Teenage athlete with near fainting

My 17 year old daughter is a competitive swimmer who is used to training and competing at the highest levels.  She verbally committed to swim at a Division I top 20 program a few weeks ago, so in addition to being concerned for her well-being, we are anxious to not interrupt her training any more than necessary.

She has had about 8-10 episodes of presyncope of varying levels of severity in the past three months.  Her symptoms (not all occurring every time) have included:  dizziness, mild nausea, mental confusion, a feeling of disconnectedness from the world, objects seeming smaller than they really are, extreme fatigue afterwards, clamminess, and extremely dilated pupils (every time).  

The first time was after an 800 meter race at the end of a four day meet this summer, which her primary care doc attributed to possible exercise induced hypoglycemia.  She has always been very careful about hydration, eats 6-8 small meals a day with plenty of protein as well as carbs, etc.including at meets, so I was a little doubtful about hypoglycemia but let it slide because she didn't have another episode for two months.  The next one was while sitting in homeroom after having a good breakfast, plenty of water, and a decent night's sleep with no morning practice.  The doc referred her to a cardiologist for possible neurocardiogenic syncope, but it wasn't considered an emergency because "teenage girls often faint," and it wasn't occurring very frequently.  Bloodwork was ordered, which was all normal, including, blood sugar, thryoid function, and hemoglobin.

However, starting ten days ago she has had about 8 episodes.  She was taking cold medicines last week, which I read can cause problems with people with heart issues.  Last week one occurred while in the middle of a practice set but the other two were not while swimming.  When swimming she suddenly felt faint and her muscles felt like they are shutting down.   Her coach said her pupils were huge, which I observed at another episode..

We got the cardiologist appt. moved up to last Wed. (10/24) since things seemed to be escalating.  Her EKG was normal.  Her echo was normal except that she has a tiny hole in her heart between the atria.  He gave her a monitor to wear for a week, but he felt like it was most likely not cardiac in nature, and referred her to a neurologist for possible migraines (even though no headache) or seizures.  According to him, the hole in heart  has been linked to migraines, although hers is tiny.  

Then this week all three of the more major episodes (some other incidents of momentary symptoms) occurred while swimming.  She tried to get back in the water after resting a little, but was very weak feeling and her heart felt fluttery.  So, she has not swam for the past couple of days but has had a couple of fluttery feelings even when not exercising, and after stretching while lying on her stomach, when she sat back up she had a sharp pain in her heart for about five minutes.

She saw the neurologist on Tues, who completely blew her off.  Said it was most likely migraines, but could possibly be seizures; he doesn't seen any clinical reason for the link between the hole and migraines, and that her symptoms were too vague to do anything with and to call if she developed further ones, otherwise come back in Dec.  

The monitor results are not in yet, but since all the episodes that occurred after she got the monitor were while she was in the water and the monitor was off, it didn't record them when they started.  She did get out and dry off and put it on and push the button, but I don't know if that is helpful. So I called the cardiologist back yesterday, and he scheduled a stress test for tomorrow (Friday).  Also, she has not been aware of a racing heart with these episodes and I don't know what her heart rate have been.

I have a few questions:

1.  If there is some sort of arrhythmia or electrical problem, is it likely to show up on the stress test?
2.  If the stress test is normal, can we be assured her heart is okay and can she attempt to resume training while we figure this out (although basically she could not train at all this week without feeling faint so that may be a moot point)? Or are there still more cardiac tests to be sure or false negatives to worry about?
3.  Could something benign like neurocardiogenic syncope produce near fainting when exercising?  The info I read said fainting or near fainting with exercising was a red flag.

Thanks!

[CCFCardio MD2]

I'm sorry your daughter is having such difficulty.  It sounds as if she is a world-class athlete and I'm sure these symptoms are frustrating and scary for both of you.  She has had a lot of the workup I would suggest to rule out a sinister cause of her symptoms.  There is a condition called postural tachycardia syndrome (POTS) which could present like this.  It is more common in young women.  You should ask your cardiologist about it and see if she can get a tilt table test.  This would probably be the direction I would head next.  Cardiac MRI wouldn't be too unreasonable to rule out something like an infiltrative disease or arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC or ARVD), though those are much less likely and you would probably see signs of them on echocardiogram.  This does not sound like an arrhythmia though it is still possible.  And while I highly doubt this is the case, illicit drug use should always be considered in cases of young patients like this as several of her symptoms could be caused by certain types of illicit drugs.  Again, doubtful, but worth keeping in the back of your mind.  Hope this helps.  Good luck to you both.

[worriedmom69]

update:  Her stress test this morning was normal, thankfully.  I was not able to be in the room during it due to space issues.  I hope she was on the treadmill long enough.  They inclined it to make it more difficult, but she is a well trained athlete, and her heart rate only got up to 170-180 for a minute at the very end (15 minute period).  I don't know all her readings, but he said there were no arrhythmias, her heart rate and bp were as expected and in line with an athlete, her oxygen levels stayed very high, there were no drop in oxygen levels in the crossover from right to left, meaning the small hole wasn't allowing unoxygenated blood to go to her brain. She was cleared for all activities.  He did say, however, that swimming is different from running on a treadmill and he can't duplicate that in the office.  

She is being referred to a different neurologist to evaluate the migraines/seizure angle since the first neuro blew us off.   We are trusting the cardiologist's opinion that her heart is fine and she is going to attempt to return to full training and swim through the near fainting as much as possible, and I just hope she doesn't have something strange not visible on the monitor except for when she is working extremely hard - I don't want her drowning from fully fainting or having a cardiac incident!  If the neuro workup is negative we might be back to the neurocardiogenic syncope, which I know is pretty benign, but it is totally disruptive to her training and ability to compete collegiately and we have to find how to fix it!

[808]

I would look further into your daughter's health condition as they appear to be quite serious. Both of my daughters are competitive swimmers as well and I would suspend their training indefinitely if it had occurred to them. A male swimmer on the University of Hawaii swim team recently passed away from an underlying heart condition. He was diagnosed with a heart problem last season after passing out while out with friends. He took a break to attend to his heart condition and returned this season. He swam at their first meet and passed away some time that evening because he didn't show up for warm ups the next morning. Please have your daughter checked out further.

[worriedmom69]

Thanks for the comments.  We are definitely taking it seriously.  A couple of questions for the expert who responded:  

1.  She has never been aware of any tachycardia feelings.  Is it possible to have it and not notice it?  Also, the one time I have observed having an episode, I checked her pulse and it was calm and steady - about 60 beats a minute.
2.  She has never actually fainted, just felt dizzy along with some of the other symptoms.  I don't know if that makes it any less serious?
3.  Some eipsodes have occurred during or after exercise, but some have not.  Would that make it less likely to be cardiac given all her test being negative?