High potassium level

I have cardiomyopathy and LBBB. My EF has just risen to 40%. I have always had fairly high potassium levels 4.8 - 5.2 but a recent blood test showed 5.7. When should I be concerned ? Thanks

[Cleveland Clinic]

It could mean that you are experiencing worsening renal function or more likely the side effect of one of the medications you are taking. Are you on an ace inhibitor, ARB or aldactone? Because these are the medications most likely to be implicated.
You need to speak to your doctor about changing the medications/doses and maybe decrease your daily potassium intake.