My 15 year old daughter is complaining of her heart beating to slow. i checked it with a blood pressure machine and it was 44. should i take her to the er?

If having no symptoms would suggest getting her pediatrician involved first, if having any symptoms otherwise such as chest pain, shortness of breath, lightheadedness, to name a few, best to take her to closest ER.

If she has symptoms including feeling faint, it is best to proceed to the Emergency room. Devices may be inaccurate, recheck manually using a stop watch, three readings seated. Keep your child well hydrated. If she is post COVID-19, cardiac conditions may be associated and further evaluation is recommended.