Improved
Potassium pages, step by step
Before
Study mode on the hyperkalaemia and hypokalaemia pages lit each step's leads but drew nothing on the tracing, and the torsades and VF forms asked you to watch a recording that no longer moved.
After
Hypokalaemia's torsades and hyperkalaemia's VF are timelines: each step plays the recording to its moment, the short-long-short start, the twist and the end, or the sine wave breaking into VF. Every other form marks each step on the tracing: the T and U, the ST, the PR, QRS and QT, the rate, and at K⁺ 2.0 the premature beat and its pause.