Sounds like obesity-related cardiomyopathy. The massive load on the heart, having to push so much blood so hard reach all those tissues, stretches the walls. The walls get more muscular to compensate, but they lack the capacity to build and rebuild properly under constant stress. So eventually, it's just too much and we get a floppy balloon desperately flailing alongside global cardiac failure.
It's a big contributor to obesity-related heart failure, but I think quite a few of these folks die before it sets in. I've had obese cadavers with rock-like hearts so squeezed in fat and thickened muscle it's hard to imagine they could ever move.
Here's a great writeup about the way obesity demolishes the heart that I'm sure HAES people would love. Also how it can be (mostly) reversed with weight loss much of the time, even with "conditions"
Interesting and beautifully simple concept with "obesity time" too. They essentially correlate that when BMI + age nears 100, heart failure risk explosion.