question about low/high HR

[CHELLETO6DOGS]

I have a question for a complicated issue with my now 6year old son. he had a large VSD patch when he was 3 months old as well as a PDA ligation and stitching of the PFO (which he still has a small PFO.) hyperdynamic muscular narrowing due to the RVOTO.I guess he doesn't have that anymore he currently has a complete RBBB,  mild infundibular stenosis  14-19 small PFO ( with bi directional shunting at times) right ventricular pressure are 26, which he said was a little high and he was going to keep an eye on it, but not to worry until it reaches 75) now the main issue. his has an implantable loop recorder and has caught his HR as low as 38 and as high as 236.It does say fast VT however the doctor has recorded that the ventricular electrogram looks essentially the same as the baseline recording so it really isn't fast VT . he does get chest pain at times when he runs, and can only run for about 30 seconds before he tires and has to stop.they say it can be normal, as long as he isn't symptomatic which to me he is by complaining of fatigue and chest pain. and he takes most every day takes a 3 hour nap wakes up at 6am naps around 3-6 and then is sleeping by 8pm for the night
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[Jeffrey R Boris, M.D.]

Dear Michelle,

It depends on what he is doing when his heart rate is >200 bpm.  At the age of 6, it is not unreasonable for him to achieve that kind of a heart rate with activity.  As well, if he has the exercise intolerance that you mention, he may not have the cardiac reserve that he needs, and may achieve that rate faster.  Conversely, his rate could absolutely achieve 38 as well if he has sinus node disease post-operatively.

[CHELLETO6DOGS]

Dear Dr. Boris,
Thank you so much for your help. I do understand it is had to ***** people over the internet. you have confirmed what I have been wondering.
I hope you can answer this one question about his Implantable loop recorder since they feel due to his complete RBBB it is showing a false arrhythmia, that he isn't really having fast VT (when his HR is over 200bpm) that is is the same as his baseline, can his beat, you know going over 200 or as low as 38( even though when it went low he was hooked up to a heart monitor at the hospital) can the heart beat number be wrong too.
Thank you
Michelle

[Jeffrey R Boris, M.D.]

Dear Michelle,

There seems to be two different issues here.  The first is the correlation of his heart rate and breathing.  Respiratory variation occurs when the heart rate speeds up when you breathe in and slows when you breathe out.  However, respiratory variation is typically fairly mild and not as extreme as the heart rate range that you are describing, so I do not think that these are related.  The second issue here is that of his heart rate range and his exercise intolerance.  Without having all of his data and seeing him, it is difficult for me to ascertain exactly what is happening here.  There are several possible problems.  I do not know how his ventricular function is; if his heart pumping ability is diminished, he can have decreased exercise tolerance.  We do know that patients who have cardiac surgery with heart-lung bypass are at risk to get dysfunction of the sinus node, the natural pacemaker of the heart; this may be an indication of that.  It is unclear to me why he has bidirectional shunting at his PFO when his right ventricular pressure is truly supposedly as low as it is; the bidirectional shunting can be a sign of pulmonary hypertension, or high blood pressure across the lungs.  Pulmonary hypertension could be another potential reason for this.

Overall, it may be helpful for him to undergo exercise stress testing to better evaluate his heart rate.  He may even be able to have a stress echocardiogram, which would also demonstrate his cardiac function, right ventricular pressure, and blood flow across the foramen ovale.   To answer your question, it certainly could be due to his heart.  As well, patients who have sinus node dysfunction do benefit from having a pacemaker to improve their heart rate response at both rest and exercise.

[CHELLETO6DOGS]

he does not have asthma as he past the PFT and he does have a 19% subglottic stenosis.

[CHELLETO6DOGS]

sorry i forgot to mention that in a few of his recordings it showed that his HR was not coordinating with his breathing as it is suppose to do.
Michelle

[CHELLETO6DOGS]

now my question and I hope that i can be understood, and if you need more information i can look up his records, and this is just for my curiosity, his speech therapist (she see him for breathe support as he can't do a spirometer for more then 6 seconds n lowest level) she says that your breathing and HR go hand and hand. (he did have something come back on his loop recorder saying something to the effect that they (HR and breathing were not coordinated as his HR was 210)  she also feels that his choking could be fatigue, meaning from the hard work his heart does. he chokes usually at dinner, the other night it was hamburg then water. we are seeing his ENT about it.
also can the implant be wrong on how fast his HR is really going? they say that the arrhythmia isn't really happening but it is showing this due to his complete RBBB
now can this all be related to cardiac like she feels it may be. if so would somehow controlling his HR say like between 60-150BPM would that help, especially with his running and exercise fatigue?
I hope I make sense
Thank you
Michelle