Abstract only
Introduction:
Recently, there have been numerous strategies for treating atrial fibrillation, including the choice of catheters However, the thermal characteristics of each catheter, ...particularly in terms of safety, have not been fully understood.
Hypothesis:
Our aim was to characterize the thermal damage to collateral tissues during 50W-HPSD ablation and 90W/4sec-vHPSD ablation using three different ablation catheters.
Methods:
In 28 pigs, we implanted thermocouples on the superior vena cava, close to the phrenic nerve, and on the esophageal, close to the inferior vena cava. We performed endocardial ablation near the fiducial markers of the thermocouples using three different RF catheters: ablation index (AI)-guided HPSD (Qmode) and vHPSD ablation (Qmode+) with QDOTMICRO, lesion size index-guided HPSD ablation (targeting 5.0) with TactiCath Sensor Enabled (Tacti), and AI-guided HPSD ablation (targeting 400) with Thermocool Smart Touch (STSF). We measured tissue temperatures during ablation, including maximum tissue temperature (Tmax), time to maximum tissue temperature (t-Tmax), time to achieve a lethal temperature of 50°C (t-50°C), and time to return to baseline from Tmax (t-Tbase).
Results:
In terms of the frequency of esophageal injury, there were no significant differences among the different catheters. However, the depth of esophageal injury from the adventitia showed a significant difference. In terms of phrenic nerve injury, Tacti had the highest frequency compared to the other catheters (100%, p=0.0012). Tmax, t-Tmax, t-50°C, and t-Tbase showed significant differences, as shown in figure.
Conclusions:
The thermal effects on collateral tissues differ among the three different catheters and settings. STSF and Qmode result in a gradual increase in tissue temperature, while Tacti and Qmode+ lead to a rapid temperature increase. These distinct thermal distributions may contribute to the risk of phrenic nerve and esophageal injuries.
Introduction
High‐power short‐duration (HPSD) ablation at 50 W, guided by ablation index (AI) or lesion size index (LSI), and a 90 W/4 s very HSPD (vHPSD) setting are available for atrial ...fibrillation (AF) treatment. Yet, tissue temperatures during ablation with different catheters around venoatrial junction and collateral tissues remain unclear.
Methods
In this porcine study, we surgically implanted thermocouples on the epicardium near the superior vena cava (SVC), right pulmonary vein, and esophagus close to the inferior vena cava. We then compared tissue temperatures during 50W‐HPSD guided by AI 400 or LSI 5.0, and 90 W/4 s‐vHPSD ablation using THERMOCOOL SMARTTOUCH SF (STSF), TactiCath ablation catheter, sensor enabled (TacthCath), and QDOT MICRO (Qmode and Qmode+ settings) catheters.
Results
STSF produced the highest maximum tissue temperature (Tmax), followed by TactiCath, and QDOT MICRO in Qmode and Qmode+ (62.7 ± 12.5°C, 58.0 ± 10.1°C, 50.0 ± 12.1°C, and 49.2 ± 8.4°C, respectively; p = .005), achieving effective transmural lesions. Time to lethal tissue temperature ≥50°C (t−T ≥ 50°C) was fastest in Qmode+, followed by TacthCath, STSF, and Qmode (4.3 ± 2.5, 6.4 ± 1.9, 7.1 ± 2.8, and 7.7 ± 3.1 s, respectively; p < .001). The catheter tip‐to‐thermocouple distance for lethal temperature (indicating lesion depth) from receiver operating characteristic curve analysis was deepest in STSF at 5.2 mm, followed by Qmode at 4.3 mm, Qmode+ at 3.1 mm, and TactiCath at 2.8 mm. Ablation at the SVC near the phrenic nerve led to sudden injury at t−T ≥ 50°C in all four settings. The esophageal adventitia injury was least deep with Qmode+ ablation (0.4 ± 0.1 vs. 0.8 ± 0.4 mm for Qmode, 0.9 ± 0.3 mm for TactiCath, and 1.1 ± 0.5 mm for STSF, respectively; p = .005), correlating with Tmax.
Conclusion
This study revealed distinct tissue temperature patterns during HSPD and vHPSD ablations with the three catheters, affecting lesion effectiveness and collateral damage based on Tmax and/or t−T ≥ 50°C. These findings provide key insights into the safety and efficacy of AF ablation with these four settings.
We aimed to investigate differences in tissue temperature characteristics during radiofrequency ablation using three catheters, commonly employed in the 50 W high‐power short‐duration (HPSD) setting and a 90 W/4 s very HPSD setting catheter. We identified temperature variations across the four ablation settings and their association with collateral damage, including injuries to the esophagus and phrenic nerve. These findings provide valuable insights into the safety and effectiveness of RF ablation across various settings.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Background
Identification of infrequent nonpulmonary vein trigger premature atrial contractions (PACs) is challenging. We hypothesized that pace mapping (PM) assessed by correlation scores calculated ...by an intracardiac pattern matching (ICPM) module was useful for locating PAC origins, and conducted a validation study to assess the accuracy of ICPM‐guided PM.
Methods
Analyzed were 30 patients with atrial fibrillation. After pulmonary vein isolation, atrial pacing was performed at one or two of four sites on the anterior and posterior aspects of the left atrium (LA, n = 10/10), LA septum (n = 10), and lateral RA (n = 10), which was arbitrarily determined as PAC. The intracardiac activation obtained from each pacing was set as an ICPM reference consisting of six CS unipolar electrograms (CS group) or six CS unipolar electrograms and four RA electrograms (CS–RA group).
Results
The PM was performed at 193 ± 107 sites for each reference pacing site. All reference pacing sites corresponded to sites where the maximal ICPM correlation score was obtained. Sites with a correlation score ≥98% were rarely obtained in the CS‐RA than CS group (33% vs. 55%, P = .04), but those ≥95% were similarly obtained between the two groups (93% vs. 88%, P = .71), and those ≥90% were obtained in all. The surface areas with correlation scores ≥98% (00,10 vs. 100,35 mm2, P = .02), ≥95% (1010,30 vs. 5010,180 mm2, P = .002) and ≥90% (6030,100 vs. 170100,560 mm2, P = .0002) were smaller in the CS‐RA than CS group.
Conclusions
ICPM‐guided PM was useful for identifying the reference pacing sites. Combined use of RA and CS electrograms may improve the mapping quality.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Introduction
Neither the actual in vivo tissue temperatures reached with 90 W/4 s‐very high‐power short‐duration (vHPSD) ablation for atrial fibrillation nor the safety and efficacy profile have been ...fully elucidated.
Methods
We conducted a porcine study (n = 15) in which, after right thoracotomy, we implanted 6–8 thermocouples epicardially in the superior vena cava, right pulmonary vein, and esophagus close to the inferior vena cava. We compared tissue temperatures close to a QDOT MICRO catheter, between during 90 W/4 s‐vHPSD ablation during ablation index (AI: target 400)‐guided 50 W‐HPSD ablation, both targeting a contact force of 8–15 g.
Results
Maximum tissue temperature reached during 90 W/4 s‐vHPSD ablation did not differ significantly from that during 50 W‐HPSD ablation (49.2 ± 8.4°C vs. 50.0 ± 12.1°C; p = .69) and correlated inversely with distance between the catheter tip and the thermocouple, regardless of the power settings (r = −0.52 and r = −0.37). Lethal temperature (≥50°C) was best predicted at a catheter tip‐to‐thermocouple distance cut‐point of 3.13 and 4.27 mm, respectively. All lesions produced by 90 W/4 s‐vHPSD or 50 W‐HPSD ablation were transmural. Although there was no difference in the esophageal injury rate (50% vs. 66%, p = .80), the thermal lesion was significantly shallower with 90 W/4 s‐vHPSD ablation than with 50W‐HPSD ablation (381.3 ± 127.3 vs. 820.0 ± 426.1 μm from the esophageal adventitia; p = .039).
Conclusion
Actual tissue temperatures reached with 90 W/4 s‐vHPSD ablation appear similar to those with AI‐guided 50 W‐HPSD ablation, with the distance between the catheter tip and target tissue being shorter for the former. Although both ablation settings may create transmural lesions in thin atrial tissues, any resulting esophageal thermal lesions appear shallower with 90 W/4 s‐vHPSD ablation.
Actual tissue temperatures, the tip‐to‐target tissue distance needed to achieve a lethal temperature, and esophageal injury with 90 W/4 s‐very high power‐short‐duration (vHPSD) ablation versus ablation index‐guided 50 W‐HPSD ablation.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Introduction
Preferential pathway conduction is mostly detected as fractionated presystolic‐potentials preceding the QRS during premature ventricular contractions (PVCs) and late‐potentials during ...sinus rhythm (SR), but the electrophysiologic mechanisms and significance of these potentials have not been fully clarified. We describe a PVC case series in which the preferential pathway conduction was three‐dimensionally visualized.
Methods
Five PVCs (two from the left coronary cusp, two from the commissure of the left and right coronary cusps, and one from the pulmonary artery) in four patients for which a fractionated presystolic‐potential during the PVCs and late‐potential during SR were recorded at the successful ablation site were reviewed, and three‐dimensional coherent activation maps with the conduction velocity vector during the PVCs and SR were reconstructed.
Results
At the successful ablation site, an “M”‐shaped discrete presystolic‐potential and “W”‐shaped discrete late‐potential were recorded in all patients. The configuration of the inverted electrogram of the presystolic‐potential was similar to that of the electrogram exhibiting the late‐potential. We created coherent activation maps annotating the onset of the presystolic‐potentials during the PVCs and offset of the late‐potentials during SR, which suggested bidirectional conduction of the preferential pathway connecting the PVC origin to the myocardium.
Conclusion
Detailed activation mapping of these PVCs is consistent with the presence of fibers along the aortic or pulmonic valve ring that have preferential directions for conduction. PVCs produce a presystolic‐potential. In SR, the fiber is activated late and from the opposite direction, producing an inverted potential inscribed on the end of the QRS.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Numerous studies have clarified the histological characteristics of the area surrounding the atrioventricular (AV) node, commonly referred to as the triangle of Koch (ToK). Although it is suggested ...that the conduction of electric impulses from the atria to the ventricles via the AV node involves myocytes possessing distinct conduction properties and gap junction proteins, a comprehensive understanding of this complex conduction has not been fully established. Moreover, although various pathways have been proposed for both anterograde and retrograde conduction during atrioventricular nodal reentrant tachycardia (AVNRT), the reentrant circuits of AVNRT are not fully elucidated. Therefore, the slow pathway ablation for AVNRT has been conventionally performed, targeting both its anatomical location and slow pathway potential obtained during sinus rhythm. Recently, advancements in high-density three-dimensional (3D) mapping systems have facilitated the acquisition of more detailed electrophysiological potentials within the ToK. Several studies have indicated that the activation pattern, the low-voltage area within the ToK obtained during sinus rhythm, and the fractionated potentials acquired during tachycardia may be optimal targets for slow pathway ablation. This review provides an overview of the tissue surrounding the AV node as reported to date and summarizes the current understanding of AV conduction and AVNRT circuits. Furthermore, we discuss recent findings on slow pathway ablation utilizing high-density 3D mapping systems, exploring strategies for optimal slow pathway ablation.
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•The conduction mechanisms of the atrioventricular (AV) node remain unclear.•The circuits of AV nodal reentrant tachycardia (AVNRT) remain a subject of debate.•Slow pathway (SP) potentials are considered effective targets for ablation.•Voltage and activation maps during sinus rhythm may be useful for SP ablation.•Fractionated potentials during AVNRT may indicate optimal targets for SP ablation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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