I'm 42, flying for 20 years, just thought I had my career set up nicely for retirement at 60. Had my class 1 renewal two weeks ago. ECG showed up an abnormality - occasional premature ventricular complexes (not had before) and sinus bradicardia (slow heart rate - always had) and I'm due to have a follow-up exercise ECG tomorrow with a cardiologist. So it's wait and see for me. As a result I was discussing ECGs with my co-pilot yesterday.
His initial ECG for class 1 issue showed abnormalities which transpired to be purely due the unusual shape of his heart. He required 3-D x-rays and ultrasound. Three men in white coats at Gatwick then scratched their heads for a couple of hours and passed him fit. Aparently there is considerable natural variation in the heart shape which can affect ECG traces.
I believe the Echocardiogram you talk about uses ultrasound for analysis so may be looking at blood flow characteristics. Although this sort of thing is deeply worrying for pilots, it seems that the CAA are generally over cautious in their approach. Best of luck.