How the model works
Electrical events and pulse strength share a reproducible beat schedule.
Rhythm selection controls atrial events, conducted or paced ventricular events, cycle duration and beat strength. Sinus rhythm, AF, flutter, ectopy, AV block, pauses and pacing therefore change more than the appearance of an ECG line.
Irregular schedules are deterministic repeating examples, not fresh randomness every animation frame. Replaying or pausing the same state at the same simulation time yields the same electrical and mechanical events.
Sinus P waves and atrial contraction precede the conducted ventricular event. AF has no discrete organized a wave. Flutter and AV block retain their own atrial activity; AV dissociation can produce mistimed atrial pressure waves. Junctional and ventricular escape examples differ in QRS width, rate and perfusion.
Extended schedules implement conducted PACs, MAT, progressive or fixed AV block and sinus pauses. A displayed rate may be the average over a repeating conduction sequence rather than the instantaneous rate of the conducted pairs.
The disease/rate model supplies nominal flow. The effective-output calculation then accounts for the repeating rhythm’s mechanical beat strengths; irregular filling and ectopy alter pulse amplitude. Ventricular rate zero and VF remove native forward output. A broad QRS alone is not assigned VF-like mechanical failure.
Temporary pacing and AV-synchronous pacing use capture/timing rules; ventricular-only pacing can retain atrial dissociation. CRT assumes a selected responsive dyssynchrony phenotype, not universal benefit for every cardiomyopathy.
Irregular intervals change ventricular pulse strength and systolic atrial loading, including regurgitant v waves. In MS/TS, shorter diastolic filling intervals retain greater LA–LV or RA–RV pressure separation; longer intervals permit more emptying. The interval spans the end of one mechanical beat and the beginning of the next.
The atrial correction is continuous across beat boundaries and recentered over the repeating 16-beat AF sequence. An illustrative exponential decay (0.18–0.53 seconds, scaled by lesion burden) changes contour without inventing a new mean filling-pressure target. Exact beat responses and tricuspid extrapolation are synthetic.
This is not a universal short-RR/high-gradient rule: aortic gradients depend on ejected flow and may be lower after an inadequately filled beat. Read representative beats and averaged measurements, not the most extreme single gradient. The displayed PAWP retains its fixed nominal-rate delay; the Wiggers LA proxy and PV valve-event calculation remove that same delay.
NSVT repeats six episodes containing 18, 16, 20, 15, 19 and 17 ventricular beats, each preceded by 16 baseline beats. Baseline can be sinus or AF. VT rate is clamped to 180–240 bpm; runs terminate within 30 seconds.
VT beat strength is reduced in proportion to its shorter duration, so the faster run does not manufacture extra flow. Arterial pressure runs down and recovers with short exponential transitions. Pressure, pleth and ventricular mechanics follow the same run timing. Amiodarone, lidocaine or metoprolol suppress runs in this chosen later response; they do not guarantee clinical efficacy or convert underlying AF.
There are currently 34 selectable rhythm entries. Each has its own wiki page, and the twelve-lead catalogue supplies compatible morphology variants. The rhythm selector, morphology selector and myocardial disease are related but distinct inputs.
