ECG abnormality in(ST-T Segmentation, v6 abnormality)

Patient: My mother aged 59 has reported a ST-T Segmentation, V6 abnormality in her ECG. Is there a chance of heart blockage. A cardiologist has suggested cardiographyh only on the basis of ECG which we think is an invasive procedure without any other check up or tests.Please advise if heart blockage could be ascertained in any other way

Symptoms: Heavy breathing if she walks for abt 15 mins, slight coughing in recent days.