How safe if bowel prep for colonoscopy in patients with heart disease and severe electrolyte abnormalities? are any of them safe?

Here are some...: Colonoscopy can usually & safely be done under brief IV sedation, but can be deferred until severe electrolyte imbalance+heart disease are optimally corrected because colonoscopy oftentimes is non-urgent and even optional esp. at the time with serious ongoing medical issues. So, ask the treating doc so to understand the balance between medical necessity & professional possibility before proceeding