Radiofrequency Ablation Research Articles

Evaluating lesion integrity with diamond temp system

Abstract Background Pulmonary vein (PV) isolation by temperature-controlled (TC) radiofrequency ablation (RFA) is regaining popularity due to tissue-temperature feedback from thermocouples attached at the distal tip. The Diamond Temp (DT) ablation catheter system is uniquely able to monitor real time tissue temp during RFAs. The DT catheter tip has a 1.1 mm split tip electrode, allowing precise bipolar pacing during RFA. Loss of capture (LOC) with High output pacing (HOP) has been considered a surrogate to assess lesion transmurality [1]. This study evaluated the utility of DT catheter distal pacing to achieve durable lesions. Standard guidelines for TC ablation recommend achieving target tissue-temperature of 60ºC to produce durable lesions. The purpose of this study was to assess whether LOC is achieved at target tissue-temperature of 60ºC. Objective Pacing during ablation from distal tip micro electrode of the DT catheter and observing the time it takes for LOC at different segments around pulmonary veins. First pass isolation (FPI) percentage was also collected. Methods While target enrollment for this prospective study is 50 patients, these preliminary findings are based on analysis of the first 15 patients enrolled, all of whom had symptomatic, drug-refractory paroxysmal AF. Point-by-point RF lesions were delivered around ipsilateral PVs, divided into 4 segments: superior, inferior, anterior, and posterior. Ablation was performed in a TC mode with max temp setting of 60°C and max power of 50 watts. HOP was performed prior to start of ablation and discontinued once LOC was observed. Time taken to LOC around all 4 segments of PVs were recorded. Intracardiac echocardiography (ICE) was used to guide contact and monitor lesion formation. Results Overall mean time to LOC was 3.32 sec. Anterior sites exceeded this mean. Inferior, superior, and posterior sites generally had shorter times. 92.53% of locations achieved LOC within 2-5 sec of ablation. The right anterior PV had the longest time at 3.73 sec, exceeding the overall mean of 3.32 sec. All patient achieved FPI. Conclusion Reaching target therapeutic temp of 60°C alone may not be sufficient to achieve LOC around PVs. Ablation duration of 4 sec led to LOC in 92.53% of lesions. Certain anatomical regions like anterior locations required prolonged ablation time. Tissue thickness on ICE correlated directly with time required to LOC. This analysis shows that TC ablation with DT is effective; however, a therapeutic stable temperature of 60°C for at least 4 sec may be needed to achieve durable lesions around PVs. Tissue thickness on ICE and stability of temperature appear to be independent variables affecting duration prior to LOC.

HMGB1/TREM1 crosstalk between heat-injured hepatocytes and macrophages promotes HCC progression after RFA

PurposeTumor recurrence after radiofrequency ablation (RFA) affects the survival rate of patients and limits its clinical application. Tumor recurrence around the ablation area may be related to the thermal injury of hepatocytes (HCs) around the tumor, but the specific mechanism is still unclear.MethodsA liver cancer thermal injury mouse model was established via RFA in the C57BL/6 mice. Primary HCs and Kupffer cells (KCs) were isolated and cultured to assess their sensitivity to thermal injury via the MTT assay. Flow cytometry was used to assess macrophage polarization. Furthermore, Western blotting and co-immunoprecipitation (co-IP) were utilized to evaluate the protein expression of intracellular signaling pathway. Finally, Transwell and wound healing assays was conducted to evaluate the invasion potential of liver cancer cells.ResultsOur findings revealed that RFA-induced liver thermal injury promoted the upregulation and secretion of HMGB1 in HCs. HMGB1 had a protective effect on HCs thermal injury, potentially mediated through autophagy regulation. Heat-injured HCs release HMGB1, which activates the TREM1/JAK2/STAT3 signaling pathway in KCs, thus fostering an immunosuppressive tumor microenvironment (TME). Moreover, HMGB1 secretion by heat-injured HCs exacerbates the migration and invasion of HCC cells by influencing macrophage polarization.ConclusionRFA-induced thermal injury triggers HMGB1 release from HCs, driving macrophage M2 polarization and increasing the invasion ability of liver cancer cells. These findings reveal a potential therapeutic target for combating liver cancer recurrence following thermal ablation.

A cost-consequence analysis comparing three distinct cardiac ablation strategies for the treatment of paroxysmal atrial fibrillation

Abstract Background Cardiac ablation is a well-established treatment option for preventing atrial fibrillation (AF). While radiofrequency, cryo-energy, and laser energies are commonly employed in catheter ablation, they present the risk of potential damage to adjacent organs such as the oesophagus and phrenic nerve. To address these concerns, new technologies are being explored including pulsed field ablation (PFA), a non-thermal energy approach that employs high-voltage, short-duration pulses to selectively destroy target cells. Purpose The present analysis aims at: i) quantifying the short-term costs related to three ablation strategies for paroxysmal AF (PFA, radiofrequency ablation -RFA-, and cryo-balloon ablation -CRYO-), identify the cost drivers, and assess potential variations in resource consumption for each treatment alternative; ii) comparing the medium-term (1-year) economic implications of adopting the three alternatives, in terms of redo procedures (effectiveness) and complications (safety). Methods A cost-consequence model was developed to compare economic outcomes of the three ablation strategies for paroxysmal AF in the short- (during procedure) and medium-term (1-year). Resource consumption data during the procedure were collected by two European medical centres specialized in cardiac ablation (N=61 patients). For the medium-term analysis, costs were correlated to the effectiveness and safety of the procedures. The clinical data (i.e., redo and complication rates) considered in the model were retrieved from published literature. Costs and tariffs were collected from economic formularies of the respective hospitals. A scenario analysis was conducted to evaluate economic outcomes under various hypothetical difference in the prices of treatment kits. Results A significant difference was registered in terms of pre-procedural (mean±SD: 13.9±4.4 min for PFA, 20.1±7.6 min for CRYO and 20.5±7.7 min for RFA; ANOVA test p=0.003) and procedural time (skin-to-skin), favouring PFA over RFA and CRYO (53.6±26.8 min for PFA, 72.4±28.1 min for CRYO and 149.9±99.9 min for RFA; p<0.0001; Table 1). PFA was associated with lower procedural costs vs CRYO (-€400) and RFA (-€827). A similar economic advantage was observed in the medium-term (Table 2). The scenario analysis showed that PFA would be cost-saving vs CRYO (Δtotal costs ≤ 0) up to a price difference of +€881 (i.e., PFA kit is more expensive than CRYO kit), and similarly, up to a price difference of +€1,306 vs RFA. Above these thresholds, PFA would be considered cost-effective vs CRYO or RFA, due to its efficacy despite being more expensive. Conclusion In summary, PFA emerges as cost-effective or even cost-saving over CRYO and RFA, thanks to its faster execution, lower redo, and complications rate. Moreover, PFA time predictability would facilitate hospital planning. For a complete analysis, these benefits should be evaluated against the difference in acquisition costs among treatments.Procedural time by phase and techniqueCumulative savings per technique

Successful elimination of double accessory pathways: a rare case of co-existence between right inferoseptal WPW and left lateral AVRT

Background: Managing double accessory pathways (APs) in the clinical setting presents significant challenges, primarily due to the rarity of this condition and the complexities involved in both diagnosis and treatment. Case Presentation: A 51-year-old male presented with recurrent episodes of palpitation. Electrocardiography (ECG) revealed a sinus rhythm with a pre-excitation pattern that was characterized by a delta wave morphology. This pattern showed a negative deflection in V1, a transitional zone in V2, and negativity in lead III and aVF, which indicated an accessory pathway through the right infero-septal pathway. Further evaluation with electrophysiology study (EPS) confirmed the presence of accessory pathways, with the right infero-septal pathway exhibiting pre-excitation during sinus rhythm. Radiofrequency ablation (RFA) successfully eliminated the right infero-septal accessory pathway. Subsequently, coronary sinus propagation shifted from a concentric to an eccentric pattern, indicating another accessory pathway from the left lateral region. Another mapping was performed retrogradely at the mitral annulus, revealing ventriculoatrial (VA) fusion at the left lateral area and demonstrating inducible atrioventricular reentrant tachycardia (AVRT). RFA successfully eliminated the left lateral accessory pathway, resulting retrograde block. Conclusion: This case highlights the importance of thorough diagnostics and tailored treatment strategies in managing dual APs, emphasizing the effectiveness of EPS-guided RFA for complex arrhythmias. Keyword: atrioventricular reentrant tachycardia, double accessory pathway, radiofrequency ablation, wolf-parkinson-white syndrome

Trans-femoral transcatheter intramyocardial septal radiofrequency ablation: a novel therapeutic approach for obstructive hypertrophic cardiomyopathy

Abstract Background Septal reduction techniques play a pivotal role in mitigating morbidity and mortality among patients with obstructive hypertrophic cardiomyopathy (oHCM). While trans-apical intramyocardial septal radiofrequency ablation (PIMSRA or LIWEN procedure) has shown promise in reducing left ventricular outflow tract (LVOT) gradients and improving symptoms in oHCM patients, it is associated with complications such as cardiac tamponade and atrioventricular block. Objective This study introduces a novel approach for transcatheter radiofrequency ablation of hypertrophic septum via femoral access, utilizing the DragonFire Transcatheter Myocardial Puncture and Radiofrequency Ablation System. We aim to evaluate its safety and medium-term outcomes in patients with oHCM. Methods A prospective, single-center, single-arm study of tf-PIMSRA was conducted in patients with drug-refractory oHCM. Ten patients were enrolled and underwent the procedure under the guidance of transesophageal echocardiography. The primary outcome was 30-day major adverse clinical events, with secondary outcomes including 90-day improvements in outflow obstruction and quality of life. Results All patients, with an average age of 57±10 years, including 4 males, underwent the procedure successfully without any complications, including major adverse clinical events or conduction abnormalities. The average duration of the procedure was 125.2±34.6 minutes, with an average ablation time of 38.69±18.29 minutes and ablation energy of 3.60±1.49KJ. At 90-day follow-up, significant reductions were observed in peak LVOT gradients (resting gradient: from 82.00 [56.00] mmHg to 14.00 [6.25] mmHg; p < 0.001; provoked gradient: from 102.00 [76.25] mmHg to 33.00 [16.50] mmHg; p = 0.002), and interventricular septum thickness (from 22.00 [19.00] mm to 17.00 [15.00] mm; p = 0.002). These improvements were associated with enhancements in NYHA functional classification (from 3.00 [2.75] to 1.00 [1.00]; p < 0.0001), Kansas City Cardiomyopathy Questionnaire scores (from 59.00 [44.50] to 80.00 [77.25]; p < 0.02), 6-minute walk distance (from 441 [400] m to 480 [465] m; p < 0.01), and pro B-type natriuretic peptide levels (from 1738.00 [1113.25] pg/ml to 252.00 [200.00] pg/ml; p = 0.002). All patients achieved New York Heart Association functional class I or II at follow-up. Conclusions Transfemoral PIMSRA appears to be a safe and effective procedure for relieving LVOT obstruction and symptoms in patients with drug-refractory oHCM. These findings support further investigation through randomized clinical trials comparing it with established septal reduction therapies.Patient-Level Outcomes for the trans-fem

Advanced mapping and ablation technologies to target pulmonary veins gaps and residual antral potentials during repeat paroxysmal AF ablation: acute and long-term follow-up

Abstract Background A comprehensive understanding of pulmonary vein (PV) reconnection and residual potentials (RAP) within the antral scar during repeat atrial fibrillation (AF) ablation, facilitated by advanced mapping and ablation technologies, is currently lacking. Optimizing radiofrequency (RF) deliveries after failed PV isolation (PVI) may enhance ablation efficiency. Purpose This study aims to assess both the acute and long-term outcomes focusing on PV gaps (PVGs) and RAPs, utilizing advanced mapping and ablation technologies during repeat PV ablation in patients (pts) with paroxysmal AF. Methods Repeat AF-CHARISMA study, a prospective, single-arm cohort study, included consecutive pts from 13 centers undergoing repeat ablation of paroxysmal AF. The Lumipoint (Boston Scientific) map-analysis tool was used sequentially on each PV component. All patients were followed-up for at least 12 months after the procedure. The ablation endpoint was PVI and electrical quiescence in the antral region. Long-term outcome was the recurrence of AT/AF over follow-up. Results One-hundred pts were included (69% after failed RF procedure, 31% after failed cryoablation procedure). A total of 276 PVGs (192 after RF ablation, 2.8±1.8/pt; 84 after cryoablation, 2.7±1.9/pt, p=0.665 vs RF) and 44 RAPs (43 after RF ablation, 0.6±1.1/pt; 1 after cryoablation, 0.03±0.2/pt, p=0.002 vs RF) were detected. In the majority of cases (75%), only PVGs were present whereas, in 21%, both PVGs and RAPs were detected (2 pts had only RAPs). In 2 pts no PVG nor RAP were identified. PVGs were most common at anterior sites (103, 37.3%), followed by posterior sites (75, 27.2%) and carina sites (49, 17.8%). PVG location sites did not differ between prior ablation approach. Only 1 pt after cryoablation showed a RAP (at carina site), whereas the 44 RAPs after RF were fairly distributed across different sites. Acute procedural success was 100%, with all PVs successfully isolated and RAPs completely abolished in all study pts. After the blanking period, over a follow-up of 480±211 days, 18 pts (18%) suffered an AT/AF recurrence (time to recurrence: 245±80 days). Previous ablation approach (HR=0.66, 95%CI: 0.2 to 2.0 for previous cryoablation, p=0.46), number of PVGs (1.05, 0.8 to 1.3, p=0.67) or number of RAPs (0.41, 0.1 to 1.2, p=0.12) were not associated to AT/AF recurrence. No major complications or adverse events occurred. Conclusion A structured ablation workflow for repeat catheter ablation, incorporating consistent high-density mapping and improved diagnostic tools to guide the procedure, demonstrated safety and efficacy in treating paroxysmal AF irrespectively of previous ablation approach. Residual potentials within the antral scar were more frequently detected after RF ablation compared to cryoablation.

Ultrasound-guided ablation for T1N0M0 papillary thyroid carcinoma adjacent and non-adjacent danger triangle area: a retrospective comparative study

Objectives To compare the safety and efficacy of ultrasound-guided radiofrequency ablation (RFA) in the treatment of T1N0M0 papillary thyroid carcinoma (PTC) with adjacent and non-adjacent danger triangle area (DTA). Materials and methods This retrospective study involved collecting clinical data of all T1N0M0 PTC patients who underwent RFA between January 2018 and December 2020 at the hospital. A total of 211 patients were enrolled in the study (mean age 43.25 ± 12.30 years, male-to-female ratio = 1:3). Among them, 91 had adjacent DTA involvement, while 120 had non-adjacent DTA involvement. Comparisons were made between the two groups patients regarding tumor volume changes, technical success rates, tumor disappearance, disease progression, complications. Results In both groups, the technical success rate was 100%, with a median follow-up period of 30 months. The rates of complete tumor disappearance were 78% (71/91) and 74.2% (89/120) for the adjacent and non-adjacent DTA(p = .517). Disease progression rates were 2.2% (2/91) and 1.7% (2/120) (p > .99), Complication rates were 3.3%(3/91) in the adjacent DTA group and 1.7% (2/120) in the non-adjacent DTA group (p = .654). At 6th month after ablation, the volume reduction rate (VRR) in the non-adjacent DTA group (42.3%) was higher than in the adjacent DTA group (37.3%) (p = .002). However, no significant differences were observed in VRR between the two groups at 1, 3, 12, 18, 24, 30, and 36 months (p > .05). Conclusion In the treatment of T1N0M0 PTC, the complication rates and short-term efficacy of RFA in adjacent to the DTA did not differ from those of non-adjacent DTA.

The intracardiac echocardiographic findings during rewarming using catheter-based cryoablation

Abstract Introduction Cryoablation unlike radiofrequency ablation (RFA) does not damage the endothelium and lining and causes less physical damage, and the mechanisms remain unclear. The increased myocardial echogenicity (iME) observed by intracardiac echocardiography (ICE) during RFA has been reported as the ablation indicator. Purpose To evaluate the ICE findings during ablation using catheter-based cryoablation. Methods In an extra vivo experiment, we set the bovine myocardium to 36°C in a constant temperature bath and experimented on a water tank that generated a non-pulsatile flow. Catheter-based cryoablation was applied to the bovine myocardium at -80 degrees for 240 seconds. The ICE images were evaluated using ViewFlex Xtra during catheter-based cryoablation. Results Macroscopic change (Figure 1): Four seconds after the start of cooling, a thin film of ice began to form between the myocardium and the catheter, and after 7 seconds, the tip of the catheter was covered with ice and the surface of the myocardium was covered with ice. After that, it grew rapidly and an ice ball was formed. There was no change after 18 seconds of cooling. ICE findings (Figure 2): 4 seconds after cooling started, the ME around the catheter tip began to increase, and the ME gradually increased with flickering. The iME stopped after cooling down for 18 seconds and did not change after that. Immediately after stopping cooling, severe flickering occurred and the area of iME began to shrink. The ME gradually returned to its original state with slight bubbles from the central ablation site. Macroscopic change and ICE findings were reproducibly confirmed. Myocardial findings after ablation: The area of cooling was discernible, but the color difference from the surrounding area was not obvious. Conclusions The catheter-based cryoablation ablation shows the severest change detected by ICE immediately after stopping cooling. In addition to tissue damage during the freezing stage, the rewarming may be more associated with tissue damage.

Speckle decorrelation rate as a robust indicator for visualizing the therapeutic thermal field with OCT.

Optical coherence tomography (OCT) is evolving from a diagnostic imaging modality to one that also facilitates therapeutic procedures. However, visualizing the therapeutic thermal field during minimally invasive thermal treatments such as laser or radio frequency ablation is challenging. This difficulty arises because tissues show minimal optical property changes until they reach the coagulation threshold at approximately 50 ∘C. To address this, we introduce the speckle decorrelation rate as a new, to our knowledge, contrast mechanism for OCT, enhancing the visualization of the therapeutic thermal field. Through ex vivo tissue experiments on a laser ablation-OCT surveillance system, we demonstrate that the speckle decorrelation rate offers superior sensitivity to detect subtle temperature changes and is less sensitive to the selection of time intervals for decorrelation calculations compared to existing speckle decorrelation methods. Our approach, which is label-free and compatible with various OCT systems, has been validated across diverse biological tissues, showing potential to augment the precision and safety of thermal therapies. Additionally, we propose a GPU-accelerated pipeline to expedite processing time, making real-time thermal field visualization feasible.

Comparison of pulsed field ablation versus cryoballon and radiofrequency ablation for pulmonary vein isolation in atrial fibrillation patients with heart failure

Abstract Background Pulmonary vein isolation (PVI) is the gold standard for atrial fibrillation (AF) ablation and can be achieved by a variety of technical methodes. While thermal ablation modalities (TA), such as cryoballon (CB) and radiofrequency ablation (RF) have been established as the standard approaches, PFA has been introduced as a nvel non-thermal modality showing comparable safety and procedural efficiency. Despite the high incidence of AF in heart failure (HF) patients, data comparing outcomes of HF patients undergoing PVI by either PFA or thermal ablation (RFA/CB) are limited. Purpose This study’s aim was to compare the efficacy and safety of PFA for AF ablation versus CB/RFA in HF patients. Methods Consecutive HF patients with preserved (HFpEF), mildly reduced (HFmrEF) and reduced (HFrEF) ejection fraction undergoing PVI for AF by either PFA or CB/RFA at our institution were included. The primary end-point was time to death or recurrence of AF. Secondary end-points were periprocedural complications and clinical and echocardiographic parameters. Results We included 140 HF patients who underwent PVI either by PFA (PFA group, 76 patients) or thermal ablation approaches (TA group, 64 patients). Our patients had a mean age of 69 years and were predominantly male (62%). There was no significant difference in the baseline characteristics and in the type of AF between both groups (42% with ParAF, 45% with PersAF) and 13% LSPersAF). The distribution of heart failure types was similar between both groups: HFpEF (PFA: 71%, TA: 75%), HFmrEF (PFA: 21%, TA: 20%) and HFrEF (PFA: 8 %, TA: 5%). After the 365-days follow-up period we observed no significant difference for the primary end-point between both groups (HR: 0.79, 95% CI 0.35-1.78; p=0.575). In total 58% of the PFA patients and 59% of the TA group were still free from AF. While symptom improvement was documented in both groups, patients in the PFA group showed significant improvement of left atrial volume index (p = 0.014), NT-pro BNP levels (p = 0.046), and left ventricular ejection fraction (LVEF) (p = 0.005). Conclusion In this study, PFA and thermal ablation modalities showed comparable results in terms of safety and procedural efficiency in patients with heart failure. Since previous studies have shown that HF patients with AF benefit from PVI using thermal ablation modalities, our results suggest that PFA might also be a promising ablation method in this vulnerable population, inducing left atrial reverse remodeling and thereby contributing to improvement of left ventricular systolic function.

Participation of epicardial connection in transverse conduction across the crista terminalis in patients with upper and lower loop reentry atrial tachycardias

Abstract Background The crista terminalis (CT) sometimes serves as a partial or complete conduction barrier, which is rate- and site-dependent. The basis, location and extent of the transverse conduction across the CT have been controversial. The pseudo-focal activation pattern indicates passive activation from the anatomically opposite chamber or structure. We previously reported cases of transverse CT conduction exhibiting a pseudo-focal activation pattern, indicating the CT conduction utilizing an epicardial connection (EC) in patients with upper loop reentry (ULR) atrial tachycardia (AT). Purpose This study aimed to investigate the prevalence and characteristics of transverse CT conduction using a high-resolution electroanatomical mapping system during CT-dependent AT and to compare between the ULR and lower loop reentry (LLR) ATs. Methods A total of 119 consecutive patients with macroreentrant AT were studied. The diagnosis of ULR/LLR AT was made based on endocardial activation mapping and entrainment pacing obtained from various sites around the superior/inferior vena cava. Transverse CT conduction utilizing an EC was defined as follows; (1) a centrifugal activation pattern with the earliest activation (EA) site >5 mm away from the CT, (2) later activation observed between the EA and the CT, and (3) the EA site exhibiting a pseudo-focal activation pattern (multiple breakthroughs or a small r wave on unipolar electrogram). Results Eighteen (15.1%) of the 119 patients were diagnosed with CT-dependent AT (15 men; median age, 71.5 years; AT cycle length, 265 ms; left atrial diameter, 42.5 mm; left ventricular ejection fraction, 49%). The 18 patients were divided into 2 groups: 9 patients with ULR and 9 with LLR AT. There were no significant differences in clinical characteristics (sex, history of cardiac surgery and organic heat disease) between ULR and LLR groups. Transverse CT conduction utilizing EC was more frequently observed in the ULR group than in the LLR group [77.8% (7/9) vs 22.2% (2/9), P=0.05]. In all patients with transverse CT conduction utilizing EC, scars extended along the CT. AT cycle length was significantly longer in the ULR group than in the LLR group (295 vs 235 ms, p=0.001). All ATs were successfully eliminated by radiofrequency ablation at the breakthrough sites and/or along the CT in ULR patients or by cavotricuspid isthmus ablation in LLR patients. Conclusions Half (9/18) of the patients with CT-dependent AT exhibited transverse CT conduction with a pseudo-focal activation pattern, suggesting the existence of an EC between the sinus venosus and the right auricle. The high prevalence of the pseudo-focal pattern in patients with the ULR compared to those with the LLR may provide insights into mechanisms.Figure1Figure2

Risk of right coronary artery injury and distance from tricuspid valve ring to right coronary artery in radiofrequency ablation

Abstract Background Coronary injury is a significant risk during catheter ablation (CA). While a shorter distance between the CA site and the coronary artery is known to increase this risk, less fat in this region might also heighten the chances of coronary damage due to greater penetration of RF energy. However, the relationship between the right coronary artery (RCA #1-3) and the basal right ventricle at the tricuspid annular ring (TVR) has not been thoroughly investigated, despite reports of coronary obstruction during ablation in this area (see Figure in reference). This study aimed to address this gap. Methods Forty-one consecutive patients (average age 64 ± 14 years, 30 males) who underwent coronary CT before ablation were enrolled. The distance between the TVR and RCA (#1-3) and the fat distribution between these structures were assessed (see Figure 1). Results The TVR-RCA#1 distance was 8.4 ± 4.7 mm, and TVR-RCA#2 was 4.1 ± 1.8 mm. In 30 (73%) patients, the closest TVR-RCA distance was <5 mm, with <2 mm in 4 (10%) patients, and 1.4 mm at the closest point (see Figure 2A). While the fat distribution at the closest TVR-RCA varied (-34.9 ± 78.1) among patients, almost no fat tissue was seen in 12 (30%) patients (see Figure 2B). Conclusion CA on the basal lateral RV should be approached with caution due to the very close proximity of TVR to RCA in 10% of cases and the lack of fat distribution in this area in 30% of cases.

Ablation of right ventricular endocavitary arrhythmias

Abstract Background The right ventricular moderator band-papillary muscle (RV MB-PM) complex has a rich subendocardial network of purkinje fibers which can lead to ventricular arrhythmias (VA)1. Catheter ablation of such arrhythmias is procedurally challenging and there remains limited studies on long-term procedural success. Purpose We aimed to systematically study RV MB-PM complex VA. Methods A single center retrospective study from January 2013 to December 2023 identified 3249 patients who underwent VA ablation. The RV MB-PM complex was targeted in 47 patients. Acute success was defined as suppression of the targeted VA >=30 minutes post ablation. Long-term success was defined as the absence of symptoms, total PVC burden <5% or improvement in EF in patients presenting with isolated PVCs and as freedom from appropriate ICD therapy in patients presenting with malignant PVCs inducing VF, sustained VT or VT storm. Results Mean age was 51.9 ± 16.7 years and 64% were male. 40 (85%) patients had VA targeted from the MB and 7 (15%) from the PM complex (2 anterior, 2 inferior and 3 septal PM). 34 (72%) had no underlying structural heart disease, 3 (6%) ischemic cardiomyopathy and 10 (21%) non-ischemic cardiomyopathy. No patient had delayed gadolinium enhancement in the RV MB-PM complex. VA were inducible in 42 (89%) of patients and activation mapping was used in 9 (19%), pace mapping in 5 (11%) and a combination of activation and pace mapping used in 33 (70%) patients. Intracardiac echocardiography was used in all cases. Pre-QRS duration was 34.0 ± 10.4 ms. Radiofrequency ablation was used in 37 (78.7%) cases, cryotherapy in 4 (8.51%) cases and a combination of the 2 energy sources in 6 (12.8%) cases. In all cases, acute peri-procedural success was achieved. 24 (51.1%) patients presented with isolated PVCs and were followed up for 4.72 ± 3.55 years after their index procedure. 3 patients underwent repeat catheter ablation targeting the same PVC focus but all patients had long term success with a PVC burden of 16.1 ± 12.5% prior to ablation and 2.40 ± 2.44% at last follow-up. 16 patients underwent ablation for recurrent ICD shocks after initially presenting with PVC induced VF. Patients were followed up for 3.22 ± 2.09 years and 14 (88%) patients remained free from ICD therapy. 7 patients had MB ablation for sustained VT and were followed up for 4.06 ± 3.77 years. 5 (71%) patients remained free from ICD therapy. A purkinje potential was seen in 8% (2/24) cases of isolated PVCs and in 39% (9/23) cases of PVC induced VF or VT (p=0.13). Conclusions RV MB-PM VA commonly present with malignant VF and a purkinje potential is more likely to be seen in these cases suggesting different VA mechanisms to isolated PVCs and catheter ablation is an effective long-term strategy.

Left atrial substrate modification for persistent atrial fibrillation and left atrial macro or microreentrant tachycardia using a single-shot pulsed field ablation system - a single centre case series

Abstract Background Pulsed field ablation (PFA) is a novel ablation technique for pulmonary vein isolation (PVI) in patients with paroxysmal and persistent atrial fibrillation. However, data for efficacy and safety of PFA for left atrial substrate modification in patients with long-standing persistent atrial fibrillation (AF) and macro- as well as microreentrant atrial tachycardia (AT) is scarce. Aim Here we provide a retrospective, single-centre case series regarding efficacy and safety of left atrial substrate modification, using a single-shot PFA system. Methods and Results Over a period of 6 months, 8 patients with long-standing persistent AF and AT underwent Re-PVI with left atrial substrate modification using a single-shot PFA system. Median age was 63 years (IQR 58 - 75), and 4/8 of patients were female. Time from first diagnosis of AF was 7 years (IQR 4 –10). All but 1 patient underwent previous PVI (IQR 1-3) with (5/7) or without (2/7) prior substrate modification using radiofrequency ablation. On transthoracic echocardiography, all patients showed severe left- and right-atrial enlargement, with LA volume of 58 ml/m2 (IQR 49.7–72) and RA diameter of 62 mm (IQR 55-75). In 8 patients, 9 ATs and 2 typical flutters were treated with PFA. Following PVI, additional posterior wall isolation was performed in 6/8 patients, roof in 6/8, and anterior wall (between superior mitral anulus and RSPV) in 4/8 patients. In addition, 2/8 patients had cavotricuspid isthmus ablation for typical atrial flutter. All patients received atropine prior to PVI, as well as bolus of nitro-glycerine prior to PFA of anterior wall and/or cavotricuspid isthmus. Acute success rate was 100% and all ATs as well as typical flutter terminated with PFA. After median follow-up time of 88 days (IQR 61-112), 3 patients had a documented recurrence of AF/AT, in 2 of which electrical cardioversion was necessary. We observed no acute and/or chronic complications following PFA, i.e. no pericardial effusion/tamponade, TIA/stroke, myocardial infarction, coronary artery spasm, AV-block, bleeding, or atrioesophageal fistula. Conclusion In this small, single-centre case series, left atrial substrate modification for long-standing persistent AF and AT using a single-shot PFA system was safe and showed an excellent acute success rate.

Comparison of complications during catheter ablation of atrial fibrillation between radiofrequency and cryoballoon ablation: insights from a nation-wide claims-based database

Abstract Background Few large-scale, real-world studies have compared the safety of radiofrequency (RF) catheter ablations (CA) with that of cryoballoon ablations of atrial fibrillation (AF), especially in east Asian countries. Methods This retrospective, cross-sectional study used a nationwide administrative claims database, to compare complication-incidence rates between patients who underwent RFCA and cryoballoon ablation of AF. We used data from Medical Data Vision Co., Ltd, that is derived from the health claims, Diagnosis Procedure Combination (DPC) system, and flat-fee payment system in Japan. We first extracted hospitalization records with CA with diagnosis of AF. Exclusion criteria were 1) records with diagnoses of atrial flutter or atrial tachycardia, 2) patients aged <20 years old, 3) CA of AF performed other than RFCA or cryoballoon, 4) records with insufficient clinical data, and 5) patients who were prescribed both direct oral coagulants and warfarin. Complications were defined using the following ICD-10 diagnosis codes: major bleeding (I31.9, I97.1, J98.5, J048, J0021); thromboembolism (H342, I24, I269, I740, I741, I744, I748, I749, K550, K868, N280, or T790); ischemic stroke (G45, or I63); cardiac tamponade (I31.9, I97.1, or J98.5); and vascular access complications (hematoma: S701, S801, T140 or T810; and/or pseudoaneurysms: I72.4). Logistic regression analyses were performed to estimate odds ratios and 95% confidence intervals (CI) for major bleeding, systemic thromboembolism, ischemic stroke, and cardiac tamponade. Results Among the 32,797,540 records between June 2011 and August 2020 from 426 hospitals, 41,347 records who underwent CA of AF (Median 68 [60–74] years old, 30.2 % women) were included in the study. A total of 36,729 RFCA (88.8%) and 4,618 cryoballoon ablation (11.2%) cases were included in the cohort. Major bleeding, systemic thromboembolism, ischemic stroke, cardiac tamponade, and vascular access complications occurred in 194 (0.5%), 193 (0.5%), 116 (0.3%), 414 (1.0%) and 115 (0.3%) patients, respectively. As a result of logistic regression analysis, when cryoballoon ablation was used as a reference, RFCA was associated with higher risk of cardiac tamponade (OR 1.54, 95% CI 1.09–2.25, P = 0.02), while it was not associated with higher or lower risk of other complications (major bleeding OR [95% CI ]1.21 [0.77–2.04]; thromboembolism 1.74 [1.03–3.22]; ischemic stroke 1.88 [0.94–4.47]; vascular access complication; 1.00 [0.58–1.87]). Conclusion Compared to cryoballoon ablations, RFCA was associated with higher risk of cardiac tamponade, using nationwide administrative claims database.

Biomarkers in early and late period after radiofrequency and pulsed field catheter ablation of atrial fibrillation

Abstract Introduction Biomarkers are routinely used parameters for disease diagnosis, treatment control and risk stratification. In connection with atrial fibrillation (AF), the importance of GDF-15 (growth differentiation factor 15), NT-proBNP (N-terminal fragment brain natriuretic factor) and hs-TnT (high sensitivity cardiac troponin T) is discussed. Catheter ablation is an established treatment method in selected population with AF. However, biomarker response to radiofrequency catheter ablation (RFCA) and pulsed field ablation (PFA) of AF has not been precisely described. Purpose Purpose of the study was to describe early and late dynamics of GDF-15, hs-TnT and NT-proBNP in different ablation technologies. Methods We prospectively enrolled 48 patients (median (IQR) age 62 (55; 70) years, 30 males) undergoing RFCA, which we compared with 30 patients (median (IQR) age 64 (56; 71) years, 18 males) undergoing PFA. All patients underwent 6 sequential blood takes: before ablation (baseline), right after ablation (0h), 24 and 48 hours after procedure (24h and 48h), 90 and 180 days after procedure. Levels of GDF-15, hs-TnT and NT-proBNP were analyzed. Results Out of all patients, 19 (40 %) and 20 (67 %) patients had paroxysmal AF in RFCA and PFA group, respectively. Additional ablation lesions over pulmonary vein isolation were done in 26 (54 %) patients in RFCA group and 11 (43 %) patients in PFA group. Median procedural time was significantly longer in RFCA than in PFA group (155 (130; 190) vs. 80 (70; 90) min; p < 0.01). Early dynamics of GDF-15 and cardiac hs-TnT are visualised in Figure 1 and 2. GDF-15 level peak was registered 48 hours after ablation with median (IQR) 1183 (824; 1988) ng/l. Compared to baseline, GDF-15 values sustained elevated up to 90 days after ablation in both groups and decreased to baseline levels after 180 days. No significant differences were found in GDF-15 levels between patients treated with RFCA and PFA. Maximal values of hs-TnT were significantly higher in PFA group than in RFCA group (1001±589 vs. 458±202 ng/l; p < 0.001). We have recognised decrease of NT-proBNP between baseline and 90 days after procedure in both groups: 338 (112; 613) vs. 209 (101; 545) ng/l; p < 0.05. Conclusion Eventhough GDF-15 is considered as a nonspecific biomarker reflecting general condition of patient, the levels are significantly affected by catheter ablation of AF for several months irrespective to ablation technology. PFA is associated with advanced elevation of hs-TnT.Dynamics of GDF-15 (median; IQR)Dynamics of hs-TnT (median; IQR)

Impact of paroxysmal atrial fibrillation ablation on cardiac sympathetic nervous system: a prospective stratified randomized comparative study in patients with and without heart failure

Abstract Background Catheter ablation of atrial fibrillation (AF) might influence the cardiac sympathetic nervous system (CSNS). We sought to investigate the impact of AF ablation with 2nd generation cryoballoon catheter (CB) and contact force sensing radiofrequency ablation catheter (RF) on CSNS and the association of this effect with early AF recurrence in patients with and without heart failure (HF), using cardiac iodine-123-metaiodobenzylguanidine (MIBG) scintigraphy. Methods and Results One hundred sixty-five paroxysmal AF patients who were scheduled for ablation were enrolled. All patients were categorized into two groups: one with HF (n=31), defined as left ventricular ejection fraction ≤ 40% or previous history of hospitalization for worsening HF, and the other without HF (n=134). They were then randomly assigned to CB (17 patients with HF and 68 without HF) or RF (14 with HF and 66 without HF). MIBG scintigraphy was performed at baseline and 3 months post-ablation and the washout rate (WR) was measured. There were no significant changes in WR from baseline to 3 months after RF and CB ablation (28.7±18.6% to 27.9±16.7% in RF and 29.4±16.7% to 30.5±16.4% in CB). WR decreased more in patients with HF at 3 months after ablation than without HF, while WR significantly increased in patients without HF and there was a significant interaction in WR change between with or without HF (interaction p<0.001). WR change from the baseline to 3 months after ablation (dWR) was not significantly different between CB and RF, irrespectively of the HF presence. In the blanking period of 3 months after ablation, early AF recurrence (EAR) was observed in 37 (22%) patients with no antiarrhythmic drugs (17(21%) patients in RF and 20(24%) in CB). dWR was significantly greater in patients with than without EAR (4.0±14.1% vs -0.9±11.0%, p=0.027). Higher dWR (≥ 6.9% (AUC 0.644, 95%CI [0.535-0.753]) by ROC curve analysis) was independently associated with EAR (adjusted odds ratio = 4.15, 95%CI [1.87-9.22], p<0.001, adjusted for age, sex, and left atrial diameter). Conclusions Irrespectively of CB and RF, AF ablation might reduce adrenergic tone in patients with HF, while it might induce more adrenergic tone in patients without HF. Excessive adrenergic tone might be associated with early AF recurrence.WR changes before and after ablationdWR in patients with or without HF

Additive Effect of Multilevel Radiofrequency Ablation in Elderly Patients with Sleep Apnea

Additive Effect of Multilevel Radiofrequency Ablation in Elderly Patients with Sleep Apnea

Pulsed field ablation using additional mapping and substrate modification to treat atrial fibrillation - one year outcome comparison

Abstract Background Pulsed field ablation (PFA) is a relatively new non-thermal form of ablation employing irreversible cell electroporation as an alternative to radio-frequency ablation. Conventional use of PFA relies on fluoroscopy. Electro-anatomical and voltages mapping (EAM) may potentially provide refinement of PFA via ablation of non-PV targets and accurate localisation of catheter placement. Currently there is limited data on the efficacy of the use of voltages criteria of EAM in conjunction PFA in the treatment of atrial fibrillation. Objective The aim of our study was to determine the effect on atrial arrhythmia recurrence with the use of EAM with PFA in patients requiring atrial fibrillation ablation. Methods This single centre retrospective observational analysis included one hundred patients with symptomatic AF (paroxysmal and persistent) undergoing ablation for the first time. Fifty patients underwent PFA-PVI alone and fifty patients underwent PFA-PVI with EAM. Data were obtained on patient characteristics, outcomes, procedure details and complications up to one year. A blanking period of three months was used post-ablation. For rhythm monitoring we utilised ECGs and holters at three, six, nine and twelve months and twenty-four hour holter monitoring at six and nine months. We also used remote monitoring in between these periods to record any symptomatic episodes atrial arrhythmias. Results Baseline patient characteristics are represented in Table 1. Despite having no significant difference in category of AF between groups (Paroxysmal, persistent, longstanding persistent) the mapping group were significantly older (68.2 years ± 10.2 vs 60.1 ± 11.11; p=0.01), longer duration of documented atrial fibrillation (45.9 ± 50 vs 28.6 ± 38 months; p=0.038), higher risk for CV events with CHA2DS2-VASc score (2.2 ± 1.5 vs 1.42 ± 1.2; p=0.04), however, procedure times were greater in the PVI and mapping group (72.8 ± 6.2 vs 41.1 ± 17 minutes; p=0.03). Successful PVI was achieved acutely in all patients upon voltage guided mapping validation and most importantly 1 year follow up revealed comparable outcome in both groups (Fig 1). Conclusion Patients who underwent PFA with mapping were older, greater co-morbidity and longer duration of AF burden. Yet, the addition of EAM with PFA did demonstrate equivalent achievement of sinus rhythm and was relatively high as higher than 80 % at one year follow up. This study may suggest a preference to using EAM in patients who may be deemed to be older and have a greater co-morbidity. It emerges as a great hope to safer approach and successful intervention to reduce AF burden.mapping vs PVI onlyGraph showing one year follow up

Atrial fibrillation ablation with temperature-controlled very high-power short-duration, with conventional-power, or with combined modes in clinical practice: 12-month outcomes from SECURE

Abstract Background/Introduction QDM is a contact force-sensing catheter optimized for temperature-controlled radiofrequency ablation in very high-power short-duration (vHPSD; 90 W/4 s), conventional-power (CP; ≤50 W), or vHPSD/CP combined modes. Purpose Evaluate 12-month (M) safety and effectiveness of atrial fibrillation (AF) ablations performed with 3 different ablation modes using the QDM catheter, a frequently used single tip catheter in Europe. Methods SECURE is an observational, prospective, post-market study collecting data on procedures performed per standard-of-care with up to 12M follow-up, in 16 enrolling sites in 8 countries across Europe and Israel. Index pulmonary vein (PV) isolation procedures are reported here. The primary safety endpoint is the incidence of primary adverse events (PAEs); the primary effectiveness endpoint is PV isolation (entrance block) of targeted PVs. Additional endpoints include acute reconnections, incidence of char and steam pop, 12M recurrence, repeat ablation, and healthcare utilization (HCU). Ablation strategy, impedance drop, and catheter stability were analysed with a cloud-based data management and artificial intelligence-powered algorithm. Results Since Feb 2021, 291 patients (70% male, 61±11 yrs, CHA2DS2-VASc 1.9±1.5) completed 12M follow-up in 11 sites. Most patients (175 [60.1%]) were treated for paroxysmal (PAF), 85 (29.2%) for persistent (PsAF), and 31 (10.7%) for long-standing persistent (LsPsAF) AF, under general anaesthesia (44.0%) or sedation (55.7%). A combined workflow was used in 66.0% of ablations, while vHPSD-only and CP-only were used in 13.4% and 20.6% of cases, respectively. Four (1.4%) patients reported a PAE; all resolved, and none were catheter related. Acute effectiveness was achieved in all targeted veins; 5.0% of PVs had acute reconnections, with the most common being the left superior PV. No steam pops were reported; 2 counts of char were noted in PsAF ablations with combined modes. Freedom from documented recurrence were 95.8% for PAF, 88.1% for PsAF, and 73.5% for LsPsAF (Fig 1). Freedom from repeat ablation post-blanking and freedom from cardioversion were both 96.8%. Cardiovascular hospitalization and emergency room visits decreased by 65.3% and 76.5% from 12M pre- to 12M post-procedure, respectively. Application-level analyses showed larger impedance drop and greater catheter stability with vHPSD. In procedures using a combined workflow, vHPSD was used preferentially for most PV segments, except anteriorly on the left wide area circumferential ablation (Fig 2). Conclusions Real-world data demonstrates that AF ablation with the QDM catheter is safe and effective with a low PAE rate, high 12M effectiveness, and reduced HCU. Most procedures were done with combined modes, where vHPSD was used preferentially, except at left anterior thicker regions. Larger impedance drop and greater catheter stability were observed with vHPSD applications.