Well, as you already mention, 5,5 is just above the 5,3cm which is the top of the reference range (3,9-5,3).
This is not too bad but if there is a cause for it, it would be better if something was done accordingly to prevent further enlargement.
Some points that come into my mind are:
-Ventricle size depends a bit on body size, so if your are very tall, the size could be quite normal for you
-It could be that you have had this larger LV all your life. A repeat echo in say half a year could clear if the size is increasing or remains constant
-If there is already found a cause, treatment might be wise. i.e. if you suffer from high blood pressure, it would be good to get your bp lowered (either lifestyle, medication or both)
Thank you so much for your feedback, I have to get a cardiac MRI because they think I have cardiomyopathy because the CTA scan showed left ventricular noncompaction. I hope I don't have cardiomyopathy tho. So scared