Confirmation of Pulmonary Vein Isolation with High-Density Mapping: Comparison to Traditional Workflows

Uncovering the Invisible: The Role of High-density Catheters in Recognizing Fractionated Signals in Pulmonary Vein Isolation

The HD Grid multipolar mapping catheter has emerged as an invaluable tool for greater effectiveness of pulmonary vein isolation (PVI). In the cases described here, fractionated signals seen with the HD Grid catheter at the left atrial appendage (LAA) and left superior pulmonary vein (LSPV) junction were ablated. These signals are not likely to be visualized with conventional catheters and may cause recurrences due to incomplete PVI. The directional sensitivity limitations of bipolar electrogram recordings and the unique anatomy of the LAA-LSPV ridge further contribute to the challenge of evaluating PVI. The HD Grid catheter's ability to record bipoles parallel and perpendicular to the catheter splines and its high-density mapping capabilities provide a superior means for identifying gaps in ablation and detecting the low-voltage isthmus. Furthermore, factors such as ablation quality, catheter stability, and thickness of the LAA-LSPV ridge influence the presence of fractionated signals and the success of PVI. Incorporating preprocedural imaging modalities, such as computed tomography or magnetic resonance imaging, and real-time intracardiac echocardiography could enhance the tailored approach to address these challenges. Future developments in the HD Grid technology, including the option for contact force measurement during mapping, may offer additional insights into the nature of these signals. This case series highlights the significance of using the HD Grid catheter for a detailed interrogation of the LAA-LSPV ridge, ultimately leading to more effective PVI and improved outcomes in patients with atrial fibrillation.

High-density mapping improves detection of conduction gaps after pulmonary vein isolation ablation with a circular mapping catheter

BACKGROUND

High-density (HD) mapping of the pulmonary vein (PVs) has been hypothesized to improve the detection of conduction gaps in the radiofrequency ablation lesions set after pulmonary vein isolation (PVI) for the treatment of atrial fibrillation (AF). We aimed to compare the incidence of gaps after PVI with a standard 20-pole circumferential mapping catheter (CMC-20) and an HD mapping catheter (HD Grid).

METHODS

This prospective study included patients scheduled for high-power short-duration PVI. Acute PVI was defined as an entrance and exit block using the CMC-20 after ≥ 20 min waiting period. The left atrium was then remapped using the HD Grid high-density mapping catheter to identify residual conduction gaps in the PVI lines by voltage and activation criteria. The primary endpoint was the number of gaps identified per patient by the HD Grid catheter.

RESULTS

A total of 20 patients were included (mean age 59.9 ± 10.8 years, 15% female, 70% paroxysmal AF). The new map with the HD Grid identified 6 gaps in 4 patients (20%) or 0.3 ± 0.7 gaps per patient (p = 0.055 when compared to CMC-20). Five gaps (83%) were located at the right PVs. There was no difference in mapping time (CMC-20 12.2 ± 2.6 min vs HD Grid 11.7 ± 3.4 min, p = 0.452); however, the number of points was significantly higher in the HD Grid map (1662.7 ± 366.1 vs 1171.6 ± 313.6, p < 0.001).

CONCLUSIONS

HD mapping during AF ablation identified PVI gaps in 1 out of 5 patients. Therefore, HD mapping may have the potential to improve AF ablation success rates in the long term.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04850508 on April 20, 2021.

Epicardial Potential in the Left Atrium During Posterior Wall Isolation in Persistent Atrial Fibrillation

Pulmonary vein isolation (PVI) is used for rhythm control in atrial fibrillation (AF). Posterior wall isolation (PWI) is often an adjunct to PVI. Successful PWI is limited by esophageal location, epicardial bridging signals, tissue thickness, and mapping catheter resolution. High-density grid mapping catheters can assist with PWI. Here, we report a case of a 71-year-old woman with persistent AF who underwent PVI and PWI with high-density grid mapping catheters, thus demonstrating the use of omnipolar technology in facilitating successful PWI.

Next-generation mapping with HD Grid and HD Wave

High-definition (HD) mapping with the Advisor HD Grid and HD Wave Solution software offers unparalleled resolution in mapping complex arrhythmias. The unique shape of a HD Grid (16 electrodes in a 4 × 4 pattern) allows for the mapping of orthogonal electrograms (EGMs). In so doing, the HD Grid catheter virtually eliminates the issue of 'bipolar blindness', a phenomenon seen when a wavefront of propagation is traveling perpendicular to a bipole pair. By improving the accuracy of the 3D electroanatomical map, HD Grid offers the potential of shorter procedure times, safer ablations and higher success rates. The following article explores the role of HD Grid in mapping a variety of arrhythmias including supraventricular tachycardias, atrial fibrillation and ventricular tachycardia. In addition, the authors explore the role of HD Grid in more recently described substrate-based advanced mapping techniques.