I just googled diuretics and heart failure, and all the results are saying they're commonly used for patients with heart failure.
"The available data from several small trials show that in patients with chronic heart failure,
conventional diuretics appear to reduce the risk of death and worsening heart failure compared to placebo."
Diuretics for heart failure
Meanwhile, Steroids have a clear negative effect.
"
This study shows that taking steroids, even for a short period of time, may cause permanent damage to the heart. Findings also suggest that the more steroids a person takes over time, the worse the heart damage will be."
Anabolic Steroids Increase Risk for Heart Disease in Young and MiddleAged Men
It's the roids dude. They're not good for you.