Combining contact force and local impedance to treat idiopathic premature ventricular contractions from the outflow tracts: impact of ablation strategy on outcomes
Vincenzo SchillaciAlberto ArestiaFrancesco MaddalunoGergana ShopovaAlessia AgrestaArmando SalitoGiuseppe StabileGiovanni MaranoGiuseppe BottaroMaurizio MalacridaFrancesco Solimene
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Ventricular outflow tract
The step-wise approach to catheter ablation for persistent atrial fibrillation (AF) requires considerable substrate modification targeting at complex fractionated atrial electrograms (CFAEs) in addition to pulmonary vein (PV) isolation. An alternative strategy that minimizes the amount of ablation would be desirable. The aim of this study was to investigate whether the use of pre-procedural amiodarone affects: (i) the amount of ablation required to achieve procedural success, and (ii) long-term outcomes.We studied 121 consecutive patients with persistent AF who underwent catheter ablation. The patients were divided into two groups: Group 1, amiodarone (n = 31); Group 2, other antiarrhythmic drugs or rate control (n = 90). All the patients underwent a step-wise ablation procedure beginning with PV isolation, then proceeding with ablation of the CFAEs and linear lesions until sinus rhythm was achieved. Mean left atrial cycle length of AF (AFCL) was recorded at each step. The number of CFAE ablation sites was recorded. The number of CFAE sites in Group 1 was significantly less than that in Group 2 (P = 0.0121). The AFCLs after each step in Group 1 were significantly longer than those in Group 2. The procedure time and the radiofrequency time of CFAE ablation in Group 1 were significantly shorter than that in Group 2 (P = 0.0276 and P = 0.0458, respectively). There was no significant difference between the two groups in early and long-term outcomes.Use of pre-procedural amiodarone prolongs AFCL during catheter ablation and reduces the number of CFAE sites requiring ablation to achieve procedural success while maintaining equivalent long-term results.
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Purpose of the study: Atrial fibrillation (AF) ablation is often performed by achieving pulmonary vein (PV) isolation (PVI) using the “wide antral circumferential ablation” (WACA) technique. We analyzed the efficacy of a novel technique based on pacing maneuvers to detect gaps in an initial WACA lesion. Method used: Patients referred to our center for AF ablation during March–June 2014 were enrolled prospectively. A WACA lesion set was performed, isolating ipsilateral PVs together. If PVI was not achieved, and for all redo procedures, the atria were paced using an ablation catheter. For each pacing site, the “activation delay” and the “activation sequence” were analyzed using a circular mapping catheter. Summary of results: 26 patients (mean age 57.8 ± 10.5 years, 22 males) were included. There were 36 residual gaps in 25 WACA lesion sets in 21 patients (one gap in 16 lesion sets, two and three gaps in seven and two lesion sets, respectively). Three patterns were identified: A) the activation delays converged towards one point with the shortest delay; no modification of the activation sequence (indicating one gap); B) activation delays converged towards ≥2 close locations; no change in the activation sequence (indicating ≥2 close gaps); C) activation delays converged towards ≥2 remote locations; modification of the activation sequence (indicating ≥2 remote gaps). This allowed precise localization of the gaps, ultimately leading to PVI in all patients. Schemas showingdifferent responses to pacing around the circumferential ablation lesions, and assumptions of gap localization.
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Cardiac Ablation
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Cardiac Ablation
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In recent years, radio-frequency catheter ablation has emerged as an effective treatment option for patients with paroxysmal and chronic atrial fibrillation (AF). Based on advances in the understanding of the pathogenesis of AF, catheter ablation has evolved primarily into two general approaches: (1) ablation strategies that create a predetermined set of lesions usually at or around specific anatomical landmarks (anatomically guided ablation) and (2) ablation strategies that attempt to identify and eliminate specific mechanisms that initiate and perpetuate AF (tailored ablation). A tailored ablation strategy also has been combined with anatomically guided ablation. In this chapter, anatomically guided ablation is discussed.
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Catheter ablation of ventricular tachycardia (VT) is demanding and time consuming. Robotically controlled catheter ablation reduces operator fatigue and exposure to X-rays, and provides greater precision and stability of the catheter. A new flexible, integrated robotic sheath and ablation catheter has recently been introduced (Lynx(TM)) and used in atrial ablation procedures. We describe the first VT substrate modification ablation in the world with the Lynx(TM) robotic radio frequency ablation catheter.
Rf ablation
Cardiac Ablation
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Objective The object of this study was to investigate the possible role of local voltage potentials (LVPs) in mapping the ventricular arrhythmias originating from right ventricular outfl ow (RVOT).Methods Forty-seven patients with RVOT VAs (ventricular arrhythmias), referred for radiofrequency catheter ablation to our hospital, were analysed retrospectively for the prevalence, characteristics and electrophysiological evaluation of the LVPs recorded in successful and unsuccessful ablation sites.Results Radiofrequency ablation was successful immediately in all the 47 cases. Catheter ablation was performed at a mean of 8 ± 6 sites per patient. There were 58 eff ective ablation sites, 5 cases with changing morphology of ventricular arrhythmias (VAs), and 318 invalid ablation sites. Activation times at eff ective ablation sites were slightly earlier than those at invalid ablation sites (-28 ± 8 ms vs-24 ± 7 ms, P < 0.05). The LVPs appeared during VAs in 47 sites of the 58 eff ective ablation sites (81.0%), far more than the 22 sites of the 318 invalid ablation sites (6.9%) (P < 0.01). In two cases VAs recurred during follow-up. They received a second catheter ablation.Conclusions Local ventricular potentials can be recorded in most patients with idiopathic VAs originating from the right outfl ow tract. The local potentials may facilitate successful radiofrequency ablation.
Ventricular outflow tract
Radiofrequency catheter ablation
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OBJECTIVE The object of this study was to investigate the possible role of local voltage potentials (LVPs) in mapping the ventricular arrhythmias originating from right ventricular outflow (RVOT). METHODS Forty-seven patients with RVOT VAs (ventricular arrhythmias), referred for radiofrequency catheter ablation to our hospital, were analysed retrospectively for the prevalence, characteristics and electrophysiological evaluation of the LVPs recorded in successful and unsuccessful ablation sites. RESULTS Radiofrequency ablation was successful immediately in all the 47 cases. Catheter ablation was performed at a mean of 8 +/- 6 sites per patient. There were 58 effective ablation sites, 5 cases with changing morphology of ventricular arrhythmias (VAs), and 318 invalid ablation sites. Activation times at effective ablation sites were slightly earlierthan those at invalid ablation sites (-28 +/- 8 ms vs-24 +/- 7 ms, P < 0.05). The LVPs appeared during VAs in 47 sites of the 58 effective ablation sites (81.0%), far more than the 22 sites of the 318 invalid ablation sites (6.9%) (P < 0.01). In two cases VAs recurred during follow-up. They received a second catheter ablation. CONCLUSIONS Local ventricular potentials can be recorded in most patients with idiopathic VAs originating from the right outflow tract.The local potentials may facilitate successful radiofrequency ablation.
Ventricular outflow tract
Radiofrequency catheter ablation
Outflow
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Ablation of papillary muscles (PMs) for refractory ventricular arrhythmias can often be challenging. The catheter approach and orientation during ablation may affect optimal radiofrequency (RF) delivery. Yet, no previous study investigated the association between catheter orientation and PM lesion size. We evaluated ablation lesion characteristics with various catheter orientations relative to the PM tissue during open irrigated ablation, using a standardized, experimental setting.Viable bovine PM was positioned on a load cell in a circulating saline bath. RF ablation was performed over PM tissue at 50 W, with the open irrigated catheter positioned either perpendicular or parallel to the PM surface. Applied force was 10 g. Ablation lesions were sectioned and underwent quantitative morphometric analysis.A catheter position oriented directly perpendicular to the PM tissue resulted in the largest ablation lesion volumes and depths compared with ablation with the catheter parallel to PM tissue (75.26 ± 8.40 mm3 vs. 34.04 ± 2.91 mm3 , p < .001) and (3.33 ± 0.18 mm vs. 2.24 ± 0.10 mm, p < .001), respectively. There were no significant differences in initial impedance, peak voltage, peak current, or overall decrease in impedance among groups. Parallel catheter orientation resulted in higher peak temperature (41.33 ± 0.28°C vs. 40.28 ± 0.24°C, p = .003), yet, there were no steam pops in either group.For PM ablation, catheter orientation perpendicular to the PM tissue achieves more effective and larger ablation lesions, with greater lesion depth. This may have implications for the chosen ventricular access approach, the type of catheter used, consideration for remote navigation, and steerable sheaths.
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