vasovagal syncope?

I am a 21 year old female who began experiencing frequent syncopal episodes about two months ago.   This episodes happen without much warning and do not seem to have any pattern of occurence (like after exercise or when I get up).   They occur at all times of the day with varying levels of activities.  The only warning I have to them is about 15 minutes before I faint, I feel extremely powerful palpitations that last for about 15 seconds during which I have difficulty breathing, and then the palpitations subside.  
I wore an event monitor for a few days, and my cardiologist was soon to diagnosis me with Supraventicular tachycardia.  So, I had an electrophysiology study done with the intent of correcting the problem by radiofrequency ablation. However, my cardiologist was unable to stir up the suspected SVT.  He, then, prescibe me a Beta Blocker and changed the diagnosis to sinus tachycardia.   The problem is that the Beta Blockers are not quelling the problem at all, but instead they are only making the onset to the syncopal espisodes more distinct.  Additionally, before the Beta Blockers, my resting pulse rate was about 45 bpm, but now with beta blockers, it has dropped to 37 bpm, which is making me extremely dizzy.   Given the above information, do you agree with the diagnosis of sinus tachycardia?  So you think Beta Blockers the best course of treatment for these supposed "neurocardiogenic" syncopal attacks?  Should I go to a different cardiologist at this point?

[CCF CARDIO MD - DLB]

As the beta blockers are making you dizzy, it is unlikely that continuing them will be helpful. I do not think sinus tachycardia is the problem that is making you faint - that would be very unlikely. A second opinion from a cardiac electrophysiologist may be a good idea at this point.

[sue]

My daughter was recently diagnosed with NCS.  She has few fainting spells, but when she does have an episode, her greatest complaint is that her heart races and she has a headache that will not go away.  The cardiologist put her on Florinef which decreased the syncope.  She had a constant headache for three months until he added the beta blocker, IC Pindolol (generic name).  I was wondering if you have had any such violent headaches when you have an episode of heart racing and syncope?  We are finding there is very little information regarding the role headaches play in this condition. Thank you for sharing your experience.

[Elizabeth]

Sue, I typically develop headaches after the syncopal episodes, but my cardiologist informed me it was a simple "by-product" from the loss of consciousness (I do not necessarily concur with that statement, but I am not a MD).   My headaches mimic migraines that surface approximately an hour after passing out and last for three to five days.  Additionally, I am having some luck with the Toprol (a beta-blocker) in the sense that the subsequent headaches persist only a few hours and are not as intense.  

I, too, have come across little relating headaches to NCS, but this is most likely because relatively little is still known about pathophysiology behind the sympathetic innervation of the heart. Additionally, the exactly flaw in the nervous system that leads to NCS is many times unique to the individual, so it can be very tricky to pinpoint the cause and then to understand why certain symptoms, like headaches, occur.   The neurocirculatory failure that occurs during NCS episodes is believed to be capable of triggering the release of various hormones.  Due to the nature of many of these hormones, some can actively linger in your body for weeks, even months.  Moreover, depending on what endocrine gland(s) is(are) being triggered and amount(s) of hormone(s) released, headaches can often develop.  None of this may pertain to your daughter's condition, but it is only info I could find in the literature documenting a link between headaches and NCS.  

I hope your daughter's treatment continues to remain successful so that she can return to a more normal life.  Trust me, I know as a 21-year-old senior in college how much this conditions can slow you down. Best wishes and good luck to you and your family.