Thank you for your query.
There little reason to panic or to worry.Sinus arrhythmia
signifies change in heart rate
with respiration and is a normal phenonmenon. Partial right bundle branch block
is usually found in many individuals and dose not need any treatment. Your child will have a preanaesthetic checkup before the surgery again.So do not worry and all the best for the surgery.Hope this answers your query.Have a nice day.