Virtual EP lab

A workstation for arrhythmologists and cardiologists: 3D activation and voltage maps, catheter signals (HRA, His, CS, RVA, ABL) and the 12-lead ECG are calculated from one model. Induce tachycardia with programmed stimulation, localize the pathway region from the patient's ECG with a published algorithm, try virtual ablation and send the case to a colleague as a link.

Building the heart model…

Activation map

Calculating…

EarlyLate

The impulse leaves the sinus node, is delayed in the AV node and, via the His–Purkinje system, excites both ventricles almost simultaneously: the QRS is narrow.

Substrate

AV node

A single pathway in the AV node: an early impulse conducts more slowly (decrement); if it is very early, it blocks in the node.

Ventricular scar

The ventricles are healthy.

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QRS

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Electrical axis

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One beat, bipolar signals. HRA — high right atrium, HIS — bundle of His, CS 9-10 proximal → CS 1-2 distal (coronary sinus), RVA — right ventricular apex, ABL — ablation catheter. Dot: the earliest ventricular signal in the coronary sinus.

25 mm/s · 10 mm/mV. Red line: the beat the 3D heart is showing in slow motion.

How it works

One model
The heart consists of about 4,400 points spaced 0.35 cm apart: the atria, both ventricles, the right ventricular outflow tract, and the sinus node, AV node, bundle of His, bundle branches and Purkinje fibers.
Propagation is calculated
When excited, each point passes the impulse to its neighbors; faster along the wall, slower across the wall. Waves collide and stop in refractory tissue, and the AV node conducts an early-arriving impulse more slowly: none of this is scripted in advance.
The ECG comes from that propagation
Every millisecond, the heart's electrical vector is summed from the boundary between excited and resting tissue and projected onto 12 leads with the Dower transform. There are no templates: the QRS shape, the delta wave and the T wave come from the model itself.
Catheter signals
Each electrode sees the potential of the nearby tissue; a bipolar channel is the difference between two electrodes, filtered as in a recording system. The A–H–V on the His catheter, the proximal-to-distal sequence in the coronary sinus and the fusion of A and V over the pathway also come from the model itself.
Patient mode
The delta wave polarities from the patient's ECG are entered into the published EASY-WPW algorithm (El Hamriti et al., Europace 2023) and compared with the model's ECG at 13 points. This is not a prediction: it is help for the doctor in planning; the location is confirmed during the EP study and mapping.
Stimulation and substrate
S1–S2(–S3) protocol from the HRA, CS or RVA. If dual AV nodal pathways, an accessory pathway or a channel in an inferior wall scar is added, AVNRT, AVRT or scar-related VT arises only from the conduction and recovery properties of the tissue: the AH jump, VA, CS sequence and cycle length are measured. After ablation, deliver the same protocol again to check the result.

The model is simplified: the heart shape is schematic, fiber orientation and body tissues are not taken into account, and amplitudes are approximate. For pathways on the right free wall the delta wave comes out weaker. Lesion size, the safe distance to the bundle of His, refractory periods, scar shape and voltage thresholds are simplified values: whether or not tachycardia is induced by stimulation does not indicate the result in the patient. Patient mode is neither a diagnosis nor a prediction of the outcome: the pathway location is confirmed by an EP study and mapping, and the doctor makes the decision.

Virtual EP lab

How it works

One model

The heart consists of about 4,400 points spaced 0.35 cm apart: the atria, both ventricles, the right ventricular outflow tract, and the sinus node, AV node, bundle of His, bundle branches and Purkinje fibers.

Propagation is calculated

When excited, each point passes the impulse to its neighbors; faster along the wall, slower across the wall. Waves collide and stop in refractory tissue, and the AV node conducts an early-arriving impulse more slowly: none of this is scripted in advance.

The ECG comes from that propagation

Every millisecond, the heart's electrical vector is summed from the boundary between excited and resting tissue and projected onto 12 leads with the Dower transform. There are no templates: the QRS shape, the delta wave and the T wave come from the model itself.

Catheter signals

Each electrode sees the potential of the nearby tissue; a bipolar channel is the difference between two electrodes, filtered as in a recording system. The A–H–V on the His catheter, the proximal-to-distal sequence in the coronary sinus and the fusion of A and V over the pathway also come from the model itself.

Patient mode

The delta wave polarities from the patient's ECG are entered into the published EASY-WPW algorithm (El Hamriti et al., Europace 2023) and compared with the model's ECG at 13 points. This is not a prediction: it is help for the doctor in planning; the location is confirmed during the EP study and mapping.

Stimulation and substrate

S1–S2(–S3) protocol from the HRA, CS or RVA. If dual AV nodal pathways, an accessory pathway or a channel in an inferior wall scar is added, AVNRT, AVRT or scar-related VT arises only from the conduction and recovery properties of the tissue: the AH jump, VA, CS sequence and cycle length are measured. After ablation, deliver the same protocol again to check the result.