Radiofrequency Ablation Duration Research Articles

The Effect of the Use of Activation 3D Mapping on the Patient X-Ray Load During Radiofrequency Ablation of Typical Atrial Flutter

Supraventricular macro re-entry tachyarrhythmias occupy the leading places among all types of tachyarrhythmias. The most common in this category is typical atrial flutter (AFL). This heart rhythm disorder has a negative impact on the patients’ quality of life. Its complications can lead to disability and death due to possible thromboembolism. Therapeutic treatment is limited in effectiveness. The main method of intervention is catheter radiofrequency ablation (RFA). The standard approach of RFA of AFL is performed without the use of navigation systems under fluoroscopy guidance. However, this results in an increased radiation exposure to the patient and the medical personnel. Modern technologies in the field of invasive electrophysiology make it possible to create anatomical models of heart and reproduce the spread of electrical excitation. However, the routine use of additional navigation methods remains controversial.
 The aim. To compare the duration of RFA of typical AFL and radiation exposure with the use of anatomical and propagation mapping.
 Materials and methods. This study is based on the analysis of the treatment results obtained for 53 patients at the National Amosov Institute of Cardiovascular Surgery in the period from 2014 to 2023. Depending on imaging methods, the patients were divided into two groups. The first group included 27 patients with an anatomical mapping of the right atrium. The second group included 26 patients with propagation mapping.
 Results. In all the patients we have achieved a bidirectional conduction block through cavotricuspid isthmus. In the first group, the total duration of confirming the diagnosis and creating the anatomical model was 312 ± 26 seconds. The mean time to the moment of AFL termination and restoration of sinus rhythm was 230 ± 19 seconds. The average duration of the procedure was 41.5 ± 3.5 minutes, the average fluoroscopy time was 120 ± 10 seconds, the average dose area product (DAP) was 15 ± 1.3 Gy·cm2. In the second group, the average time for creating a 3D propagation model of right atrium and verifying the diagnosis was 748 ± 65 seconds. The average time from the first application to the termination of tachycardia was 227 ± 20 seconds. The average duration of the procedure was 55 ± 4.7 minutes, X-ray time was 93 ± 8 seconds, average DAP was 13 ± 1.1 Gy·cm2. The duration of the procedure in the second group was significantly longer (p = 0.03), however, the radiation exposure and DAP were not statistically different (p = 0.31) between the observation groups.
 Conclusions. The use of propagation mapping increases the time of the procedure by 24.5% and does not give a significant advantage in reducing the radiation exposure. The use of a navigation system during cavotricuspid isthmus RFA is recommended for concomitant radical treatment of complex supraventricular arrhythmias, such as atrial fibrillation.

PO-04-034 NOVEL HIGH DENSITY OCTA-SPLINE MAPPING CATHETERS IMPROVED LEFT ATRIAL MAPPING EFFICIENCIES IN ATRIAL FIBRILLATION

The standard of care for atrial fibrillation (AF) ablation involves a high-density mapping of the left atrium and has until recently been performed with a penta-spline multipolar mapping catheter capable of acquiring 10 points simultaneously. A novel high density, multi-spline (octa-splines/24 points simultaneously) mapping catheter with a close internal unipolar reference electrode became available, which may improve mapping efficiencies and image resolutions. Compare mapping efficiency the penta-spline and the novel octa-spline high density mapping catheters in patients who underwent left atrial mapping and ablation for atrial fibrillation. Procedure related complications were evaluated as well. The REAL AF registry is a prospective multi-center observational study of real-world clinical experience of AF ablation. Consecutive first-time AF ablation patients between August 2020-September 2022 from 3 sites with complete procedure data and corresponding electro-anatomical maps were included in this analysis. Patients with paroxysmal and persistent atrial fibrillation were included. Mapping data were analyzed via a cloud-based artificial intelligence analytic platform. A total of 706 eligible patients were included in this analysis (Penta-spline: 636; Octa-spline: 70). Patients in the octa-spline cohort were older, but otherwise comparable to those in the penta-spline cohort. Procedures using the octa-spline mapping catheter had a significantly lower mean mapping time (11.74 vs. 16.57 minutes, p=0.018), procedure time (52.86 vs. 70.32 minutes, p=0.006) as well as >4x higher mapping density (13,201 vs 3,142 points, p=0.001) relative to procedure performed with the penta-spline catheter (Figure). There were no statistically significant differences in the total RF time between the two groups. The novel octa-spline high density mapping catheter improved left atrial mapping efficiencies with significantly shorter mapping and procedures times and higher point density per map. As expected, the radiofrequency ablation duration is not different, while the percentage of scar trends towards a larger area with the octa-spline catheter likely as a result of a higher density, more uniform point collection.

Abstract #1403009: Radiofrequency Ablation for Low-Risk Papillary Thyroid Microcarcinoma: First Reported Cases in the US

The incidence of papillary thyroid microcarcinoma (PTMC) is rising with increased utility and advancement of radiology imaging. Conservative treatment is highly considered given indolent nature of the disease. There has been a growing trend around the world to treat low risk PTMC with thermal ablation, such as radiofrequency ablation (RFA), a minimally invasive procedure that preserves most of thyroid parenchyma and function. This study is the first to report the efficacy and safety of RFA for low-risk PTMC in a large referral center in the US. The study included 10 patients who underwent RFA to treat low risk PTMC between July 2020 and February 2022. Patients who had cytological confirmation of single PTMC without evidence of metastasis, and ineligibility or refusal to undergo surgery were included. RFA were performed by three interventional radiologists. RFA technique and type of anesthesia were described. Thyroid function, changes in ablated tumor sizes, as well as procedure-related complications were retrospectively analyzed up to 18 months follow-up. Nine females and 1 male were included; median age was 44 years (range 29 – 69). Nine patients had normal thyroid function before and after RFA, and one patient had transient hyperthyroidism at 3 months follow up. Seven patients underwent general anesthesia, 2 patients had deep sedation, and 1 patient had moderate sedation. Mean duration of RFA was 6.32 minutes (SD +/- 4.25) with energy delivered ranging between 25 – 45 Watts. Mean volume of PTMC at baseline was 0.3 mL SD+/- 0.22. There was an increase in ablated volume at 3 months measuring 1.02 mL SD +/- 0.76, followed by a reduction in ablated nodule volume at 6 months measuring 0.42 mL SD +/- 0.38, and at 12 months measuring 0.26 mL SD +/- 0.28. The ablated nodules almost disappeared by 18 months follow-up, measuring 0.05 mL +/- 0.03 with no evidence of recurrence. There were no procedure-related major complications in any of the patients. This is the first reported cases of low risk PTMC treated with RFA in the US. The ablated volume initially increased as expected due to ablation beyond the nodules margin, followed by a gradual decrease in volume. RFA is safe and effective for the treatment of low risk PTMC. This therapy is potentially expanding in the US. Further study with longer follow up is needed to evaluate the risk of recurrence.

Electro-characteristics of Myocardial Pouches and Reduction of the Frequency of Steam Pops During Radiofrequency Ablation.

Background: Radiofrequency ablation (RFA) effectively treats arrhythmia. Steam pop (SP) is a dangerous complication of RFA, which can lead to pericardial tamponade or even death.Objective: This study aimed to explore the electro-characteristics of myocardial pouches, and the relationship between SP, pouch, and impedance.Methods: Swine myocardium was divided into the pouch group and smooth myocardium group. Continuous RFA at 50 W was applied. The initial impedance reduction within the first 3 s of ablation and the time from the start of ablation to SP were recorded. After enabling the delta impedance cutoff function, RFA was performed at different percentage of delta impedance (PDI) cutoff thresholds.Results: The impedance was higher for the pouch myocardium compared to the smooth myocardium (123.22 ± 8.63 Ω and 95.75 ± 4.75 Ω, respectively; p < 0.001). The RFA duration before SPs was shorter in the pouch group compared to the smooth myocardium group [9 s (interquartile range, IQR: 6.25–13 s) and 33 s (IQR: 26.25–40.75 s), respectively; p < 0.001]. Within the first 3 s of RFA, impedance reduction (24.65 ± 6.57 Ω and 12.78 ± 3.35 Ω, respectively; p < 0.001) and PDI [19.18% (IQR: 16.39–24.20%) and 12.96% (IQR: 11.17–14.39%), respectively; p < 0.001] were greater in the pouch group compared to the smooth myocardium group. A PDI of 15% and delta time of 3 s effectively reduced the frequency of SPs without seriously affecting RFA use.Conclusion: SPs occur more frequently in the pouch area during RFA. Appropriate delta impedance cutoff settings (PDI: 15%; delta time: 3 s) can reduce the frequency of SPs and improve the RFA safety.

Improved Procedural Efficiency of Atrial Fibrillation Ablation Using a Dedicated Ablation Protocol and Lean Management.

In this study the authors hypothesized that "Lean management" within a dedicated ablation protocol could standardize the pulmonary vein isolation (PVI) procedure and improve quality. There is a large variability in safety, effectiveness, and efficiency of PVI. This was a single-center prospective study with inclusion of all consecutive PVI procedures from 2017 to2019. A 3-step intervention was introduced based on Lean management: step 1) simplification (CLOSE protocol); step2) waste elimination (higher power shorter duration); and step 3) improved standardization (Lab Optimization Tool [LOT]). PVI was divided into steps that were tracked (in minutes) using LOT. Parameters were compared in 6-month intervals. Overall, 295 patients (146 patients with LOT) were analyzed. Step 1 reduced skin-to-skin procedure duration (2017: 119 ± 21min vs. 2018: 77 ± 15min; p<0.001) and variance (from 2018 to 2019p=0.024). Step 2 reduced the radiofrequency time (2017: 38 ± 6min vs. 2018: 20 ± 3min; p<0.001) and variance (from 2018 to 2019 p<0.001). Analysis of step 3 demonstrated that only 53% of the entire procedure length (143 ± 22min) was used for treatment (skin-to-skin time 77 ± 16min), the remaining time being devoted for setup (42 ± 12min, 29%); left atrial access (16 ± 7min, 12%); respiratory gating, left atrial map, and pseudo-circle annotation (10 ± 6min, 7%); ablation (39 ± 10min, 27%); and bilateral block validation (10 ± 8min, 7%). Standardization of PVI using a dedicated ablation protocol and Lean management can help to reduceprocedure and radiofrequency ablation duration and variance, and increase procedural efficiency without compromising safety. To improve health care utilization, increased efficiency should become an accepted goalinadditionto procedural safety and effectiveness.

COMPARATIVE EFFECTIVENESS OF RADIOFREQUENCY PULMONARY VEIN ISOLATION PLUS AMIODARONE THERAPY IN PREVENTING POST-CORONARY ARTERY BYPASS GRAFTING ATRIAL FIBRILLATION

Objective. To evaluate the effectiveness of epicardial bipolar radiofrequency ablation (RFA) of pulmonary vein ostia (PV) in comparison with its being combined with amiodarone administration for post-CABG atrial fibrillation (AF) prevention.Methods. A single-centre, prospective randomized study (PULVAB), including 96 CAD patients with no history of AF, was conducted between January 2015 and December 2018. Group 1 (control; n=34) had standard CABG alone. Group 2 (n=29) received RFA of PV as an adjunct to CABG for prevention of postoperative AF (POAF). Group 3 patients (n=33) had RFA at the time of CABG and were given amiodarone. Allocation was concealed using sequentiallynumbered opaque envelopes. The efficacy and safety of RFA concomitant with CABG were assessed, as both performed independently and combined with amiodarone administration, as well as intra-and postoperative course.Results. No differences were seen in operation length (p=0.937), cardiopulmonary bypass (CPB) or the aorta clamping times (р=0.377 and p=0.072, respectively). The study groups (CABG, CABG-RFA, CABG-RFA-amiodarone) did not differ statistically in the number of shunts placed - 3.17±0.61, 3.10±0.51 and 2.94±0,6 (p=0,121). No significant difference was noted in RFA duration between Groups 2 and 3 - 11.7±3.7 and 11.4±6.3 min, respectively (p=0,834).AF was found to occur most commonly at postoperative days two or four. The isolated CABG surgery group patients developed POAF most often of all (32,4%). The incidence of POAF was lower after RFA concomitant to CABG - 20.7% (р=0,29). A significant difference was identified in POAF incidence between Groups 1 and 3- 32.4% and 6.1%, respectively (p = 0.0065). Differences between Groups 2 and 3 proved not to be statistically significant (р= 0,086). Sinus rhythm in most of those who had developed arrhythmias was restored by pharmacological cardioversion except for three patients (one in each group). At discharge, 97.1% , 96.7% and 97% of the subjects in Groups 1, 2 and 3, respectively, exhibited sinus rhythm (p&gt;0,05).There was no in-hospital mortality in any of the groups. Neither were there any wound complications, reoperations, perioperative myocardial infarction or cerebral circulatory disorders observed. No difference was revealed in the severity and frequency of renal or respiratory failure. The mechanical lung ventilation time and duration of stay in the ICU in the isolated CABG group were shown to be increased as compared with the CABG-RFA and CABG-RFA-amiodarone groups (p&lt;0.05).Conclusion. The evidence from the pilot study (PULVAB) suggests that bipolar ablation of PV does not significantly complicate CABG, while being combined with amiodarone administration for prevention of rhythm disorders it significantly reduces the incidence of POAF. The in-hospital incidence of POAF tended to decrease, which was not statistically significant, though. Evaluating the efficacy of RFA concomitant with CABG, as performed independently, invites further investigation with more data analysis.

Percutaneous ultrasound-guided ‘three-step’ radiofrequency ablation for giant hepatic hemangioma (5–15 cm): a safe and effective new technique

Purpose To evaluate the safety and efficacy of percutaneous ultrasound-guided ‘three-step’ radiofrequency ablation (RFA) for the treatment of giant hepatic hemangioma. Materials and methods Patients with giant hepatic hemangioma who underwent percutaneous ultrasound-guided ‘three-step’ RFA (n = 52) and conventional RFA (n = 54) at our center from June 2013 to December 2017 were retrospectively analyzed. The ‘three-step’ RFA proceeds as follows. Step 1: Ablate the feeding artery of the hemangioma. Step 2: Aspirate blood from the tumor. Step 3: Ablation the lesion. Intraoperative information, postoperative recovery, therapeutic effects, and complications were compared between the two groups. Results The duration of RFA was significantly shorter (19.2 ± 0.8 min versus 44.5 ± 2.8 min, p < 0.001), the number of punctures was significantly lower (3.2 ± 0.1 versus 4.7 ± 0.3, p = 0.002), and the duration of hospital stay was significantly shorter (9.0 ± 0.5 versus 11.5 ± 0.7, p = 0.013) in the TS-RFA group than in the C-RFA group. The complete ablation rate (86.5% versus 40.7%), the maximum postoperative pain score (2.5 ± 1.3 versus 4.1 ± 2.0) and symptom relief were also significantly better in the TS-RFA group than in the C-RFA group (p < 0.05). No postoperative death occurred in either group. There were no grade III or higher complications in the TS-RFA group, but one patient in the C-RFA group developed the grade III complication of postoperative abdominal bleeding. Conclusions ‘Three-step’ RFA is a safe and effective minimally invasive treatment for giant hepatic hemangioma. It is worthy of further promotion and application.

Radiofrequency Ablation Duration per Tumor Volume May Correlate with Overall Survival in Solitary Hepatocellular Carcinoma Patients Treated with Radiofrequency Ablation Plus Lyso-Thermosensitive Liposomal Doxorubicin.

To determine whether burn time per tumor volume (BPV) (min/mL), where burn time is the total time during which radiofrequency (RF) energy is being applied, is correlated with hepatocellular carcinoma (HCC) treatment outcomes using RF ablation and lyso-thermosensitive liposomal doxorubicin (LTLD). The HEAT study was a double-blind, randomized controlled phase III trial of RF ablation only versus RF ablation+ LTLD in patients with HCCs 3-7 cm in diameter. Effect of BPV on progression-free survival and overall survival (OS) was analyzed. BPV demonstrated statistically significant differences between study groups for OS (P= .038, hazard ratio [HR]= 0.85), but not for progression-free survival (P= .389, HR= 1.059). In a separate analysis, treatment groups were independently analyzed to determine the effect of BPV within each individual group. OS improved as BPV increased for patients receiving RF ablation+ LTLD (P= .017, HR= 0.836, confidence interval [0.722, 0.968]). This same association was not observed in patients receiving RF ablation only (P= .57, HR= 0.99). BPV may be a useful metric for RF ablation+ LTLD combination therapy for solitary HCC. The analysis suggested that the burn time for the tumor needs to be adjusted depending on the tumor volume. Because this is a post hoc study, the results are only suggestive and need to be confirmed with prospective studies.

Evaluation of the Increased High-Sensitivity Cardiac Troponin in Patients Undergone Radiofrequency Ablation in Emergency Service

Aim: In our study; we explored which ablation parameter is mostly associated with the increased high-sensitivity troponin tests (hs-cTnT) in patients undergone radiofrequency ablation (RFA).Methods: We included patients who underwent RFA within the previous year, and later admitted to emergency service with chest pain to our study. ECG and echocardiographic examination were performed before the electrophysiological study (EPS) for all patients. After RFA, information regarding the total duration, energy and mean temperature was recorded. Blood samples were collected via venous route from patients who underwent RFA, and later admitted to emergency service with chest pain to study hs-cTnT.Results: There were 119 patients [38 males, median age 51years (IQR:29)] included in our study. 6 of them (80.7%) were detected to have atrioventricular nodal re-entrant tachycardia (AVNRT), 14(11.8%) Wolff Parkinson White Syndrome (WPW), and 9 (7.5%) Right Ventricular Outflow Tract (RVOT) Tachycardia. Hs-cTnT and total RFA duration (r=0.683,p&lt;0.001), total energy (r=0.423, p&lt;0.001) and mean temperature (r=0.371, p&lt;0.001) were correlated. In linear regression analysis; total RFA duration (OR:0.842, 95% CI: 0.685-0.999, p&lt;0.001) and mean temperature (OR:10.738, 95% CI: 6.420-15.055, p&lt;0.001) were detected to be independent predictors for hs-cTnT. Conclusion: This study has shown us that it should be noted that patients who underwent RFA for a prolonged duration and at high temperature may admit to the emergency service with chest pain, therefore, their troponin levels may increase, and also in these patients no further work-up or treatment would be required.

Phase III HEAT Study Adding Lyso-Thermosensitive Liposomal Doxorubicin to Radiofrequency Ablation in Patients with Unresectable Hepatocellular Carcinoma Lesions

Purpose: Lyso-thermosensitive liposomal doxorubicin (LTLD) consists of doxorubicin contained within a heat-sensitive liposome. When heated to ≥40°C, LTLD locally releases a high concentration of doxorubicin. We aimed to determine whether adding LTLD improves the efficacy of radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) lesions with a maximum diameter (dmax) of 3 to 7 cm.Experimental Design: The HEAT Study was a randomized, double-blind, dummy-controlled trial of RFA ± LTLD. The 701 enrolled patients had to have ≤4 unresectable HCC lesions, at least one of which had a dmax of 3 to 7 cm. The primary endpoint was progression-free survival (PFS) and a key secondary endpoint was overall survival (OS). Post hoc subset analyses investigated whether RFA duration was associated with efficacy.Results: The primary endpoint was not met; in intention-to-treat analysis, the PFS HR of RFA + LTLD versus RFA alone was 0.96 [95% confidence interval (CI), 0.79-1.18; P = 0.71], and the OS HR ratio was 0.95 (95% CI, 0.76-1.20; P = 0.67). Among 285 patients with a solitary HCC lesion who received ≥45 minutes RFA dwell time, the OS HR was 0.63 (95% CI, 0.41-0.96; P < 0.05) in favor of combination therapy. RFA + LTLD had reversible myelosuppression similar to free doxorubicin.Conclusions: Adding LTLD to RFA was safe but did not increase PFS or OS in the overall study population. However, consistent with LTLD's heat-based mechanism of action, subgroup analysis suggested that RFA + LTLD efficacy is improved when RFA dwell time for a solitary lesion ≥45 minutes. Clin Cancer Res; 24(1); 73-83. ©2017 AACR.

In Vivo Arthroscopic Temperatures: A Comparison Between 2 Types of Radiofrequency Ablation Systems in Arthroscopic Anterior Cruciate Ligament Reconstruction—A Randomized Controlled Trial

To compare a plasma ablation device with a standard ablation device in anterior cruciate ligament (ACL) reconstruction to determine which system is superior in terms of intra-articular heat generation and diathermy efficiency. This was a prospective, randomized controlled trial. The inclusion criteria were adult patients undergoing primary ACL reconstruction. Patients were randomized preoperatively to the standard ablation group or the plasma ablation group. A thermometer was inserted into the inferior suprapatellar pouch, and the temperature, time, and duration of radiofrequency ablation were measured continually. No significant differences were found between the standard ablation system and the plasma ablation system for maximum temperature (29.77°C and 29.34°C, respectively; P= .95), mean temperature (26.16°C and 26.99°C, respectively; P= .44), minimum temperature (22.66°C and 23.94°C, respectively; P= .54), and baseline temperature (26.80°C and 27.93°C, respectively; P= .35). Similarly, no significant differences were found for operative time (82.90minutes and 80.50minutes, respectively; P= .72) and mean diathermy activation times (2.6minutes for both systems; P= .90). The between-system coefficient of variation for the measured parameters ranged from 0.12% to 3.69%. No intra-articular readings above the temperature likely to damage chondrocytes were recorded. The mean irrigation fluid temperature had a significant correlation with the maximum temperature reached during the procedure (Spearman rank correlation, r= 0.87; P < .01). No difference in temperature was observed between the standard ablation and plasma ablation probes during ACL reconstruction. Temperatures did not exceed critical temperatures associated with chondrocyte death. Level I, randomized controlled trial.

13 The Ablation Effectiveness Quotient: A Novel Marker to Predict the Success of Atrial Fibrillation Ablation

BackgroundInability to predict clinical success on follow up in spite of successful Pulmonary vein isolation (PVI) remains the Achilles’ heel of AF Ablation (AFA). When patients with arrhythmia recurrence (ARec)...

Is routine echocardiography necessary after catheter ablation of atrioventricular nodal re-entrant tachycardia?

The aim of this study was to investigate whether pericardial effusion (PE) detected by transthoracic echocardiography (TTE) was clinically significant and whether routine echocardiography was necessary after catheter ablation of atrioventricular nodal re-entrant tachycardia (AVNRT). A total of 202 patients with AVNRT were included in the study from three centers. The patients received basic electrophysiology-guided therapy, followed by radiofrequency ablation (RFA). All patients underwent TTE before and after RFA therapy. The mean age of the study population was 46.2 ± 17.9 and 30.7% of the patients were male. Of these patients, six (3%) had postoperative PE, as detected by TTE. However, none of them had cardiac tamponade (CT). Four patients had minimal PE, while two had mild PE. Repeated TTE at one to three months showed resolved PE. No significant difference was seen among the patients with and/or without PE in terms of age, gender, the number of RFA applications, or RFA duration; however, significantly prolonged duration of fluoroscopy exposure was observed in the patients with PE. PE was detected in 3% of the patients by TTE and associated with prolonged duration of fluoroscopy exposure. However, no patients with moderate or large PE or cardiac tamponade were found in the study. In conclusion, we suggest that TTE should only be performed in the presence of clinical indications following ablation of AVNRT.

Propofol: a safe drug for physician-led procedures?

This editorial refers to ‘Propofol sedation administered by cardiologists without assisted ventilation for long cardiac interventions: an assessment of 1000 consecutive patients undergoing atrial fibrillation ablation’ by T.V. Salukhe et al. , on page 325 The recent unfortunate death of the singer Michael Jackson as a result of suspected propofol misuse has highlighted the dangers of patient-administered propofol. However, under proper supervision, propofol is a very safe drug.1The question is who is safe to supervise it? In this issue of Europace , Salukhe et al .2report their experience of the use of non-anaesthesiologist administered propofol sedation (NAAP) during the ablation of atrial fibrillation in 1000 consecutive patients. Radiofrequency ablation of the heart is painful. It requires the patient to lie still, often for considerable periods of time. This has become increasingly important with the development of complex ablations for atrial fibrillation and ventricular tachycardia. Not only do these techniques involve a significantly greater duration of radiofrequency ablation but they are often dependent on the use of three-dimensional mapping techniques. Frequent movement of the patient in response to pain can lead to large shifts in the reconstructed geometry, rendering it unusable. Ablation for atrial fibrillation is extremely effective for symptom relief, but currently there is little evidence for any prognostic benefit. It is thus incumbent on the electrophysiologist to ensure the procedure is as safe as possible. Great strides have been taken in this direction with the most recent world-wide survey showing a mortality rate of only 0.15%.3 Two broad approaches have been taken to ensure adequate sedation and analgesia in the electrophysiology lab: physician-led sedation with a combination of opiates and benzodiazepines or anaesthesiologist-led …

High-sensitivity troponin T as a marker of myocardial injury after radiofrequency catheter ablation

The aim of our study was to monitor radiofrequency catheter ablation-induced myocardial damage by measuring high-sensitivity cardiac troponin T (hs-cTnT). Serum concentrations of hs-cTnT (Elecsys 2010 system, Roche) were measured in 73 healthy blood donors and serially in 27 patients who had samples taken both before and 24 h after radiofrequency ablation (RFA) for atrioventricular nodal re-entry tachycardia (AVNRT), atrial fibrillation (AF) or right atrial flutter (AFL). Significant increases of hs-cTnT were seen in patients after RFA (AVNRT: P = 0.0115, AF: P = 0.0011, AFL: P = 0.0009). Postprocedural serum hs-cTnT correlated with the number of radiofrequency applications and with the duration of RFA procedure. Spearman's coefficient of rank correlation (r) were as follows: hs-cTnT versus RFA duration: r = 0.771 (P < 0.001); hs-cTnT versus number of pulses: r = 0.708 (P < 0.001). Patients with the diagnosis of AVNRT had lower serum hs-cTnT concentration after RFA compared with AFL (P < 0.0001) and AF (P < 0.0001) patients. Our data indicate that RFA causes a significant increase of serum hs-cTnT concentration that could be used to monitor myocardial injury.

Tolerance of radiofrequency ablation by patients of hepatocellular carcinoma

Radiofrequency ablation (RFA) is currently an effective method for ablation of hepatocellular carcinoma (HCC). Early reports have indicated that RFA is safe and virtually free from major complications. Unlike partial hepatectomy for HCC on patients with cirrhosis, there are no data on the safety limit of RFA. However, information is vital for selection of appropriate patients for the procedure. In this study, we analyzed results from use of RFA on HCC patients and determined the lower limit of liver function with which HCC patients can tolerate RFA. Preoperative variables of 310 patients who underwent RFA for HCC were analyzed to identify the risk factors in RFA intolerance in terms of morbidity associated with stress-induced complications. Thirty-nine (12.6%) patients developed intolerance of RFA. Postoperative morbidity was mainly because of intractable ascites (n = 13), hyperbilirubinemia (n = 10), massive pleural effusion (n = 7), and other complications (n = 14). Multivariate analysis revealed that serum albumin level (P = 0.001), serum bilirubin level (P = 0.000), tumor number (P = 0.002), and RFA duration (P = 0.017) all played a role in this issue. Simple data such as serum bilirubin, serum albumin level, and tumor number can be used to predict HCC patients' tolerance of RFA. Avoidance of excessive RFA time and careful monitoring of patients at risk are important means of reducing the postoperative morbidity rate.

Radiofrequency ablation of the gastrointestinal tract with a stent-like electrode: experimental study.

ObjectiveTo assess the technical feasibility of a newly designed stent-like electrode in rabbits.Materials and MethodsA stent-like electrode was knitted from a single thread of nitinol wire and interconnected to a generator using similar wire. In order to gauge the extent of radiofrequency ablation (RFA), we measured the depth of the ablated area in cow liver using a combination of 180-sec time intervals and 20-watt power increments. For data processing, Cox regression analysis was used. RFA was also applied to the small intestine of rabbits using this stent-like electrode under six different sets of conditions: 10 watts for 1 min, 10 watts for 2 mins, 20 watts for 1 min, 20 watts for 2 mins, 30 watts for 1 min, and 30 watts for 2 mins. To determine the gross and microscopic findings, six animals were sacrificed immediately after the procedure and the results obtained under the different sets of conditions were correlated. Eight rabbits were monitored for 4 weeks prior to sacrifice.ResultsFor both ex-vivo and in-vivo ablations, the depth of the thermal lesion showed linear correlation with both the duration of RFA and the power applied. RFA of the duodenum was technically successful in all 14 rabbits. The acute changes occurring in the rabbits' small intestine included color change, cytoplasmic denaturation, fibrin deposition and hemorrhage, among which hemorrhage of the mucosal layer was the earliest finding. RF ablation for 2 mins at 30 watts caused serosal hemorrhage. The gross and histologic changes occurring showed close correlation under all six sets of conditions.ConclusionUse of the stent-like electrode proves technically feasible but to determine the nature of the chronic change occurring in the gastrointestinal tract after RF ablation, further investigation and long-term follow-up in animals are required.

An Increase in Body Temperature During Radiofrequency Ablation of Liver Tumors

Radiofrequency ablation (RFA) therapy using an active needle electrode inserted into liver tumors has been used clinically. To avoid hyperthermia, we investigated the relationship between the total output energy of the applied radiofrequency wave and changes in body temperature (BT) in patients receiving RFA. Fifteen patients undergoing RFA of liver tumors with general anesthesia were enrolled. The total output energy of radiofrequency waves was calculated from the power and duration of RFA. Changes in rectal (T(rect)) and tympanic temperatures were measured throughout the study. The mean number of liver tumors per patient was 1.7 +/- 1.3. The mean RFA time was 30.0 +/- 26.3 min. The mean total output energy was 125,935 +/- 114,506 J. The mean value of T(rect) increased from 36.3 degrees C +/- 0.5 degrees C to 37.0 degrees C +/- 1.0 degrees C (P < 0.01). A linear correlation was obtained between the total output energy and the changes in T(rect), indicating that T(rect) increased approximately by 1 degrees C for every 3000 J/kg of total output energy. The increase in BT during RFA of liver tumors under general anesthesia is predictable. Close observation of total output energy delivered and BT are required, and preparation of cooling measures is important, in RFA of liver tumors. The increase in body temperature (BT) is predictable during radiofrequency ablation (RFA) of liver tumors under general anesthesia. Close observation of total output energy delivered and BT are required, and preparation of cooling measures is important, in RFA of liver tumors.