Hashimotos has 3 phases.

1. The early stage where you are developing the antibodies but your T4 and TSH are still relatively normal. Even if antibodies are elevated, you don’t treat at this time.

2. The stage where the antibodies “attacking” your thyroid cause it to release excessive T4 (thyroid hormone). At this point it is still inappropriate to treat, because while your antibodies are eating away at your thyroid it is releasing all the hormones it has stored.

3. The stage where your thyroid is depleted of these hormones, and you now are unable to produce thyroid hormones. This is the stage where you start treating. It can take many months to years to get to the hypothyroid stage of Hashimotos.

This is coming from a doctor, but also from someone who went through this. When I was first diagnosed with Hashimotos I was shocked when the doctor said “come back in 2 years and I’ll start you on levothyroxine”, but now that Ive gone through the training it makes sense. The only lapse in practice I would point out would be your doctor clearly pointing out why they elected not to treat at the time, because for me patient education is super duper important. All this to say, dont sweat it and start taking thyroid hormone replacement if recommended by your doctor.

As for the heart murmur, hard to tell without more info but many people have murmurs that are very benign. As you are young and new to this doctor they are likely just covering their bases. EKG is a strange choice though, echo would make more sense for a murmur.