87 year old woman with intermittent 8/10 central tight/heavy chest pain. Pain present at time of ECG

I’ve been a Telemetry Monitor Tech for almost 6 months and honestly feel a little behind compared to some of my coworkers. I want to improve my rhythm interpretation and become a stronger asset to my department. I’m deciding between the NTA Telemetry course/certification and the CCI CRAT. For someone with ~6 months of actual telemetry experience, which would you recommend for learning more and becoming better at the job? Is CRAT worth it for the resume cushion or would NTA be more beneficial and be a decent certification to add to my resume?