Should you have an echo cardiogram before a cardiac stress test?

My daughters best friend is 22 she is approx. 100lbs overweight, she’s a large farm girl, her breasts alone must account for at least 25% of this excess. She has been having heart rate issues, when sitting her heart rate is 90 if she walks down the street it goes up to 160 this was verified by a halter. She has had a ct scan and they saw no blockages. Her cardiologist has ordered a stress test later this week, but I think she should have a echo cardiogram first to make sure their are no internal cardio problems prior to the stress test. I’m afraid she could have a heart attack if her heart rate is pushed too high. Please advise! thanks (—)

Age: 22
Female
Medications: none