reasons) on shipping you to the E.R. in an ambulance – where you’ll be subjected to a battery of unnecessary tests and probably an overnight stay in the hospital. Another advantage of aborting the actual syncope is that when you do, you also avoid the prolonged period of feeling “sick” (wasted, washed out, nauseated, and dizzy) that often follows a vasovagal episode.
People who are prone to vasovagal syncope often have periods of days or weeks in which syncope is particularly likely to occur. These “sensitive periods” often seem to occur for no identifiable reason, but they can follow a viral illness, or they can be related to the menstrual cycle, to allowing yourself to become fatigued or run down, or to an ongoing gastrointestinal, urinary, or gynecological problem. If you have had one or two recent syncopal episodes, it pays to be particularly vigilant for prodromal symptoms that might herald another episode. It also pays during these times to make special efforts to remain well hydrated.
Drug therapy: In some patients, vasovagal syncope occurs with disturbing frequency even when all appropriate precautions are taken. For these patients, drug therapy is often attempted.
Several types of drugs have been used in patients with vasovagal syncope. These include beta blockers, serotonin uptake inhibitors (i.e., drugs in the Prozac category), florinef (a drug that prevents dehydration by retaining sodium), and midodrine (a drug that tends to limit the dilation of blood vessels). These drugs substantially reduce the episodes of syncope only 60 - 70% of the time, and finding the "right" drug treatment is a matter of trial and error. Patience is required on the part of both the doctor and patient.
What about pacemakers for vasovagal syncope? Several years ago there was much enthusiasm for using pacemakers to treat vasovagal syncope. The enthusiasm dropped off rapidly, however, after it was finally noted patients with vasovagal syncope who received pacemakers continued to pass out - they just did it with better heart rates. As it turns out, in the large majority of patients with this vasovagal syncope, it is the pooling of blood in the legs – and not the slow heart rate – that produces syncope.
In the last few years, reports from various investigators have again raised the enthusiasm for using pacemakers in highly selected patients with vasovagal syncope. While it still seems clear that the majority of patients do not respond favorably to pacemakers, there may be a small subset that do respond favorably.
