Frequency Catheter Ablation Research Articles

Radiation dose to the eye of physicians during radio frequency catheter ablation: a small-scale study.

Radio frequency catheter ablation (RFCA), a treatment for arrhythmia, requires a long fluoroscopy time that increases the radiation exposure dose to the physician, particularly to the lens of the eye. It is recommended that a lens-specific dosimeter such as DOSIRIS® is used to measure the dose to the lens. In this study, we investigated whether conventional glass badges can be used as an alternative to lens dosimeters. The doses to the lenses of two physicians (physician A, main operator; physician B, assistant; physician B was further away from the patient than physician A) were measured for 126 RFCA procedures performed over a 6-month period (fluoroscopy rate of 3.0 p/s with use of a ceiling-hanging shield). The cumulative value measured by a lens dosimeter attached to the inside of Pb glasses (0.07-mm dose equivalent) next to the left eye was 4.7mSv for physician A, and 0.8mSv for physician B. The reading on the glass badge worn on the left side of the neck was 4.7mSv for physician A and 1.3mSv for physician B. Lens dosimeter and glass badge values showed a good correlation for the left eye and left neck (r = 0.86, p < 0.01). We show that glass badges may be a viable alternative to lens-equivalent dosimetry when using low-pulse fluoroscopy and a ceiling-hanging shield.

Perioperative management of a patient with haemophilia B and PSVT undergoing radiofrequency ablation: A case report.

Haemophilia B is a rare inherited bleeding disorder in which patients have impaired coagulation. This study describes a patient with Haemophilia B and paroxysmal supraventricular tachycardia (PSVT) who underwent radio frequency catheter ablation (RFCA). The perioperative replacement therapy with coagulation factor IX (FIX) was agreed upon after an interdisciplinary consultation involving a team of specialists in haematology, cardiovascular medicine and cardiothoracic surgery. There were no obvious bleeding points or complications during the perioperative period following the treatment, nor recurrence of PSVT within a three-year follow-up period. In summary, RFCA can be performed safely in patients with haemophilia B on the premise of developing an individualized perioperative exogenous coagulation factor supplementation regimen based upon an adequate preoperative evaluation and clinical monitoring and management by an interdisciplinary team.

Meshless Simulation of Multi-site Radio Frequency Catheter Ablation through the Fragile Points Method.

Computational models for radio frequency catheter ablation (RFCA) of cardiac arrhythmia have been developed and tested in conditions where a single ablation site is considered. However, in reality arrhythmic events are generated at multiple sites which are ablated during treatment. Under such conditions, heat accumulation from several ablations is expected and models should take this effect into account. Moreover, such models are solved using the Finite Element Method which requires a good quality mesh to ensure numerical accuracy. Therefore, clinical application is limited since heat accumulation effects are neglected and numerical accuracy depends on mesh quality. In this work, we propose a novel meshless computational model where tissue heat accumulation from previously ablated sites is taken into account. In this way, we aim to overcome the mesh quality restriction of the Finite Element Method and enable realistic multi-site ablation simulation. We consider a two ablation sites protocol where tissue temperature at the end of the first ablation is used as initial condition for the second ablation. The effect of the time interval between the ablation of the two sites is evaluated. The proposed method demonstrates that previous models that do not account for heat accumulation between ablations may underestimate the tissue heat distribution.Clinical relevance- The proposed computational model may be used to build and update a heat map for ablation guidance taking into account the contribution from previously ablated sites. Being a meshless model, it does not require significant input from the user during preprocessing. Therefore, it is suitable for application in a clinical setting.

A new workflow including Coherent algorithm in sinus rhythm for the treatment of Ventricular Tachycardia in patients with scar related heart disease

Abstract Funding Acknowledgements Type of funding sources: None. Background Catheter ablation is a well establish therapy in patients with structural heart disease (SHD) and sustain ventricular tachycardia (VT). Scar substrate modification is one of the two endpoint of a VT ablation procedure. Dechanneling is one of the described successful techniques that shown to be effective for substrate modification Aim This is a pilot study aiming to evaluate the feasibility and the acute efficacy of a new mapping approach for VT ablation with the combination of high density (HD) mapping and Coherent mapping algorithm. Methods All enrolled patients underwent radio frequency catheter ablation (RFCA) for drug-refractory VT or VT storm. Before mapping, programmed ventricular stimulation was performed in all patients for the induction of clinical VT or any other ventricular arrhythmias (VA), if VA was inducible, then electrical cardioversion was conducted to restore sinus rhythm. After transseptal puncture, left ventricular (LV) HD mapping was conducted using a 3D mapping system aiming &amp;gt;5000 mapping points during sinus rhythm, intrinsic atrial rhythm, or ventricular pacing with a multielectrode catheter. During HD mapping, all late potentials (LPs) were tagged as double potentials (DP) and all potentials below 0,2 mV were tagged as scar. Then, Coherent mapping was used to visualize electrical propagation through the LV, based on velocity vector identification, highlighting how the electrical signal enters the scar and identifying the "entrance points" (EP). RFCA was delivered in a power-controlled mode on all the individuated EPs using an open, irrigated-tip ablation catheter with contact force sensor. After RFCA, a second remap was conducted to evaluate the LPs abolition. Then, a programmed ventricular stimulation was performed to validate non inducibility of any VAs. Results 10 consecutive patients (age 71,25±10,32 years, 100% male) undergoing RFCA for drug-refractory VT or VT storm (50%). Acute procedural end-point were: abolition of the LPs and non-inducibility of any VA at the end of the procedure. Abolition of LPs was reached in all cases while non inducibility was reached in 9 patients (90%). Mean procedural time was 214±33,81 min, mean mapping time was 89±15,40 min with mean number of acquired points of 5218±359,56. Mean fluoroscopy time and dose were 15±33,81 min and 5218±7149,8 µGm2, respectively. Mean entrance points identified was 2,6±0,84. In 5 patents (50%), after ablation a modification in the refractory period of the left ventricular myocardium was observed. Mean RF time was 1216±565,46 seconds, with mean number of Visitag of 33±29,98. No acute complication were reported. Conclusion High-density mapping in sinus rhythm combined with Coherent algorithm facilitates the understanding of the substrate and provides targets for effective ablation. This approach has been proven safe and with high acute success rates.

The impact of rate and rhythm control strategies on quality of life for patients with atrial fibrillation: a protocol for a systematic review

BackgroundAtrial fibrillation (AF) is the most common heart arrhythmia globally and it adversely affects the quality of life (QoL). Available rate and rhythm control strategies equally reduce mortality but may impact QoL differently. A number of systematic reviews have focused on the impact of specific strategies on QoL, though a 2006 review synthesized the evidence on the effect of all strategies on QoL, allowing for a clinically important comparison between the types of strategies. Many trials have been published since the review undertook the search in 2005; therefore, an update is needed. This systematic review aims to provide an update to the 2006 review on the impact of all rate and rhythm control strategies on QoL in people with AF.MethodsThe following four databases and three clinical trial registries will be searched for primary studies: CENTRAL, MEDLINE, Embase, CINAHL, WHO International Clinical Trials Registry Platform, ClinicalTrials.gov, and ClinicalTrialsRegister.eu. No language restriction will be applied. The search will be limited to 2004 or later publication year to allow overlap with the search conducted by the 2006 review authors. Any randomized control trial that reports the QoL of adult (≥ 18 years) AF patients following an eligible rate or rhythm control intervention will be eligible for inclusion. Eligible interventions (and comparators) include pacing, atrioventricular node junction and bundle of HIS ablation, pharmacological therapy, radio frequency catheter ablation, cryoablation, pulmonary vein isolation, maze operation, pace maker implantation, and defibrillator implantation. Two reviewers will independently screen for eligible studies, extract the data using a piloted tool, and assess bias by QoL outcome using the RoB 2 tool. The suitability of conducting a meta-analysis will be assessed by the clinical and methodology similarities of included studies. If it is feasible, standardized mean differences will be pooled using a random-effects model and assessed appropriately.DiscussionThe findings from this review will allow for meaningful comparisons between various rate and rhythm control strategies regarding their impact on QoL. This review will be useful for a wide range of stakeholders and will be crucial for optimizing the overall wellbeing of AF patients.Systematic review registrationPROSPERO CRD42021290542

Risk factors associated with the development of post-ablation atrial fibrillation

The article presents the main clinical, instrumental, and electrophysiological risk factors of atrial fibrillation (AF) occurence in patients with typical atrial flutter (TAF) who underwent radio frequency catheter ablation (RFA) of the cavotricuspidal isthmus (CTI). The term “post-ablation AF” is defined. The role of such a factor as endocardial provocation test in predicting post-ablation AF in patients with TAF is indicated. Studies evaluating the effectiveness of preventive maintenance of RFA AF in patients undergoing RFA CTI are also represented. Mathematical models for predicting AF in the general population and in patients with TAF are discussed.

STIFF LEFT ATRIAL SYNDROME: THE MYSTERY BEHIND A PRESUMPTIC DIAGNOSIS OF PULMONARY ARTERY HYPERTENSION

SESSION TITLE: Global Case Report Posters SESSION TYPE: Global Case Reports PRESENTED ON: October 18-21, 2020 INTRODUCTION: Atrial Fibrillation (AF) is one of the most prevalent arrhythmia. Radio frequency catheter ablation (RFCA) is an effective treatment for AF and is superior to medical therapy. here we report a case of he stiff left atrium syndrome (SLAS) is a newly recognized post-procedure complication of RFCA due to left atrial (LA) scarring and fibrosis. CASE PRESENTATION: A 66 y/o female with a history of AF status post four RFCAs, suspected heart failure with preserved ejection fraction (HFpEF) with associated PH presented to the emergency room with shortness of breath. An echo cardiogram showed normal left ventricular (LV) systolic function and dilation of the Left atrium. Right heart catheterization (RHC) showed a pulmonary capillary wedge pressure (PCWP) of 32mmHg, a mean pulmonary artery pressure (PAP) of 62mmHg, and near normal peripheral vascular resistance indicating PVH. Due to refractory symptoms a follow up left and RHC showed similar MPAP and PCWP but left ventricular end diastolic pressure (LVEDP) was surprisingly normal at 12mmHg. A CT scan showed normal pulmonary veins without stenosis. Given the discrepancy of elevated LA pressure with a normal LVEDP, a diagnosis of SLAS was confirmed. Treatment with diuretics and control of risk factors were initiated. DISCUSSION: The differential diagnosis for a patient presenting with dyspnea and pulmonary hypertension with a history of prior RFCA includes HfpEF, pulmonary vein stenosis, valvular pathology, and SLAS, with HFpEF begin the most common . The estimated incidence of SLAS after RFCA is 1.4% - 8%. Key distinguishing features of SLAS include prominent V-waves on LA pressure tracings (via PCWP) disproportionate to the LVEDP. The diagnosis of SLAS is challenging and can be easily missed. For example, isolated post-capillary PH with a normal LV ejection fraction would suggest a diagnosis of HFpEF. However, a LHC in a patient with a stiff left atrium that demonstrated a significantly elevated LA V-wave and a surprisingly normal LVEDP would indicate no LVDD. Thus, in addition to imaging with echocardiography, invasive hemodynamic testing with simultaneous LHC to measure the LVEDP in addition to RHC for the PAP and PCWP is essential to make the difficult diagnosis of SLAS. Diuretics are currently considered mainstay treatment for SLAS. Recent studies have evaluated the novel use of an interatrial septal device to create an atrial septostomy which relieves LA pressure by creating a left-to-right shunt. In a trial for patients with HFpEF, an atrial septostomy led to a significant decrease in PCWP (28%), symptomatic improvement, a longer 6-minute walk distance, and better quality of life after 30 days. CONCLUSIONS: This case demonstrates the diagnostic challenge of SLAS and the importance of invasive hemodynamic testing with simultaneous RHC and LHC in addition to imaging to identify the true underlying cause of pulmonary hypertension. Reference #1: Gibson, D.N., et al., Stiff left atrial syndrome after catheter ablation for atrial fibrillation: clinical characterization, prevalence, and predictors. Heart Rhythm, 2011. 8(9): p. 1364-71. Reference #2: Maeder, M.T., et al., Pulmonary hypertension in stiff left atrial syndrome: pathogenesis and treatment in one. ESC heart failure, 2018. 5(1): p. 189-192. Reference #3: Chandrashekar, P., et al., Atrial Septostomy to Treat Stiff Left Atrium Syndrome. Circulation. Heart failure, 2017. 10(7): p. e004160. DISCLOSURES: No relevant relationships by Mark Cromer, source=Web Response No relevant relationships by Abhijit Raval, source=Web Response

Radio frequency catheter ablation of arrhythmias with low dose X-ray guided by three-dimensional mapping system in 14 children

Objective: To assess the feasibility and efficacy of radiofrequency catheter ablation (RFCA) of arrhythmias with low dose X-ray in children guided by three-dimensional mapping system. Methods: Fourteen children with tachyarrhythmia who were transferred to Tianjin Medical University General Hospital after being hospitalized in Tianjin Children's Hospital and underwent RFCA from April 2017 to May 2018 were included.The results of intraoperative electrophysiological examination, intraoperative X-ray dosage,the immediate success rateand complications of RFCA,and the recurrence during the follow-up for at least 6 months were recorded. Results: Among the 14 children, 11 cases were diagnosed with supraventricular tachycardia.Five cases had atrioventricular reentrant tachycardia (AVRT) which included two cases with left accessory pathway and three cases with right accessory pathway, and four cases had atrioventricular nodular reentrant tachycardia (AVNRT), one case had atrial flutter (AFL), one case had both AFL and AVNRT. One case had focal atrial tachycardia, one case had ventricular tachycardia, and one case had premature ventricular contraction. Eleven cases underwent RFCA with zero radiation, and 3 cases underwent atrial septal puncture with low dose X-ray. The exposure amounts were 3.85, 3.23 and 4.67 mGy, respectively. No complications occurred except for one case with AVRT had atrioventricular block and recovered to normal in 25 days after operation.During the follow-up of 7 to 20 months, no arrhythmias had been found in 13 cases, and one case with AVRT and AFL recurred. Conclusion: Under the guidance of three-dimensional mapping system, RFCA of tachyarrhythmia with low dose X-ray in children is feasible.

Cryoablation for atrial fibrillation.

Cryoballoon ablation for the treatment of atrial fibrillation has established itself as an effective and efficient modality for achieving pulmonary vein isolation. Over the past 13 years more than 100,000 Cryoballoon ablation procedures have been performed with the first to fourth generation cryoballoons. Over that time there have been significant advances in our understanding regarding the optimal procedural techniques. The purpose of this "topic in review" is to focus on the practical aspects of performing a Cryoballoon ablation procedure, within the context of the contemporary literature. Specifically there is a focus on how contemporary studies can inform clinical decision making and ensure operators are able to perform a safe and effective procedure.

Elongation of the high right atrium to coronary sinus conduction time predicts the recurrence of atrial fibrillation after radiofrequency catheter ablation

BackgroundThe impact of intra-atrial conduction delay on the recurrence of atrial tachyarrhythmia after radio frequency catheter ablation (RFCA) has not been fully elucidated. MethodsWe retrospectively analyzed 155 AF patients who were sinus rhythm at the start of RFCA. The conduction time from the onset of the earliest atrial electrogram at the high right atrium (HRA) to the end of the latest electrogram at the coronary sinus (CS) during sinus rhythm was defined as HRA-CS conduction time. Pulmonary vein isolation (PVI) was performed followed by linear roof lesion and complex fractionated atrial electrogram (CFAE) ablation until AF termination. We evaluated atrial tachyarrhythmia recurrence 12 months after RFCA. ResultsThe follow-up data were available for 148 patients. The recurrence of atrial tachyarrhythmia was noted in 28 (18.9%) patients. Atrial tachyarrhythmia recurrence patients had longer HRA-CS conduction times (151.3 ± 22.1 ms vs 160.1 ± 32.6 ms, p = .017). The patients were divided into the long or short HRA-CS conduction time group. The Kaplan–Meier analysis revealed that the long HRA-CS conduction time group held a higher risk of atrial tachyarrhythmia recurrence (log-rank test, p = .019). The multivariable Cox hazard analysis revealed that a long HRA-CS conduction time was a significant risk factor for the recurrence of atrial tachyarrhythmia, despite a long AF duration, persistent AF, and larger left atrial diameter (LAD) were not statistically significant. ConclusionsThe HRA-CS conduction time was the primary influencing factor that predicted the recurrence of atrial tachyarrhythmia after catheter ablation.

P1863Establishing safe working parameters for radio frequency catheterization along with acoustic sensing

Abstract Background Studies comparing angles of application in Radio Frequency (RF) catheter ablation other than 0 and 90 degrees are absent from the literature. Likewise, using acoustics to predict steam pop occurrences and prevent a catastrophic rupture of the myocardium has not been examined previously. Purpose Evaluate the effect of various parameters on the ablated volume and the probability of creating a boiling pop. Methods A low-cost testing and educational platform to work with generic RF catheters was set up. The in-vitro system allows controlling the blood flow surrogate over the cardiac tissue, the catheter contact force, electric power, and ablation time. Acoustic transducers have been employed with the setup to detect preliminary acoustic signals. Results Obtained results show a positive correlation between variations of the ablated surface geometry and power intensity changes. Generated figures provide percentages of a boiling pops for any given set of parameters fig1 (Top left: Probability of popping vs power and time). The probability of a boiling pop occurring increased if the ovine specimen is non-irrigated. The ratio of the burn correlates with the power and the angle of the catheter (30°, 45°, 60°, and 90°). However, the probability of the popping mostly depends on the power fig1 (Top right: Burn ratio vs power for 30°, 45°, 60°, and 90°) and fig1 (Bottom right: Cross sectional view of the corresponding lesions -same scale used for all images). Benign precursory bubbles detected by acoustics preceded the occurrence of catastrophic boiling pops fig1 (Bottom left: Acoustic signal showing a precursory pop before the major cavitation). Figure 1 Conclusion The established parameters for power intensity and exposure time should be respected to maintain a safe procedure. Acoustics can be further implemented to provide a warning for electrophysiologists before the occurrence of a boiling pop. Acknowledgement/Funding The funding for this project was provided from the URB and the MPP at the AUBMC and the AUB.

P1037Relationship between left atrium low voltage areas and atrial fibrillation radiofrequency ablation success-rate: preliminary results of the SMOP study

Abstract Background radio frequency catheter ablation (CA) is an effective therapy for atrial fibrillation (AF). Some authors have described a potential relationship between the presence of areas of fibrosis in the left atrium (LA) and the success of CA, nevertheless there is a lack of multicenter studies in this field. Objective the aim of our study was to assess the relationship between the of presence of low voltage areas of the LA detected during subtrate mapping at the time of the procedure and recurrences of AF after CA. Methods we analyzed 214 patients of the SMOP-AF (Substrate Mapping as Outcome Predictor in Atrial Fibrillation Ablation), a prospective multi-centric study enrolling patients with both paroxysmal and persistent AF undergoing a first radio-frequency CA procedure. High-density mapping was performed in sinus rhythm using the CARTO system before performing pulmonary vein isolation. Areas with less than 0,5 mV on mapping were defined as low voltage zone (LVZ), while between 0,5 mV and 1,5 mV intermediate voltage zone (IVZ). IVZ and LVZ were expressed as a percentage of the LA surface. Comparisons were made by Pearson correlation, cross-tables and Chi-square test or Student T test. Results the mean age of the enrolled population was 59±9 years, left ventricular ejection fraction was 59±9%, 86.4% of the pts had tested at least one anti-arrhythmic drug. Persistent atrial fibrillation was present in 10.3% of patients. The rate of documented AF recurrence at 3 months was 15,3% (n=29). There was a statistical significant correlation between the presence of IVZ and the rate of recurrences at 3 months (r=0.16, p value 0.03). Patients with IVZ greater than 4% of the left atrium surface showed a higher risk of recurrences (19.5% vs. 8,7%, p value 0.04). No statistical difference was observed in other procedural variables (number of lesions, contact force, force-time integral) among patients with or without recurrences. Conclusion Our study showed a relationship between CA short-term success rate and the presence of areas of intermediate voltage zone detected with high-density substrate mapping at the time of the procedure. The presence of areas of intermediate voltage zone greater than 4% of the LA determines a 2.5 folds increased risk of short-term recurrence. Our data needs to be confirmed in a longer follow-up.

The predictive value of E/e′ for recurrence after radiofrequency catheter ablation in persistant atrial fibrillation patients by dual gate Doppler

Objective To discuss the value of E/e′ index measured by dual gate Dopper predicting recurrence after radio frequency catheter ablation (RFCA) in persistant atrial fibrillation (PeAF) patients. Methods Fifty-three patients with PeAF who had successful RFCA and 25 controls were prospectively enrolled. The patients with PeAF were divided into AF recurrence group (n=21) and AF non-recurrence group (n=32) with median follow-up time of (25.94±2.78)months. All patients with PeAF underwent echocardiography in the preoperative 7 days. With dual gate Doppler, transmitral flow peak velocity (E) and mitral annular septal or lateral peak velocity e′(S), and e′(L) in early diastolic were measured simultaneously in the same cardiac cycle, then E/e′(S) and E/e′(L) were automatically calculated.With traditional method, E, e′(S) and e′(L) were measured in different cardiac cycles, then E/e′(S) and E/e′(L) were manually calculated.The time of whole analysis process with each method was recorded. Results PeAF patients had bigger E/e′(S) and E/e′(L) with both dual gate Doppler and traditional method than controls. Compared with those in controls and AF non-recurrence group, E/e′(S) and E/e′(L) increased in AF recurrence group with both dual gate Doppler and traditional method (all P 0.05). Cut-off values of 10.90 (sensitivity of 71.4%, specificity of 87.5%) for E/e′(S) was obtained by dual gate Doppler and 10.70 (sensitivity of 81.0%, specificity of 62.5%) was obtained by traditional method for predicted AF recurrence. Areas under curves between the two methods in ROC analysis was not significant (0.819 vs 0.728, P>0.05). The whole analysis time of dual gate Doppler was less than that of traditional method. Between inter- and intraobservers, the interclass correlation coefficient with dual gate Doppler was higher and 95% confidence interval range was smaller. Conclusions E/e′(S) is a valuable predictor for PeAF recurrence after RFCA in patients with PeAF. Dual gate Doppler can noninvasively assess single-beat E/e′ with less analysis time and better reproducibility compared with traditional method. Key words: Echocardiography; Atrial fibrillation; Ventricular function, left; Dual gate Doppler

Anesthesia in outpatient phlebology practice

Tumescent and/or conductive anaesthesia is the most frequently performed procedure to anesthetize the thermal types of surgical interventions, mini-phlebectomy and stripping of subcutaneous veins in outpatient settings. These interventions have become a common outpatient procedure almost everywhere, which made the issue of local anaesthesia more sensitive over the past 5 years in Russia. The aim is to compare the efficacy, safety and comfort when injecting various anaesthetic solutions to relieve pain during endovenous laser obliteration/radio frequency catheter ablation, stripping of the subcutaneous veins and mini-phlebectomy. Searching method. We searched for original articles in PubMed, in the archives of «Phlebology» and «Angiology and Vascular Surgery» journals issued for the period between 2001 and November 2018 and the search for official instructions in the state register of medicinal products. Selection criteria. We included all comparative studies: randomized and non-randomized, in which pain was assessed both during injection of a tumescent solution before EVLO and/or mini-phlebectomy and during surgery, as well as systematic reviews and monographs. Data analysis. In total, we identified 9 studies: 7 randomized and 2 non-randomized, one systematic review and two monographs. The advantage of a buffered solution over unbuffered one in terms of reducing pain during injection is revealed in three randomized, one simple comparative study and on the basis of systematic review data. A great efficacy of combining tumescent anaesthesia with a femoral nerve blockade, which was equivalent to spinal anaesthesia, was found in 4 randomized trials, two of which were double-blind, and one non-randomized. In addition, a smaller degree of motor block was reported after blocking the femoral nerve in comparison with spinal anaesthesia. In one randomized trial in which pain was assessed using cold and warm solutions, no significant differences in pain were observed either during or after surgery. In order to prepare a tumescent solution, lidocaine, prilocaine and mepivacaine were used at concentrations ranging from 0.028% to 0.2%; the advantages of higher concentrations over the lower ones have not been revealed. No adverse reactions and complications of anaesthesia have been reported in the studies, except for one where methaemoglobinemia of mild degree was detected in a small number of patients when using 0.2% prilocaine. The conclusion. Local anaesthesia, namely, conductive and tumescent anaesthesia, is an effective and safe anaesthesia method in outpatient surgery. Even very low concentrations of anaesthetic solutions are effective for tumescent anaesthesia. The use of buffered solutions increases significantly patient comfort during the injection. The combination of tumescent anaesthesia and femoral nerve block increases the effectiveness of anaesthesia. The femoral nerve block has significant advantages in comparison with spinal anaesthesia in terms of safety.

Integrated catheter for simultaneous radio frequency ablation and optoacoustic monitoring of lesion progression

Radio frequency (RF) catheter ablation is commonly used to eliminate dysfunctional cardiac tissue by heating via an alternating current. Clinical outcomes are highly dependent on careful anatomical guidance, electrophysiological mapping, and careful RF power titration during the procedure. Yet, current treatments rely mainly on the expertise of the surgeon to assess lesion formation, causing large variabilities in the success rate. We present an integrated catheter design suitable for simultaneous RF ablation and real-time optoacoustic monitoring of the forming lesion. The catheter design utilizes copper-coated multimode light guides capable of delivering both ablation current and near-infrared pulsed-laser illumination to the target tissue. The generated optoacoustic responses were used to visualize the ablation lesion formation in an ex-vivo bovine heart specimen in 3D. The presented catheter design enables the monitoring of ablation lesions with high spatiotemporal resolution while the overall therapy-monitoring approach remains compatible with commercially available catheter designs.

Hierarchical Algorithms for Causality Retrieval in Atrial Fibrillation Intracavitary Electrograms.

Multichannel intracavitary electrograms (EGMs) are acquired at the electrophysiology laboratory to guide radio frequency catheter ablation of patients suffering from atrial fibrillation. These EGMs are used by cardiologists to determine candidate areas for ablation (e.g., areas corresponding to high dominant frequencies or complex fractionated electrograms). In this paper, we introduce two hierarchical algorithms to retrieve the causal interactions among these multiple EGMs. Both algorithms are based on Granger causality, but other causality measures can be easily incorporated. In both cases, they start by selecting a root node, but they differ on the way in which they explore the set of signals to determine their cause-effect relationships: either testing the full set of unexplored signals (GS-CaRe) or performing a local search only among the set of neighbor EGMs (LS-CaRe). The ensuing causal model provides important information about the propagation of the electrical signals inside the atria, uncovering wavefronts and activation patterns that can guide cardiologists towards candidate areas for catheter ablation. Numerical experiments, on both synthetic signals and annotated real-world signals, show the good performance of the two proposed approaches.

Randomised clinical trial of cryoballoon versus irrigated radio frequency catheter ablation for atrial fibrillation—the effect of double short versus standard exposure cryoablation duration during pulmonary vein isolation (CIRCA-DOSE): methods and rationale

IntroductionPulmonary vein isolation (PVI) is an effective therapy for paroxysmal atrial fibrillation (AF), but it has limitations. The two most significant recent advances have centred on the integration of real-time...

P2675The predictive value of left atrial synchronization for recurrence after radio frequency catheter ablation in paroxysmal atrial fibrillation patients by dual gate Dopper

P2675The predictive value of left atrial synchronization for recurrence after radio frequency catheter ablation in paroxysmal atrial fibrillation patients by dual gate Dopper

EVALUATION OF LONG-TERM SUCCESS RATE OF OUTFLOW TRACT ABLATION IN PATIENTS WITH VENTRICULAR TACHYCARDIA

Introduction: Radio Frequency catheter ablation has become the cornerstone for treatment of ventricular tachycardia (VT) in patients refractory to antiarrhythmic agents. Little is known about VT ablation performed outside clinical trial setting. This study aims to examine the success rate of Left

GW27-e0211 Evaluation of atrial electromechanical characteristics by tissue doppler imaging and prediction recurrence of atrial fibrillation after successful radio frequency catheter ablation

GW27-e0211 Evaluation of atrial electromechanical characteristics by tissue doppler imaging and prediction recurrence of atrial fibrillation after successful radio frequency catheter ablation