• Added iPhone Duo layouts that adapt to folding and rotation while retaining selected patterns, leads and learning state. • Added a first-launch guide and a free three-step tutorial covering normal ECG, two-lead comparison and Normal versus Right Bundle Branch Block. • Organized the purpose, steps and observation points for all six workspaces in the offline ? guide. • Improved the relationship between vectors, projections and waveforms, plus panel layout and playback controls on compact screens. • Updated the in-app website, support and privacy links.

Learn the mechanisms behind ECGs, from cell currents to cardiac rhythm. - Added Ventricular Action Potential with synchronized Luo–Rudy I membrane voltage, ion currents, and gates. Pause at the sodium-current peak. The standard model and stimulus adjustment are free; conductance adjustment, suppression experiments, and standard-trace comparison are included in the existing Pro purchase. - Added Cardiac Rhythm. Follow activation from the sinus node to the ventricle and adjust sinus cycle, conduction speed, and AV delay. All features, including schematic bradycardia, tachycardia, and AV-block examples, are free. - Expanded Ion & ECG adjustments, including Na⁺ and H⁺ (pH), and clarified clinical connections and differences from the reference. Added voltage ticks and units to the action-potential plot. - Improved single-lead and 12-lead comparisons, including representative pediatric, fever-related heart-rate increase, and higher-BMI examples. ECG Mechanism and comparison selections now remain independent. - Refined pediatric waveforms, bundle-branch conduction, atrial fibrillation, ST changes, and ECG/3D consistency. Included representative P-wave flattening and PR prolongation with high K⁺, and ST depression in the LVH strain pattern. - Improved the 3D heart, membrane diagram, two-lead comparison, and playback alignment. Electrode placement includes all 10 electrodes, including neutral RL. - Improved text, buttons, and layouts. Wider screens show quiz waveforms alongside answers and explanations. Refined the iPhone feature list, navigation, and landscape layouts. - Clarified model purposes and limitations, and made phase, gate, and current explanations more accurate when conditions change. Educational models only—not for diagnosis or treatment decisions.

Learn the mechanisms behind ECGs, from cell currents to cardiac rhythm. - Added Ventricular Action Potential with synchronized Luo–Rudy I membrane voltage, ion currents, and gates. Pause at the sodium-current peak. The standard model and stimulus adjustment are free; conductance adjustment, suppression experiments, and standard-trace comparison are included in the existing Pro purchase. - Added Cardiac Rhythm. Follow activation from the sinus node to the ventricle and adjust sinus cycle, conduction speed, and AV delay. All features, including schematic bradycardia, tachycardia, and AV-block examples, are free. - Expanded Ion & ECG adjustments, including Na⁺ and H⁺ (pH), and clarified clinical connections and differences from the reference. Added voltage ticks and units to the action-potential plot. - Improved single-lead and 12-lead comparisons, including representative pediatric, fever-related heart-rate increase, and higher-BMI examples. ECG Mechanism and comparison selections now remain independent. - Refined pediatric waveforms, bundle-branch conduction, atrial fibrillation, ST changes, and ECG/3D consistency. Included representative P-wave flattening and PR prolongation with high K⁺, and ST depression in the LVH strain pattern. - Refined the 3D heart cutaway. A faintly visible front wall makes depth easier to understand. Atrial activation spreads across the atria, while ventricular conduction is shown as septal bundles and a branching network. - Improved projection vectors on the lead axes and +/− markers, and added 2D diagrams to compare the cardiac electrical vector with its projections. Select leads in the 3D panel and resize the 3D and waveform panels. - Also improved the membrane diagram, two-lead comparison, and playback alignment. Electrode placement includes all 10 electrodes, including neutral RL. - Improved text, buttons, and layouts. Wider screens show quiz waveforms alongside answers and explanations. Refined the iPhone feature list, navigation, and landscape layouts. - Clarified model purposes and limitations, and made phase, gate, and current explanations more accurate when conditions change. Educational models only—not for diagnosis or treatment decisions.

Explore the connections between clinical conditions, ion changes, and ECG patterns more clearly. - Ion & ECG: Expanded the adjustable parameters, including Na⁺ and H⁺ (pH), and clarified links to clinical conditions and differences from the reference. Improved consistency between action-potential calculations and ECG timing displays. - ECG & Conditions: Compare representative patterns with the normal reference in single-lead or 12-lead views, with clearer explanations of waveform features and mechanisms. Explore examples of a healthy child around age 5, fever-related sinus tachycardia, and higher-BMI body habitus. - Refined the medical consistency of the educational models, including pediatric waveforms, bundle-branch conduction, atrial fibrillation, and ST changes. Improved alignment between ECG traces and 3D activation and repolarization. Added representative P-wave flattening and PR prolongation at high K⁺, and ST depression in the left ventricular hypertrophy strain pattern. - ECG Mechanism: Made two-lead comparison easier to find and improved alignment between waveforms, 3D views, and playback position. Electrode placement now includes all 10 electrodes used for a standard 12-lead ECG, including the neutral RL electrode. - Improved text, buttons, and layouts throughout the app, including the iPhone feature list and navigation, iPad numerical displays, and Pro screen controls. Revised quiz presentation and explanations. This is an educational model, not a tool for diagnosis, treatment decisions, or patient-specific waveform prediction.