Re: Magnisium Chloride vs Magnesium Oxide, which is better?

I have been prescribed (& have been taking) Magnesium Chloride- [Extended Release] 10Meq in Capsule form, 1-ea. twice a day. These were prescribed by my Cardiologist and his team. I have a rare form of Cardiac Amyloidosis [the ATTR version] In the process, I have had 2-Cardioversion, both of which have failed, and a Cardiac-Ablation that lasted merely 9-months. I've been on Eliquis ever since I was diagnosed with the Amalyoide issue some 2-years ago, and was recently placed on TIKOSYN when the Ablation was no longer controlling my episodes of A-FIB and Atypical-Flutter.

Recently I saw a Cardiologist @ the VA, and he wrote me a RX for Magnesium Oxide - 400 MG in Tablet form. [they just arrived!] so why the different forms of Magnesium? I noted one poster mentioned that the MG-Oxide was cheaper. This sounds like the VA, as they seem to offer the least expensive version of medications as I had a dickens of a time getting Eliquis from them. I need to understand the difference in the two forms of Magnesium.
I welcome any information that will help me ask the right questions when I approach the VA Dr. Than ks.