Orthogonal high-density mapping with ventricular tachycardia isthmus analysis vs. pure substrate ventricular tachycardia ablation: A case–control study

Abstract

BackgroundSubstrate-based ablation has become a successful technique for ventricular tachycardia (VT) ablation. High-density (HD) mapping catheters provide high-resolution electroanatomical maps and better discrimination of local abnormal electrograms. The HD Grid Mapping Catheter is an HD catheter with the ability to map orthogonal signals on top of conventional bipolar signals, which could provide better discrimination of the arrhythmic substrate. On the other hand, conventional mapping techniques, such as activation mapping, when possible, help to identify the isthmus of the tachycardia.AimThe purpose of this study was to compare clinical outcomes after using two different VT ablation strategies: one based on extensive mapping with the HD Grid Mapping Catheter, including VT isthmus analysis, and the other based on pure substrate ablation.MethodsForty consecutive patients undergoing VT ablation with extensive HD mapping method in the hospital clinic (November 2018–November 2019) were included. Clinical outcomes were compared with a historical cohort of 26 consecutive patients who underwent ablation using a scar dechanneling technique before 2018.ResultsThe density of mapping points was higher in the extensive mapping group (2370.24 ± 920.78 vs. 576.45 ± 294.46; p < 0.001). After 1 year of follow-up, VT recurred in 18.4% of patients in the extensive mapping group vs. 34.6% of patients in the historical control group (p = 0.14), with a significantly greater reduction of VT burden: VT episodes (81.7 ± 7.79 vs. 43.4 ± 19.9%, p < 0.05), antitachycardia pacing (99.45 ± 2.29 vs. 33.9 ± 102.5%, p < 0.001), and implantable cardioverter defibrillator (ICD) shocks (99 ± 4.5 vs. 64.7 ± 59.9%, p = 0.02).ConclusionThe use of a method based on extensive mapping with the HD Grid Mapping Catheter and VT isthmus analysis allows better discrimination of the arrhythmic substrate and could be associated with a greater decrease in VT burden.

Challenges in Ventricular Arrhythmia Ablation: Difficult Substrates and Advanced Ablation Strategies

“…Additionally, high-density (HD) mapping emerges as a promising approach for accurate detailing of substrates for VT. HD mapping catheters provide detailed and comprehensive electroanatomical information across a number of points with superior resolution, enabling more accurate discrimination of local abnormal electrograms [18]. This high-resolution mapping enhances the precision of substrate delineation and characterization of scar substrates [19] [20] frequently leading to more accurate ablation target delineation.…”

Catheter ablation of ventricular tachycardia: strategies to improve outcomes

“…High density multi-electrode mapping has brought about a paradigm shift in substrate characterization during VT ablation. Local electrogram voltages are dependent on the recording electrode size, inter-electrode spacing, and direction of wavefront propagation ( 68 ). The use of multi-electrode mapping catheters with small (1.0 mm) closely spaced electrodes resulted in a 22% smaller low voltage area (<1.5 mV) and a 47% reduction in dense scar size (<0.5 mV) in animal models ( 69 , 70 ).…”

Ventricular Tachycardia Ablation Guided by Functional Substrate Mapping: Practices and Outcomes

“…Those RF targets are subject to some extent to interpretation and their assessment is limited by several factors: first, it depends on the capability of the mapping catheter to correctly detect the EGMs according to the electrode size, interelectrode spacing, and angle of the incoming wavefront to the bipolar pairs [15,16]. Concerning this matter, some studies have compared traditional point-bypoint catheters with new high-density (HD) catheters showing a better discrimination of abnormal electrograms and better clinical outcomes with the HD catheters [17][18][19]. Second, it is known that the abnormal EGMs can be hidden within the far-field signal and occur during the surface QRS and not after it.…”