Her2+ treatment and latent cardiac dysfunction/abnormal GLS

Hello. I was treated for stage T1cN1aM0 triple positive starting in March 2015 with lumpectomy, TCH chemo and left-side radiation including a 'boost' to the axillary. No recurrence to date, thankfully. My oncologist states my lifelong risk for a recurrence at 2%.

I have had inherited mildly high cholesterol, now in excellent control with medication, and high blood pressure. I received treatment for the latter starting in 2020. I asked to see an-onco-cardiologist. This was delayed by covid and the doctor moving out of state. I have a new cardiologist who ordered an Echo. The echo revealed LVEF of 64% (it was 74% during treatment but 64% is good). I don't believe the global longitudinal strain was measured at that time but it is now abnormal at -15.6. My cardiologist attributes the drop to age, high blood pressure, but predominantly Her2+ treatment. Doc said it is essential that my blood pressure and cholesterol be controlled, that I exercise regularly and control weight gain (my bmi is 24; never had a weight gain issue and eat a healthy diet). Frankly I am astonished at the degree of loss to the gls (it predicts future LVEF loss and cardio damage from chemo). Any one else had this issue discovered years after treatment? My treatment is at a major teaching hospital and I am surprised that my heart was not monitored after treatment. In fact, the final echo when I finished treatment was not ordered/performed. (There were assumptions made at the time I had treatment that patients undergoing treatment with TCH would not suffer cardiac damage.)

I suggest anyone who has had Herceptin with or without anthracyclines, request to be monitored by a cardiologist during and indefinitely after treatment.