@pleasant7 Welcome to Connect. My dad had heart disease for many years including heart attack, heart failure and an electrical malfunction. He also had Type 2 diabetes which is linked to heart disease. Has your cardiologist explained how diabetes affects the heart and what steps you can take with dietary changes to improve your health? That is something you can control and a support group for healthy eating may help you.

Here is some Mayo Clinic information about a diet for diabetes
https://www.mayoclinic.org/diseases-conditions/diabetes/in-depth/diabetes-diet/art-20044295
https://www.mayoclinic.org/diseases-conditions/diabetes/expert-answers/diabetes/faq-20058545
https://myheart.net/articles/choosing-the-right-sources-of-carbohydrates-is-essential-for-preventing-cardiovascular-disease/
I found a link that explains a lot about heart issues that illustrates everything with moving imaging. There is still a lot of terminology to look up, but here it is: https://myheart.net/articles/heart-function-including-ejection-fraction-ef/

What comes to my mind if the left atrium is not filling enough would be a question of if the valves are operating correctly. The left side of the heart brings oxygenated blood from the lungs through valves into the L atrium, and from there blood passes through more valves into the L ventricle which pumps it out to the rest of the body. The valves prevent back flow of blood and close under normal circumstances briefly before opening again.

This link from the Texas Heart Institute explains a lot about heart failure, medications and treatment.
https://www.texasheart.org/heart-health/heart-information-center/topics/heart-failure/
This explains Hypertrophic Cardiomyopathy
https://www.mayoclinic.org/diseases-conditions/hypertrophic-cardiomyopathy/symptoms-causes/syc-20350198
This link has a lot of resources about cardiac tests. https://myheart.net/tests-investigations/

I did at one time have chest pains that turned out to be stress related, but because my dad was a heart patient, I went to a cardiologist for a full work up and had the treadmill stress test, echo cardiogram, and a nuclear test that shows the way the heart beats in 3 D imaging. I know it will be hard to wait for your test results, but only your cardiologist and heart specialists can give you a diagnosis and tell you how your heart disease is progressing as well as what interventions could change the direction toward better health. I think the first question I would ask is what can I do and what changes in lifestyle and diet can I make to better my health?

How are you managing your diabetes?