Hyperkalemia is probably the most common reason for an urgent nephrology consult. Most of us are familiar with the EKG changes associated with hyperkalemia, though surprisingly, only ~55% of patients with serum potassium levels greater than 6.8 mEq/L have shown to have these changes. Here is an interesting demonstration of the effect of hyperkalemia on myocardial contractility seen on POCUS shared by Dr. Mackenzie, an ER physician.

First image shows the parasternal short axis view in a patient with severe hyperkalemia. Note significantly decreased contractility – heart walls are not thickening with contraction and are barely moving. After treatment with calcium and insulin, note the dramatic improvement. Interestingly, this patient had tall T waves on EKG but no ST elevation or bundle branch block pattern. Below are a few slides on how hyperkalemia effects the heart’s impulse generation and propagation.