My 8-year-old Granddaughter Is Getting Her First Filing Today At

My 8-year-old granddaughter is getting her first filing today at the dentist. She was born with aortic stenosis, had a balloon inserted to open her valve at 2 months old but no other procedures so far. Her dentist plans to sedate her with nitrous oxide today and I'm concerned about if it is safe for her with her heart condition. She has not received nitrous before and also was not prescribed any medication for her appointment today. Thank you