Ripple Mapping Research Articles

The value of ripple mapping in the age of coherent mapping in scar-related atrial tachycardia.

An accurate display of scar-related atrial tachycardia (ATs) is a key determinant of ablation success. The efficacy of ripple mapping (RM) in identifying the mechanism and critical isthmus of scar-related ATs during coherent mapping is unknown. A total of 97 patients with complex ATs who underwent radiofrequency catheter ablation at our center between October 2018 and September 2022 were included. ATs was mapped using a multielectrode mapping catheter on the CARTO3v7 CONFIDENCE module. Coherent and RM were used to identify the reentrant circuit. The mechanisms of 128 ATs were analyzed retrospectively (84 anatomic-reentrant ATs and 44 non-anatomic reentrant ATs). The median AT cycle length was 264±25ms. The correct diagnosis was achieved in 83 ATs (68%) using only coherent mapping. Through coherent mapping plus RM, 114 ATs (84.2%) were correctly diagnosed (68% vs. 89%, p=.019). In non-anatomical reentrant ATs, 81% of the diagnostic rate was achieved by reviewing both coherent and ripple mapping compared to reviewing coherent mapping alone (81% vs. 52%, p=.03). Reviewing coherent mapping and ripple mapping showed a higher diagnostic rate in patients who underwent cardiac surgery than those with Coherent mapping alone (64% vs. 88%, p=.04). Coherent mapping combined with RM was superior to coherent mapping alone in identifying the mechanism of scar-related ATs post-cardiac surgery and non-anatomic reentrant ATs.

RIPPLE-VT study: Multicenter prospective evaluation of ventricular tachycardia substrate ablation by targeting scar channels to eliminate latest scar potentials without direct ablation

BackgroundRecurrent ventricular tachycardia (VT) can be treated by substrate modification of the myocardial scar by catheter ablation during sinus rhythm without VT induction. Better defining this arrhythmic substrate could help improve outcome and reduce ablation burden. ObjectiveThe study aimed to limit ablation within postinfarction scar to conduction channels within the scar to reduce VT recurrence. MethodsPatients undergoing catheter ablation for recurrent implantable cardioverter-defibrillator therapy for postinfarction VT were recruited at 5 centers. Left ventricular maps were collected on CARTO using a Pentaray catheter. Ripple mapping was used to categorize infarct scar potentials (SPs) by timing. Earliest SPs were ablated sequentially until there was loss of the terminal SPs without their direct ablation. The primary outcome measure was sustained VT episodes as documented by device interrogations at 1 year, which was compared with VT episodes in the year before ablation. ResultsThe study recruited 50 patients (mean left ventricular ejection fraction, 33% ± 9%), and 37 patients (74%) met the channel ablation end point with successful loss of latest SPs without direct ablation. There were 16 recurrences during 1-year follow-up. There was a 90% reduction in VT burden from 30.2 ± 53.9 to 3.1 ± 7.5 (P < .01) per patient, with a concomitant 88% reduction in appropriate shocks from 2.1 ± 2.7 to 0.2 ± 0.9 (P < .01). There were 8 deaths during follow-up. Those who met the channel ablation end point had no significant difference in mortality, recurrence, or VT burden but had a significantly lower ablation burden of 25.7 ± 4.2 minutes vs 39.9 ± 6.1 minutes (P = .001). ConclusionScar channel ablation is feasible by ripple mapping and can be an alternative to more extensive substrate modification techniques.

Enhanced identification of ventricular tachycardia isthmus within a scar using Ripple map and Octaray catheter

Enhanced identification of ventricular tachycardia isthmus within a scar using Ripple map and Octaray catheter

Characterization of conduction system activation in the postinfarct ventricle using ripple mapping

BackgroundThree-dimensional (3D) mapping of the ventricular conduction system is challenging. ObjectiveThe purpose of this study was to use ripple mapping to distinguish conduction system activation to that of adjacent myocardium in order to characterize the conduction system in the postinfarct left ventricle (LV). MethodsHigh-density mapping (PentaRay, CARTO) was performed during normal rhythm in patients undergoing ventricular tachycardia ablation. Ripple maps were viewed from the end of the P wave to QRS onset in 1-ms increments. Clusters of >3 ripple bars were interrogated for the presence of Purkinje potentials, which were tagged on the 3D geometry. Repeating this process allowed conduction system delineation. ResultsMaps were reviewed in 24 patients (mean 3112 ± 613 points). There were 150.9 ± 24.5 Purkinje potentials per map, at the left posterior fascicle (LPF) in 22 patients (92%) and at the left anterior fascicle (LAF) in 15 patients (63%). The LAF was shorter (41.4 vs 68.8 mm; P = .0005) and activated for a shorter duration (40.6 vs 64.9 ms; P = .002) than the LPF. Fourteen of 24 patients had left bundle branch block (LBBB), with 11 of 14 (78%) having Purkinje potential–associated breakout. There were fewer breakouts from the conduction system during LBBB (1.8 vs 3.4; 1.6 ± 0.6; P = .039) and an inverse correlation between breakout sites and QRS duration (P = .0035). ConclusionWe applied ripple mapping to present a detailed electroanatomic characterization of the conduction system in the postinfarct LV. Patients with broader QRS had fewer LV breakout sites from the conduction system. However, there was 3D mapping evidence of LV breakout from an intact conduction system in the majority of patients with LBBB.

Ripple AT Plus — isthmus-guided vs conventional ablation in the treatment of scar-related atrial tachycardia: study protocol for a randomised controlled trial

BackgroundCatheter ablation is routinely used to treat scar-related atrial tachycardia (s-AT). Conventional ablation often involves creating anatomical “lines” that transect myocardial tissue supporting reentry. This can be extensive, creating iatrogenic scar as a nidus for future reentry, and may account for arrhythmia recurrence. High-density mapping may identify “narrower isthmuses” requiring less ablation, with ripple mapping proven to be an effective approach in identifying. This trial explores whether ablation of narrower isthmuses in s-AT, defined using ripple mapping, results in greater freedom from arrhythmia recurrence compared to conventional ablation.MethodsThe Ripple-AT-Plus trial (registration ClinicalTrials.gov, NCT03915691) is a prospective, multicentre, single-blinded, randomised controlled trial with 12-month follow-up. Two hundred s-AT patients will be randomised in a 1:1 fashion to either “ripple mapping-guided isthmus ablation” vs conventional ablation on the CARTO3 ConfiDENSE system (Biosense Webster). The primary outcome will compare recurrence of any atrial arrhythmia. Multicentre data will be analysed over a secure web-based cloud-storage and analysis software (CARTONETTM).ConclusionThis is the first trial that considers long-term patient outcomes post s-AT ablation, and whether targeting narrower isthmuses in the era of high density is optimal.

Use of Ripple mapping to enhance localization and ablation of outflow tract premature ventricular contractions.

Accurate localization of septal outflow tract premature ventricular contractions (PVCs) is often difficult due to frequent mid-myocardial or protected origin. Compared with traditional activation mapping, CARTO Ripple mapping provides visualization of all captured electrogram data without assignment of a specific local activation time and thus may enhance PVC localization. Electroanatomic maps for consecutive catheter ablation procedures for septal outflow tract PVCs (July 2018-December 2020) were analyzed. For each PVC, we identified the earliest local activation point (EA), defined by the point of maximal -dV/dt in a simultaneously recorded unipolar electrogram, and the earliest Ripple signal (ERS), defined as the earliest point at which three grouped simultaneous Ripple bars appeared in late diastole. Immediate success was defined as full suppression of the clinical PVC. Fifty-seven unique PVCs in 55 procedures were included. When ERS and EA were in the same chamber (RV, LV, or CS), the odds ratio for the successful procedure was 13.1 (95% confidence interval [CI] 2.2-79.9, p = .005). Discordance between sites was associated with a higher likelihood of needing multi-site ablation (odds ratio [OR] 7.9 [1.4-4.6; p = .020]). Median EA-ERS distance in successful versus unsuccessful cases was 4.6 mm (interquartile range 2.9-8.5) versus 12.5 mm (7.8-18.5); (p = .020). Greater EA-ERS concordance was associated with higher odds of single-site PVC suppression and successful septal outflow tract PVC ablation. Visualization of complex signals via automated Ripple mapping may offer rapid localization information complementary to local activation mapping for PVCs of mid-myocardial origin.

Efficacy of functional substrate map-guide approach for wide circumferential pulmonary vein isolation

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulmonary vein isolation (PVI) with anatomical approach targeting closer interlesion distance (ILD) would be effective, but not efficient. A functional substrate map (FSM) can reveal the unnecessary application site including physiological block and the critical ablation site including direct epicardial connections. Purpose We investigated the efficacy of FSM-guide approach for wide circumferential PVI. Methods We enrolled 55 consecutive patients underwent radiofrequency PVI for atrial fibrillation. In earlier 27 patients were ablated by anatomical approach with closer ILD (&amp;lt;5mm) (control group), in latter 28 patients were by real time PV electrogram and high density electro-anatomical map guide (FSM-guide group). In FSM-guide group, characteristics of electrical conduction including voltage, direction , velocity and barrier between PV and left atrium and epicardial connection were assessed by local activation, coherent and ripple map before ablation. Distributions of the segments required or unnecessary ablation for PVI completion were examined. Results The success rate of first-pass isolation was higher in FSM-guide group than in control (96.4% vs. 74.1%). The number of required ablation tags for PVI were significantly lesser in FSM-guide group than control group (left-sided PV (LPV); 23.2±1.6 vs. 29.2±1.6, p=0.0112, right-sided PV (RPV); 22.6±1.7 vs. 32.4±1.8, p=0.0124, respectively). The time for PVI completion was significantly shorter in FSM-guide group than control group (RPV; 17.0±2.2 min vs. 25.2±2.8 min, p=0.0124, LPV; 18.7±1.5 min vs. 20.5±1.5 min, p=0.042, respectively). In FSM-guide group, unnecessary application sites were frequently located at posterior of RIPV (46%), anterior of LIPV (43%) and anterior of RSPV (35.7%). Frequently required segments for PVI completion were roof and carina of LPV and roof and posterior of RPV. In most cases of control group, full circumferential ablation was required (LPV 22/27(81%) and RPV 24/27(89%)). Acute reconnections during procedure were similar in FSM-guide group and control group (LPV; 6/28 (21.4%) vs. 4/27 (14.8%), p=0.7287, RPV; 9/28 (32.1%) vs. 4/27 (14.8%), p=0.2047, respectively). All of reconnection sites in FSM-guide group were ablated site. Conclusions FSM-guide approach for extensive PVI could reveal unnecessary application sites and result in shorter procedure with comparable ablation quality.

Ripple mapping in ventricular tachycardia substrate mapping and ablation of nonischemic ventricular tachycardia.

Substrate-based ablation for ventricular tachycardia (VT) using Ripple map (RM) is an effective treatment strategy for patients with ischemic cardiomyopathy but has yet to be evaluated in patients with nonischemic cardiomyopathy (NICMO). The aim of this study is to determine the feasibility and effectiveness of an RM-basedablation for NICMO patients. This was a single-center, retrospective study including all NICMO patients undergoing VT ablation at St Vincent Hospital between January 1, 2018 and January 12, 2019. Retrospective RM analysis was performed on those that had a substrate-based ablation to identify the location and number of Ripple channels as well as their proximity to ablation lesions. Thirty-three patients met the inclusion criteria and had a median age of 65 (58, 73.5) with 15.2% of the population being female, and were followed for a median duration of 451 (217.5, 586.5) days. Of these patients, 23 (69.7%) had a substrate-based ablation with a median procedural duration of 196.4 (186.8, 339) min, 1946 (517, 2750) points collected per map, and 277 (141, 554) points were within the scar. Two (8.6%) procedural complications occurred, and 7 (30.4%) patients had VT recurrence during follow-up. RM analysis revealed an average of two Ripple channels and the patients without VT recurrence had ablation performed closer to the Ripple channels: 0 (0, 4.7) versus 14.3 (0, 23.5) cm; p = .02. An RM-basedsubstrate ablation can be performed in NICMO patients and ablation within Ripple channels is a predictor of VT freedom.

An approach to help differentiate postinfarct scar from borderzone tissue using Ripple Mapping during ventricular tachycardia ablation.

Ventricular scar is traditionally highlighted on a bipolar voltage (BiVolt) map in areas of myocardium <0.50 mV. We describe an alternative approach using Ripple Mapping (RM) superimposed onto a BiVolt map to differentiate postinfarct scar from conducting borderzone (BZ) during ventricular tachycardia(VT) ablation. Fifteen consecutive patients (left ventricular ejection fraction 30 ± 7%) underwent endocardial left ventricle pentaray mapping (median 5148 points) and ablation targeting areas of late Ripple activation. BiVolt maps were studied offline at initial voltage of 0.50-0.50 mV to binarize the color display (red and purple). RMs were superimposed, and the BiVolt limits were sequentially reduced until only areas devoid of Ripple bars appeared red, defined as RM-scar. The surrounding area supporting conducting Ripple wavefronts in tissue <0.50 mV defined the RM-BZ. RM-scar was significantly smaller than the traditional 0.50 mV cutoff (median 4% vs. 12% shell area, p < .001). 65 ± 16% of tissue <0.50 mV supported Ripple activation within the RM-BZ. The mean BiVolt threshold that differentiated RM-scar from BZ tissue was 0.22 ± 0.07 mV, though this ranged widely (from 0.12 to 0.35 mV). In this study, septal infarcts (7/15) were associated with more rapid VTs (282 vs. 347 ms, p = .001), and had a greater proportion of RM-BZ to RM-scar (median ratio 3.2 vs. 1.2, p = .013) with faster RM-BZ conduction speed (0.72 vs. 0.34 m/s, p = .001). Conversely, scars that supported hemodynamically stable sustained VT (6/15) were slower (367 ± 38 ms), had a smaller proportion of RM-BZ to RM-scar (median ratio 1.2 vs. 3.2, p = .059), and slower RM-BZ conduction speed (0.36 vs. 0.63 m/s, p = .036). RM guided ablation collocated within 66 ± 20% of RM-BZ, most concentrated around the RM-scar perimeter, with significant VT reduction (median 4.0 episodes preablation vs. 0 post, p < .001) at 11 ± 6 months follow-up. Postinfarct scars appear significantly smaller than traditional 0.50 mV cut-offs suggest, with voltage thresholds unique to each patient.

Ripple Frequency Determined via a Novel Algorithm Is Associated With Atrial Fibrillation Termination and Freedom From Atrial Fibrillation.

Persistent atrial fibrillation (AF) is a complex arrhythmia, and attaining freedom from AF with ablation has been challenging. This study evaluated a novel CARTO software algorithm based on the CARTO Ripple map for AF termination and 18-month freedom from AF. Consecutive patients who underwent first-time ablation for persistent AF were included. A high-density Ripple map was created using a Pentaray catheter. Following PVI, ablation was performed at locations with rapid Ripple activations, a protocol previously described by us. Patients were followed for 18 months to assess rhythm outcomes. A retrospective analysis was performed using the CARTO Ripple frequency software algorithm. The Ripple frequency algorithm quantifies amplitude changes in the bipolar electrogram. A total of 115 AF maps were analyzed from 84 patients (mean age 65.9 years, 63.1% men). The top quartile of Ripple frequency corresponded to a visual reference with 96.7% sensitivity and 91.1% specificity. AF terminated during ablation in 88.1% of patients: pulmonary vein antrum alone (14.9%) or pulmonary vein plus nonantral sites (85.1%). The top quartile of Ripple frequency was present in nonantral areas associated with AF termination with 90.2% sensitivity and 86.5% specificity. After 14.0 ± 6.5 months and 1.2 ± 0.4 ablations, 78 (92.9%) of 84 patients were free of AF, and 79.8% were free of any atrial arrhythmia. A novel algorithm for automated analysis of CARTO Ripple frequency demonstrated good sensitivity and specificity for detecting atrial regions in persistent AF in which ablation is associated with frequent AF termination and freedom from AF during follow-up.

Innovations in ventricular tachycardia ablation.

Catheter ablation of ventricular arrhythmias (VAs) has evolved significantly over the past decade and is currently a well-established therapeutic option. Technological advances and improved understanding of VA mechanisms have led to tremendous innovations in VA ablation. The purpose of this review article is to provide an overview of current innovations in VA ablation. Mapping techniques, such as ultra-high density mapping, isochronal late activation mapping, and ripple mapping, have provided improved arrhythmogenic substrate delineation and potential procedural success while limiting duration of ablation procedure and potential hemodynamic compromise. Besides, more advanced mapping and ablation techniques such as epicardial and intramyocardial ablation approaches have allowed operators to more precisely target arrhythmogenic substrate. Moreover, advances in alternate energy sources, such as electroporation, as well as stereotactic radiation therapy have been proposed to be effective and safe. New catheters, such as the lattice and the saline-enhanced radiofrequency catheters, have been designed to provide deeper and more durable tissue ablation lesions compared to conventional catheters. Contact force optimization and baseline impedance modulation are important tools to optimize VT radiofrequency ablation and improve procedural success. Furthermore, advances in cardiac imaging, specifically cardiac MRI, have great potential in identifying arrhythmogenic substrate and evaluating ablation success. Overall, VA ablation has undergone significant advances over the past years. Innovations in VA mapping techniques, alternate energy source, new catheters, and utilization of cardiac imaging have great potential to improve overall procedural safety, hemodynamic stability, and procedural success.

Differentiating border-zone tissue from post-infarct scar using ripple mapping during VT ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Areas of post-infarct ventricular scar and border-zone slow conduction are often highlighted on a bipolar voltage map with generalized values 0.5mV–1.5mV. The true voltage that differentiates regions of conducting from non-conducting tissue is unknown. Ripple Mapping (RM)displays allows conducting tissue to be seen as areas supporting Ripple activation, and non-conducting tissue as areas devoid of Ripple activation. Purpose We describe application of Ripple Maps to differentiate areas of scar from conducting tissue during ischemic VT ablation. Methods Dense bipolar voltage maps were created (Pentaray catheter, pacing 80-100bpm) and presented as a single value (e.g. 0.5mV-0.5mV) to binarize the color display (red and purple). RMs were superimposed on the voltage map and played above a pre-set noise threshold (&amp;gt;0.05mV). The voltage map mV limit was sequentially reduced ("border-zone threshold") until only those areas devoid of Ripple bars appeared red. The surrounding border-zone supporting ripple activation thus appeared purple. We performed off-line analysis of border-zone voltage thresholds from a series of RM guided VT ablations. Results 10 consecutive patients (LVEF 32.3±7.5%) with remote myocardial infarction underwent VT ablation (median 19days (IQR 8-33) since last VT). Bipolar voltage mapping (5873±2841 points, median shell area 224cm2), revealed voltages&amp;lt;0.5mV covered a median 11% (IQR 7-17%) of the shell. The border-zone voltage threshold was median 0.2mV (range 0.12mV - 0.3mV). Non-conducting tissue below this value covered only median 5% (IQR 3-7%) of the entire shell. VT was mappable in 4 patients, and the isthmus was bordered by tissue below the same border-zone threshold as found in normal rhythm. The border-zone was homogenized with ablation(40-50W, median 29 mins (IQR 22-33), and clinical VT was non-inducible in all, and 9 pts (91%) remain sustained VT-free at median 90-day follow-up (IQR 23-139), 2-weeks blanking period). Picture 1 presents an infero-lateral LV infarct collected in an RV paced rhythm (7340points) and displayed at conventional bipolar voltage settings 0.5-1.5mV. Tissue with voltages&amp;lt;0.5mV appear red and cover 30% of the total area. In this case, this border-zone voltage threshold was defined as 0.25mV. Non-conducting tissue, seen as areas devoid of ripple bars below this value, now appeared as red, and covered only 11% of the total area. Picture 2 demonstrates the morphologies of 4 poorly tolerated induced VTs during this case. Each had near perfect pacemaps to the exit sites of border-zone tissue defined using this approach, and were targets for ablation resulting in complete non-inducibility and no VT recurrence in early follow-up. Conclusion The bipolar voltage that differentiates putative scar from bordering conducting tissue is unique to each patient, and far lower than 0.5mV-1.5mV. RM presents a practical approach to visualize the border-zone activation to guide ablation.

CE-520-03 USE OF RIPPLE MAPPING TO ENHANCE LOCALIZATION AND ABLATION OF OUTFLOW TRACT PREMATURE VENTRICULAR CONTRACTIONS

Mapping outflow tract (OT) premature ventricular contractions (PVCs) can be difficult given a frequent mid-myocardial origin. Compared to local activation time mapping, Carto® Ripple Mapping provides visualization of both far field and near field signals independent of local annotation that may enhance PVC localization.

PO-634-03 RIPPLE MAPPING: A PRACTICAL APPROACH TO DIFFERENTIATE VENTRICULAR SCAR FROM BORDER-ZONE SLOW CONDUCTION USING CARTO RIPPLE MAPPING DURING VENTRICULAR TACHYCARDIA ABLATION

Areas of ventricular scar and border-zone slow conduction are often highlighted on a bipolar voltage map with generalized values 0.5mV-1.5mV. The true voltage that differentiates regions of conducting tissue from non-conducting scar is unknown. Ripple mapping (RM) is a core feature within CARTO3 that displays the bipolar electrogram amplitude from each point as a white moving bar. Conducting tissue is seen as areas supporting Ripple activation, and electrical scar as areas devoid of Ripple activation.

PO-694-02 UTILITY AND LIMITATION OF A NOVEL MAPPING ALGORITHM UTILIZING VECTORS AND GLOBAL PATTERN OF PROPAGATION IN ATRIAL TACHYCARDIA

A novel mapping algorithm utilizing vectors and global pattern of propagation has been described to help identifying the mechanism of atrial tachycardia (AT, Coherent™, BiosenseWebster). However, the utility and limitation of coherent mapping in comparison with ripple mapping remains uncertain.

Ripple mapping: A precise tool for atrioventricular nodal reentrant tachycardia ablation.

Ablation for atrioventricular nodal reentrant tachycardia (AVNRT) classically utilizes evaluation of signal morphology within the anatomic region of the slow pathway (SP), which involves subjectivity. Ripple mapping (RM;CARTO-3© Biosense Webster Inc) displays each electrogram at its three-dimensional coordinate as a bar changing in length according to its voltage-time relationship. This allows prolonged, low-amplitude signals to be displayed in their entirety, helping identify propagation in low-voltage areas. We set out to evaluate the ability of RM to locate the anatomic site of the SP and assess its use in guiding ablation for AVNRT. Patients ≤18 years with AVNRT in the EP laboratory between 2017 and 2021 were evaluated. RM was performed to define region of SP conduction in patients from 2019 to 2021, whereas standard electro-anatomical mapping was used from 2017 to 2019. All ablations were performed using cryotherapy. Demographics, outcomes, and analysis of variance in number of test lesions until success was compared between groups. A total of 115 patients underwent AVRNT ablation during the study; 46 patients were in the RM group and 69 were in the control group. There were no demographic differences between groups. All procedures, in both groups, were acutely successful. In RM group, 89% of first successful lesions were within 4 mm of the predicted site. There was significantly reduced variability in number of test lesions until success in the RM group (p = .01). RM is a novel technique that can help identify SP location, allowing for successful ablation of AVNRT with decreased variability.

Parameter Optimization for Reducing Torque Ripple and Harmonic Losses of Multi-Layered Interior Permanent-Magnet Synchronous Motors

In this paper, parameter optimization of multi-layered interior permanent-magnet synchronous motors for electric vehicle propulsion is carried out to improve torque ripple and efficiency at low- and high-speed regions. First, we establish a torque ripple map based on <i>d-q</i> currents. The ripples of the <i>d-q</i> parameters and harmonics of the phase flux linkages are then analyzed to investigate the relationship between the torque ripple and the parameters. Second, we compose and analyze an iron loss map based on <i>d-q</i> currents, and then investigate the parameters that affect the harmonics of the flux density. In particular, because the high-speed region is highly vulnerable to iron loss, the parameters related to this tendency are also analyzed. Based on the analysis results, we develop a parameter optimization strategy that leads to an optimal design. To analyze the electro-magnetic performances of the motors, two- and three-dimensional finite elements analyses are carried out by employing sinusoidal and inverter-controlled currents, and the improvement achieved are demonstrated by the experimental validations on prototypes.

Postinfarct ventricular tachycardia substrate: Characterization and ablation of conduction channels using ripple mapping.

Conduction channels have been demonstrated within the postinfarct scar and seem to be co-located with the isthmus of ventricular tachycardia (VT). Mapping the local scar potentials (SPs) that define the conduction channels is often hindered by large far-field electrograms generated by healthy myocardium. The purpose of this study was to map conduction channel using ripple mapping to categorize SPs temporally and anatomically. We tested the hypothesis that ablation of early SPs would eliminate the latest SPs without direct ablation. Ripple maps of postinfarct scar were collected using the PentaRay (Biosense Webster) during normal rhythm. Maps were reviewed in reverse, and clusters of SPs were color-coded on the geometry, by timing, into early, intermediate, late, and terminal. Ablation was delivered sequentially from clusters of early SPs, checking for loss of terminal SPs as the endpoint. The protocol was performed in 11 patients. Mean mapping time was 65 ± 23 minutes, and a mean 3050 ± 1839 points was collected. SP timing ranged from 98.1 ± 60.5 ms to 214.8 ± 89.8 ms post QRS peak. Earliest SPs were present at the border, occupying 16.4% of scar, whereas latest SPs occupied 4.8% at the opposing border or core. Analysis took 15 ± 10 minutes to locate channels and identify ablation targets. It was possible to eliminate latest SPs in all patients without direct ablation (mean ablation time 16.3 ± 11.1 minutes). No VT recurrence was recorded (mean follow-up 10.1 ± 7.4 months). Conduction channels can be located using ripple mapping to analyze SPs. Ablation at channel entrances can eliminate the latest SPs and is associated with good medium-term results.

B-PO05-116 RIPPLE-VT STUDY: MULTICENTRE, PROSPECTIVE EVALUATION OF CONDUCTION CHANNEL ENTRANCE ABLATION IN ISCHEMIC VENTRICULAR TACHYCARDIA WITH LATEST SCAR POTENTIAL ELIMINATION WITHOUT DIRECT ABLATION AS AN ENDPOINT

Recurrent implantable cardioverter-defibrillator (ICD) therapies for post-infarct ventricular tachycardia (VT) can cause significant morbidity. Substrate modification of the ventricular scar by targeting conduction channels has been proposed as a potential intervention. To prospectively assess ICD therapies after substrate modification using Ripple Mapping to locate and ablate channel entrances with loss of latest scar potentials without direct ablation as an endpoint. Patients with ICD therapies for post-infarct VT were prospectively recruited. High-density ventricular scar maps were collected using the Pentaray. Ripple Maps of the scar were viewed in reverse-play from the end of the T-wave to peak QRS to identify clusters of >3 Ripple bars. Ablation was delivered at clusters of earliest scar potentials and the Pentaray was used to monitor the effect on the latest scar potentials. Patients were followed up for a combined primary endpoint of ICD therapy, VT recurrence and mortality for 1 yr. Fifty patients (mean age 70.2±7.1 years, mean EF 32.9±9.5%) were enrolled from 5 centres. 24% had previous VT ablation and 48% were on amiodarone. There were 42.3±75.4 VT episode and 2.3±2.7 shock in the 12 months prior. High-density substrate maps (median points 2606 [2211 - 3254]) were collected. In 37pts (74%) the latest scar potentials were eliminated without direct ablation and 11pts (22%) required direct ablation of latest scar potentials as well. The protocol was not feasible in 1pt and abandoned in 1pt due to vascular complication. After ablation of channel entrances (n=37), VT was non-inducible in 91% (29 of 32 tested) and 30/35pts (86%) remained free of VT recurrence during median follow up of 6.5 [1.2 - 12.0] months. In pts where channel entrance ablation alone did not eliminate latest scar potentials (n=11), VT was non-inducible in 6/11 (55%) pts and 8/10pts (80%) remained free of VT over follow up of 4.6 [1.2 - 7.8] months. On an intention-to-treat basis, 40/50pts (80%) were free from the primary endpoint at a median 5.7 [1.8 - 12.0] months. 3pts died during follow up without VT recurrence. Ablation of conduction channel entrances using Ripple Mapping is feasible and has comparable outcomes to other techniques.

B-PO03-088 ATRIAL FIBRILLATION TERMINATION AND FREEDOM FROM ATRIAL FIBRILLATION IS ASSOCIATED WITH ABLATION OF ATRIAL REGIONS WITH HIGHER RIPPLE FREQUENCY

Persistent atrial fibrillation (AF) is a complex arrhythmia with multiple pathophysiologic mechanisms. Achieving a high rate of freedom from AF post ablation has been challenging. Carto® Ripple map has previously been identified as one possible method to improve ablation outcomes. The purpose of this study was to evaluate a novel CARTO® software algorithm based on CARTO® Ripple map for automated detection of visually identified high Ripple frequency locations, and the relationship of these sites to AF termination and 18 month freedom from AF. Consecutive patients underwent first time ablation for persistent AF. A high-density Ripple map was created using a Pentaray catheter. If AF did not terminate with pulmonary vein antral isolation, ablation was performed at sites with visually identified fast Ripple activations until AF termination, a protocol previously described and published by us. Patients were followed 18 months for rhythm outcome. Retrospectively analysis was then performed using a novel CARTO® software algorithm developed to analyze Ripple frequency, defined as the number of Ripple identified changes in dV/dT per second. A total of 69 maps from 38 patients (mean age 65.6, 65.8% male) were analyzed. A mean of 11.8 ± 4.9 electrograms per cm2 were present on which the automated Ripple Frequency maps were generated. The Ripple frequency ranged from 0 to 140 Ripple activations per second and the top quartile of Ripple frequency corresponded to a visual reference with 95.0% sensitivity and 88.4% specificity. AF was observed to terminate with ablation in 94.7% of patients; PV antrum alone (21.1%), or PV plus non antral sites (78.9%). The three most common non-PV antral locations were LA septum 66.7%, LA roof 61.1%, and Inferior LA 38.9%. The top quartile of Ripple frequency was present in non-PV sites necessary for AF termination with an 89.6% sensitivity and 91.4% specificity. On follow up of 18 months, 37 of 38 patients (97.4%) were free of AF. This novel algorithm for automated analysis of CARTO® Ripple frequency demonstrated a good sensitivity and specificity for detecting atrial regions in persistent AF where ablation is associated with both termination and a high freedom from AF after 18 months.