Investigation into the importance of using natural PVCs and pathological models for potential-based ECGI validation

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Imaging

Background:

• Premature ventricular contractions (PVCs) are frequently used to validate electrocardiographic imaging (ECGI).
• Ventricular stimulation is common for mimicking PVCs, but its physiological fidelity to spontaneous PVCs, especially R-on-T events, is uncertain.
• Understanding these differences is crucial for accurate ECGI interpretation.

Purpose of the Study:

• To compare the accuracy of ECGI in reconstructing spontaneous PVCs versus ventricular-stimulated beats.
• To investigate the impact of pathophysiological changes, like hyperkalemia, on ECGI reconstruction accuracy.
• To evaluate ECGI performance during R-on-T phenomena and in the presence of conduction block.

Main Methods:

• Utilized Langendorff-perfused pig hearts in a torso tank model.
• Induced local hyperkalemia via high-K+ solution perfusion.
• Simultaneously recorded from heart and torso surfaces during ventricular pacing and spontaneous PVCs (including R-on-T) at baseline and high K+.

Main Results:

• Spontaneous PVCs showed significantly better ECGI reconstruction accuracy (electrogram morphology, potential maps, activation time maps) than stimulated beats at baseline.
• High potassium levels reduced ECGI reconstruction accuracy for both spontaneous and stimulated beats.
• Localization error did not significantly differ between spontaneous and stimulated beats, but worsened with high K+.
• ECGI accuracy for spontaneous PVCs decreased during R-on-T events and when encountering conduction block.

Conclusions:

• ECGI accuracy differs between spontaneous PVCs and ventricular-stimulated beats, with spontaneous events being reconstructed more faithfully.
• Pathophysiological conditions and electrical obstacles (e.g., R-on-T, line of block) significantly reduce ECGI reconstruction accuracy.
• Physiologically realistic models are essential for robust ECGI validation, particularly for complex arrhythmias and heterogeneous electrical substrates.