Low heart rate

my 14 year old grandson had his appendix removed 3 weeks ago.  30 hours after surgery his heart rate went from 76 ( his normal) to 43.  The cardiologist that examined him said it must be normal for him.....his EKG and echo were fine....no problems,  and he feels fine. They gave him Lortabs for pain the day of the surgery and the next day. They said it is out of his system now, but his heart rate still is low
What could cause his problem????

[Marie M Gleason, M.D.]

If your gransdon's cardiac structure and function is normal on the echocardiogram, and the EKG showed normal conduction intervals and no evidence of heart block, and he feels fine and is maintaining a normal blood pressure, then slowing of the heart rate is likely due to high vagal tone.  This is especially common after manipulations in the gut.  Also if he is athletic, then the heart rate can run slower.  If he is asymptomatic, and the cardiologist felt all looked well, then there is likely nothing further that needs to be done.  He can certainly check his own pulse rate periodically (at rest and with exercise) and keep a log of these numbers, if your family is concerned.  That would be information to give to his primary doctor if people are concerned.