Hi,
TCM services do not include EKGs. Per EncoderPro:
"Do not report these codes when reporting 90951-90970, 98960-98962, 98966-98969, 99071, 99078, 99080, 99091, 99339, 99340, 99358, 99359, 99366-99368, 99374-99380, 99441-99444, 99487-99489, or 99605-99607 when performed within the same 30-day period of 99495 or 99496."
You do not need a modifier.