Built for iPhone Duo. Open, ECG Builder is the full studio: the sheet across the top and every tool below it. Closed, the cover runs the guided builder. Fold or unfold mid-build and nothing is lost: the tracing, the step you were on and your board marks all stay where they were. On iPhone Duo the tools move into the side column beside the clock, so the paper keeps the screen: Layout, Paper, Header, New patient, Share and Refine on the cover, and the whole teaching rail when it is open. The teaching board now draws with a finger when no Apple Pencil is set up, on iPhone Duo and on any iPad without a Pencil. One finger draws, two fingers move the sheet. Also fixed: the builder's cards could sit off-centre, the studio's top bar could run past the edge of a narrow screen, and Record could say it was recording before it had started.

Hide the tools and the sheet becomes a teaching board. Draw on it with Apple Pencil, and your marks stay on the beats you drew them on at any zoom. Two figures sit beside it, the frontal axis wheel and the chest lead map, each with its own space for the pen. Play runs all twelve leads live at the speed printed on the sheet. Record the screen while you teach and send the video straight to your students. Save exports the board as a Letter handout. Every setting the engine has is now a slider or a picker: - Rhythm options: flutter ratio and variable block, VF coarseness, escape focus and rate in complete block, retrograde P, Wenckebach cycle, Mobitz conduction, VT origin, torsades twist, P-wave asystole, sinus pauses - ST slope, extent and reciprocal weighting - T inversion depth, peaking, symmetry and the U wave - QRS amplitude, electrical alternans, P mitrale and P pulmonale - PVC origin and count, atrial ectopics - Pacemaker failure to capture and to sense - R-wave transition - Intraventricular conduction delay Two new tools: - Syndromes applies a named pattern in one tap: Wellens A and B, de Winter, Brugada 1 and 2, S1Q3T3, pericarditis, early repolarisation, hypothermia, digoxin, electrical alternans, low voltage, P mitrale and P pulmonale, LVH with strain, RVH, hyperkalaemia and hypokalaemia, long QT, poor R-wave progression, left axis deviation - Sequence changes the rhythm partway through the strip, with a shock where you want it The paper prints at 25 or 50 mm/s. Baseline drift, muscle tremor and mains hum each have their own slider. AI Build understands the new patterns and rhythm options. Fixed: - Choosing R-on-T no longer crashes the app - The tool panel keeps one size in landscape, so the