Ablation of right bundle branch Purkinje-origin ventricular parasystole: The role of omnipolar frequency mapping

Figures

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  Figure 1. Surface electrocardiogram demonstrating ventricular parasystole with intermittent fusion beats. The ectopic QRS complexes exhibit complete left bundle branch block morphology with a superior axis. Fusion beats are denoted by asterisks. Sinus P waves are labeled as “P” to indicate an underlying independent sinus rhythm. The parasystolic cycle length was constant at 800 ms, confirming a dissociated ectopic pacemaker activity.

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  Figure 2. A: Sinus rhythm activation map demonstrating the earliest activation site in the right ventricular free wall (white arrow). High-frequency potentials suggestive of Purkinje-like potentials were recorded at this site. B: The activation map of ventricular parasystole identified 2 earliest activation sites located in the right ventricular free wall: one at the basal site and another at the apical site. Both sites exhibited potentials preceding the onset of the parasystolic QRS complex by 32 ms; however, the basal site showed a sharp, high-frequency Purkinje-like potential whereas the apical site exhibited a dull, low-frequency potential.

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  Figure 3. Intracardiac electrogram (EGM) recording demonstrating a high-frequency potential preceding the QRS complex by 32 ms recorded at a sweep speed of 200 mm/s. The EGM was obtained from the basal site identified as the high-frequency target on the frequency map during ablation catheter placement.

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  Figure 4. Combined activation and frequency map (threshold > 400 Hz). An activation map overlaid with a frequency map, allowing simultaneous visualization of early activation timing and high-frequency components. Activation mapping identified 2 earliest activation sites at the basal and apical right ventricular free wall. The addition of frequency mapping highlighted only the basal site exhibited high-frequency potentials. LAT = local activation time.

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  Figure 5. Radiofrequency ablation targeting the earliest activation site identified by activation mapping and an Omnipolar Technology Near Field (OTNF) analysis. The upper scale bar indicates activation prematurity relative to the QRS onset, whereas the lower scale bar represents ablation duration.

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  Figure 6. Electrocardiographic recordings during radiofrequency ablation. Immediately after the energy application, acceleration of the parasystolic rhythm was observed, as indicated by the shortening of the cycle length. Subsequently, the cycle length gradually prolonged, leading to the complete termination of the parasystole.

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  Supplementary Figure 2.

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  Supplementary Figure 3.

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  Supplementary Figure 1.