Acute procedural safety of the latest radiofrequency ablation catheters in atrial fibrillation ablation: Data from a large prospective ablation registry.

BACKGROUND: Safety data of the latest radiofrequency (RF) technologies during atrial fibrillation (AF) ablation in real-world clinical practice are limited. OBJECTIVES: We sought to evaluate the acute procedural safety of the four latest ablation catheters commonly used for AF ablation. METHODS: A total of 3957 AF ablation procedures performed between January 2022 and December 2023 at 20 centers with either the THERMOCOOL SMARTTOUCH SF (STSF), TactiCath (TC), QDOT Micro (QDM), or TactiFlex (TF) were retrospectively analyzed. RESULTS: In total, QDM, STSF, TF, and TC were used in 343 (8.7%), 1793 (45.3%), 1121 (28.4%), and 700(17.7%) procedures. Among 2406 index procedures, electrical pulmonary vein isolations were successfully achieved in 99.5%. Despite similar total procedure times in the four groups, the total fluoroscopic time was significantly shorter for QDM/STSF with CARTO than TF/TC with EnSite (18.7 ± 14 vs. 27.6 ± 20.6 min, p < .001) and longest in the TF group. The incidence of cardiac tamponade was 0.7% (0.5% and 0.9% during index and redo procedures, 0.8% and 0.3% for paroxysmal and non-paroxysmal AF) and was significantly lower for QDM/STSF than TF/TC (0.2% vs. 1.1%, p = .008) and highest in the TF group. The incidence of cardiac tamponade was higher for TF than TC and STSF than QDM. In the multivariate analysis, TF/TC with EnSite was a significant independent predictor of cardiac tamponade during both the index (odds ratio [OR] = 4.8, 95% confidence interval [CI] = 1.3-17.5, p = .02) and all procedures (OR = 3.0, 95% CI = 1.3-7.2, p = .01). CONCLUSIONS: The incidence of cardiac tamponade and the fluoroscopic time during AF ablation significantly differed among the latest RF catheters and mapping systems in real-world clinical practice.

Prevalence and electrocardiographic and electrophysiological characteristics of idiopathic ventricular arrhythmias originating from the septal left ventricular summit.

INTRODUCTION: The left ventricular summit (LVS) is the highest point on the epicardial surface of the left ventricle. A part of the LVS that is located between the left coronary arteries (lateral-LVS) is one of the major sites of idiopathic ventricular arrhythmia (VA) origins. Some idiopathic epicardial VAs can be ablated at endocardial sites adjacent to the epicardial area septal to the lateral-LVS (septal-LVS). This study examined the prevalence and electrocardiographic and electrophysiological characteristics of septal-LVS VAs. METHODS: We studied consecutive patients with idiopathic VAs originating from the LVS (67 patients) and aortic root (93 patients). RESULTS: Based on the ablation results, among 67 LVS VAs, 54 were classified as lateral and 13 as septal-LVS VAs. As compared with the lateral-LVS VAs, the septal-LVS VAs were characterized by a greater prevalence of left bundle branch block with left inferior-axis QRS pattern, later precordial transition, lower R-wave amplitude ratio in leads III to II, lower Q-wave amplitude ratio in leads aVL to aVR, and later local ventricular activation time relative to the QRS onset during VAs (V-QRS) in the great cardiac vein. The electrocardiographic and electrophysiological characteristics of the septal-LVS VAs were similar to those of the aortic root VAs. However, the V-QRS at the successful ablation site was significantly later during the septal-LVS VAs than aortic root VAs (p < .0001). The precordial transition was significantly later during the septal-LVS VAs than aortic root VAs (p < .05). CONCLUSIONS: Septal-LVS VAs are considered a distinct subgroup of idiopathic VAs originating from the left ventricular outflow tract.

Combined approach of high-power and very high-power, short-duration ablation in superior vena cava isolation.

INTRODUCTION: The effectiveness and safety of 50 W, high-power, short-duration (HPSD) ablation in superior vena cava isolation (SVCI) for patients with atrial fibrillation (AF) have been reported. However, the acute outcomes of SVCI combined with 90 W/4 s, very high-power, short-duration (vHPSD) ablation remain unknown. In this study, we aimed to investigate a novel approach that combines 50 W-HPSD and 90 W/4 s-vHPSD ablation in SVCI and to elucidate the characteristics, outcomes, and safety of this approach by comparing SVCI with conventional ablation index (AI)-guided middle-power, middle-duration (MPMD) ablation. METHODS: Overall, 126 patients who underwent AF ablation with SVCI using the QDOT MICROTM catheter were retrospectively reviewed; one group underwent SVCI with a combined approach of HPSD and vHPSD ablation (50 W/90 W group, n = 73) and another group underwent AI-guided MPMD ablation (30-40 W group, n = 53). This study compared the procedural details, radiofrequency (RF) ablation profiles, and complications. The RF settings used in the 50 W/90 W group were 50 W/7 s for the lateral segment close to the phrenic nerve and 90 W/4 s for the nonlateral segment. RESULTS: The 50 W/90 W group required a significantly shorter procedural time (3.2 vs. 5.9 min, p < .001), shorter RF duration (42.0 vs. 162.0 s, p < .001), and lower RF energy (2834 vs. 5480 J, p < .001) than the 30-40 W group. Procedural success, first-pass SVCI, number of RF applications, and SVC reconnection after isoproterenol loading were comparable between the groups. The maximum tip-electrode temperature of the multi-thermocouple system was significantly higher in the 50 W/90 W group than in the 30-40 W group (50.0°C vs. 47.0°C, p < .001). No complications, such as phrenic nerve injury or bleeding requiring transfusion, were observed in either group. CONCLUSIONS: The combined approach of 50 W/7 s-HPSD and 90 W/4 s-vHPSD ablation resulted in successful and safe SVCI with shorter procedural time, shorter RF duration, and lower RF energy.

Association between triglyceride-glucose index trajectories and radiofrequency ablation outcomes in patients with stage 3D atrial fibrillation.

BACKGROUND: This study investigates the relationship between triglyceride-glucose (TyG) index trajectories and the results of ablation in patients with stage 3D atrial fibrillation (AF). METHODS: A retrospective cohort study was carried out on patients who underwent AF Radiofrequency Catheter Ablation (RFCA) at the Cardiology Department of the Fourth Affiliated Hospital of Zhejiang University and Taizhou Hospital of Zhejiang Province from January 2016 to December 2022. The main clinical endpoint was determined as the occurrence of atrial arrhythmia for at least 30 s following a 3-month period after ablation. Using a latent class trajectory model, different trajectory groups were identified based on TyG levels. The relationship between TyG trajectory and the outcome of AF recurrence in patients was assessed through Kaplan-Meier survival curve analysis and multivariable Cox proportional hazards regression model. RESULTS: The study included 997 participants, with an average age of 63.21 ± 9.84 years, of whom 630 were males (63.19%). The mean follow-up period for the participants was 30.43 ± 17.75 months, during which 200 individuals experienced AF recurrence. Utilizing the minimum Bayesian Information Criterion (BIC) and the maximum Entropy principle, TyG levels post-AF RFCA were divided into three groups: Locus 1 low-low group (n = 791), Locus 2 low-high-low group (n = 14), and Locus 3 high-high group (n = 192). Significant differences in survival rates among the different trajectories were observed through the Kaplan-Meier curve (P < 0.001). Multivariate Cox regression analysis showed a significant association between baseline TyG level and AF recurrence outcomes (HR = 1.255, 95% CI: 1.087-1.448). Patients with TyG levels above 9.37 had a higher risk of adverse outcomes compared to those with levels below 8.67 (HR = 2.056, 95% CI: 1.335-3.166). Furthermore, individuals in Locus 3 had a higher incidence of outcomes compared to those in Locus 1 (HR = 1.580, 95% CI: 1.146-2). CONCLUSION: The TyG trajectories in patients with stage 3D AF are significantly linked to the outcomes of AF recurrence. Continuous monitoring of TyG levels during follow-up may help in identifying patients at high risk of AF recurrence, enabling the early application of effective interventions.

Efficacy and Safety of Analgesics and Sedatives during Radiofrequency Catheter Ablation of Atrial Fibrillation: A Network Meta-Analysis.

Background: Atrial fibrillation is the most common tachyarrhythmia, while catheter ablation is an effective therapy for atrial fibrillation. However, pain and nervousness may occur during the procedure. Moreover, a consensus has still not been reached on which is the best kind of analgesic and sedative to use in these procedures. Therefore, we conducted a network meta-analysis to evaluate the efficacy and safety of analgesics and sedatives used in catheter ablation for atrial fibrillation. Methods: We searched PubMed, Cochrane Library, Web of Science, EMBASE, China National Knowledge Infrastructure, and Baidu Wenku document download website for randomized controlled trials from their inception to February 26, 2023. Only studies that made comparisons among analgesics or sedatives and involved patients with atrial fibrillation undergoing radiofrequency catheter ablation were included. The efficacy endpoints were Ramsay sedation scores and visual analog scale scores during the radiofrequency catheter ablation for atrial fibrillation. The safety endpoints were the incidence of respiratory depression, hypotension, nausea, and vomiting. Pairwise comparisons and frequency method analyses were conducted. Results were reported as odds ratio (OR), mean difference (MD), and corresponding 95% confidence intervals (CIs). We assessed the risk bias of the studies in accordance with the Cochrane Handbook for Systematic Reviews of Interventions. Results: Out of the 709 articles initially retrieved, 14 studies, with a total of 1156 participants, were included. In terms of efficacy, patients receiving dexmedetomidine during radiofrequency ablation for atrial fibrillation had higher Ramsay sedation scores than those receiving midazolam plus fentanyl, or its derivatives (MD -0.88, 95% CI [-0.04 to -0.72]). Compared with morphine, dezocine (MD 1.88, 95% CI [1.16 to 2.60]), hydromorphone (MD 4.07, 95% CI [3.56 to 4.58]), butorphanol (MD 3.18, 95% CI [2.38 to 3.96]), and fentanyl or its derivatives (MD 1.57, 95% CI [1.25 to 1.89]) had a better analgesic effect. In terms of safety, propofol (OR 16.46; 95% CI [1.54 to 175.95]) and midazolam plus fentanyl or its derivatives (OR 7.02; 95% CI [1.33 to 36.99]) significantly increased the incidence of respiratory depression compared with dexmedetomidine plus fentanyl or its derivatives. Dexmedetomidine plus fentanyl or its derivatives reduced the incidence of nausea and vomiting compared with fentanyl alone (OR 4.74; 95% CI [1.01 to 22.22]). Propofol was associated with a lower incidence of nausea and vomiting than hydromorphone (OR 0.01; 95% CI [0.00 to 0.59]) and fentanyl or its derivatives (OR 0.01; 95% CI [0.00 to 0.51]). There was no statistically significant difference in the incidence of hypotension between any two strategies. Conclusions: Hydromorphone and butorphanol had better analgesic effects than fentanyl or its derivates. Dexmedetomidine had better sedative effects. In terms of safety, dexmedetomidine, oxymorphone, and butorphanol were superior. It is necessary to explore the regimen that can consider both the effectiveness and safety during radiofrequency catheter ablation for atrial fibrillation (AF). The PROSPERO Registration: This study was registered with PROSPERO, number: CRD42023403661.

Meta-Analysis of the Efficacy and Safety of Radiofrequency Catheter Ablation for Pediatric Paroxysmal Supraventricular Tachycardia.

INTRODUCTION: This meta-analysis was to evaluate the efficacy and safety of radiofrequency catheter ablation (RFCA) in treating children with paroxysmal supraventricular tachycardia (PSVT). METHODS: From inception to December 16, 2023, PubMed, Embase, Cochrane Library, Web of Science, CNKI (China National Knowledge Infrastructure), VIP (Chinese Science and Technology Periodical Database), and WanFang were searched for this meta-analysis. Children under the age of 18 diagnosed with atrioventricular reentrant tachycardia (AVRT) and atrioventricular nodal reentrant tachycardia (AVNRT) were enrolled. The outcomes included the success rate of RFCA, the recurrence rate of PSVT following RFCA treatment, and any complications associated with the procedure. Newcastle-Ottawa Scale (NOS) was used to assess the quality of studies. The outcome data were represented as rates (RATE) and corresponding 95% confidence intervals (CIs). Subgroup analyses were conducted based on regions and follow-ups. RESULTS: Fourteen articles encompassing 6,032 children were included in the study. RFCA demonstrated remarkable efficacy in children patients, achieving success rates of 98% (RATE: 0.98, 95% CI: 0.96-0.99) for AVRT and 99% (RATE: 0.99, 95% CI: 0.98-1.00) for AVNRT. The analysis also reveals that post-RFCA, the recurrence rates for AVRT were 5% (RATE: 0.05, 95% CI: 0.03-0.07), while for AVNRT, they were slightly lower at 4% (RATE: 0.04, 95% CI: 0.02-0.08). In the subset of Asian children patients, these recurrence rates were observed to be 5% for AVRT and 3% for AVNRT. Monitoring for a duration of up to 12 months of post-RFCA indicated recurrence rates of 4% for AVRT and 3% for AVNRT. However, for follow-up periods extending beyond 1 year, there was a slight increase in these rates to 4% for AVRT and 6% for AVNRT. Additionally, the complication rates associated with RFCA in the children population were relatively minimal, recorded at 2% (RATE: 0.02, 95% CI: -0.01-0.06) for AVRT and 1% (RATE: 0.01, 95% CI: 0.00-0.02) for AVNRT. CONCLUSION: RFCA appears to be a highly effective and safe treatment option for AVRT and AVNRT in children, with high success rates and relatively low recurrence and complication rates. However, long-term follow-up may be necessary to monitor for potential recurrences. These findings are valuable for clinicians and patients in making informed decisions about the treatment of these cardiac arrhythmias in pediatric patients.

Combination of Epicardial Adipose Tissue and Left Atrial Low-Voltage Areas Predicting Atrial Fibrillation Recurrence after Radiofrequency Ablation.

INTRODUCTION: Atrial fibrillation (AF) is a common arrhythmia, with radiofrequency catheter ablation (RFCA) being first-line therapy. However, the high rate of post-ablation recurrence necessitates the identification of predictors for recurrence risk. Left atrial low-voltage areas (LA-LVASs), reflecting atrial fibrosis, have been confirmed to be related to recurrence of AF. Recently, epicardial adipose tissue (EAT) has been studied due to its role in initiating and maintaining AF. In this study, we try to evaluate the significance of the combined use of left atrial epicardial adipose tissue (LA-EAT) and percentage of LA-LVAs (LA-LVAs%) for predicting the recurrence of AF. METHODS: A total of 387 patients with AF who had undergone RFCA for the first time were followed up for 1, 3, 6, and 12 months. They were divided into two groups: the recurrence group (n = 90) and the non-recurrence group (n = 297). Before the ablation, all patients underwent computed tomography angiography examination of the left atrium, and the LA-EAT was measured using medical software (Advantage Workstation 4.6, GE, USA). After circumferential pulmonary vein isolation, a three-dimensional mapping system was used to map the LA endocardium and evaluate the LA-LVAs in sinus rhythm. RESULTS: After a median follow-up of 10.2 months, 90 patients developed AF recurrence after RFCA. Compared to patients without recurrence, the volume of LA-EAT (33.45 ± 13.65 vs. 26.27 ± 11.38; p < 0.001) and the LA-LVAs% (1.60% [0%, 9.99%] vs. 0.00% [0%, 2.46%]; p < 0.001) was significantly higher. Multivariate analysis indicated that PersAF, LA-EAT volume, and LA-LVAs% were independent predictors. Compared to PersAF (AUC 0.628; specificity 0.646; sensitivity 0.609), LA-EAT volume (AUC 0.655; specificity 0.675; sensitivity 0.586), or LA-LVAs% (AUC 0.659; specificity 0.836; sensitivity 0.437), the combined use of LA-EAT volume and LA-LVAs% offers higher accuracy for predicting AF recurrence after ablation (AUC 0.738; specificity 0.761; sensitivity 0.621). CONCLUSION: The combined LA-EAT and LA-LVAs% can effectively predict the risk of AF recurrence after radiofrequency ablation.

Predictors of improvement in left ventricular systolic function after catheter ablation in patients with persistent atrial fibrillation complicated with heart failure.

AIMS: The current management of patients with atrial fibrillation (AF) and concomitant heart failure (HF) remains a significant challenge. Catheter ablation (CA) has been shown to improve left ventricular ejection fraction (LVEF) in these patients, but which patients can benefit from CA is still poorly understood. The aim of our study was to determine the predictors of improved ejection fraction in patients with persistent atrial fibrillation (PeAF) complicated with HF undergoing CA. METHODS AND RESULTS: A total of 435 patients with persistent AF underwent an initial CA between January 2019 and March 2023 in our hospital. We investigated consecutive patients with left ventricular systolic dysfunction (LVEF < 50%) measured by transthoracic echocardiography (TTE) within one month before CA. According to the LVEF changes at 6 months, these patients were divided into an improved group (fulfilling the '2021 Universal Definition of HF' criteria for LVEF recovery) and a nonimproved group. Eighty patients were analyzed, and the improvement group consisted of 60 patients (75.0%). In the univariate analysis, left ventricular end-diastolic diameter (P = 0.005) and low voltage zones in the left atrium (P = 0.043) were associated with improvement of LVEF. A receiver operating characteristic analysis determined that the suitable cutoff value for left ventricular end-diastolic diameter (LVDd) was 59 mm (sensitivity: 85.0%, specificity: 55.0%, area under curve: 0.709). A multivariate analysis showed that LVDd (OR = 0.85; 95% CI: 0.76-0.95, P = 0.005) and low voltage zones (LVZs) (OR = 0.26; 95% CI: 0.07-0.96, P = 0.043) were significantly independently associated with the improvement of LVEF. Additionally, parameters were significantly improved regarding the left atrial diameter, LVDd and ventricular rate after radiofrequency catheter ablation (all p < 0.05). CONCLUSIONS: The improvement of left ventricular ejection fraction (LVEF) occurred in 75.0% of patients. Our study provides additional evidence that LVDd < 59 mm and no low voltage zones in the left atrium can be used to jointly predict the improvement of LVEF after atrial fibrillation ablation.

Relationships between biatrial substrate and recurrence after radiofrequency ablation in patients with persistent atrial fibrillation.

BACKGROUND: Global longitudinal strain (GLS) and atrial voltage are acknowledged markers for worse rhythm outcome after ablation of persistent atrial fibrillation (PeAF). The majority of research efforts have been directed towards the left atrium (LA), with relatively fewer studies focusing on the right atrium (RA). The aim of this study was to investigate the effect of the biatrial substrate on the outcome following radiofrequency catheter ablation (RFCA). METHODS: All patients underwent two-dimensional speckle tracking echocardiography (2D-STE) and high-density mapping (HDM) on LA and RA in preoperative and postoperative stages of RFCA. Atrial substrate was assessed by GLS, average voltage, and low voltage zone (LVZ). RESULTS: This retrospective study enrolled 48 patients. With a follow-up of 385.98 ± 161.78 days, 22.92% (11/48) of all patients had AF recurrence and 63.64% in low strain group. Left atrial-low voltage zone (LA-LVZ) prior to RFCA was 67.52 ± 15.27% and 54.21 ± 20.07%, respectively, in the recurrence group and non-recurrence group. Multivariate regression analysis showed that preoperative LA-GLS (OR 0.047, 95%CI 0.002-0.941, p = .046) was independent predictors of AF recurrence. Biatrial average voltage in preoperative and postoperative stages were positively correlated (preoperative: r = 0.563 p < .001; postoperative: r = 0.464 p = .002). There was no significant difference in the proportion of RA in the recurrence group except the septum in preoperative and postoperative stages. CONCLUSIONS: Low LA-GLS and high LA-LVZ may be predictors of RFCA recurrence in PeAF patients. Biatrial average voltage were positively correlated in preoperative and postoperative stages.

A case of atrial tachycardia originating from the left atrial roof successfully ablated via the pulmonary artery approach.

A 60-year-old male patient suffered from frequent episodes of atrial tachycardia (AT), after the index procedure of catheter ablation for paroxysmal atrial fibrillation. During the repeat procedure, the activation map showed that the earliest activation site was located at the roof of left atrium. Multiple ablations at the earliest activation site on the roof failed to terminate the AT; however, ablation within the pulmonary artery at an adjacent anatomical site successfully eliminated the AT, even without recording distinct near-field potential.

Nomogram to predict recurrence risk factors in patients with non-valvular paroxysmal atrial fibrillation after catheter radiofrequency ablation.

BACKGROUND: Radiofrequency catheter ablation (RFCA) is an effective method for controlling the heart rate of paroxysmal atrial fibrillation (PAF). However, recurrence is trouble under the RFCA. To gain a deeper understanding of the risk factors for recurrence in patients, we created a nomogram model to provide clinicians with treatment recommendations. METHODS: A total of two hundred thirty-three patients with PAF treated with RFCA at Guizhou Medical University Hospital between January 2021 and December 2022 were consecutively included in this study, and after 1 year of follow-up coverage, 166 patients met the nadir inclusion criteria. Patients with AF were divided into an AF recurrence group and a non-recurrence group. The nomogram was constructed using univariate and multivariate logistic regression analyses. By calculating the area under the curve, we analyzed the predictive ability of the risk scores (AUC). In addition, the performance of the nomogram in terms of calibration, discrimination, and clinical utility was evaluated. RESULTS: At the 12-month follow-up, 48 patients (28.92%) experienced a recurrence of AF after RFCA, while 118 patients (71.08%) maintained a sinus rhythm. In addition to age, sex, and TRV, LAD, and TTPG were independent predictors of recurrence of RFCA. The c-index of the nomogram predicted AF recurrence with an accuracy of .723, showing good decision curves and a calibrated nomogram, as determined by internal validation using a bootstrap sample size of 1000. CONCLUSION: We created a nomogram based on multifactorial logistic regression analysis to estimate the probability of recurrence in patients with atrial fibrillation 1 year after catheter ablation. This plot can be utilized by clinicians to predict the likelihood of recurrence.

A change in QT interval and ST-segment after radiofrequency catheter ablation in pediatric patients with Wolff-Parkinson-White syndrome.

BACKGROUND: Few studies have examined QT, JT interval, and ST-segment changes due to radiofrequency catheter ablation (RFA) in manifest Wolff-Parkinson-White (WPW) syndrome in pediatric patients. METHODS: The study involved 27 patients (male-to-female, 13:14; age, 12 (5-16) years) who were diagnosed with WPW syndrome and underwent RFA in our hospital between 2009 and 2022. Electrocardiographic (ECG) changes were compared between the group with ventricular preexcitation due to an accessory pathway (manifest group, n = 16) and those without it (concealed group, n = 11). RESULTS: The QT interval before RFA was significantly longer in the manifest group than in the concealed group (402 [362-482] vs. 344 [323-427]; p = 0.001). The QT interval was significantly shortened in the manifest group before and after RFA (402 [362-482] vs. 360 [298-422] msec; p = 0.01). At 1 month, the QT interval difference between the manifest and concealed groups disappeared (366 [305-437] vs. 335 [301-436] msec; p = 0.001). ST-segment changes were found after RFA in 56 % (9/16) of the patients in the manifest group but not in the concealed group. ECG changes presenting the Brugada-pattern was found in one patient. One month later, ECG abnormalities persisted in only one patient. CONCLUSIONS: In pediatric patients, the QT interval was prolonged in manifest WPW syndrome but shortened after RFA. In the manifest group, transient ST-segment change and T-wave abnormalities were often observed after RFA; however, the ECG normalized in approximately 1 month.

Efficacy of High-Density Three-Dimensional Mapping for Verapamil-Sensitive Left Posterior Fascicular Ventricular Tachycardia in Pediatric Patients.

In verapamil-sensitive left posterior fascicular ventricular tachycardia (LPF-VT), radiofrequency catheter ablation (RFA) is performed targeting mid-to-late diastolic potential (P1) and presystolic potential (P2) during tachycardia. This study included four patients who had undergone electrophysiological study (EPS) and pediatric patients with verapamil-sensitive LPF-VT who had undergone RFA using high-density three-dimensional (3D) mapping. The included patients were 11-14 years old. During EPS, right bundle branch block and superior configuration VT were induced in all patients. VT mapping was performed via the transseptal approach. P1 and P2 during VT were recorded in three of the four patients. All patients initially underwent RFA via the transseptal approach. In three patients, P1 during VT was targeted, and VT was terminated. The lesion size indices in which VT was terminated were 4.6, 4.6, and 4.7. For one patient whose P1 could not be recorded, linear ablation was performed perpendicularly in the area where P2 was recorded during VT. Among the three patients in whom VT was terminated, linear ablation was performed in two to eliminate the ventricular echo beats. In all patients, VT became uninducible in the acute phase and had not recurred 8-24 months after RFA. High-density 3D mapping with an HD Grid Mapping Catheter allows recording of P1 and P2 during VT and may improve the success rate of RFA in pediatric patients with verapamil-sensitive LPF-VT.

Relationship between Lesion Parameters after Radiofrequency Catheter Ablation in Striated Muscles and Parenchymal Tissue.

Background and Objectives: Radiofrequency catheter ablation (RFCA) is a highly successful intervention. By comparing the lesion changes in prostate parenchymal and striated muscle tissues after RFCA with and without cooling, it was possible to assess the correlation between the shape regularity, area, and perimeter of the thermal lesion, and to predict the geometric shape changes of the lesions. Materials and Methods: A standard prostate and striated muscle RFCA procedure was performed on 13 non-purebred dogs in two sessions: no cooling and cooling with 0.1% NaCl solution. Microtome-cut 2-3 µm sections of tissue samples were stained with haematoxylin and eosin and further examined. The quotient formula was employed to evaluate the geometric shape of the damage zones at the ablation site. Results: The extent of injury following RFCA in striated muscle tissue was comparable to that in prostate parenchymal tissue. Regression analysis indicated a strong and positive relationship between area and perimeter in all experimental groups. In the experimental groups of parenchymal tissues with and without cooling, an increase in the area or perimeter of the damage zone corresponded to an increase in the quotient value. A similar tendency was observed in the striated muscle group with cooling. However, in the striated muscle group without cooling, an increase in lesion area or perimeter lowered the quotient value. Standardised regression coefficients demonstrated that in the striated muscle with cooling, the damage zone shape was more determined by area than perimeter. However, in the parenchymal tissue, the perimeter had a more substantial impact on the damage zone shape than the area. Conclusions: The damage area and perimeter have predictive power on the overall shape regularity of damage zone geometry in both striated muscles and parenchymal tissue. This approach is employed to achieve a balance between the need for tumour eradication and the minimisation of ablation-induced complications to healthy tissue.

Premature ventricular contraction arising from the left coronary sinus cusp: Which signal is the target of ablation?

We described a premature ventricular contraction arising from the left coronary sinus cusp, in which we discussed about the interpretations of the signals recorded there. Our case provided further insights into the interpretation of signals recorded at the coronary sinus cusp during premature ventricular contraction ablation.

Effects of radiofrequency catheter ablation for premature ventricular complexes originating from the right ventricular outflow tract on right ventricular function.

INTRODUCTION: This study aimed to elucidate the relationship between premature ventricular complexes (PVCs) and right ventricular (RV) dysfunction, and the effects of radiofrequency catheter ablation (RFCA) on RV function. METHODS: A total of 110 patients (age, 50.8 ± 14.4 years; 30 men) without structural heart disease who had undergone RFCA for RV outflow tract (RVOT) PVCs were retrospectively included. RV function was assessed using fractional area change (FAC) and global longitudinal strain (GLS) before and after RFCA. Clinical data were compared between the RV dysfunction (n = 63) and preserved RV function (n = 47) groups. The relationship between PVC burden and RV function was analyzed. Change in RV function before and after RFCA was compared between patients with successful and failed RFCA. RESULTS: PVC burden was significantly higher in the RV dysfunction group than in the preserved RV function group (p < .001). FAC and GLS were significantly worse in proportion to PVC burden (p < .001 and p < .001, respectively). The risk factor associated with RV dysfunction was PVC burden [odds ratio (95% confidence interval), 1.092 (1.052-1.134); p < .001]. Improvement in FAC (13.0 ± 8.7% and -2.5 ± 5.6%, respectively; p < .001) and GLS (-6.8 ± 5.7% and 2.1 ± 4.2%, respectively; p < .001) was significant in the patients with successful RFCA, compared to the patients in whom RFCA failed. CONCLUSIONS: Frequent RVOT PVCs are associated with RV dysfunction. RV dysfunction is reversible by successful RFCA.

Catheter ablation of atrial fibrillation with a multi-electrode radiofrequency balloon; first and early two centre experience in Europe.

INTRODUCTION: The Heliostar™ ablation system is a novel RF balloon ablation technology with an integrated three-dimensional mapping system. Here, we describe our early experience and procedural outcomes using this technology for atrial fibrillation catheter ablation. METHODS: We sought to comprehensively assess the first 60 consecutive patients undergoing pulmonary vein isolation using the novel HELISOTAR™ RF balloon technology including procedural outcomes. A comparison of the workflow between two different anaesthetic modalities (conscious sedation [CS] vs. general anaesthesia [GA]) was made. Procedural data were collected prospectively from two high-volume centers (Barts Heart Centre, UK and University Hospital of Zurich, Zurich). A standardized approach for catheter ablation was employed. RESULTS: A total of 35 patients had the procedure under CS and the remaining under GA. Mean procedural and fluoroscopy times were 84 ± 33 min and 1.1 min. The median duration of RF energy application was 7 (5-9.8) mins per patient. All veins were successfully isolated, and the median isolation time was 10 (7-15) seconds. Our cohort's rate of procedural complications was low, with no mortality within 30 days postprocedure. CONCLUSION: Our early experience shows that catheter ablation using the Heliostar™ technology can be performed efficiently and safely; however, long-term data is yet to be established. Low fluoroscopy requirements, short learning curves and use of this technology with CS is possible, including the use of an oesophageal temperature probe.

Effects of different ablation settings on lesion dimensions in an ex vivo swine heart model: Baseline impedance, irrigant, and electrode configuration.

INTRODUCTION: Intramural or epicardial locations of the arrhythmogenic substrate are regarded as one of the main reasons for radiofrequency (RF) catheter ablation failure. This study aims to conduct a comprehensive analysis of various factors including baseline impedance, irrigant and electrode configuration at similar ablation index (AI) value. METHODS: In 12 ex vivo swine hearts, RF ablation was performed at a target AI value of 500 and a multistep impedance load (100-180 Ω) in 4 settings: (1) conventional unipolar configuration with an irrigant of normal saline (NS); (2) conventional unipolar configuration with an irrigant of half normal saline (HNS); (3) bipolar configuration with an irrigant of NS; (4) sequential unipolar configuration with an irrigant of NS. The relationships between lesion dimensions and above factors were examined. RESULTS: Baseline impedance had a strong negative linear correlation with lesion dimensions at a certain AI. The correlation coefficient between baseline impedance and depth, width, and volume were R = -0.890, R = -0.755 and R = -0.813, respectively (p < .01). There were 10 (total: 10/100, 10%; bipolar: 10/25, 40%) transmural lesions during the whole procedure. Bipolar ablation resulted in significantly deeper lesion than other electrode configurations. Other comparisons in our experiment did not achieve statistical significance. CONCLUSION: There is a strong negative linear correlation between baseline impedance and lesion dimensions at a certain AI value. Baseline impedance has an influence on the overall lesion dimensions among irrigated fluid and ablation configurations. Over a threshold impedance of 150 Ω, the predictive accuracy of AI can be compromised.

Combining conventional technique with fluoroscopy integration module in accessory pathway ablation.

INTRODUCTION: Accessory pathway (AP) ablation is a straightforward approach with high success rates, but the fluoroscopy time (FT) is significantly longer in conventional technique. Electroanatomical mapping systems (EMS), reduce the FT, but anatomical and activation mapping may prolong the procedure time (PT). The fluoroscopy integration module (FIM) uses prerecorded fluoroscopy images and allows ablation similar to conventional technique without creating an anatomical map. In this study, we investigated the effects of combining the FIM with traditional technique on PT, success, and radiation exposure. METHODS: A total of 131 patients who had undergone AP ablation were included in our study. In 37 patients, right and left anterior oblique (RAO-LAO) images were acquired after catheter placement and integrated with the FIM. The ablation procedure was then similar to the conventional technique, but without the use of fluoroscopy. For the purpose of acceleration, anatomical and activation maps have not been created. Contact-force catheters were not used. 94 patients underwent conventional ablation using fluoroscopy only. RESULTS: FIM into AP ablation procedures led to a significant reduction in radiation exposure, lowering FT from 7.4 to 2.8 min (p < .001) and dose-area product from 12.47 to 5.8 µGym² (p < .001). While the FIM group experienced a reasonable longer PT (69 vs. 50 min p < .001). FIM reduces FT regardless of operator experience and location of APs CONCLUSION: Combining FIM integration with conventional AP ablation offers reduced radiation exposure without compromising success rates and complication.

Recurrences of ventricular tachycardia after stereotactic arrhythmia radioablation arise outside the treated volume: analysis of the Swiss cohort.

AIMS: Stereotactic arrhythmia radioablation (STAR) has been recently introduced for the management of therapy-refractory ventricular tachycardia (VT). VT recurrences have been reported after STAR but the mechanisms remain largely unknown. We analysed recurrences in our patients after STAR. METHODS AND RESULTS: From 09.2017 to 01.2020, 20 patients (68 ± 8 y, LVEF 37 ± 15%) suffering from refractory VT were enrolled, 16/20 with a history of at least one electrical storm. Before STAR, an invasive electroanatomical mapping (Carto3) of the VT substrate was performed. A mean dose of 23 ± 2 Gy was delivered to the planning target volume (PTV). The median ablation volume was 26 mL (range 14-115) and involved the interventricular septum in 75% of patients. During the first 6 months after STAR, VT burden decreased by 92% (median value, from 108 to 10 VT/semester). After a median follow-up of 25 months, 12/20 (60%) developed a recurrence and underwent a redo ablation. VT recurrence was located in the proximity of the treated substrate in nine cases, remote from the PTV in three cases and involved a larger substrate over ≥3 LV segments in two cases. No recurrences occurred inside the PTV. Voltage measurements showed a significant decrease in both bipolar and unipolar signal amplitude after STAR. CONCLUSION: STAR is a new tool available for the treatment of VT, allowing for a significant reduction of VT burden. VT recurrences are common during follow-up, but no recurrences were observed inside the PTV. Local efficacy was supported by a significant decrease in both bipolar and unipolar signal amplitude.