Temperature-controlled Radiofrequency Ablation Research Articles

Temperature-controlled Ablation Versus Conventional Ablation for Pulmonary Vein Isolation in the Treatment of AF: A Systematic Review and Meta-Analysis

Background: This study compared the efficacy and safety of temperature-controlled and conventional contact-force-sensing radiofrequency ablation catheters for pulmonary vein isolation (PVI) in AF. Methods: Seven studies (1,138 patients) were included. Randomised controlled trials and observational (single-arm and two-arm) studies that reported freedom from AF ≥3 months after PVI with temperature-controlled radiofrequency ablation catheters (Biosense Webster QDOT MICRO operating in QMODE or Medtronic DiamondTemp) were included. Results: Freedom from AF at a mean (± SD) follow-up of 9.0 ± 3.6 months did not differ significantly between temperature-controlled and conventional ablation (OR 1.22; 95% CI [−0.79, 1.64]; p=0.24). Total procedure duration (−13.5 minutes; 95% CI [−17.1, −10.0 minutes]; p<0.001) and total ablation duration (−8.9 min; 95% CI [−10.3, −7.5 min]; p<0.01) were significantly shorter for temperature-controlled ablation. There were no significant differences between temperature-controlled and conventional ablation in either the aggregated rates of procedural complications (OR 0.69; 95% CI [−0.15, 1.54]; p=0.11) or in the rate of any individual complication. Conclusion: Temperature-controlled ablation was found to be at least non-inferior to conventional ablation in all measures of efficacy and safety. Further randomised controlled trials are warranted to evaluate long-term rates of freedom from AF and patient comfort.

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.

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.

Peri-procedural anesthesia and patient pain experience in pulmonary vein isolation by means of very high-power short-duration radiofrequency ablation.

Very high-power short-duration (vHPSD) temperature-controlled radiofrequency ablation (vHPSD) may reduce ablation times and improve patient tolerability, permitting pulmonary vein (PV) isolation under mild conscious sedation. We evaluated of the anesthetic drugs use and patients' pain experience during vHPSD PV isolation. Fifty-eight patients, with paroxysmal and persistent atrial fibrillation (AF), treated with QDot Micro catheter and vHPSD (90 w for 4s) (vHPSD group), were compared with the last 33 patients treated with a surround flow contact force-sensing catheter guided by the ablation index (450 anteriorly at 50 W, 330 posteriorly at 40 W) (AI group). Anesthetic drugs use was compared as well as pain experience, measured using a 0-10 scale. All PVs were acutely isolated. Procedural time (78 ± 10min vs 84 ± 12min, p = 0.012), fluoroscopy time (369 ± 139s vs 441 ± 172s, p = 0.03), and RF time in the vHPSD group (8.3 ± 2.1min) were shorter than in the AI group (25 ± 11min, p < 0.001). Only 4 patients experienced an access site-related vascular complication (groin hematoma). Midazolam was required in 36 (62%) vHPSD group patients vs 31 (94%) AI group patients (p < 0.001). Fentanyl was required in 4 (7%) vHPSD group patients vs 25 (76%) AI group patients (p < 0.001). No patients required general anesthesia. Twenty-two (38%) vHPSD group patients underwent PV isolation without any anesthetic drug. Pain experience was significantly lower in vHPSD group (4.9 ± 2 vs 6.6 ± 1.8, p < 0.001). vHPSD radiofrequency ablation for PVI can be performed under conscious sedation using only benzodiazepine in most of patients without compromising patient pain experience.

Optimized workflow for pulmonary vein isolation using very high power short duration radiofrequency ablation

Abstract Background Point-by-point radiofrequency ablation is the most used invasive treatment of atrial fibrillation (AF). However, single-shot technologies are largely widespread due to their proved safety and efficacy. QDOT MICRO (QDM) is a novel contact force–sensing catheter optimized for temperature-controlled radiofrequency (RF) ablation that allows to maintain target temperature during 90 W ablations for ≤4 seconds. Purpose This study evaluates procedural safety and effectiveness as well as long-term effects of an optimized procedural workflow using QDM catheter to perform wide atrial circumferential ablation in patients with paroxysmal AF. Methods Consecutive patients referred for paroxysmal AF first ablation through pulmonary vein isolation (PVI) were prospectively enrolled. Every procedure was performed in general anesthesia by using CARTO3 Electroanatomical Mapping System BiosenseWebster QDM catheter and Deflectable Sheet VIZIGO as single sheet in left atrium. VHPSD was performed to encircling the posterior wall, while conventional-power temperature-controlled (CPTC) mode was used to encircling the anterior wall. The primary safety endpoint was incidence of primary adverse events within ≤7 days of ablation. The primary effectiveness endpoint was freedom from documented atrial tachyarrhythmia recurrence and acute procedural, repeat ablation, and antiarrhythmic drug failure. Results 120 enrolled participants (61 ± 12 years, 45% female) met eligibility criteria. Median procedural skin-to-skin time and RF application for ablating PVs were 56 and 17 minutes, respectively. Median ablation time was 22 minutes. First-pass isolation (entrance and exit block validation) was obtained in 98 % and inter-lesion distance was 4,8 ± 0,8 mm. In 100% of patients PVI was obtained without adverse events. The Kaplan-Meier estimated 12-month rate for clinical success (freedom from symptomatic recurrence of AF) was 93%, freedom from AF was 89% Conclusions PVI performed with point by point optimized workflow using VHPSD RF catheter in combination with steerable sheet is highly efficient and effective without compromising safety.

Impact of temperature-controlled endobiliary radiofrequency ablation for inoperable hilar cholangiocarcinoma: A propensity score-matched analysis.

Background and study aims Endobiliary radiofrequency ablation (RFA) can be an effective palliative treatment, but few studies have evaluated its outcomes for malignant obstruction in the hilar bile duct, which has a thin wall and complex duct-vascular contacts. We evaluated the efficacy and safety of temperature-controlled endobiliary RFA, which can reduce the risk of unintentional thermal injury by maintaining the temperature of the ablation segment, in the treatment of inoperable hilar cholangiocarcinoma (CCA). Patients and methods After propensity score matching, 64 patients with inoperable hilar CCA were categorized to the RFA + stent group (endobiliary RFA with stenting; n=32) or stent-only group (stenting only; n=32). The evaluated outcomes were the median time to recurrent biliary obstruction (RBO), overall survival (OS), and adverse events (AEs). Results Technical success was achieved in all patients. The clinical success rate was 93.8% in the RFA + stent group and 87.5% in the stent-only group ( P =0.672). The median time to RBO was 242 days in the RFA + stent group and 168 days in the stent-only group ( P =0.031). The median OS showed a non-significant tendency to be higher in the RFA + stent group (337 versus 296 days; P =0.260). Overall AE rates were comparable between the two groups (12.5% vs 9.4%, P =1.000). Conclusions Temperature-controlled endobiliary RFA resulted in favorable stent patency without increasing the rate of AEs but it did not significantly increase OS in patients with inoperable hilar CCA (Clinical trial registration number: KCT0008576).

Power-Controlled, Irrigated Radio-Frequency Ablation of Gastric Tissue: A Biophysical Analysis of Lesion Formation

BackgroundRadio-frequency ablation of gastric tissue is in its infancy compared to its extensive history and use in the cardiac field.AimsWe employed power-controlled, irrigated radio-frequency ablation to create lesions on the serosal surface of the stomach to examine the impact of ablation power, irrigation, temperature, and impedance on lesion formation and tissue damage.MethodsA total of 160 lesions were created in vivo in female weaner pigs (n = 5) using a combination of four power levels (10, 15, 20, 30 W) at two irrigation rates (2, 5 mL min−1) and with one temperature-controlled (65 °C) reference setting previously validated for electrophysiological intervention in the stomach.ResultsPower and irrigation rate combinations above 15 W resulted in lesions with significantly higher surface area and depth than the temperature-controlled setting. Irrigation resulted in significantly lower temperature (p < 0.001) and impedance (p < 0.001) compared to the temperature-controlled setting. No instances of perforation or tissue pop were recorded for any ablation sequence.ConclusionPower-controlled, irrigated radio-frequency ablation of gastric tissue is effective in creating larger and deeper lesions at reduced temperatures than previously investigated temperature-controlled radio-frequency ablation, highlighting a substantial improvement. These data define the biophysical impact of ablation parameters in gastric tissue, and they will guide future translation toward clinical application and in silico gastric ablation modeling.Graphical Combination of ablation settings (10–30 W power, 2–5 mL min-1 irrigation) were used to create serosal spot lesions. Histological analysis of lesions quantified localized tissue damage.

Peri-procedural anesthesia and patient pain experience in pulmonary vein isolation by means of very high power short duration radiofrequency ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Very high-power short-duration (vHPSD) temperature-controlled radiofrequency ablation (vHPSD) may reduce ablation times and improve patient tolerability, permitting pulmonary vein (PV) isolation under mild conscious sedation. Purpose Evaluate the anesthetic drugs use and patients ‘pain experience during vHPSD PV isolation. Methods Thirty-three consecutive patients, with paroxysmal atrial fibrillation (AF), treated with QDot Micro catheter and vHPSD (90 w for 4 s) (vHPSD Group), were compared with the last 33 consecutive patients, with paroxysmal AF, treated with a surround flow contact force-sensing catheter guided by the ablation index (450 at anterior and superior sites at 50 W, 330 at posterior and inferior sites at 40 W) (AI Group). Anesthetic drugs (midazolam and fentanyl) use were compared as well as pain experience, measured using a 0-10 scale. Results All PVs were isolated. PV isolation ablation time in the vHPSD Group (5.9±1.4 min) was shorter than in the AI Group (25±11 min, p&amp;lt;0.001). Pain experience was significantly lower in vHPSD group (4.5±2 vs 6.6±1.8, p&amp;lt; 0.001). No patients required general anesthesia; fentanyl use was required in 4 vHPSD Group patients vs 25 AI Group patients (p&amp;lt;0.001). A lower dose of midazolam was required in vHPSD Group (2.3±1.2 mg vs 3.6±1.7 mg, p &amp;lt; 0.001). Conclusions vHPSD radiofrequency ablation for PVI can be performed under conscious sedation using only benzodiazepine in most of patients without compromising patient pain experience.

Cavotricuspid isthmus ablation by means of very high power short duration temperature controlled lesions: acute and mid term outcome

Abstract Funding Acknowledgements Type of funding sources: None. Background Very high-power short-duration (vHPSD) temperature-controlled radiofrequency ablation minimizes conductive heating and increase resistive heating, achieving uniform and transmural lesion while reducing the risk of collateral tissue damages. The shape of the vHPSD lesion, wider and shallower than standard radiofrequency, raises some concerns during atrial flutter ablation (AFL). Purpose We evaluated the feasibility, efficacy and safety of the vHPSD ablation of the cavotricuspid isthmus (CTI) in patients presenting with typical AFL. Methods Sixty-one consecutive patients, with typical AFL, underwent CTI ablation using the QDot Micro catheter and vHPSD (90 w for 4 s). Patients were followed-up by means of visits and ECG in the outpatient clinic 1, 6 and 12 months after the procedure and later on with telephone interviews or by 24-h Holter monitoring in case of symptoms. Results Acute CTI bidirectional block was achieved in all patients (91% of first-pass block) with a mean fluoroscopy time of 114±29 s and a mean procedure time of 37±9 min. Two steam pops were observed. Two patients had groin hematoma, no further complications were observed. During a mean follow-up of 14±7 months, two (3.2%) patient had typical AFL recurrence, and four (6.5%) patients had an atrial fibrillation recurrence. Conclusions The vHPSD ablation represents an effective and safe ablation strategy to achieve bidirectional block for the treatment of typical AFL.

PO-01-005 GANGLIONATED PLEXI MEDIATED BRADYCARDIA RESPONSES: A PRE-CLINICAL STUDY OF DIFFERENCES BETWEEN PULSED FIELD AND RADIOFREQUENCY ABLATION IN THE LEFT ATRIUM

During left atrial catheter ablation procedures, the peri-atrial neural network of ganglionated plexi (GP) can be affected by the ablative energy. Bradycardic responses (BR) from GP stimulation have been reported during both radiofrequency (RF) and pulsed field (PF) ablation procedures. To assess differences in BR between RF and PF during canine left atrial ablation. Healthy canines (n=14) underwent transeptal access under general anesthesia. A multielectrode spherical array catheter (Globe PF System; Kardium Inc., Canada) capable of both cardiac mapping and ablation with either RF or PF was deployed in the left atrium. For each application, electroanatomic maps with ostial tags, contact maps based on blood flow detection, and animated voltage maps were created to help verify isolation. Either temperature-controlled RF ablation (63°C for 3 minutes) or PF ablation (1.7-1.8 kV) was used to circumferentially isolate two PVs/animal and create a linear and focal lesion along the posterior wall and roof of the left atrium. GP stimulation as evidenced by BR was recorded if either sinus bradycardia or AV block was noted during and/or immediately after the pulse train (Figure). A total of 11 and 3 animals underwent PF and RF ablation, respectively. All ablations were successfully delivered to all locations without adverse events. Of the animals treated with RF, none (0 of 3) displayed any evidence of GP stimulation at any locations. All animals treated with PF showed evidence of GP stimulation: all animals (11 of 11,100%) exhibited BR during ablation at the inferior common vein, with 6 of 10 (60%) animals demonstrating BR at the roof and posterior wall (Table). BR of less severity was noted during subsequent pulse trains but remained most frequent at the inferior common vein. Ganglionated plexi-mediated bradycardic responses occur with PF ablation, with evidence of some degree of stunning when repeated pulse trains are delivered. This pre-clinical model with ablation at this location will serve as a good model to further our understanding of this phenomenon. The lack of any bradycardic responses with RF either represents a lack of stimulation (perhaps because of the inability of the RF energy to reach the epicardial GPs, unlike the volumetric nature of the pulsed electrical fields) or, complete ablation without stimulation. Further work is needed to explore these differences.

Very High-Power Short-Duration, Temperature-Controlled Radiofrequency Ablation in Paroxysmal Atrial Fibrillation: The Prospective Multicenter Q-FFICIENCY Trial

BackgroundQDOT MICRO (QDM) is a novel contact force–sensing catheter optimized for temperature-controlled radiofrequency (RF) ablation. The very high-power short-duration (vHPSD) algorithm modulates power, maintaining target temperature during 90 W ablations for ≤4 seconds. ObjectivesThis study aims to evaluate safety and 12-month effectiveness of the QDM catheter in paroxysmal atrial fibrillation (AF) ablation using the vHPSD mode combined with conventional-power temperature-controlled (CPTC) mode. MethodsIn this prospective, multicenter, nonrandomized study, patients with drug-refractory, symptomatic paroxysmal AF underwent pulmonary vein (PV) isolation with QDM catheter with vHPSD as primary ablation mode, with optional use of the CPTC mode (25 to 50 W) for PV touch-up or non-PV ablation. The primary safety endpoint was incidence of primary adverse events within ≤7 days of ablation. The primary effectiveness endpoint was freedom from documented atrial tachyarrhythmia recurrence and acute procedural, repeat ablation, and antiarrhythmic drug failure. ResultsOf 191 enrolled participants, 166 had the catheter inserted, received RF ablation, and met eligibility criteria. Median procedural, RF application for ablating PVs, and fluoroscopy times were 132.0, 8.0, and 9.1 minutes, respectively. The primary adverse event rate was 3.6%. Imaging conducted in a subset of participants (n = 40) at 3 months did not show moderate or severe PV stenosis. The Kaplan-Meier estimated 12-month rate for primary effectiveness success was 76.7%; freedom from atrial tachyarrhythmia recurrence was 82.1%; clinical success (freedom from symptomatic recurrence) was 86.0%; and freedom from repeat ablation was 92.1%. ConclusionsTemperature-controlled paroxysmal AF ablation with the novel QDM catheter in vHPSD mode (90 W, ≤4 seconds), alone or with CPTC mode (25 to 50 W), is highly efficient and effective without compromising safety. (Evaluation of QDOT MICRO Catheter for Pulmonary Vein Isolation in Subjects With Paroxysmal Atrial Fibrillation [Q-FFICIENCY]; NCT03775512)

温控射频消融温度场快速计算方法的研究

温控射频消融温度场快速计算方法的研究

"Massive hemoptysis" and shock after fever and cough

A boy, aged 11 years, was admitted due to intermittent fever for 15 days, cough for 10 days, and "hemoptysis" for 7 days. The boy had fever and cough with left neck pain 15 days ago, and antibiotic treatment was effective. During the course of disease, the boy developed massive "hemoptysis" which caused shock. Fiberoptic bronchoscopy revealed a left pyriform sinus fistula with continuous bleeding. In combination with neck and vascular imaging examination results, the boy was diagnosed with internal jugular vein injury and thrombosis due to congenital pyriform sinus fistula infection and neck abscess. The boy was improved after treatment with temperature-controlled radiofrequency ablation for the closure of pyriform sinus fistula, and no recurrence was observed during the follow-up for one year and six months. No reports of massive hemorrhage and shock due to pyriform sinus fistula infection were found in the searched literature, and this article summarizes the clinical features, diagnosis, and treatment of this boy, so as to provide a reference for the early diagnosis of such disease and the prevention and treatment of its complications.

PO-711-02 POST- ABLATION UNIPOLAR ELECTROGRAM CHANGES: A PRECLINICAL EVALUATION COMPARING RADIOFREQUENCY VS PULSED FIELD ABLATION USING A “MAP AND ABLATE” MULTIELECTRODE ARRAY CATHETER

A multielectrode spherical array catheter (Globe, Kardium Inc, Canada) capable of mapping and ablation with either radiofrequency (RF) and pulsed field (PF) energy has been developed. To compare acute unipolar electrogram changes in atrial tissue after RF vs PF ablation. Healthy canines underwent transseptal access under general anesthesia, followed by circumferential pulmonary vein isolation, as well as linear and focal ablation as part of an efficacy and safety evaluation. Temperature controlled RF ablation (63ºC for 3 min) or PF using 1.6-2 kV/application (either gated or ungated modes) were used in separate animal cohorts. Only animals where focal/linear ablations were placed on the left atrial roof were selected so as to compare electrogram features at identical anatomic sites in both cohorts. We compared pre-ablation with post-ablation unipolar electrograms (1-225 Hz) recorded at i) the electrodes selected for ablation (Row 1), ii) from immediately adjacent electrode rows (Row 2, 3.5-6mm away), and iii) from electrodes 2 rows away (Row 3, 7-12 mm away; Figure). A total of 21 ablated sites (Row 1) and 27 adjacent Rows (2 & 3) were analyzed in the RFA group; similarly 77 and 81 sites were analyzed in the PFA group. Lesion transmurality was seen across the focal lesions on the left atrial roof for both the RF and PF applications. With both RF and PF ablation, there was complete loss of the negative deflection of the unipolar electrogram, as well as diminution of the R wave accompanied by a current of injury in Row 1. In the RF cohort, Row 2 demonstrated minimal loss of the negative deflection with mild injury current. However, PF ablation resulted in significantly greater loss of the negative deflection and current of injury was observed in Row 2, compared to RF ablation. Furthermore, in the PF group, even Row 3 demonstrated some degree of loss of negative deflection and injury current, whereas in the RF group this row was completely preserved. Loss of negative deflection of the unipolar electrogram, a feature that suggests transmural ablation in the setting of RF ablation is also seen with PF . However, the extent of unipolar changes extend further (7-12 mm) from the site of ablation with PF compared to RF, where these changes were milder and restricted to 3.5-6 mm.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Initial experience of temperature-controlled irrigated radiofrequency ablation for ischaemic cardiomyopathy ventricular tachycardia ablation

BackgroundThe DiamondTemp ablation (DTA) catheter system delivers high power, open-irrigated, temperature-controlled radiofrequency (RF) ablation. This novel ablation system has not been previously used for ventricular tachycardia (VT) ablation.ObjectiveFeasibility of using the DTA catheter system for VT ablation in ischaemic cardiomyopathy (ICM) patients.MethodTen ICM patients with optimal anti-arrhythmic drug therapy and implantable cardiac defibrillators (ICD) were recruited. VT inducibility testing was performed at the end of the procedure. ICD data for device detected VT episodes and device treated VT episodes were collected for 6-months pre- and post-ablation.ResultsSubstrate analysis demonstrated reductions in the borderzone area of 4.4 cm2 (p = 0.026) and late potential area of 3.5 cm2 (p = 0.0449) post-ablation, with reductions in the mean bipolar and unipolar voltages of the ablation target areas (0.14 mV (p = 0.0007); 0.59 mV (p = 0.0072) respectively). Complete procedural success was achieved in 9 procedures. Post-ablation VT inducibility testing was not performed in 1 procedure due to a steam pop complication resulting in pericardial tamponade requiring drainage. Mean follow-up of 214 ± 33 days revealed an 88% reduction in total VT episodes (n = 266 median 16 [IQR 3–57] to n = 33 median 0; p = 0.0164) and 77% reduction in ICD therapies (n = 128 median 5 [IQR 2–15] to n = 30 median 0; p = 0.0181).ConclusionThe DTA system resulted in adequate lesion characteristics with effective substrate modification, acute procedural success and improved outcomes at intermediate-term follow-up. Randomised controlled trials are required to compare the performance of the DTA system against conventional ablation catheters.

Study of flow effects on temperature-controlled radiofrequency ablation using phantom experiments and forward simulations.

Blood flow is known to add variability to hepatic radiofrequency ablation (RFA) treatment outcomes. However, few studies exist on its impact on temperature-controlled RFA. Hence, we investigate large-scale blood flow effects on temperature-controlled RFA in flow channel experiments and numerical simulations. Ablation zones were induced in tissue-mimicking, thermochromic phantoms with a single flow channel, using an RF generator with temperature-controlled power delivery and a monopolar needle electrode. Channels were generated by molding the phantom around a removable rod. Channel radius and saline flow rate were varied to study the impact of flow on (i) the ablated cross-sectional area, (ii) the delivered generator power, and (iii) the occurrence of directional effects on the thermal lesion. Finite volume simulations reproducing the experimental geometry, flow conditions, and generator power input were conducted and compared to the experimental ablation outcomes. Vessels of different channel radii affected the ablation outcome in different ways. For mm, the ablated area decreased with increasing flow rate while the energy input was hardly affected. For mm and mm, the energy input increased toward larger flow rates; for these radii, the ablated area decreased and increased toward larger flow rates, respectively, while still being reduced overall as compared to the reference experiment without flow. Directional effects, that is, local shrinking of the lesion upstream of the needle and an extension thereof downstream, were observed only for the smallest radius. The simulations qualitatively confirmed these observations. As compared to performing the simulations without flow, including flow effects in the simulations reduced the mean absolute error between experimental and simulated ablated areas from 0.23 to 0.12. While the temperature control mechanism did not detect the heat sink effect in the case of the smallest channel radius, it counteracted the heat sink effect in the case of the larger channel radii with an increased energy input; this explains the increase in ablated area toward high flow rates (for mm). The experiments in a simple phantom setup, thus, contribute to a good understanding of the phenomenon and are suitable for model validation.

Very high-power short-duration temperature-controlled ablation versus conventional power-controlled ablation for pulmonary vein isolation: The fast and furious - AF study.

BackgroundCatheter ablation for atrial fibrillation (AF) treatment provides effective and durable pulmonary vein isolation (PVI) and is associated with encouraging clinical outcome. A novel CF sensing temperature-controlled radiofrequency (RF) ablation catheter allows for very high-power short-duration (vHP-SD, 90 W/4 s) ablation aiming a potentially safer, more effective and faster ablation. We thought to evaluate preliminary safety and efficacy of vHP-SD ablation for PVI utilizing a novel vHP-SD catheter. The data was compared to conventional power-controlled ablation index (AI) guided PVI utilizing conventional contact force (CF) sensing catheters.Methods and ResultsFifty-six patients with paroxysmal or persistent AF were prospectively enrolled in this study. Twenty-eight consecutive patients underwent vHP-SD based PVI (vHP-SD group) and were compared to 28 consecutive patients treated with conventional CF-sensing catheters utilizing the AI (control group). All PVs were successfully isolated using vHP-SD. The median RF ablation time for vHP-SD was 338 (IQR 286, 367) seconds vs control 1580 (IQR 1350, 1848) seconds (p < 0.0001), the median procedure duration was vHP-SD 55 (IQR 48–60) minutes vs. control 105 (IQR 92–120) minutes (p < 0.0001). No differences in periprocedural complications were observed.ConclusionsThis preliminary data of the novel vHP-SD ablation mode provides safe and effective PVI. Procedure duration and RF ablation time were substantially shorter in the vHP-SD group in comparison to the control group.

Assessing the Relationship of Applied Force and Ablation Duration on Lesion Size Using a Diamond Tip Catheter Ablation System.

Background:Contact force has proven to be influential for lesion formation in power-controlled radiofrequency ablation. Lesion formation and morphology from a temperature-controlled diamond tip radiofrequency ablation catheter is not well described. We hypothesize that lesion formation from a temperature-controlled radiofrequency system is independent of applied force over short application durations.Methods:This study examined lesion depth, surface width, temperature, and ablation parameters of the DiamondTemp Ablation (Medtronic, Inc) system for ablation applications delivered with varying application duration (5, 10, and 15 s) and applied force (5, 10, and 30 g). Lesions from perpendicular radiofrequency applications were analyzed in a stepwise fashion from a computational model, thermochromic gel data (n=36), and porcine thigh preparation (n=231) experiments.Results:Varying applied force across each application duration consistently generated comparable lesion dimensions for each model. In the computational model, lesion depths from a 5 s application with 5, 10, and 30 g of applied force were similar (2.3, 2.6, and 3.0 mm, respectively). Also, the 5 s lesion depths in the gel model were consistent across applied force (5 g, 3.2±0.1 mm; 10 g, 3.5±0.1 mm; 30 g, 3.5±0.2 mm). In the thigh model, the 5, 10, and 30 g applied forces for 5 s created lesion depths of 3.1±0.5, 3.2±1.0, and 3.2±1.1 mm, respectively. For the 10 and 15 s durations, the lesion depth and width remained consistent for the 10 and 30 g applied forces. Increases in lesion depth and width, percentage of impedance reduction, minimum power, and maximum temperature were only significant when application duration increased (from 5 to 15 s).Conclusions:Lesion dimensions with the DiamondTemp Ablation temperature-controlled radiofrequency ablation system showed no marked change with increased applied force. Short application durations generated consistent lesion dimensions across computational, thermochromic gel, and thigh models.

Very high-power short-duration temperature-controlled ablation for pulmonary vein isolation: The Fast-and-Furious study

Abstract Funding Acknowledgements Type of funding sources: None. Background Catheter ablation for atrial fibrillation (AF) treatment provides effective and durable PVI associated with encouraging clinical outcome. The novel QDot ablation catheter with Qmode + ablation mode (90W/4sec, Figure 1) offers the ability to possibly improve safety and decrease ablation procedure times. Aims We aim to evaluate safety and efficacy of the very high-power short-duration (vHP-SD) temperature-controlled radiofrequency (RF) ablation Qmode + mode for pulmonary vein isolation (PVI) utilizing the novel QDot micro ablation catheter. The data was compared to conventional power-controlled ablation index (AI) guided PVI. Methods Twenty-five consecutive patients with paroxysmal or persistent AF were prospectively enrolled, underwent vHP-SD based PVI (vHP-SD group) and were compared to 25 consecutive patients treated with conventional CF-sensing catheters (control). Results All PVs were successfully isolated utilizing Qmode +. The total median RF ablation time was vHP-SD: 334 (282, 369) sec. vs control: 1567 (1250, 1756) sec. (p &amp;lt; 0.0001), the median procedure time was vHP-SD: 56 (48-62) vs. control: 104 (92-122) min (p &amp;lt; 0.0001). No differences in periprocedural complications were observed. Conclusions The novel Qmode + provides safe and effective PVI with impressive short RF time and short procedures times. Procedure time and RF time were substantial lower in the vHP-SD group. Abstract Figure 1

Percutaneous endobiliary ablation of malignant biliary strictures with a novel temperature-controlled radiofrequency ablation device.

We aimed to determine the safety and effectiveness of percutaneous endobiliary radiofrequency ablation of malignant biliary obstructions with a temperature-controlled radiofrequency ablation device. In this single center retrospective study, a total of 62 consecutive patients with malignant biliary obstruction were evaluated. Thirty patients who underwent endobiliary radiofrequency ablation with metallic stent placement were in the study group and 32 patients who underwent only metallic stenting were in the control group. Outcomes of this study were technical success, complications related to the procedure, stent patency, and overall survival. All procedures were technically successful in both groups. There was no procedure-related mortality in either group. Procedural complication rates were similar between the groups. Although statistically not significant, the only two major complications (hemobilia requiring endovascular treatment) were in the control group. Median primary stent patency was significantly longer in the study group than in the control group (223 days vs. 158 days; P = 0.016). Median survival rates were also longer in the study group (246 days vs. 198 days; P = 0.004). Percutaneous endobiliary radiofrequency ablation is safe and feasible with this novel radiofrequency ablation device in patients with malignant biliary obstruction. Percutaneous endobiliary radiofrequency ablation has a potential to improve both stent patency and survival.