Additional Radiofrequency Ablation Research Articles

Continuous positive airway pressure is unsafe for radiofrequency ablation of lung cancer under sedation: a randomised controlled trial

ObjectiveTo evaluate the safety of a minimum continuous positive airway pressure of 4 cmH2O (CPAP + 4) during computed tomography (CT)-guided radiofrequency ablation (RFA) for lung malignancies under procedural sedation and analgesia (PSA).MethodsThis was a prospective, randomised, single-blind, parallel-group, placebo-controlled trial with an open-label medical device conducted at a single tertiary university hospital in Barcelona, Spain. Forty-six patients over 18 years of age scheduled for CT-guided RFA of a malignant pulmonary tumour under PSA were randomised to receive either CPAP + 4 or a modified mask for placebo CPAP (Sham-CPAP). Exclusion criteria included contraindications for RFA, refusal to participate, inability to understand the procedure or tolerate the CPAP test, lung biopsy just prior to RFA, intercurrent diseases, or previous randomisation for additional pulmonary RFA. Primary outcomes were the percentage of patients reporting at least one serious adverse event (SAE), classification for complications from the Cardiovascular and Interventional Radiological Society of Europe (CIRSE), and Clavien-Dindo classifications for complications, hospital stay, and readmissions. Secondary outcomes included adverse events (AEs), respiratory parameters, airway management, and the local radiological efficacy of pulmonary ablation.ResultsCPAP + 4 prolonged hospital stay (1.5 ± 1.1 vs. 1.0 ± 0 inpatient nights, p = 0.022) and increased the risk of AE post-RFA (odds ratio (95% CI): 4.250 (1.234 to 14.637), p = 0.021 with more pneumothorax cases (n = 5/22, 22.7% vs. n = 0/24, 0%, p = 0.019). Per-protocol analysis revealed more SAEs and CIRSE grade 3 complications in the CPAP + 4 group (23.5% vs. 0%, p = 0.036). No significant differences were found in the effectiveness of oxygenation, ventilation, or pulmonary ablation.ConclusionCPAP is unsafe during CT-guided RFA for lung cancer under PSA even at the lowest pressure setting.Trial registrationClinicalTrials.Gov, ClinicalTrials.gov ID NCT02117908, Registered 11 April 2014, https://www.clinicaltrials.gov/study/NCT02117908Critical relevance statementThis study highlights the hazards of continuous positive airway pressure during radiofrequency ablation of lung cancer, even at minimal pressures, deeming it unsafe under procedural sedation and analgesia in pulmonary interventional procedures. Findings provide crucial insights to prioritise patient safety.Key PointsNo prior randomised controlled trials on CPAP safety in percutaneous lung thermo-ablation.Standardised outcome measures are crucial for radiology research.CPAP during lung RFA raises hospital stay and the risk of complications.CPAP is unsafe during CT-guided RFA of lung cancer under procedural sedoanalgesia.Graphical

The impact of additional radiofrequency ablation for atrial fibrillation substrates using with ExTRa-Mapping analysis after Cryo-ablation in patients with persistent atrial fibrillation

Abstract Background Pulmonary vein isolation (PVI) for persistent atrial fibrillation (AF) is well established. Cryo-ablation for persistent AF has been reported to be safe and effective and comparable to radiofrequency (RF) ablation in long term arrhythmia-free survival, but the outcome is limited. Phase mapping using software of ExTRa-Mapping is a new tool to clarify the real-time imaging of the AF wave dynamics. Purpose We investigated the distribution of rotors of left atrium (LA) after PVI by Cryo-ablation, and the efficacy and safety of additional RF ablation for AF substrates (rotor modification) after Cryo-ablation. Methods A total of 50 patients who underwent persistent AF ablation in our hospital were enrolled. The Cryo-ablation alone group (Cryo group; n=25) and the Cryo-ablation + additional RF substrates ablation group (Cryo+RF group; n=25) were randomly divided. First, PVI with Cryo-ablation was performed. Second, if AF did not term after PVI, the rotor of LA were analyzed using the NAVX and ExTRa-Mapping system. In Cryo+RF group, the extensive RF ablation of the PV antrum to modify the rotor area were performed (Abstract Picture 1). The recurrence rate of any atrial tachy-arrhythmia without anti-arrhythmic drugs and safety were evaluated in both groups. Results The patient characteristics (69 ± 9.2 years old, body-mass index 24 ± 3.2 kg/m2, LA diameter 43 ± 5.1 mm, left ventricular ejection fraction 60 ± 7.8 %, persistent AF duration 4.2 ± 5.1 months) did not differ between the both groups. The distribution of rotors of LA were predominantly present in the anterior (n = 36) and inferior (n = 27) walls of the LA, with only a few in the posterior wall (n = 7) in the both groups. In Cryo+RF group, except for 4 cases in which AF was termed by PVI or a rotor was not detected, extensive RF modification in anterior antrum of right pulmonary vein was performed in 18 of 21 cases. In an average follow-up of 482 ± 273 days, the recurrence rate of any atrial tachy-arrhythmia was significantly lower in Cryo+RF group compared with Cryo group (p=0.029, Abstract Picture 2). No serious complications occurred in both groups. Conclusion Additional extensive RF ablation of the PV antrum to modify the Rotor area resulted in a lower recurrence rate in patients with persistent AF.Modify the rotor areaRecurrence rate

Initial experience with ablation of ventricular arrhythmias using a pulsed-field system

Abstract Introduction Catheter ablation using radiofrequency (RF) current is a well-established method of treatment of ventricular arrhythmias (VA). However, RF ablation may fail to eliminate deeply located arrhythmogenic substrate. Pulsed-field (PF) is a novel energy source with a potential to create deeper lesions, especially in scar tissue. Purpose This study aims to present the data on safety and efficacy (acute outcome data) of VA ablation using PF. Methods The population consists of 15patients (5 women, age: 61 ± 19years) after previously failed RF ablation of VA. The underlying condition was nonischemic cardiomyopathy (53%), coronary artery disease (13%), and congenital heart disease (13%), respectively. No structural heart disease was present in 20% of cases. The mean left ventricular ejection fraction was 39 ± 13%. Eighty percent of patients had sustained VA, the remaining patients presented with frequent ventricular ectopy. Ablation was performed using a conventional irrigated 4-mm tip catheter in a combination with commercially available PF generator. Peripheral venous blood samples for the assessment of the plasmatic levels of high-sensitivity troponin T (hsTnT) were obtained the next day (usually 18-24hours) after the procedure. Results A mean of 17±12 PF applications (25A) per patient were delivered. In 5 patients (33%), an additional RF ablation (4±9 applications) was performed. Acute success as assessed by non-inducibility of VA or elimination of ectopic focus was achieved in all but one patient (93%). In 4 cases (27%), PF energy was applied within the great cardiac vein and subsequent coronary angiography did not reveal any abnormality. On the other hand, transient conduction system block occurred in 3 cases (20%) during PF application on the lateral LV wall remotely from the LV septum (complete AV block in one, LBBB in two patients). These events resolved in all cases within one hour. Ablation using PF did not result in excessive increase of hsTnT (657±482ng/l, with upper reference level of 14ng/l). Conclusion Initial experience with PF for the treatment of VA indicates high acute efficacy. The long-term effect is to be determined. PF applications in the ventricle may be associated with unexpected but transient conduction system damage, even when applications are performed remotely from the interventricular septum. The postprocedural increase in plasma troponin levels is only moderate.

Tissue characterization of acute lesions during cardiac magnetic resonance-guided ablation of cavo-tricuspid isthmus-dependent atrial flutter: a feasibility study.

To characterize acute lesions during cardiac magnetic resonance (CMR)-guided radiofrequency (RF) ablation of cavo-tricuspid isthmus (CTI)-dependent atrial flutter by combining T2-weighted imaging (T2WI), T1 mapping, first-pass perfusion, and late gadolinium enhancement (LGE) imaging. CMR-guided catheter ablation offers a unique opportunity to investigate acute ablation lesions. Until present, studies only used T2WI and LGE CMR to assess acute lesions. Fifteen patients with CTI-dependent atrial flutter scheduled for CMR-guided RF ablation were prospectively enrolled. Directly after achieving bidirectional block of the CTI line, CMR imaging was performed using: T2WI (n = 15), T1 mapping (n = 10), first-pass perfusion (n = 12), and LGE (n = 12) imaging. In case of acute reconnection, additional RF ablation was performed. In all patients, T2WI demonstrated oedema in the ablation region. Right atrial T1 mapping was feasible and could be analysed with a high inter-observer agreement (r = 0.931, ICC 0.921). The increase in T1 values post-ablation was significantly lower in regions showing acute reconnection compared with regions without reconnection [37 ± 90 ms vs. 115 ± 69 ms (P = 0.014), and 3.9 ± 9.0% vs. 11.1 ± 6.8% (P = 0.022)]. Perfusion defects were present in 12/12 patients. The LGE images demonstrated hyper-enhancement with a central area of hypo-enhancement in 12/12 patients. Tissue characterization of acute lesions during CMR-guided CTI-dependent atrial flutter ablation demonstrates oedema, perfusion defects, and necrosis with a core of microvascular damage. Right atrial T1 mapping is feasible, and may identify regions of acute reconnection that require additional RF ablation.

Acute mitral isthmus block during catheter ablation with vein of Marshall ethanol infusion: Angiographic considerations

Achieving bidirectional mitral isthmus block is still challenging. Conventional ablation methods involve radiofrequency applications on the endocardial aspect of the lateral mitral isthmus, and often epicardial applications inside the coronary sinus. To evaluate the impact of the systematic use of ethanol infusion in the vein of Marshall on the achievement of acute mitral isthmus block of additional epicardial component lesion. We evaluated patients referred to two centres for long-standing persistent atrial fibrillation ablation or recurrent peri-mitral flutter. All patients had pulmonary vein isolation and mitral isthmus line using ethanol infusion in the vein of Marshall for the first procedure and additional radiofrequency ablation lesion if necessary. For redo procedures, additional ablations (atrial lines and complex fractionated atrial electrogram ablations, if needed) were also performed. We included 149 patients, and ethanol infusion in the vein of Marshall was not performed in 27 patients (18%). Among 122 patients, 115 had long-standing persistent atrial fibrillation (94.2%) and seven had peri-mitral flutter (5.8%). The mean duration of continuous atrial fibrillation was 53 months before ablation. Acute bidirectional mitral isthmus block was obtained in 115 (94.2%) of the 122 patients who received ethanol infusion in the vein of Marshall (77% when considering the total population). The mean radiofrequency delivery time to obtain mitral isthmus block was 2.6minutes for the endocardial mitral isthmus radiofrequency ablation and 2.6minutes for the epicardial mitral isthmus radiofrequency ablation. Failure to obtain mitral isthmus block was associated with increased mitral isthmus length and left atrial dilation. No major complications related to ethanol infusion in the vein of Marshall were observed. Ethanol infusion in the vein of Marshall, when feasible (82%), was a safe approach to obtaining a high success rate (94%) of acute bidirectional endocardial and epicardial mitral isthmus block.

Our Single Center Experience in Osteoid Osteoma Patients Treated with CT-Guided Percutaneous Radiofrequency Ablation Treatment and Follow-up.

Introduction Osteoid osteoma (OO) is a painful benign bone tumor. Typically, it causes pain that is most noticeable during the night, which is improved by nonsteroidal anti-inflammatory drugs. In the treatment of symptomatic lesions, open surgery for nidus removal is the gold standard. However, surgical technical difficulties and morbidities vary by location. Percutaneous radiofrequency ablation (RFA) therapy guided by computed tomography (CT) is now a popular treatment option for OO. This study aims to assess our single-center experience with the technique, complications, and procedure effectiveness. Materials and Methods The study included fifteen patients who were treated between 2017 and 2021. A retrospective analysis was carried out on archive images and file records. The lesions' location, nidus width, and affected area (cortical, medullary) were all recorded. The procedure and technical success, as well as postoperative complications and the need for repeat ablation, were all documented. Results A total of 20 patients, 18 men, and 2 women, were included in the study, and 12 of them were pediatric patients. The patients' mean age was 16.9±7.3 years old, and the mean nidus diameter was 7.1±8.7 mm. There were 13 cortical niduses, 2 intramedullary niduses, and 5 corticomedullary niduses. The lesions were in the femur (n=12), tibia (n=6), scapula (n=1), and vertebrae (n=1). Two recurrences (10%) were observed in our patients during the follow-up. Patient with a femoral OO, the pain started again 12 weeks after the procedure and we performed additional RFA. The patient with vertebral OO had fewer symptoms and full recovery was not achieved. Therefore, the vertebral OO was ablated again 4 months later, and clinical success was achieved. One patient had a minor burn at the entry site that went away on its own after a short period of time. Except for the patient who was scheduled for a repeat RFA, no recurrence has been observed so far. The primary and secondary success rates are, respectively, 90% (18/20) and 100% (20/20). Conclusion RFA has a high success rate in treating OO. The procedure failure and recurrence rates are low. There are possibilities for posttreatment pain relief, early discharge, and a quick return to daily life. For inappropriate lesion localization, the RFA process replaces surgical treatment. The procedure-related complication rate is low. On the other hand, the burn during the procedure can be a serious problem.

Prevalence of sustained atrial arrythmias and treatment with zero fluoroscopy or near zero fluoroscopy catheter ablation in Slovenian orthotopic heart transplant recipients

Abstract Funding Acknowledgements Type of funding sources: None. Background Due to advances in surgical techniques and immunosuppression survival of heart transplant (HT) recipients has improved significantly, with that the prevalence of sustained atrial arrhythmias (SAA) in these patients is increasing. In HT recipients antiarrhythmic therapy options are limited. Radiofrequency ablation (RFA) represents a viable but underutilized option after other etiologies of SAA such as acute allograft rejection and vasculopathy are excluded. Limiting radiation exposure in HT recipients, who are exposed to 3,5 times (1) greater radiation dose compared to general population and are significantly more susceptible to develop malignancies, is essential. Purpose Our aim was to analyse prevalence and type of SAA in Slovenian orthotopic HT recipients and analyse feasibility and procedural outcomes of zero (ZF) or near zero fluoroscopy (NZF) RFA treatment approaches. Methods We performed a retrospective analysis of HT recipients between 2002 and 2022. We re-evaluated all available ECGs of suspected arrhythmias of included patients for presence and type of SAA. We further analysed HT patients that underwent RFA for SAA at our centre. All procedures were performed primarily with 3D electroanatomical mapping system and intracardiac echocardiography guidance. Either ZF or NZF approaches were used. The primary endpoint of all procedures was SAA termination and acute success was deemed when subsequent attempts to reinduce SAA failed. Long-term success was defined as the absence of any spontaneous SAA during 12-month follow-up. Results Among 364 consecutive HT recipients 19 patients (5,2%) were evaluated for SAA. Of those 7 (37%) presented as typical atrial flutters (AFL), 9 (47%) as atypical AFL, 2 (11%) as focal atrial tachycardia (FAT) and 1 (5%) as slow-fast atrioventricular nodal reentry tachycardia. In 2 (11%) patients with AFL, SAA was a result of acute allograft rejection. In 10 (53%) patients SAA occurred in first 3 months after HT. In the remaining 9 patients SAA occurred late, median 6,6 years after HT (25th-75th IQR: 7,7 years). RFA was performed in 7 (37%) patients. In all patients procedures were acutely successful however in 2 patients additional RFA procedures were needed for long-term success. All in all, 10 RFA procedures were performed (Table 1). All cases had macro or micro reentrant AFL with a median of 2,0 re-entry circuits mapped (25th-75th IQR: 3,3 re-entry circuits) during the procedure – that included typical cavotricuspid isthmus AFL, perimitral AFL, and several right atrium (RA) scar-related or incision related AFL. In 2 cases additional RA FAT were ablated. Five (50%) procedures were performed with ZF. No major procedure related complications were observed. Conclusion In HT recipients ZF or NZF RFA of SAA appears to be feasible and safe, but still underutilised, treatment option. Our case series demonstrates favourable acute and long-term outcomes however larger data is needed to support these results.

Clinical Approach for Thyroid Radiofrequency Ablation

Radiofrequency ablation (RFA) is a non-surgical treatment for symptomatic, benign thyroid nodules. This treatment works by heating and destroying the nodule tissue, which results in reduction of its size and alleviation of the symptoms involved. RFA is indicated for nodules which are confirmed to be benign on two or more cytological or histological examinations, and which result in clinical symptoms requiring medical treatment. It is associated with good short-term outcomes on one-year follow-up; however, 20%-30% of the nodules regrow after more than three years. Therefore, on the basis of long-term follow-up, management of regrowth is key to patient care following RFA. Regrowth is more likely to occur in nodules that are large in size prior to RFA, and in those with high or increased vascularity. Recently, new techniques such as hydrodissection, artery-first ablation, and venous ablation have been introduced to inhibit regrowth. In addition, appropriate criteria for additional RFA should be applied to manage regrowth and prolong its therapeutic effects. RFA is essentially an alternative to surgery; therefore, the ultimate goal of this procedure is to avoid surgery permanently, rather than to achieve temporary effects.

Pulsed-field ablation for the treatment of left atrial reentry tachycardia

BackgroundWe describe our initial experience using a multipolar pulsed-field ablation catheter for the treatment of left atrial (LA) reentry tachycardia.MethodsWe included all patients with LA reentry tachycardia treated with PFA at our institution between September 2021 and March 2022. The tachycardia mechanism was identified using 3D electro-anatomical mapping (3D-EAM). Subsequently, a roof line, anterior line, or mitral isthmus line was ablated as appropriate. Roof line ablation was always combined with LA posterior wall (LAPW) ablation. Positioning of the PFA catheter was guided by a 3D-EAM system and by fluoroscopy. Bidirectional block across lines was verified using standard criteria. Additional radiofrequency ablation (RFA) was used to achieve bidirectional block as necessary.ResultsAmong 22 patients (median age 70 (59–75) years; 9 females), we identified 27 LA reentry tachycardia: seven roof dependent macro-reentries, one posterior-wall micro-reentry, twelve peri-mitral macro-reentries, and seven anterior-wall micro-reentries. We ablated a total of 20 roof lines, 13 anterior lines, and 6 mitral isthmus lines. Additional RFA was necessary for two anterior lines (15%) and three mitral isthmus lines (50%). Bidirectional block was achieved across all roof lines, 92% of anterior lines, and 83% of mitral isthmus lines. We observed no acute procedural complications.ConclusionAblation of a roof line and of the LAPW is feasible, effective, and safe using this multipolar PFA catheter. However, the catheter is less suited for ablation of the mitral isthmus and the anterior line. A focal pulsed-field ablation catheter may be more effective for ablation of these lines.Graphical This study shows the feasibility to ablate linear lesions with a multipolar pulsed-field ablation catheter. 27 left atrial reentry tachycardia were treated in 22 patients.

Effect of radiofrequency and ethanol ablation on epicardial conduction through the vein of Marshall: How to detect and manage epicardial connection across the mitral isthmus.

The vein of Marshall (VOM), which is surrounded by the Marshall bundle (MB), behaves as an epicardial connection bypassing the mitral isthmus. The influence of radiofrequency ablation and VOM ethanol infusion (VOM-EI) on epicardial MB conduction remains unclear. The purpose of this study was to evaluate MB conduction status during mitral isthmus ablation. Of 57 consecutive patients undergoing mitral isthmus ablation, 50 with electrode catheter cannulation into the VOM were analyzed. MB conduction was investigated by evaluating electrograms inside the VOM. Endocardial ablation was initially performed, followed by ablation inside the coronary sinus (CS), if required. Selective VOM-EI was performed if the MB potentials still exhibited early activation after radiofrequency ablation, suggesting the presence of MB connection bridging the mitral isthmus. VOM electrograms composed of near-field MB and far-field left atrial potentials were recorded in all patients. Solely with endocardial ablation, 33 patients (66%) achieved entire mitral isthmus block, and 43 patients (86%) achieved an epicardial MB conduction block. MB potentials exhibited early activation in the remaining 7 (14%), even after requiring CS ablation. VOM-EI then was performed. Elimination of MB potentials was verified by electrode catheter reinsertion after VOM-EI. Mitral isthmus conduction was successfully blocked during VOM-EI in 4 patients and during additional radiofrequency ablation in the remaining 3. All patients finally achieved entire mitral isthmus block. MB is effectively ablated by radiofrequency ablation. Continuous evaluation of MB conduction can reveal epicardial conduction and ablation effect. A residual MB epicardial connection is relatively rare but can be ablated by VOM-EI.

Long-term outcome of adenosine-induced atrial fibrillation after atrial fibrillation ablation: A propensity score matching analysis.

Nonpulmonary vein (non-PV) foci, in addition to pulmonary vein (PV), are considered important in initiating atrial fibrillation (AF). This study investigates the adenosine triphosphate (ATP) as a method for inducing non-PV ectopy. The study cohort consisted of 1388 patients with AF (728 with paroxysmal AF, 650 with nonparoxysmal AF) who underwent catheter ablation. To confirm dormant PV conductions and non-PV foci, 20 or 40mg ATP was administered intravenously at the end of the procedure. The ATP test induced AF in 36 of 1388 (2.6%) patients, in whom two (6%) had ectopy arising from the both atria, 15 (42%) from the right atrium (RA), and five (14%) from left atrium (LA). Because of a lack of reproducibility, the accurate location of non-PV foci was unidentified in the remaining 11 (31%) patients. Additional radiofrequency ablation to non-PV foci induced ATP administration was not performed in 34 patients. Among all 1388 patients, 64 were assigned to the ATP-AF(+) and ATP-AF(-) groups using a propensity score matching analysis (32 patients in each group). During the follow-up period, recurrent AF was observed in 9 of 32 (28%) patients in the ATP-AF(+) group and in 10 of 32 (31%) patients in the ATP-AF(-) group (log-rank p=.84, hazard ratio 0.91 [95% confidence interval 0.36-2.27]). In the univariate analysis, AF induction by ATP test was not predictive of AF recurrence (p=.78). ATP-induced AF was not associated with AF recurrence in the distant period.

Long-term follow-up of the radiofrequency ablation of benign thyroid nodules: the value of additional treatment.

PurposeThis study aimed to evaluate the efficacy of additional radiofrequency ablation (RFA) treatment for benign thyroid nodules.MethodsElectronic medical records at a single institution from September 2008 to August 2016 were searched, and consecutive patients treated with RFA due to benign thyroid nodules with cosmetic or symptomatic problems were enrolled. All patients were followed up for at least 30 months. The nodules were divided into three groups: group 1 included nodules that met the criteria for additional treatment and underwent additional treatment, group 2 included nodules that met the criteria but did not undergo additional treatment, and group 3 included nodules that did not meet the criteria. The ablation results were compared among the three groups in terms of the initial ablation ratio (IAR) and volume reduction ratio (VRR).ResultsNinety nodules from 88 patients were included in the study. At the last follow-up, group 1 showed a significantly smaller nodule volume and larger VRR (2.5 mL and 84.6%, respectively) than group 2 (8.1 mL and 39.8%, respectively, P<0.001), but did not present a significant difference from group 3 (0.9 mL, P=0.347, and 92.8%, P=0.238). The IAR was significantly higher in group 3 (94.5%) than in the other two groups (group 1, 81.1%; group 2, 82.8%; P<0.001).ConclusionMultiple treatment sessions achieve greater VRR. Therefore, additional treatment could be considered for patients who meet the corresponding criteria.

Multipolar pulsed-field ablation for the treatment of left atrial reentry tachycardia

Abstract Funding Acknowledgements Type of funding sources: None. Background A multipolar pulsed field ablation (PFA) catheter was recently introduced for pulmonary vein isolation and combines the benefits of high procedural efficacy and safety. It may also be used to treat left atrial (LA) reentry tachycardia. Purpose To describe our initial experience using a multipolar PFA catheter for the treatment of LA reentry tachycardia. Methods We included all patients with LA reentry tachycardia treated with a multipolar PFA catheter at our institution. Using 3D electro-anatomical mapping (3D-EAM), we identified the tachycardia mechanism and applied linear lesions either at the left atrial roof, mitral isthmus or on the anterior wall, as appropriate. Positioning of the PFA catheter was verified by integration into 3D-EAM. Applications were performed using 2.0kV with the catheter in basket or flower configuration, depending on ablation site. Bidirectional block across linear lesions was verified using standard criteria. Additional focal radiofrequency ablation (RFA) was used to achieve bidirectional block if necessary. Results We treated 17 LA reentry tachycardia with a multipolar PFA catheter in 13 patients (median age 69 (59-73) years; 5 females). The tachycardia mechanism was identified as roof-dependent in five, peri-mitral in eight and anterior scar-related in four cases. PFA lesion sets consisted of 12 posterior wall isolations (i.e. roof lines), four mitral isthmus lines (MIL) and eight anterior lines. For ablation of the mitral side of the anterior line, we always used the PFA catheter in basket configuration, while we targeted the posterior wall and the superior side of the anterior line exclusively with the catheter in flower configuration. To ablate the MIL we used both flower and basket configurations. Three roof-dependent, six peri-mitral, and four anterior scar-related tachycardias were successfully terminated by PFA (76%). Additional RFA was necessary for two MIL, two anterior lines and no roof line (17%). Finally, we achieved bidirectional block across all lines. PFA triggered, vagal-mediated and reversible AV block was observed in one case. Otherwise, there were no acute procedural complications. Conclusion Linear lesion sets are feasible and safe using a multipolar PFA catheter. Posterior wall isolation by PFA for the treatment of roof-dependent LA reentry tachycardia is highly efficient while anterior lines and MIL remain challenging and may need complementary RFA or a PFA catheter designed for focal or linear ablations.

Catheter ablation of atrial fibrillation using 2nd-generation cryoballoon in congenital heart disease patients — significance of RF ablation of additional atrial macro-reentrant tachycardia

BackgroundPrevalence of atrial fibrillation (AF) is increasing in adult patients with congenital heart disease (CHD). Experience using the cryoballoon to achieve pulmonary vein isolation (PVI) in adult CHD patients is limited. The aim of the present study was to assess the value of PVI by cryoballoon in adult CHD patients and to evaluate the significance of additional radiofrequency (RF) ablation of atrial tachycardia (AT).Patients and methodsProspective data analysis; all patients with CHD and AF and PVI using the cryoballoon from January 2017 through November 2021 were included.ResultsNineteen patients with various types of CHD were included. Median age was 58 (IQR 47–63) years. A total of 12/19 (63%) patients had had RF ablation of right atrial AT before. Median procedure duration was 225 (IQR 196–261) min. Median fluoroscopy time was 12.3 (IQR 5.2–19.5) min and median freeze time was 32 (IQR 28–36.3) min. Procedural success was achieved in all patients. Additional RF catheter ablation of intraatrial reentrant tachycardia within the left atrium was performed in 3/19 (16%) subjects and within the right atrium in 6/19 (32%) patients. Median follow-up was 26 (IQR 9–49) months. Excluding a 90-day blanking period, recurrence of AF was observed in 6/19 subjects (32%). After one redo procedure deploying RF energy only, 84% of all patients remained free from recurrence. Phrenic nerve palsy was observed in 1 subject.ConclusionResults after PVI using the cryoballoon plus additional RF ablation of AT were promising (84% success including one redo procedure). Success of AF ablation was unsatisfactory in all patients who had no additional AT ablation. Ablation of any AT in these patients should therefore be considered in addition to PVI.

Ultrasound-guided percutaneous radiofrequency ablation in treatment of neuroendocrine tumor liver metastases：a single-center experience

Purpose To investigate the local tumor control of ultrasound-guided percutaneous radiofrequency ablation (RFA) in treating neuroendocrine tumor liver metastases (NETLM). Materials and methods From March 2011 to December 2020, 23 patients with 39 NETLM treated with percutaneous RFA were studied. The study assessed the therapeutic outcomes after RFA, including the rates of technical success, technical efficacy, major complications, local tumor progression (LTP) and overall survival. Cumulative LTP rates were estimated with the Kaplan–Meier method. Results The technical efficacy rate was 91.3% (21/23) at one month after RFA. No major complication occurred in the treatment. LTP occurred in 50% (11/22) of patients who had complete ablation, with a median progression-free survival time of 15 months (1–61 months). Patients with Ki-67 < 5% had a longer progression-free survival than those with Ki-67 ≥ 5% (22.0 vs. 3.5 months, p<.001). Four patients, who had sporadic recurrent liver metastases, received 1-6 times of additional RFA after the initial treatment. Twenty patients were alive at the end of this study, except three patients withdrawn. The overall survival was at a median of 48 months (9–182 months). Conclusion RFA provides effective local tumor control with low morbidity and it can be applied repeatedly over years to control recurrence of NETLM. Patients with Ki-67 < 5% have better local tumor control with percutaneous RFA of NETLM.

Assessment of Radiofrequency Ablation for Papillary Microcarcinoma of the Thyroid

Papillary microcarcinomas of the thyroid (mPTCs) account for an increasing proportion of thyroid cancers in past decades. The use of radiofrequency ablation (RFA) has been investigated as an alternative to surgery. The effectiveness and safety of RFA has yet to be determined. To evaluate the effectiveness and safety of RFA for low-risk mPTC. Embase, MEDLINE via Ovid, Web of Science Core Collection, Cochrane Central Register of Controlled Trials, and the top 100 references of Google Scholar were searched from inception to May 28, 2021. Articles reporting on adult patients with mPTC treated with RFA were included. Studies that involved patients with pre-ablation lymph node or distant metastases, recurrence of disease, or extrathyroidal extension were excluded. Final article selection was conducted by multiple reviewers based on consensus. The proportion of eligible articles was 1%. This meta-analysis was conducted in accordance with the MOOSE guidelines. Random and fixed-effect models were applied to obtain pooled proportions and 95% CIs. The primary outcome was the complete disappearance rate of mPTC. Secondary outcomes were tumor progression and complications. Fifteen studies were included in this meta-analysis. A total of 1770 patients (1379 women [77.9%]; mean [SD] age, 45.4 [11.4] years; age range, 42.5-66.0 years) with 1822 tumors were treated with RFA; 49 tumors underwent 1 additional RFA session and 1 tumor underwent 2 additional RFA sessions. Mean (SD) follow-up time was 33.0 (11.4) months (range, 6-131 months). The pooled complete disappearance rate at the end of follow-up was 79% (95% CI, 65%-94%). The overall tumor progression rate was 1.5% (n = 26 patients), local residual mPTC in the ablation area was found in 7 tumors (0.4%), new mPTC in the thyroid was found in 15 patients (0.9%), and 4 patients (0.2%) developed lymph node metastases during follow-up. No distant metastases were detected. Three major complications occurred (2 voice changes lasting >2 months and 1 cardiac arrhythmia). Minor complications were described in 45 patients. The findings of this systematic review and meta-analysis suggest that RFA is a safe and efficient method to treat selected low-risk mPTCs. Radiofrequency ablation could be envisioned as step-up treatment after local tumor growth under active surveillance for an mPTC or initial treatment in patients with mPTCs with anxiety about active surveillance.

Spray cryotherapy versus continued radiofrequency ablation in persistent Barrett's esophagus.

Radiofrequency ablation (RFA) is the first-line treatment for flat Barrett's esophagus (BE) with dysplasia, however its role for persistent Barrett's esophagus (PBE) is unclear. PBE requires additional RFA sessions or application of cryotherapy to improve therapeutic response. We performed a retrospective cohort study evaluating cases of PBE treated by endoscopic eradication programs, with and without spray cryotherapy, and evaluated their safety and efficacy. We retrospectively identified patients with PBE, defined as ≤50% BE reduction or unchanged dysplasia after at least two RFA sessions. PBE was treated either by continued RFA (RFA Group) or converting to spray cryotherapy (CRYO Group), both followed by surveillance period. The rate of adverse events (AE), complete response of intestinal metaplasia (CRIM) and complete response of dysplasia (CRD) were recorded. A total of 46 patients, 23 per group, underwent 622 endoscopic therapies. Circumferential BE length was longer in the CRYO Group, but other baseline characteristics were similar, including maximal BE length. Esophageal strictures accounted for 14/16 total AE, 71% of which were RFA related, compared with 14% related to spray cryotherapy (P = 0.02). Overall CRIM/CRD rates in CRYO (83%) and RFA (96%) groups were not statistically different (P = 0.16), however cases in the CRYO Group required more treatment encounters (Median 19 vs. 12, P ≤ 0.01). Multimodal endotherapy is effective for eradicating PBE. Treatment programs incorporating spray cryotherapy are associated with less esophageal strictures but may require more treatment sessions to achieve eradication.

Safety margin for CT- and US-guided radiofrequency ablation after TACE of HCC in the hepatic dome

Introduction We evaluated the safety margin in patients with hepatocellular carcinoma (HCC) in the hepatic dome who underwent computed tomography (CT)- or ultrasound (US)-guided radiofrequency ablation (RFA). Material and methods Included in this single-center study were 46 patients with 56 HCCs in the hepatic dome undergoing RFA after transarterial chemoembolization from January 2009 to December 2016. Thirty were addressed with CT fluoroscopy and 26 with US guidance. The technical success, safety margin, and local tumor progression (LTP) were evaluated. Results Technical success rate was 100% in the CT-RFA and 84.6% in the US-RFA group (p = .04). The average safety margin was 4.8 mm in the CT-RFA and 3.0 mm in the US-RFA group (p = .01). There was no LTP among the HCCs with a safety margin >3 mm achieved in 73.3% CT-RFA and 42.3% US-RFA group tumors (p = .03). Of the US-RFA group, six required additional RFA. There was no significant inter-group difference in LTP (p = .36). Conclusion CT-guided RFA was superior to US-guided RFA with respect to the technical success rate and the acquisition of an appropriate safety margin in patients with HCC in the hepatic dome.

Endobiliary Radiofrequency Ablation Using a Short-Type Balloon Enteroscope in Patients with Surgically Altered Anatomy.

Endoscopic radiofrequency ablation (RFA) is expected to prolong stent patency for malignant biliary obstruction (MBO). However, its feasibility when used in conjunction with a balloon enteroscope (BE) in patients with surgically altered anatomy (SAA) remains unknown. This study aimed to investigate the feasibility of RFA combined with metal stent insertion under BE guidance for MBO in patients with SAA. Thirty-seven patients who underwent treatment between October 2016 and January 2021 and met the eligibility criteria were investigated retrospectively. Study outcomes included technical and clinical success, recurrent biliary obstruction (RBO), and other adverse events besides RBO associated with RFA with metal stent placement using BE. Technical and clinical success rates were 100% (37/37) each. The rates of early and late adverse events were 8.1% (3/37) and 8.1% (3/37), respectively. RBO occurred in 32.4% (12/37) of the patients, and the median time to RBO was 296days. The cause of RBO was ingrowth in eight patients, overgrowth in three patients, and indeterminate in one patient. All reinterventions for RBO were successful using the BE approach; all ingrowths, except one, were recanalized using additional RFA without additional stent placement. The frequency of reintervention-related adverse events was 9.1% (1/11). The median time to RBO after reintervention was 166days. This study demonstrated the technical safety and feasibility as well as good long-term outcomes of endobiliary RFA combined with metal stent placement under BE guidance. This approach may be a useful option for treating MBO in patients with SAA.

The Efficacy and Safety of Radiofrequency Ablation for Bilateral Papillary Thyroid Microcarcinoma.

ObjectiveTo investigate the long-term clinical results of radiofrequency ablation (RFA) for bilateral papillary thyroid microcarcinoma (PTMC).Materials and MethodsFrom October 2014 to February 2018, 47 patients (37 females, 10 males, mean age 43.39 ± 9.26 years) with 100 bilateral PTMC (mean volume 75.22 ± 73.87 mm3) treated by RFA were included in this retrospective study. Bilateral PTMC was defined as at least one tumor located in the contralateral lobe. Patients were followed up at 1, 3, 6, 12 months and every 6–12 months thereafter. Volume, volume reduction ratio (VRR) and local tumor recurrence were evaluated during the follow-up period.ResultsAfter a mean follow-up period of 47.77 ± 11.54 months, the mean volume of bilateral PTMC decreased from 75.22 ± 73.87 mm3 to 0.09 ± 0.44 mm3. The mean VRR was 99.94 ± 0.28% and the complete disappearance rate was 92.00%. During the follow-up, one patient (2.13%) developed lymph node metastasis and two patients (4.26%) had recurrent PTMC. All the recurrent lesions underwent additional RFA and two of them disappeared completely. No life-threatening or delayed complications occurred.ConclusionsWith sufficient preoperative evaluation, RFA might be a promising alternative for bilateral PTMC patients who were unsuitable for surgery or refused surgery.