Potassium levels and risk of in-hospital arrhythmias and mortality in patients admitted with suspected acute coronary syndrome

•Dyskalemia at admission is associated with adverse in-hospital outcomes in ACS.•Associations remain after adjusting for important presentation characteristics.•No interaction is observed between final diagnosis and potassium categories.•Hyperkalemia is associated primarily with in-hospital mortality.•Hypokalemia is associated with in-hospital cardiac arrest and new-onset atrial fibrillation.