Dear Kelly,
Without being able to evaluate your daughter, I can’t say for sure what’s going on. However, I have had patients in my practice with this kind of history before. Certainly, if the neurologist does not think that this is a seizure, this could be a form of syncope, or passing out, in which the blood pressure falls. The most common type of syncope is vasovagal (or vasodepressor), in which the blood pressure falls and the heart rate goes up to make up for the fall in blood pressure. However, in my experience, younger children like your daughter have a less frequent type of syncope called cardioinhibitory syncope, in which the blood pressure AND the heart rate fall. The reason for this is not because of the heart or the blood vessels; it is because of sensitivity of the autonomic nervous system, the part of the nervous system that controls automatic functions, like heart rate, blood pressure, intestinal motility, etc. One way to try to diagnose this is to use an event recorder, which is a special box that you place on your daughter’s chest to record her heart rate at the time of an event. You would keep this monitor for one month to try to capture an event. If the heart rate is very slow, or even zero, this supports the diagnosis. Rarely, this may also be associated with dysautonomia, or abnormal global functioning of the autonomic nervous system.
Treatment for this has included the use of medications, such as selective serotonin reuptake inhibitors (sertraline and citalopram) or glycopyrrholate, and placement of a pacemaker. That said, this is not a very common finding in children. If your cardiologist does not feel comfortable with this evaluation or management, you may want to consider a second opinion.
Thank you very much for your opinion, Dr. Boris. I'll certainly take your opinion to my own doctors to see if we can explore this further,
Thank you,
Kelly