Ablation Time Research Articles

Comparative study of the therapeutic effects of radiofrequency ablation of ganglionated plexi guided by high-frequency stimulation and anatomical localization methods in the treatment of vagal syncope in young people.

To investigate the differences in safety and efficacy between high-frequency stimulation (HFS) and anatomically guided endocardial catheter ablation (AA) of the ganglionated plexi (GPs) for treating vasovagal syncope (VVS) in individuals engaged in high-intensity physical training. Forty-five patients (age 22.5 ± 4.4 years) undergoing high-intensity physical training were included from January 2020 to January 2023 at our hospital. Patients underwent GP ablation for recurrent syncope. Comprehensive evaluations, including head MRI, cardiac ultrasound, electrocardiogram (ECG), ambulatory ECG (Holter), ambulatory blood pressure monitoring, plate motion tests, and head-up tilt tests (HUT), were conducted to exclude other systemic disorders causing syncope. HFS and AA-guided GP ablation were performed on 10 and 35 patients, respectively, all of whom tested positive for HUT. Differences between the two groups were compared regarding ablation sites, ablation time, safety, and effectiveness. The ablation time was significantly shorter in the AA group compared to the HFS group (P < 0.001). The number of GPs selected for ablation using the AA method was reduced (P < 0.001). All patients in the HFS group experienced palpitations and discomfort, whereas only 31.43% of patients in the AA group reported these symptoms (P = 0.001). Fentanyl analgesia was administered in both groups, and no significant complications arose from the ablation. The longest follow-up duration was 52 months, while the shortest was 15 months. One case of pre-syncope occurred in the HFS group 8 months post-ablation, and one case of pre-syncope and two cases of syncope occurred in the AA group at 1 and 3 months post-ablation, respectively. There were no statistically significant differences in heart rate variability (HRV) and cardiac deceleration capacity (DC) between the two groups after ablation (P > 0.05). Two cases in the AA group still exhibited type II second-degree atrioventricular block during sleep. Both groups of patients were able to complete high-intensity physical training and showed significant symptom improvement post-ablation. Young individuals with VVS engaged in high-intensity physical training can benefit from GP ablation using both HFS and AA methods. The AA method requires relatively simple equipment, shorter procedure time, and results in less discomfort during the ablation.

Abstract 4136869: Time Course and Predictors of PVC Recurrence After Acutely Successful Catheter Ablation

Introduction: In prior studies, predictors of long-term success following acutely successful radiofrequency (RF) ablation have included female-sex, single-PVC morphology and EGM-QRS &gt; 24ms. Time course and predictors of PVC recurrence following acutely successful ablation has been less well documented. Use of extended ambulatory monitoring in the immediate post-procedural period can help to identify those with early recurrence. Goals: To define time to recurrence and predictors of recurrence of PVCs after RF ablation following acutely successful ablation. Methods: Consecutive patients from January 1 st , 2016 through December 31 st , 2023 undergoing PVC ablation with available post-ablation extended ambulatory monitoring (Zio, iRhythm, San Francisco, CA) were retrospectively analyzed. Recurrence was defined as an increase in PVC burden to &gt;5% during monitoring after acute success or failure to have sustained reduction in PVC burden of &gt;80%. Acute success was defined as elimination of the targeted PVC after the last ablation lesion. Long-term succes was defined as absence of targeted PVC's during all follow-up visits and PVC-burden &lt; 5% on follow-up monitoring. Results: Among 121 patients who underwent successful PVC ablation, 101 (83.4%) had long-term success and 20 (17%) had recurrence. Patients with recurrence were older (62.4 ± 12 vs 55 ± 13., p = 0.019), had a higher incidence of CAD (13 (13%) vs 9 (45%), p = 0.001) and CHF (40 (40%) vs 15 (75%), p = 0.004). At time of ablation, the recurrence group was also more likely to have &gt;1 PVC morphology (6 (6%) vs 8 (40%), p = &lt;0.001). Location and earliest activation time of the predominant PVC were not assocated with likelihood of recurrence. Within the recurrence group, 13 (65%) had recurrence in the immediate 2 week post-procedural period with an average time to recurrence of 3.9 days. Conclusion: Recurrence occured in slightly less than 20% of cases with a relatively high proportion of those occuring within the immediate 2 week post-procedural period during extended ambulatory monitoring. The presence of greater than 1 PVC morphology at time of ablation is a risk factor for recurrence suggesting a higher likelihood of acute suppression without durable resolution in those instances.

Abstract 4135194: Safety and Efficacy of Mechanical Circulatory Support during VT ablation

Introduction: Ventricular arrythmias are prevalent in patients with advanced heart failure and associated with increased mortality. Outcomes of electrophysiology ablation on patients requiring mechanical circulatory support (MCS) are not well described. We aimed to analyze the safety and efficacy of ventricular tachycardia (VT) ablation in patients requiring MCS at the Emory system. Methods: Patients were identified via retrospective chart review from October 2022 through August 2023. Patients who underwent VT ablation with the support of Impella, left ventricular assist device (LVAD), intra-aortic balloon pump (IABP), and venoarterial extra-corpeal membrane oxygenation (VA ECMO), or any combination of these were included. Results: A total of 7 patients of average age 56 ± 10 years, predominantly male (85.7%), with cardiomyopathy of mean EF 18.6% +/- 8.5 (ischemic 71.4%) underwent MCS supported VT ablation. One patient had 2 separate VT ablation procedures for refractory VT. Of these 8 procedures, 4 utilized a single type of MCS (2 impella, 2 LVAD) while 4 used a second type of MCS in combination with an Impella (2 impella RP, 1 VA ECMO, 1 IABP). Success at time of ablation was present in 75% of cases. Average time of outpatient follow up was 82 ± 31 days. At time of follow up, 50% of patients remained free of VT or with a single VT episode not requiring implantable cardioverter-defibrillator (ICD) shock. One patient had gone on to undergo successful heart transplantation. Procedural complications were noted in one patient, who suffered cardioembolic cerebrovascular accident (CVA) 2 days post-op. Transthoracic echo (TTE) 5 days post-op revealed LV mural thrombus as likely etiology of CVA. Conclusion: While there are no clear guidelines directing the use of MCS during VT ablation, our single academic institution experience suggests safety and feasibility of its use to support select, high risk cases.

Abstract 4136452: Acute Cardiac Function Change After Catheter Ablation of Ventricular Arrhythmias in Patients with Arrhythmogenic Right Ventricular Cardiomyopathy

Introduction: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disorder characterized by fibrofatty replacement of myocardial tissue, creating areas of electrical heterogeneity and increasing the risk of ventricular arrhythmias (VAs) and sudden cardiac death (SCD). Catheter ablation is commonly performed in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) for management of ventricular arrhythmias (VAs). Whether catheter ablation affects cardiac function post-procedurally is uncertain. Research Question: Does catheter ablation for ARVC result in acute change in cardiac function? Goals/Aims: To assess the impact of catheter ablation for VAs on cardiac function in the acute post-procedure setting. Methods: This retrospective study included patients with ARVC who underwent catheter ablation for VAs at Mayo Clinic. Cardiac function was assessed on pre- and post-procedure transthoracic echocardiograms (TTEs). Post-procedure TTEs were obtained within 4 weeks after the ablation procedure. Right ventricular (RV) enlargement and systolic dysfunction were evaluated as continuous variables (0=none, 1=mild, 2=mild-moderate, 3=moderate, 4=moderate-severe, 5=severe). Results: The study included 32 patients who underwent a total of 44 ablations. Mean age at the time of ablation was 49±16 years, and 24 (75%) were male. After a mean follow-up duration of 2.6±5.5 days, there was a significant worsening in mean RV dysfunction (1.6±1.5 to 2.0±1.4, P = 0.001). There were no significant changes in mean left ventricular ejection fraction (LVEF), left ventricular (LV) dimensions, and RV size. 6 (14%) patients had a &gt;5% decline in LVEF, and 14 (32%) patients had worsening RV function. Transient inotropic support was required in 4 (9%) patients. Conclusion(s): This study is the first to assess the acute impact of catheter ablation for VAs on cardiac function in ARVC patients. These results underscore the importance of careful post-procedure monitoring and planning of the ablation target in these patients to avoid excessive ablation and therefore impairment in cardiac function.

Percutaneous microwave ablation of HCC: comparison between 100 and 150W technology systems.

To evaluate the differences in efficacy and safety between the 100 and 150W percutaneous microwave ablation (MWA) systems in the treatment of hepatocellular carcinoma (HCC). We retrospectively reviewed all patients who underwent percutaneous MWA (Emprint™ HP Ablation System, Medtronic) between January 2021 and May 2023. We divided the cohort into two groups: Group 1, treated with MWA at 100 W power system, and Group 2, treated with 150 W one. Effectiveness was defined as the absence of residual disease at 1-month CT follow-up; safety was defined as the absence of grade II-VI complications. A total of 135 HCC nodules were treated with MWA in 87 patients with a median age of 66 ± 10years: 76 procedures in 42 patients were carried out in group 1, while 59 procedures in 45 patients in group 2. Cases treated with 150 W had a shorter ablation time (p: 0.002; mean 227.37 ± 92.5 vs 180.51 ± 75.6s (100 vs 150W)) and a larger ablation volume (p 0.008; mean 13,920.0 ± 10,723.2 vs 21,241.4 ± 18,374.7 mm3 (100 vs 150W)), and a major effectiveness at 1-month CT follow-up (p: 0.013). A higher rate of complications (grade II and III) was observed in Group 2 (p < 0.001). In conclusion, these preliminary results showed a good correlation between intended-to-treat area and ablation volume and intended-to-treat area and ablation time for both Groups. A minor ablation time, and major ablation volume, but also a higher incidence of complications was observed in 150 W Group.

Radiofrequency balloon ablation: 1-year outcomes of the AURORA study.

A novel irrigated radiofrequency balloon (RFB) for pulmonary vein isolation (PVI) integrated into a 3D mapping platform was recently launched. Patients undergoing a first atrial fibrillation (AF) ablation at two German high-volume EP centers were included into the prospective AURORA registry. All patients underwent clinical follow-up (FU) at 90, 180, and 360days following ablation including 48-h Holter ECGs. A total of 99 patients were enrolled (43/99 (43.4%) women, median age 67years (interquartile range [IQR] 59-74), 43/99 (43.4%) persistent AF (Pers-AF), median left ventricular ejection fraction (LVEF) 60% (IQR 62-55)). Eighty-eight patients completed the follow-up. Acute PVI was achieved in 383/383 (100%) PV. Single-shot PVI was achieved in 211/383 (55.1%) PVs. Primary adverse events occurred in 3% of patients (1 postprocedural pharyngeal bleeding, 1 myocardial infarction, 1 non-cardiovascular death); no pericardial effusion, stroke, or phrenic nerve paralysis was observed. Median ablation and procedure times were 23 (IQR 18-32) and 67 (IQR 57-85) min, respectively. Median dose area product was 761 (IQR 509-1534) mGycm2. AF-free survival after a median FU of 361 (IQR 261-375) days was 78.4% for paroxysmal AF (PAF) and 75.4% for Pers-AF (p value = 0.828). Early recurrence of atrial tachyarrhythmia at the 90-day visit was the only independent predictor for AF recurrence at 1year upon multiple regression analysis (hazard ratio [HR] 3.198; 95% confidence interval [95% CI] 1.036-10.32, p value = 0.0433). RFB-based PVI is acutely successful, appears safe, and has comparable rhythm outcomes to other single-shot AF ablation tools. A recurrence of AF at 90days predicts later AF recurrence.

Significance of the local largest bipolar voltage for the optimized ablation strategy using very high-power short duration mode.

Very high-power short-duration (vHPSD) ablation creates shallower lesions, potentially reducing efficacy. This study aims to identify factors leading to insufficient lesions during pulmonary vein antral isolation (PVAI) with vHPSD-ablation and to develop an optimized PVAI strategy using this technology. PVAI was performed on 41 atrial fibrillation patients using vHPSD-ablation (90 W/4 s). Lesion parameters were recorded and analyzed to identify predictors of insufficient lesions. An optimized PVAI strategy, based on these predictors, was tested in subsequent 42 patients. In total, 3099 RF-applications, including 103(3.3%) insufficient lesions, were analyzed. First-pass PVAI was achieved in 19/40(47.5%) right PVs and 24/41(58.5%) left PVs. Multivariate analysis identified significant predictors of insufficient lesions: local largest bipolar voltage (Bi-V), average contact force, baseline impedance, impedance drop, temperature rise, inter-lesion distance (ILD), and anatomical location (carina or not). An ILD:4-6 mm increased the risk of insufficient lesions 2.2-fold, and lesions at the carina increased it 3.6-fold for both ILD < 4 mm and ILD:4-6 mm. Local largest Bi-V was the strongest predictor for insufficient lesions. The optimized PVAI approach, utilizing vHPSD-ablation with an ILD < 4 mm in non-carinal areas with Bi-V < 4 mV, and high-power ablation-index guided ablation (HPAI, 50 W, ablation-index:450-550) in remaining areas, achieved first-pass PVAI in 92.7% of right PVs and 88.1% of left PVs, using vHPSD-ablation in approximately 65% of total RF-applications. The optimized PVAI achieved significantly higher first-pass PVI rate (p < .0001) with shorter ablation time (p = .04). Appropriate use of vHPSD and HPAI, based on local largest Bi-V and anatomical information, may achieve high first-pass PVAI rates in shorter ablation time with minimal energy delivery.

Optical absorption studies of pulsed-laser-engineered silver nanospheres and their enhanced catalytic performance in the degradation of toxic methylene blue dye

Pulsed laser ablation in liquid is an environment-friendly and one of the fastest physical routes to synthesize surfactant-free and stable metal/metal oxide nanoparticles with high purity and no harmful residues. In this study, we report the synthesis of silver nanospheres (AgNSs) using the nanosecond pulsed laser ablation in liquid (PLAL) technique resulting in the formation of a colloidal solution. Investigation of the optical properties using UV–Vis spectroscopy revealed the effects of laser wavelength, frequency, fluence, ablation time, and re-irradiation on the light absorption of the produced silver nanospheres. Physicochemical characterizations included FE-SEM, XRD, DLS, FTIR, and XPS techniques to evaluate the size, morphology, crystal structure, size distribution, zeta potential, and surface chemistry. FE-SEM studies revealed the formation of well-dispersed spherical Ag nanospheres with an average particle size of 209 nm without any agglomeration. DLS measurements showed high stability with a recorded zeta potential value of −38.27 (+/−1.81) mV and a wider size distribution. The XRD analysis indicated a face-centered cubic crystal structure with the formation of an oxide layer over the metallic silver core. The presence of silver and oxygen was confirmed through XPS studies with binding energies at 368.1 eV and 374.1 eV and oxide formation on the surface of Ag NSs. Finally, the catalytic activity of the Ag colloid was examined for the degradation of the toxic methylene blue dye. The results revealed an excellent catalytic response with 90 % of the dye degraded in just 15 min of reaction time. The kinetics of the degradation process were studied with a rate constant of 0.054/min−1 showcasing the effectiveness of the pulsed laser-synthesized silver colloidal nanomaterial as a sustainable approach for environmental remediation.

A test on fire-induced damage of concrete with multiple parameters analysis—Based on tunnel linings of China

Fires in highway tunnels will have a significant impact on the structural performance of lining materials. A ablation test was conducted on 288 concrete specimens (1500 ×1500 ×1500 mm) with four commonly used grades of C20, C25, C30, and C35 at temperature levels of 300 ℃, 600 ℃, 750 ℃, and 900 ℃ for constant periods of 1 h, 2 h, and 4 h. The experiment revealed that: (1) From low to high temperatures, the specimens experienced cracking, spalling, explosion and eventually complete collapse; all grades of concrete remained intact or mostly intact at 600 ℃ but suffered varying degrees of damage above 750 ℃. (2) At the same fire temperature, the damage rate increased linearly with longer ablation time; while at the same ablation time, the damage rate increased quadratically with higher fire temperature. (3) The ultrasonic wave velocity ratio decreased exponentially as the ablation time increased; higher fire temperatures resulted in lower wave velocity ratios within the same ablation time period and there was a turning point at a two-hour ablation time where specimen integrity was lost. (4) For concrete specimens of the same grade and under identical exposure times to fire, as the fire temperature increased,the rate of compressive strength reduction accelerated significantly; sudden drops in compressive strength occurred at temperatures of 600 °C，750 °C，and900°C,and there was a turning point for compressive strength reduction loss after one hour's ablation to fire.(5) When subjected to high ablation temperatures,the decrease rate in concrete strength exceeded that in wave velocity,and changes in strength were more sensitive than changes in wave velocity.

Comparative efficacy of microwave ablation and radiofrequency ablation for treating metastatic liver cancer: a systematic review and meta-analysis.

This study aims at evaluating and juxtaposing the efficacy of radiofrequency ablation (RFA) and microwave ablation (MWA) for hepatic metastases treatment. We undertook an extensive literature search across the Cochrane Library, Web of Science, Embase, PubMed, CNKI, and databases for studies published up to December 2023, assessing the outcomes of RFA versus MWA in hepatic metastases treatment. Studies were included or excluded based on established criteria. Continuous variables were analyzed with the aid of the weighted mean difference (WMD) and its 95% confidence interval (CI), while the odds ratio (OR) with its 95% CI was utilized for dichotomous variables. Data were processed by use of STATA 17.0 software. Key outcomes assessed included ablation time, post-operative local tumor progression (LTP), disease-free survival (DFS), and post-operative complications (POCs). Seven studies, comprising 357 patients undergoing MWA and 452 patients undergoing RFA, fulfilled the inclusion criteria. As unveiled by the meta-analysis, RFA and MWA did not significantly differ in ablation time, DFS, and POCs. Nonetheless, MWA resulted in a strikingly reduced rate of post-operative LTP versus RFA. MWA offers superior control over post-operative LTP, suggesting better overall efficacy in hepatic metastases treatment compared with RFA. https://www.crd.york.ac.uk/prospero/, identifier CRD42023385201.

Impact of the underlying rhythm during cavotricuspid isthmus ablation on the incidence of future new-onset atrial fibrillation: insights from an international multi-centre registry

Abstract Background Radiofrequency catheter ablation of the cavotricuspid isthmus (RF-CTI) is the estabslished treatment of typical atrial flutter (AFL). After RF-CTI for AFL patients without previously documented atrial fibrillation (AF) may also develop AF. It is unknown whether the presence or absence of AFL at the time of ablation can predict the future occurence of AF. Purpose To compare baseline characteristics, procedural data, and long-term follow-up (FU) of patients with AFL. Methods Consecutive patients with documented AFL undergoing RF-CTI were enrolled in a multi-center registry in five centers in two countries between February 2017 and July 2023. For patients with AFL, entrainment mapping was performed for confirming CTI dependent AFL. Patients were categorized into two groups, those with AFL and those with sinus rhythm (SR) during RF-CTI. FU data were collected, including clinical assessments, 12-lead electrocardiogram (ECG) and 24-hour Holter-ECGs during each visit. Results Of the 949 subjects, 36% were excluded from the analysis due to a history of AF. A total of 574 patients were included (mean age 68 +/- 11 yrs, 14% females), 62% presented in AFL group and 38 % SR group during CTI. Median FU was 364 days. Patients in AFL group were older (P &amp;lt; 0.029), more likely to have diabetes (P = 0.026), and were less frequently treated with antiarrhythmic drugs (P &amp;lt; 0.001). In the first 12 months of FU, 40% of the patients underwent three FU examinations, while 77% of the patients underwent at least one 24-hour Holter-ECGs during FU. In the Kaplan-Meier analysis patients in AFL group significantly less often developed AF during FU (log-rank, P &amp;lt; 0.016, central ). In the multivariate Cox regression analysis, sinus rhythm during ablation (hazard ratio 1.474; 95% CI 1.043-2.084; P = 0.028), male gender (hazard ratio 1.722; 95% CI 1.116-2.658; P = 0.014) and coronary artery disease (hazard ratio 1.711; 95% CI 1.145-2.555; P = 0.009) were identified as predictors for the occurence of AF during FU. Conclusion Over a one year follow-up, new onset AF occurs significantly less frequently in patients with ongoing atrial flutter during RF-CTI ablation.

A multi-center retrospective cohort analysis of age and racial disparities in patients undergoing repeat ablation for recurrent atrial fibrillation

Abstract Introduction Atrial fibrillation (AF) is the most common type of cardiac arrhythmia, and its prevalence has been increasing worldwide. Current data shows that AF is more common in white males compared to blacks despite blacks having multiple cardiovascular comorbidities. There is paucity of data showing the recurrence of AF re-ablation after index ablation specifically as it pertains to race, gender, and age. We sought to explore the rates of recurrent AF re-ablation in this retrospective cohort analysis. Methods Using a multi-center database, we examined 23,558 encounters and 10,530 had readmission records i.e. readmitted within 3 years. The encounters included adults (18+) who had an ablation procedure for atrial fibrillation between 1/1/2018-06/30/2020. We used binary logistic regression models and Tukey-Kramer procedure to analyze pairwise comparisons among different subgroups of race, sex, and age group. The primary endpoint was recurrence of repeat ablation. Secondary endpoints included non-fatal stroke and myocardial infarction. Results Our sample size was 23,558 patients, 20,276 were white patients (86%) and 3,282 were non-white patients (14%). The average age was 66.29 years (SD 10.43) and average age at the time of repeat ablation was 65.97 years. The average BMI was 21.55. Out of the 23,558 patients, 14.30% (N= 3368) had re-ablation within 3 years of the index ablation. The odds ratio of re-ablation for patients in their 50s is 1.4229 (95% CI [1.1172, 1.8122]) compared to patients in their 80s. Similarly, the odds ratio is 1.4330 (95% CI [1.1466, 1.7909]) for the 60-69 group, 1.3075 (95%CI [1.0458, 1.6346]) for the 70-79 group and 1.3443 (95% CI [1.0088, 1.7914]) for patients below 50 compared to over 80 group. The LR for re-ablation was 0.8438 (p=0.3583) in females. The incidence of non-fatal stroke and MI were 0.27% (N= 63) and 0.19% (N= 45). Average length of time to re-ablation was 415.5 days. Discussion When controlling for age group and sex, race was not significantly associated with an increased likelihood of repeat ablation. When controlling for race and age group, sex was not significantly associated with an increased likelihood of repeat ablation. When controlling for race only, females were not at a higher risk of re-ablation. However, when controlling for race and sex, patients in their 50s are 42.3% more likely to have re-ablation when compared to patients in their 80s. In contrast, the age of patients at their first ablation increased, there appeared to be a rising trend indicating a higher chance of AF recurrence within 3 years when controlling for race and sex. Conclusion The incidence of repeat AF ablation is not higher in racial minorities when compared to whites. Interestingly, there appears to be an decreasing rate of AF re-ablation in older patients despite a higher rate of AF recurrence as age increases possibly owing to more conservative therapeutic approach such as medical management.

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.

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 &amp;lt; 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 &amp;lt; 0.0001), Kansas City Cardiomyopathy Questionnaire scores (from 59.00 [44.50] to 80.00 [77.25]; p &amp;lt; 0.02), 6-minute walk distance (from 441 [400] m to 480 [465] m; p &amp;lt; 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

Accuracy of a non-invasive mapping system for the localisation of re-entrant VT site of origin and its relationship to myocardial scar on cross-sectional imaging

Abstract Introduction View in ventricular onset (VIVO) is a non-invasive mapping system used for localising the site of earliest activation in ventricular arrhythmia, utilising a mathematical algorithm, patient specific cardiac model (constructed using cross-sectional imaging data), 3D images of the patient’s torso (for localising surface electrodes), and a 12-lead electrocardiogram (ECG).(1, 2) Several publications have examined its role in the localisation of premature ventricular contractions (PVCs), and a 5 patient case series assessed its role in scar related re-entrant VT.(1-4) However, its validity in a larger cohort and of the relationship to the relevant myocardial scar has not been investigated. Objective Assess the accuracy of the VIVO mapping system in localising the VT-SoO for patients with scar related re-entrant VT and its relationship to the relevant myocardial scar on cross-sectional imaging. Methods 20 patients with structural heart disease (18 ischaemic cardiomyopathy (ICM), 1 dilated cardiomyopathy (DCM), 1 hypertrophic cardiomyopathy (HCM)) (Male n=18, 63±14 years) and recent cross-sectional cardiac imaging, were recruited over a 16-month period (table 1). All patients had a clinical indication for VT ablation and were on optimal medical therapy, 19 had an implantable cardiac defibrillator. Invasive electro-anatomical mapping (EAM) was performed with the Advisor HD Grid multipolar catheter and maps were generated using Omnipolar electrograms (EGMs). The VT-SoO was identified using an activation- or pace-map by an experienced operator and the location defined using the American heart association’s 17 segment model of the left ventricle during the procedure.(5) VIVO maps were reviewed by a second independent operator and a segment allocated, scar segments were obtained from cross-sectional imaging. A "complete match" was defined as exact segment concordance between allocated segments, "partial match" as adjacent segments, and "no match" if it does not satisfy either of those requirements. Results Mean left ventricular ejection fraction was 35.5 ± 10.6%. Mean procedure time was 242 ± 70 minutes, with a mean ablation time of 20 ± 11.1 minutes. A total of 32 re-entrant VTs were mapped. The VT exit site was identified in all cases (11 activation-map; 21 pace-map). A complete match between the EAM and VIVO map was seen in 75% of VTs and partial match in a further 15% (table 2). The VT-SoO was located withing the myocardial scar (or directly adjacent to is) in 83% of accurately mapped VTs. Procedural success (defined as freedom from device treated episodes) was seen in 90% of patients at mean follow up of 7.3 ± 4.7 months. Conclusion VIVO non-invasive mapping system was able to accurately map the VT-SoO in scar dependent VT, and identify the relevant myocardial scar as seen on cross sectional imaging. Further research assessing its ability to accurately identify relevant ablation targets is ongoing.

Collision mapping enables accurate localization of the slow pathway in atrioventricular nodal reentrant tachycardia

Abstract Introduction Atrioventricular Node Reentry Tachycardia (AVNRT) is commonly treated with catheter ablation, with high success and low complication rates. However a small risk of complete AV block still remains. Recent studies could show that using collision map is a feasible approach in mapping the slow pathway. The aim of the current study is to show a reduction of the total ablation points needed to modify/ablate the slow pathway using the collision mapping compared to conventional 3D mapping guided slow pathway modulation/ablation and therefore minimize the risk of a complete heart block. Methods Patients diagnosed with AVNRT (n = 24) underwent collision mapping for slow pathway identification, compared to a historical cohort (n=76) using conventional mapping. For collision mapping a dynamic visualization of atrial propagation during sinus rhythm was condcted. Two propagation fronts were observed to collide at the triangle of Koch, one propagation through the slow and one through the fast pathway. The designated collision zone was considered ideal for catheter ablation (Figure 1). The endpoint after ablation in both groups was non-inducibility of AVNRTs. Results After propensity score matching the collision mapping group needed significantly fewer ablation impulses (2 (IQR 1 - 5) vs. 6 (IQR 2,5 - 11,5) p = 0.002) and shorter ablation time (p &amp;lt; 0.001) compared to the conventional group (Table 1). No significant differences were observed in procedure time (p = 0.209), fluoroscopy time (p = 0.296), or dose area product (p = 0.391). Conclusion Collision Mapping in AVNRT ablation showed a notable reduction in ablation points, suggesting enhanced procedural efficiency and safety.Figure 1Table1

Early ablation leads to better outcome in patients < 55 years with persistent atrial fibrillation

The question of optimal timing for catheter ablation of atrial fibrillation (AF) to achieve best outcomes remains a crucial clinical issue. As AF occurs less frequently in younger patients, data regarding Diagnosis-to-Ablation Time (DAT) is especially limited in patients under the age of 55 years with persistent AF. We therefore analyzed the temporal relationship between initial AF presentation and timing of catheter ablation in this cohort. We conducted a retrospective single-centre study of patients ≤ 55 years with persistent AF who underwent first-time catheter ablation at our center. The cohort was divided into patients that underwent catheter ablation after diagnosis of persistent AF within a DAT of ≤ 12 months and patients with a DAT of > 12 months. A total of 101 patients (median age 51 years; female n = 19 (18.8%)) with persistent AF were included. Ablation was performed within 12 months (“early DAT”) in 51 patients and > 12 months (“late DAT”) in 50 patients. Pulmonary vein isolation was performed using high-power short-duration (HPSD) radiofrequency ablation. Median DAT was 5 months (1–12 months) in the early ablation group and 36 months (13–240 months) in the late ablation group. The median follow-up was 11.3 months (0.03–37.1 months). The rate of any atrial arrhythmia recurrence after a 30-day blanking period was significantly lower in the early DAT group (13/51 patients; 25.5%) as compared to the late DAT group (26/50 patients; 52.0%) (log rank test; p = 0.003). Catheter ablation performed > 12 months after the initial AF diagnosis was an independent predictor for the occurrence of any atrial arrythmia (OR: 2.58; (95%-CI: 1.32–5.07). Early first-time catheter ablation (DAT ≤ 12 months) in patients ≤ 55 years with persistent AF is associated with a significantly lower rate of arrhythmia recurrence.

Comparing Low-to-Zero Fluoroscopic Navigation Systems for AVNRT Catheter Ablation: A Network Meta-Analysis.

Low-to-zero fluoroscopic navigation systems lower radiation exposure which improves health outcomes. Conventional x-ray fluoroscopy (CF) has long been the standard to guide to catheter location for cardiac ablation. With advancements in technology, alternative safety navigation systems have been developed. Three primary modalities commonly utilized are three-dimensional electroanatomic mapping (3D-EAM), magnetic navigation system (MNS), and intracardiac echocardiography (ICE), all of which can reduce radiation exposure during the procedure. We aim to compare the efficacy and safety among ICE, EAM, MNS, and CF in ablation of atrioventricular nodal reentrant tachycardia (AVNRT). This is a meta-analysis consisting of observational studies and randomized controlled trials, which evaluated the performance of navigation systems of catheter ablation in AVNRT patients. Primary endpoint was to access the AVNRT recurrence after the procedure during follow-up periods. Secondary endpoints were technical success, fluoroscopic time, fluoroscopic dose area product, radiofrequency ablation time, and adverse events. Random-effect model was applied for pooled estimated effects of included studies. A total of 21 studies (21 CF, 2 ICE, 9 EAM, 11 MNS) including 1716 patients who underwent catheter ablation for AVNRT treatment were analyzed. Of these, 16 were observational studies and 5 were randomized controlled trials. Point estimation of AVNRT recurrence showed ICE exhibited a pooled odds ratio (ORs) of 1.06 (95% confidence interval [CI]: 0.064-17.322), MNS with ORs of 0.51 (95% CI: 0.214-1.219], and EAM with ORs of 0.394 (95% CI: 0.119-1.305) when compared to CF. EAM had significant higher technical success with ORs of 2.781 (95% CI: 1.317-5.872) when compared to CF. Regarding fluoroscopy time, EAM showed the lowest time with mean differences (MD) of -10.348 min (95% CI: -13.385 to -7.3101) and P-score of 0.998. It was followed by MNS with MD of -3.712 min (95% CI: -7.128 to -0.295) and P-score of 0.586, ICE with MD of -1.150 min (95% CI: -6.963 to 4.662) with a P-score of 0.294 compared to CF, which has a P-score of 0.122. There were insignificant adverse events across the procedures. AVNRT ablation navigated by low-to-zero fluoroscopic navigation systems achieves higher efficacy and comparable safety to conventional fluoroscopywhile also reducing risk of radiation exposure time.

Microwave Ablation after VATS in Patients with Multiple Pulmonary Nodules.

The management of residual nodules after video-assisted thoracoscopic surgery (VATS) for multiple pulmonary nodules (MPNs) is challenging. Microwave ablation (MWA), which is highly repeatable and minimally invasive, has garnered widespread attention in the treatment of MPNs. Ninety-one patients with MPNs who underwent VATS for resection of high-risk nodules followed by MWA for residual nodules were examined. Clinical efficacy and complications were assessed. The primary end points were MWA success rate and complete ablation rate. Secondary end points were local progression-free survival (LPFS), overall survival (OS), and complications. MWA was successfully completed in all patients. Mean tumor diameter, ablation time, and ablation output power were 0.81 cm, 3.4 minutes, and 39 W, respectively. LPFS was 100% at 3, 6, 12, and 24 months, respectively. OS was 100% at 12 and 24 months, respectively. No intraoperative or postoperative deaths occurred. Complications with MWA were infrequent. Pneumothorax was most common, occurring in 31 patients (34.07%); among these, seven (7.69%) required closed thoracic drainage. Pleural effusion occurred in six patients (6.59%), hydropneumothorax in five (5.49%), and pneumonia in three (3.30%). The pain level after MWA was moderate-to-severe in 29 patients (31.87%). MWA is safe and feasible for treating residual nodules in patients with MPNs who have undergone VATS. The incidence of complications was low, and most complications were mild.

Invasive management of atrial tachycardias using a novel lattice-tip catheter combining high-density mapping and dual ablation properties: initial real-world experience.

Invasive management of atrial tachycardias(ATs) requires proper diagnosis of the mechanism followed by elimination of the responsible substrate. A novel lattice-tip catheter with both high-density mapping and dual ablation properties(radiofrequency-RF/pulsed field ablation-PFA) has been recently introduced for catheter ablation of atrial fibrillation. We present the first study to assess its performance in the management of ATs (diagnostic and therapeutic). Patients with documented ATs were selected. Activation mapping was used for the establishment of the AT mechanism. Confirmation with entrainment was performed, whenever appropriate. Accuracy of the activation mapping in diagnosis, acute ablation efficacy, and procedural characteristics were the study endpoints. Twenty patients were included (12 cavotricuspid isthmus-dependent atrial flutters, 5 mitral flutters, 2 roof flutters, and 2 focal ATs). Proper diagnosis was established by activation mapping in all cases. The mean mapping time was 7.85 ± 3.06 min with 296.82 ± 150.9 mean mapping points/minute. The mean ablation time was 54.25 ± 42.97 s. Conversion to sinus rhythm during ablation was achieved in all cases with the exception of a roof flutter that converted to mitral flutter and a case of a parahisian AT in which ablation was not attempted. Patients that received ablation did not experience any arrhythmia recurrence in a mean follow up of 4.14 ± 0.91months. No major or minor complications occurred. The lattice-tip catheter and its dedicated electroanatomical mapping system provided sufficiently detailed activation mapping for the diagnosis of the AT mechanism. The delivered lesions were highly effective acutely, with no adverse events. However, limitations exist and should be acknowledged.