Read the recording
A / H / V: local atrial, His and ventricular deflections. AH mainly reflects AV nodal conduction; HV reflects conduction from the His bundle toward the ventricles. They are not interchangeable with PR or QRS duration.
S1 / S2: S1 is the repeated drive stimulus. S2 is a single earlier stimulus after that train. Here atrial capture and a constant 10 ms stimulus-to-local-A delay are assumed, so S1–S2 and A1–A2 are equal.
Channel map: HRA = high right atrium; His = His-region bipolar signal; CS 9–10 = proximal, CS 1–2 = distal coronary sinus in this model; RV = right ventricular signal. Channel names alone do not confirm catheter position.
The surface channel is a continuous synthetic lead-II-style rhythm strip with rounded P and T waves and an 80 ms QRS complex. During this mock SVT, retrograde atrial activity overlaps the QRS and may not be separately visible. This is a single rhythm strip, not a diagnostic 12-lead ECG. HRA, His, CS and RV display continuous, smooth multiphasic bipolar electrograms with distinct shapes. HRA and CS emphasize atrial components with small modeled far-field ventricular components; His shows separate A, H and V components; RV emphasizes ventricular activation. These are intracardiac electrograms, not surface P–QRS–T waves. Choose Beat close-up to inspect their contours. Waveforms are schematic, with arbitrary amplitude and no clinical filtering. Small components and far-field signals are simplified. Time is linear within each view; full-recording mode compresses detail.