Focal Tachycardia Research Articles

PO-02-226 NON-INVASIVE ELECTROCARDIOGRAPHIC IMAGING FOR THE CHARACTERIZATION OF COMPLEX ATRIAL TACHYARRHYTHMIAS

Non-invasive characterization of complex atrial tachyarrhythmias, regarding atrial flutter (AFL) and focal atrial tachycardia (AT) is challenging. Conventional electrocardiogram (ECG) faces several limitations. Planning a preprocedural strategy before AFL-AT catheter ablation (CA) is needed. To evaluate the diagnostic capacity of a novel non-invasive electrocardiographic imaging (ECGI) system that does not require previous CT or MRI cardiac imaging. 42 patients (27 males, CHA2DS2-VASc score 2±1, LVEF 54.5 ± 11.0 %, and LA area 31.3 ± 7.0 cm2) undergoing CA for AT-AFL were prospectively included in the study. Before the procedure, the ECGI system estimated the patient atria geometry using a 3D torso reconstruction and an artificial intelligence-based algorithm. Multiple electrocardiograms were recorded using a 64-electrodes vest during the CA procedure. The different diagnostic capacities of the periprocedural ECG and ECGI were assessed compared with endocavitary electroanatomical mapping (EAM) regarding three endpoints: (1) the involved atrial cavity, (2) the mechanism (focal or macro-reentry), and (3) the ablation target site defined as the area where the earliest activation was located for focal arrhythmias, and the precise anatomical pathway for macro re-entrant tachyarrhythmias. Regarding the ECG, endpoints were assessed based on validated algorithms by 2 different observers blinded from the diagnosis. 48 atrial tachyarrhythmias were evaluated and its characterization using this novel ECGI system was possible in 94% of the cases: directly for 36 arrhythmias and after decreasing ventricular response using vagal maneuvers for 9. ECGI obtained global accuracy to identify the involved atrial cavity of 92%, the mechanism of 90%, and the ablation target of 83% (Table). In challenging cases, such as in patients with a history of CA for atrial fibrillation and in patients without a final diagnosis of typical counterclockwise AFL, the accuracy of ECGI was consistent compared to the whole study population (Table). The ECGI diagnostic capacity significantly outclassed the ECG regarding the identification of the involved cavity (p<0.001), the mechanism (p<0.05), and the ablation target (p<0.001). ECGI could have prevented all unnecessary transseptal punctures (n=7), representing 28% of the overall punctures. This novel non-invasive ECGI system accurately characterizes complex atrial tachyarrhythmias (Figure) without needing previous CT or MRI cardiac imaging.

PO-02-122 TRACKING AND ABLATING THE MUSCLE SLEEVE/FASCICLE FOR PULMONARY VEIN ISOLATION

Pulmonary vein isolation (PVI) remains the cornerstone for atrial fibrillation (AF) ablation. However, it yields unsatisfactory outcomes requiring repeat procedures especially in persistent AF. Additional linear ablation, or of complex fractionated atrial electrograms, atrial rotors or ganglionated plexi prolongs procedure time and increases complications with small additional benefits. We evaluated the efficacy of a new method of tracking and ablating pulmonary vein (PV) muscle sleeve/fascicle followed by wide area circumferential ablation (WACA) as a method of treatment of AF. To track a muscle sleeve/fascicle, a Lasso catheter was placed into one PV and based on the electrograms pattern on the catheter, sites of exit of muscle sleeves/fascicles were determined along the wide area circumferential ablation (WACA) line. (Panel A of figure shows the electrogram pattern, which suggests two muscle fascicles [red and blue arrows]). Focal ablation at sites on the planned WACA line was then performed to interrupt the muscle sleeve/fascicle connection with atrium (Panel B and C of figure shows point ablation resulting in partial and complete isolation; black arrow marks the location of ablation catheter). The same method was repeated to the ipsilateral PV before full WACA of both PVs was commenced. The strategy was repeated on the contralateral PVs. Ablation of these fascicle-atrium connections resulted in PVI isolation before WACA was completed in all 18 patients. Intravenous adenosine was used at the end to elicit dormant PV connections. We schematically labeled the areas around the PVs into zones and summarized the location of these muscle fascicles in each patient. (Panel D; each dot represents a fascicle and color matches with the PV with which it is associated). Eighteen patients (61±11 years old, 56% male) with AF (12 persistent {67%}) were analyzed in this study. Fascicles were identified in all patients and focal ablation of fascicles resulted in isolation of the PVs. In addition to PVI, 8 had Cavotricuspid isthmus ablation, 1 for right focal atrial tachycardia (AT), one left focal AT, and 1 for biatrial reentrant AT. With a follow-up of 155 ±120 days, 83% of paroxysmal and 75% of persistent AF remained in sinus rhythm. Left atrial dwell time for PVI alone was less than 2 hrs and no complications were seen. The tracking and ablating muscle sleeve/fascicle before performing WACA is a strategy with outcomes superior to previously reported in literature.

PO-01-037 RISK FACTORS FOR PRESENCE OF NON-PULMONARY VEIN TRIGGERS FOR ATRIAL FIBRILLATION

Targeting of non-pulmonary vein triggers (NPVTs) after pulmonary vein isolation (PVI) may reduce atrial fibrillation (AF) recurrence. Incrementally dosed isoproterenol infusion (up to 30mcg/min) and cardioversion of induced AF used to provoke NPVTs typically requires additional vasopressor support and increases procedure time. We aimed to identify risk factors for the presence of NPVTs in order to identify patient profiles in which NPVT provocation would have greatest yield. Using the Hospital of the University of Pennsylvania AF ablation registry, we compared patients in whom NPVTs were observed to patients in whom NPVTs were not observed using a standard provocation protocol. NPVTs were defined as a single or sequence of non-pulmonary vein atrial ectopic beats triggering non-sustained or sustained AF or focal atrial tachycardia. Continuous variables were compared using unpaired t-Test and categorical variables were compared using Fisher exact test. In a total of 1,306 AF ablation patients between January 2021 and August 2022, 87% underwent NPVT standard provocation testing and 10% of all patients had NPVTs observed. Compared to those without NPVTs, patients who had NPVTs were more likely to be female (41% vs 30%, OR 1.62 [1.12-2.35], p=0.01), and to have sinus node dysfunction (17% vs 7%, OR 2.83 [1.72-4.65], p=0.0002), prior AF ablation (68% vs 34%, OR 4.16 [2.82-6.19], p=<0.0001), and left atrial scar (>2cm2) (71% vs 36%, OR 4.28 [2.78-6.53], p=<0.0001) identified during voltage mapping (defined as peak to peak bipolar voltage <0.5mV of at least three abnormal contiguous electrograms outside pulmonary veins, Table 1). In this patient cohort, the absence of these four risk factors yielded NPVT provocation rate of 0.02%, while the presence of three or four risk factors led to NPVT provocation rate of 30-50% (Figure 1). Incremental presence of the NPVT associated risk factors allows prediction of the likelihood that provocation testing will lead to the induction of NPVTs and may influence decision making to undertake NPVT provocation testing during AF ablation.Tabled 1Table 1VariableOverall (N=1306)NPVT (N=130)No NPVT (N=1006)P ValueOdds Ratio (95% CI)Age (years)130665.89 ± 9.9965.00 ± 10.590.36BMI130629.16 ± 5.6229.95 ± 6.270.17LVEF (%)126656.42 ± 9.5755.28 ± 11.210.27LA volume index (mL/m2)62639.34 ± 17.8939.25 ± 17.180.97CHA2DS2VASc score13002.40 ± 1.452.41 ± 1.560.94Female40353 (41)350 (30)0.011.62 (1.12-2.35)Hx of CVA/TIA12314 (11)109 (9)0.53Diabetes20215 (12)187 (16)0.25Heart Failure / CM41738 (29)379 (32)0.55Hypertension1031105 (81)926 (79)0.65Obstructive Sleep Apnea42343 (33)380 (32)0.84Sinus Node Dysfunction10122 (17)79 (7)0.00022.83 (1.72-4.65)Non-Paroxysmal AF478/124151 (41)427 (38)0.63Had Previous AF Ablation48288 (68)394 (34)<0.00014.16 (2.82-6.19)Has LA scar (Any LVA)426/106978 (71)348 (36)<0.00014.28 (2.78-6.53)Values are reported as mean ± SD, or number (%). P value is comparing NPVT group vs No NPVT group. Continuous variables compared using unpaired t-Test, and categorical variables compared using Fisher exact test. BMI=body mass index; LVEF=left ventricular ejection fraction; LA=left atrium; CVA=cerebrovascular accident; TIA=transient ischemic attack, CM=cardiomyopathy; AF=atrial fibrillation; LVA=low voltage area; NPVT=non-pulmonary vein trigger Open table in a new tab

MP-453088-7 PROOF-OF-CONCEPT FORWARD-SOLUTION MAPPING OF A FOCAL ATRIAL TACHYCARDIA ORIGIN USING THE OUTPATIENT 12-LEAD ELECTROCARDIOGRAM

Arrhythmia source mapping is essential to the delivery of targeted catheter ablation for cardiac arrhythmias. Whether mapping may be performed using outpatient 12-lead electrocardiogram (ECG) data was unknown. The objective of this proof-of-concept study was to evaluate the feasibility, temporal efficiency, and accuracy for forward-solution mapping using clinical ECG data obtained outside the electrophysiology laboratory. The patient is a 24-year-old female with recurrent, symptomatic focal atrial tachycardia (focal AT) diagnosed by 12-lead ECG in the outpatient clinic. After unsuccessful medical therapy, she elected to proceed with catheter ablation at Kaiser Santa Clara Medical Center. 12-lead ECG data from the clinical ECG database (Muse, GE Medical) was exported and transferred to the forward-solution mapping system (vMap, Vektor Medical). After data upload and system confirmation of acceptable data quality, a selection window was placed around the focal AT P-wave of interest (Figure A). The mapping process was initiated and the probabilistic source locations for the focal AT were displayed by the system. These results were then compared to the results of invasive activation mapping. Results from the forward-solution analysis demonstrated a highest probability focal AT source at the anterior base of the left atrial appendage (Figure B). Total processing time following upload of the ECG data into the clinical system was less than 3 minutes. Invasive activation mapping using the electroanatomic mapping system (Carto, Biosense-Webster) also demonstrated the site of early activation at the anterior base of the left atrial appendage (Figure C). Center-to-center spatial error between the forward-solution result and the site of early activation by invasive mapping was 8.8 mm. Forward-solution arrhythmia source mapping using data from a commercial ECG system obtained outside the electrophysiology laboratory is feasible, time-efficient, and demonstrates excellent agreement with invasive electroanatomic mapping. Future studies are required to determine whether this process may facilitate the delivery of targeted arrhythmia therapy in larger populations.

A rare focal atrial tachycardia arising from the proximal middle cardiac vein: a case report

BackgroundFocal atrial tachycardia (FAT) always originates from atrium specific sites and can be successfully cured by radiofrequency (RF) ablation. However, the middle cardiac vein (MCV) is a rare site of focal atrial tachycardia. Herein, we present a case of a 20-year-old young woman with FAT. Electrophysiological examination showed FAT arising from the proximal middle cardiac vein (pMCV), and successful RF ablation was applied with a low power and short-ablation.Case presentationA 20-year-old woman with no structural heart disease suffered recurrent supraventricular tachycardia for 1 year. Physical examination, laboratory studies and the echocardiography results of this patient were normal. A 12-lead electrocardiogram (ECG) showed a narrow QRS and long RP tachycardia which was always triggered by a sinus rhythm. The patient underwent an electrophysiological study and found the earliest activation was in the proximal MCV (pMCV). After a low power and short-ablation, AT was terminated and noninducible by programmed pacing with or without isoproterenol infusion.ConclusionThis case presented a rare case of FAT arising from the pMCV. We demonstrate that low power and short-ablation are effective in AT arising from specific areas such as the coronary sinus ostium and pMCV.

Successful treatment of the focal ectopic atrial tachycardia in an infant with a single dose of ivabradin.

We report on a 12-month-old boy with an ectopic atrial tachycardia successfully treated with the ivabradine that acts on cardiac pacemaker cells by selectively inhibiting the If channel. The patient was diagnosed with supraventricular tachycardia in another centre, and multi-drug therapy was unsuccessful to restore sinus ryhthm, so he was sent to our hospital for catheter ablation. We stopped the medications the patient was taking and started using ivabradine. Sinus rhythm was restored 2 hours after ivabradine treatment was started.

Long-term follow-up in preschool children after radiofrequency catheter ablation of arrhythmias.

Radiofrequency ablation (RFA) is the standard method of treatment for tachyarrhythmias in school children, and it leads to complete recovery in children without structural heart disease. However, RFA in young children is limited by the risk of complications and unstudied remote effects of radiofrequency lesions. To present the experience of RFA of arrhythmias and the results of follow-up of younger children. RFA procedures (n=255) were performed in 209 children with arrhythmias from 0 to 7 years old. The arrhythmias were presented with atrioventricular reentry tachycardia withWolff-Parkinson-White(WPW) syndrome (56%), atrial ectopic tachycardia (21.5%), atrioventricular nodal reentry tachycardia (4.8%), and ventricular arrhythmia (17.2%). The overall effectiveness of RFA, considering the repeated procedures performed due to the primary ineffectiveness and recurrencies, was 94.7%. There was no mortality associated with RFA in patients, including young patients. All cases of "major" complications are associated with RFA of the left-sided accessory pathway and tachycardia foci and are represented by the mitral valve damage in three patients (1.4%). Tachycardia and preexcitation recurred in 44 (21%) patients. There was a correlation between recurrences and parameters of RFA (odds ratio 0.894; 95% confidence interval: 0.804-0.994; p=.039). Reducing the maximum power of effective applications in our study increased the risk of recurrence. The use of the minimum effective parameters of RFA in children reduces the risk of complications, but increases arrhythmia recurrence rate.

Emergent Zero-Fluoroscopy Mapping and Thoracoscopic Ectomy of Appendage in Pregnant Women with Life-Threatening Atrial Tachycardia: A Case Report and Literature Review

Background: Focal atrial tachycardia (AT) originating from the right atrial appendage (RAA), often persistent and refractory, is clinically rare in pregnant woman, and the therapy is much more challenging. We report that a pregnant woman presented with hypotension due to persistent and refractory atrial tachycardia and was successfully cured by a multidisciplinary treatment (MDT) approach, consisting of a combination of zero-fluoroscopy mapping and thoracoscopic atrial appendectomy. We also carried out a literature review of this topic. Methods and Results: A 26-year-old woman in pregnancy at 21 weeks presented with severe palpitation and hypotension due to persistent rapid supraventricular tachycardia (SVT). Since adenosine triphosphate could not terminate the tachycardia, a catheter ablation procedure was planned and finally canceled when the zero-fluoroscopy mapping using Carto 3TM system revealed an atrial tachycardia originating from the RAA. Thoracoscopic RAA ectomy was recommended after multidisciplinary consultation and successfully performed without fluoroscopy. EnsiteTM velocity mapping system was used for accurately locating the origin of the arrhythmia during ectomy. The woman finally produced a healthy baby during follow-up. Conclusions: Focal AT originating from appendage in pregnant patients can be persistent, refractory, and life-threatening; traditional strategies, such as medicine or catheter ablation, are limited in this situation. MDT measures, using a thoracoscopic ectomy and zero-fluoroscopy three-dimensional electroanatomical mapping technique, is minimally invasive and a promising strategy.

Adenosine-sensitive perinodal atrial tachycardia. What is the mechanism?

Termination of focal atrial tachycardia with adenosine is considered a defining feature for triggered activity. Recent evidence, however, suggests that the perinodal adenosine-sensitive AT has reentry as the mechanism of tachycardia. In this report, we were able to confirm the mechanism of AT as reentry by observing the response to programmed electrical stimulation and demonstrating the fallacy of traditional teaching that the adenosine responsiveness of AT is a criterion for labeling the mechanism as triggered activity.

Ivabradine monotherapy in pediatric patients with focal atrial tachycardia: a single-center study.

Ivabradine is well-tolerated and may provide early heart rate control in pediatric FAT and can be considered early, especially in the presence of left ventricular dysfunction. Further investigations are deserved to confirm the optimal dose and long-term efficacy in this population. •Focal atrial tachycardia (FAT) is the most common arrhythmia associated with tachycardia-induced cardiomyopathy (TIC) in children, and the efficacy of conventional antiarrhythmic medications in the treatment of FAT is poor. •Ivabradine is currently the only selective hyperpolarization-activated cyclic nucleotide-gated (HCN) inhibitor, which can effectively low HR without negative effect on blood pressure or inotropy. • Ivabradine (0.1-0.2 mg/kg every 12 h) can effectively suppress focal atrial tachycardia in 50% of pediatric patients. •Ivabradine provides early control of heart rate and hemodynamic stabilization in children with severe left ventricular dysfunction due to atrial tachycardia within 48 h.

Catheter ablation for supraventricular arrhythmias in adults with congenital heart disease: Recurrence rates and predictors of acute procedural success

AimsTo define the cohort of adult congenital heart disease (ACHD) patients undergoing catheter ablation for supraventricular arrhythmia in a large tertiary centre, characterise outcomes, and determine factors associated with arrhythmia recurrence. MethodsSingle centre retrospective study of all catheter ablations for atrial arrhythmias in ACHD patients between September 2014 and October 2021. Patients were identified using a field search through a centralised database. Pre-specified clinical and procedural data of interest, and time from ablation to recurrence, were determined. Cox regression analyses were used to determine potential predictors of acute procedural success and arrhythmia recurrence. ResultsCardiac ablation for supraventricular arrhythmia was undertaken in 142 cases across 100 unique patients (median age 41, interquartile range 31–52), with 70 (49%) cases treated for macro-reentrant atrial tachycardia, 16 (11%) for focal atrial tachycardia, 19 (13%) for multifocal atrial tachycardia, 17 (12%) for atrial fibrillation, 7 (5%) for atrioventricular nodal reentrant tachycardia, and 8 (6%) for atrioventricular reentrant tachycardia; and 68 cases (48%) had recurrent arrhythmia with a median time to recurrence of 800 days. Multivariable analysis identified acute procedural success as an independent predictor of freedom from arrhythmia, and ablation for persistent atrial fibrillation as an independent predictor for recurrence of arrhythmia. ConclusionCatheter ablation for supraventricular arrhythmia in ACHD patients is safe and effective, with most patients achieving multiple arrhythmia-free months. Procedural success and arrhythmia mechanism are important predictors of recurrence.

“ECG AND ECHOCARDIOGRAPHIC FINDINGS IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE”

Background: Chronic Obstructive Pulmonary Disease (COPD) which encompasses both chronic bronchitis and emphysema is one of the commonest respiratory condition of adults in the developing world.Aim:To study the electrocardiographic and echocardiographic changes in chronic obstructive pulmonary disease. Methods: All COPD patients above 30 years of age, diagnosed clinically and satisfying the spirometric criteria were included in the study. All patients were subjected to both 2 D and Doppler Echocardiogram and pulmonary artery pressure measured. - Pulmonary function test was done using spirometry. Results: ECG abnormalities suggestive of pulmonary hypertension (Right ventricular hypertrophy) was found in more than half of these cases. Poor progression with R/S is &lt; 1 was found in 12 cases, right ventricular strain patterns like ST depression in II, III AVF and T wave inversion was found in 7 and 6 cases respectively, low voltage QRS in 5 cases. Other rare ECG abnormalities like lead I sign and SI, S II, S III was found in 2 and 1 cases respectively. Rhythm abnormalities like ventricular ectopics, RBBB are found in 2 cases and multi focal atrial tachycardia in 1 case. Conclusion: COPD is commonly seen in persons above 40 years of age ie., in the middle and old aged people. - It is more common among males. - It is associated with the smoking pattern of more than 20 pack years

Focal Atrial Tachycardia as Presenting Feature of Left Atrial Myxoma

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One ominous case of focal atrial tachycardia in pregnancy, two victims and a successful outcome: a case report

BackgroundPregnancy is associated with both new-onset and exacerbation of pre-existing arrhythmias, particularly supraventricular tachycardia, with increased maternal and fetal risks and with added concerns on the safety of the available drug therapy and catheter ablation techniques.These are often withheld, with worse outcomes, and lead to challenging decisions in the approach to pregnant women with refractory supraventricular arrhythmias.Case presentationWe present a case of a 28-year-old 37-weeks pregnant woman with symptomatic, almost incessant, atrial tachycardia causing tachycardia-induced cardiomyopathy, refractory to medical therapy, that evolved in acute cardiac failure and needed emergency cesarian delivery. The patient was afterward submitted to catheter ablation therapy, with an electrical isolation of the ectopic foci on the lower left pulmonary vein with radiofrequency and total suppression of the arrhythmia. The patient and infant were discharged clinically well and during follow-up the patient was asymptomatic, without recurrence of tachycardia and with complete recovery of left ventricle function.ConclusionsThis case highlights the challenges in the treatment of this special population with a stepwise medical approach that proved ineffective and clinical deterioration requiring termination of pregnancy and catheter ablation in the postpartum period, with a successful maternal and fetal outcome.

Epicardial ablation of refractory focal atrial tachycardia after a failed endocardial approach

Endocardial ablation is effective for most focal atrial tachycardias (FATs). In rare circumstances, the FAT can originate from the epicardial side of the atrium. In the present study, we retrospectively assessed the percutaneous approach for epicardial ablation of FAT when standard endocardial ablation had failed. Among a consecutive 186 patients undergoing ablation for 198 FATs, epicardial mapping and ablation via a percutaneous subxiphoid approach were attempted in 10 patients because of failed endocardial ablation. In 3 cases, the origin of FAT was at the epicardial side of the junction of the right atrial appendage and superior vena cava. In 3 cases, the origin of FAT was located in the epicardial region of the left atrial insertion of Bachmann bundle. In 2 cases, the FAT originated from the epicardial side of the right atrial free wall. In 1 case, the FAT was successfully ablated from the epicardial side of the right atrial appendage, and in the remaining case, the origin of FAT was located in the epicardial region of the vein of Marshall. All FATs were successfully eliminated by ablation at the epicardial earliest activation site. Epicardial mapping and ablation can be considered as an effective and safe option for FAT resistant to endocardial ablation.

10-year single center experience of catheter ablation of focal atrial tachycardia.

Focal atrial tachycardias (ATs) represent 5-15% of sustained supraventricular tachycardias (SVTs). Characteristic distribution of sites of origin and detailed electrophysiologic characterization of AT from specific sites of origin (SOO) have been described. Acute success and recurrence are less favorable than for other SVTs. In this series, we present our experience of focal AT ablation over a 10-year period. We undertook a retrospective review of an electronically maintained database of all patients undergoing AT ablation at our institution between January 2011 and December 2020. Demographic, procedural, and outcomes data were reviewed. A total of 293 distinct atrial tachycardias were treated during 279 procedures in 256 patients, including 207 first AT ablations. Acutely successful AT suppression was achieved in 91% of first-time ablations. Acute success was dependent on SOO of AT with lowest rates of acute suppression in the para-Hisian region and the crista terminalis (CT). The most common reason for failure to acutely suppress the AT was proximity to a critical structure (phrenic nerve, sinus node, and AV node). 8.9% of patients in this series presented with a tachycardia-mediated cardiomyopathy (TCM). 48% of TCM patients underwent an ablation attempt during an acute medical admission. Among the TCM group, median LV ejection fraction increased from 25% (range 10-50%) to 55% (range 35-65%) with successful treatment of AT. Five patients undergoing a repeat procedure had planned pericardial access for displacement of the phrenic nerve to permit ablation of the AT, which was successful in all cases. Among patients without a pre-existing diagnosis of AF, peri-procedural AF was not associated with a higher incidence of a subsequent diagnosis of AF (odds ratio 1.169, 95% CI 0.4058-3.475, p = 0.7628). Median duration of follow-up was 832days. By Kaplan-Meier estimate, recurrence-free survival was 78% (95% CI 67-88%). In this series, focal AT ablation is associated with good acute results and a low rate of complications, but outcomes remain less favorable than previously reported for other forms of SVT.

Focal atrial tachycardias: diagnostics and therapy

In this article, typical characteristics of focal atrial tachycardias are described and asystematic approach regarding diagnostics and treatment options in the field of invasive cardiac electrophysiology (EP) is presented. Subjects of this article include the definition of focal atrial tachycardias, knowledge about localizing the origin of such, and guidance on how to approach an invasive EP study (e.g., administration of medication during the EP study to provoke tachycardias). Further, descriptions will be found on how to localize the origin of focal atrial tachycardias with the help of the 12-lead ECG and invasive three-dimensional mapping to successfully treat focal atrial tachycardias with catheter ablation.

A novel wide-band dielectric imaging system to guide radiofrequency ablation for pulmonary vein isolation.

Recently, the wide-band dielectric mapping system Kodex-EPD was introduced. This study reports the first clinical experience using a novel system to guide pulmonary vein isolation (PVI) with radiofrequency (RF)ablation. METHODSAND RESULTS: The study included 20 consecutive patients undergoing de-novo PVI for symptomatic paroxysmal or persistent atrial fibrillation guided by Kodex-EPD. The primary efficacy endpoint was successful PVI. Secondary endpoints included procedural parameters and complications. In all 20 patients (mean age 68 ± 8 years, 12 male patients, paroxysmal fibrillation in 14/20 [70%] patients), PVI was successfully completed. One patient underwent additional cavo-tricuspid isthmus ablation for concomitant typical atrial flutter and one patient required additional ablation of a focal atrial tachycardia. A conventional three-dimensional image of the left atrium as well as the innovative endocardial panoramic view were used to guide catheter manipulation and ablation. Median procedure time was 115 [1st; 3rd quartile 93,75; 140] min and median total fluoroscopy time was 9.9 [9.7; 11.2] min, of which a median of 0.8 [0.6; 0.9] min was required to create left atrial maps. Complete left atrial imaging using Kodex-EPD was achieved within a median of 7.1 [5.7; 8.3] min. Median RFablation time was 45.1 [34.6; 58.7] min. No major complications were observed. RF ablation PVI guided by Kodex-EPD seems safe and feasible. The system provides effective three-dimensionalguidance for PVI.

Spatiotemporal signatures of response to atrial fibrillation ablation

Abstract Background Atrial fibrillation (AF) can have organized regions, in the form of consistent dominant frequency sites, focal or reentrant sites, but it is unclear how these overlap with or differ from focal atrial tachycardias (AT) or potential drivers. We set out to develop an intuitive method based on fundamental electrogram shape and timing to separate types of AF. Objective To test the hypothesis that spatial regions of electrogram (EGM) in AF that show similar shapes over time based on cross-correlation analysis may separate patients with differing response to ablation. Methods We recruited N=133 patients (63.8±12.1 Y, 32% women), (i) N=10 had AT, (ii) N=122 AF that was or was not terminated by ablation, and (iii) N=1 pacing. All patients had left atrial mapping by 64 pole baskets. We applied repetitive activity (REACT) mapping that correlates EGMs in contiguous 2x2 regions (Fig. 1A) over 4sec. To calibrate REACT, we introduced simulated variations in shape (gaussian noise) and timing (gaussian delay) to pacing EGMs and computed nomograph over 100 random trials (Fig. 1C). Results Fig. 1B shows that REACT in a 71-year-old man with AT is more organized than in a 65 YO man with AF (100% vs 40% mapped field). Overall, REACT was higher in AT than AF (0.63±0.15 vs 0.36±0.22, p&amp;lt;0.001). There were 24 cases in which global REACT between AF and AT groups had the overlapping range of values, indicating organized “islands” in AF analogous to AT. From nomograph in Fig. 1C we identified that this overlap reflects 15 ms variation in cycle length and 20% variation in EGM shape (labelled “x” in Fig. 1C). Conclusion Basic electrogram properties in AF of similar shapes in spatial areas over time can separate response to ablation and may represent “islands” of AT. Future studies should investigate the mechanisms for such islands and whether they may be targeted for therapy. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): US National Institutes of Health

Three-dimensional activation maps of sinus rhythm and focal atrial tachycardia in a dog

A five-year-old, female-spayed boxer was referred for frequent and medically refractory paroxysmal supraventricular tachycardia. Diagnostic evaluation found no underlying structural heart or systemic diseases. Three-dimensional electroanatomical mapping and radiofrequency ablation were pursued. Activation mapping of normal sinus rhythm demonstrated the location of the sinus node in the posterolateral region of the right atrium. Activation mapping of the tachyarrhythmia identified a centrifugal activation pattern originating from the right atrium at the posterolateral aspect of the tricuspid valve orifice, suggestive of focal atrial tachycardia. A total of 10 ablation lesions were delivered to the earliest activation site. The dog recovered without complications and no recurrence of supraventricular tachycardia was noted on subsequent follow-ups.