This has come up before
An ECG is no different from any other medical test. The results need to be analysed by a doctor or healthcare worker who is qualified to do so. The problem with ECGs is that the manufacturer adds in a small algorithm that prints out a list of basic diagnoses based on basic parameters. Some are correct, others are not. Many many ECGs report abnormalities
I would suggest you ask the doctor who undertook your ECG to read it and advise you. However given that you cannot modify your ECG there seems little point in spending time and money on it before your medical
Tachycardia merely means a fast pulse which you can measure with your finger on your wrist. It goes up with exercise and fear and falls at rest. If your resting rate is under 80 and you are otherwise well I would not worry
A minor ST depression again is not alarming. The minimum the machine can measure is 1 mm and in general we ignore this. It need to be bigger but we also need to know which leads it can be seen in and the shape of the ST segment
Hope this helps. Let us know how you get on