My 6 year old has a resting heart rate of 198 bets per minute. He has no fever. Is this to high?

High heart rate . Yes a heart rate of 198 is too high. He needs to have an ekg and a doctors visit. Could be thyroid problems or an electrical problem of the heart.
Yes. A resting hr persistently at 198 is too high for a 6 year old. I definitely recommend getting it checked. Anemia, high thyroid, and fever can cause rapid hr, but persistently at 198, i would recommend an ekg at least to rule out some types of arrhythmia like something called svt.
TOO high tachycardia. Dr. Wimberly is quite correct to suggest a visit with the pediatrician to evaluate the tachycardia. But something as simple as chocolate or caffeine intake could cause this level of tachycardia, as could otc medications. Your doctor will review these with you to be sure unnecessary tests or treatments are not done on your child.