Sometimes when during sleep i have 120 heart byte is it normal?

Such high heart rate is not considered normal though when One is Dreaming (REM- Sleep) the heart rate could be up. Question is how did One find out their Pulse=120 while Sleeping. Was there a Sleep study or was one wearing a Smart Wrist watch or Cardiac Monitor? WWAre there other associated Symptoms? A Face to face, Virtual or in Person with the Cardiologist is a good place to start.