Focal Tachycardia Research Articles

The relation between atrial arrhythmias and heart failure in adult patients with congenital heart disease

Abstract Background Advances in care have significantly improved survival in patients with adult congenital heart disease (ACHD). This growing population is now confronted with new challenges due to their structural malformations, surgical scars, cyanosis and/or longstanding abnormal pressure and volume load that lead to progressive atrial fibrosis. Atrial arrhythmias (AA) and heart failure (HF) have become the leading causes of hospitalisation in patients with ACHD and pose specific challenges in management. Purpose To assess the relationship between a first AA diagnosis and development of HF in patients with ACHD and investigate the impact of HF on the treatment success of radiofrequency ablation (RFA) for AA. Methods This single-centre, retrospective study included 3995 patients with ACHD. AA was defined as: (I) Atrial fibrillation (AF); (II) Intra-atrial re-entrant tachycardia (IART); (III) Atrial flutter (AFL); or (IV) Focal atrial tachycardia (AT). HF was defined as clinical signs and/or symptoms of HF necessitating medical intervention, along with one of the following: (I) impaired ventricular function with elevated intracardiac pressures; (II) elevated N-terminal B-type natriuretic peptide; (III) peak oxygen consumption in the lowest quartile as per specific ACHD subtype; or (IV) distinctive HF manifestations in patients with a Fontan circulation. Both AA and HF were collected with corresponding dates of first presentation. Details on RFA procedures were collected and acute and long-term success rates were calculated using Kaplan-Meier analysis. Results The mean age of the ACHD cohort at last follow-up was 35.4 ± 13.2 y. As per Bethesda complexity classification, 28.0% of ACHD patients had mild defects, 59.4% moderate and 12.6% severe defects. AA was documented in 348 (8.7%) patients with mean age at first presentation of 37.3 ± 19.6 y (Figure 1). Patients with Fontan circulation (38.5%), cyanotic ACHD (21.0%), and systemic right ventricle (24.2%) were more likely to present with AA. Furthermore, patients with a Fontan circulation (18.8 ± 12.4 y) or a systemic right ventricle (29.7 ± 16.1 y) presented with AA at younger age. The overall prevalence of HF was 6.4%. A total of 130 (3.3%) patients were diagnosed with AA as well as HF. Of these, 103 (79.2%) patients were diagnosed with AA 8.2 ± 7.4 y before HF diagnosis. RFA procedures were performed in 119 patients (34.2%), of which 45 (21.0%) were performed in patients with HF. Overall, 72% of patients undergoing RFA remained free from AA at 2 years after RFA (Figure 2.A). Acute success rates were higher and recurrence rates lower in those without HF (Figure 2.B, p=0.0001). Conclusions In patients with ACHD AA and HF are prevalent, especially in complex ACHD, and a first AA occurs on average 8 years prior to HF diagnosis. The main outcome is driven by HF and not AA. RFA can be an effective treatment for AA with 72% being recurrence free 2 years after RFA, but outcome is affected by coinciding HF.Overview of relation between AA and HFKaplan-meier analysis of AA RFA.

Atrial pace mapping with automatic intracardiac pattern matching for non-pulmonary vein trigger ablation: accuracy and feasibility

Abstract Atrial pace mapping (APM) is an alternative method to localize non-pulmonary vein (non-PV) triggers of atrial fibrillation(AF) that are otherwise not eligible for activation mapping due to their instability. The technique applies pattern matching of p-waves and intracardiac signals of atrial trigger and pacing from the site of the suspected origin. A new automated algorithm for intracardiac (IC) pattern matching was recently introduced into the 3D mapping system using the unipolar signal of the reference catheter. The study aims to assess the accuracy and feasibility of APM using IC-pattern matching for localizing non-PV triggers. Methods We assessed the precision of APM using a single chamber and double chamber reference in 20 patients who underwent index pulmonary vein isolation. APM was performed at the anterior and posterior wall of the left atrium (LApost, Laant) and the posterior and lateral wall of the right atrium (Rapost, Ralat). The first pacing point was declared as the origin. The IC-pattern matching algorithm was applied to calculate the similarity of the IC-pattern of the origin to the paced IC-pattern across various distances. The distribution of IC-pattern similarities was analyzed in the Python environment. The feasibility of APM was tested in patients who underwent REDO ablation of AF if all PVs were isolated and no low-voltage substrate was detected. The induction protocol for non-PV triggers included programmed and burst atrial pacing, high-dose isoproterenol, and adenosine infusion. If the IC pattern of the trigger was reproducible, the IC pattern matching was conducted. Ablation was performed at the site of the best IC-pattern matching. Results Atrial PM with IC-pattern matching and a single referent catheter showed lower precision in the RA lateral region (the median[Q1; Q3 ]area of 5% best matching score 1.48 [0.76; 2.01], 0.62[0.15; 1.06], 0.6[0.38; 1.19] and 5.68[2.89; 11.1] cm2 for LApost, LAant, RApost, RAlat accordingly, p = 0.0316). IC-pattern matching with double referent catheter showed high precision at all four anatomical regions (the median [Q1; Q3] area of 5% best matching score 0.126 [0.0879; 0.356], 0.486 [0.205; 0.717], 0.269 [0.198; 0.719], and 0.257 [0.0740; 0.572] cm2 for LApost, LAant, RApost, RAlat accordingly, Fig. 1). Seven out of 37 patients referred to REDO ablation had all PV isolated and absence of low-voltage substrate. In 3 of them, sustained tachycardias (AVNRT, focal atrial tachycardia and typical atrial flutter) were induced, mapped, and ablated. Non-sustained FAT from the RA posterior wall and PAC in the RA septum were induced under the high-dose isoproterenol infusion in two patients. Atrial pace mapping with double chamber referent and successful ablation of these non-PV triggers were performed (Fig.2). Conclusion The atrial pace mapping of non-PV triggers employing the automatic intracardiac pace mapping algorithm is feasible with high accuracy if a double-chamber referent is used.Accuracy of atrial pace mappingNon-PV trigger pace mapping

Prognostic factors for the effectiveness of catheter ablation of focal atrial tachycardia in school-age children: data from a single-center registry study

Prognostic factors for the effectiveness of catheter ablation of focal atrial tachycardia in school-age children: data from a single-center registry study

Catheter ablation for focal atrial tachycardias during pregnancy: A systematic review

ObjectivePregnancy can trigger maternal tachycardias, and the onset of recurrent or incessant focal atrial tachycardia (AT) can lead to tachycardia-induced cardiomyopathy. Medical interventions are commonly employed, but they carry potential fetal and maternal risks. Catheter ablation (CA), particularly with non-fluoroscopic navigation systems, may be considered as an alternative. This systematic review aims to explore the feasibility and outcomes of CA for focal AT during pregnancy. MethodsA thorough literature search was conducted until September 30th, 2023, on PubMed, Embase, and Cochrane databases. Included articles described maternal focal ATs diagnosed through electrophysiological studies and treated with CA. Data derived from these studies were organized into tables and subsequently analyzed. ResultsOut of 278 papers reviewed, 15 articles involving 24 patients were retrieved. CA, utilizing radiofrequency energy achieved acute success in 95.8% of cases. Sixteen patients (66.7%) underwent complete fluoroless procedures, with two adverse events directly related to the procedure reported. Long-term follow-up revealed minimal AT recurrences, with a 0.06% arrhythmia burden in one case. ConclusionFocal ATs during pregnancy can be incessant and refractory to medical intervention, precipitating an acute decline in left ventricular ejection fraction. In this setting, CA emerges as an efficacious treatment modality, particularly in cases of tachycardia-induced cardiomyopathies. Whenever feasible, it is advisable to perform these procedures with minimal or no fluoroscopy guidance. Larger studies are needed to establish the safety and the efficacy of CA for focal ATs during pregnancy, as current research consists of case reports or small case series.

Benefits from catheter ablation in patients with pulmonary hypertension: Recent advances.

Supraventricular tachycardia (SVT) is a frequent complication of pulmonary hypertension (PH). The most prevalent SVTs are atrial fibrillation (AF) and typical atrial flutter (AFL), followed by focal and macroreentrant atrial tachycardia (AT) and nodal arrhythmia (AV nodal reentry tachycardia or AV reentry tachycardia). SVT is frequently associated with functional deterioration and right ventricular failure in PH patients. According to some data, reestablishing sinus rhythm is associated with clinical improvement. Catheter ablation of typical AFL, nodal tachyarrhythmias, or other less complex focal ATs have been shown to be feasible, acutely effective, and safe in patients with PH. However, the long-term clinical outcome is modified by the recurrence of index arrhythmia and the onset of a new SVT. Due to right atrial dilatation, technical issues can arise when ablation is carried out. The role of catheter ablation in patients with AF or more complex AT is even less effective. The results mirror the success rate in the general AF population with non-paroxysmal AF. However, the data is limited, and electrophysiological procedures are also more often complicated by specific adverse events in a severely frail population. Despite these limitations, catheter ablation is the treatment of choice in less complex SVT, but the indications for AF ablation must be more individualized.

Aberrancy masquerading as ventricular tachycardia: Importance of invasive electrophysiology study for diagnosis of wide complex tachycardias

BackgroundDifferentiation between ventricular tachycardia (VT) and supraventricular tachycardia (SVT) with aberrancy based on the 12‑lead ECG alone can be imprecise. Implantable cardiac defibrillators (ICD) may be inserted for presumed VT, particularly in patients with syncopal presentation or atypical aberrancy patterns. Accurate diagnosis of these patients facilitated by an electrophysiology study (EPS) may alter diagnosis and management. MethodsWe present a prospective collection of cases across 3 cardiac centers of consecutive patients with WCT presumed to be VT who were referred for consideration of an ICD, and in whom further evaluation including an EPS ultimately demonstrated SVT with aberrancy as the culprit arrhythmia. Results22 patients were identified (17 male, mean age 50±13 years. Available rhythm data at the time of referral was presumptively diagnosed as monomorphic VT in 16 patients and polymorphic VT in 6 patients. Underlying structural heart disease was present in 20 (91%). EPS resulted in a diagnosis of SVT with aberrancy in all cases: comprising AV nodal re-entry tachycardia (n=10), orthodromic reciprocating tachycardia (n=3), focal atrial tachycardia (n=3), AF/AFL (n=3) and 'double fire' tachycardia (n=2). 21 (95%) patients underwent successful ablation. All patients remained free of arrhythmia recurrence at a median of 3.4 years of follow-up. ICD insertion was obviated in 18 (82%) patients, with 1 patient proceeding to ICD extraction. ConclusionSVT with atypical aberrancy may mimic monomorphic or polymorphic VT. Careful examination of all available rhythm data and consideration of an EPS can confirm SVT and obviate the need for ICD therapy.

A novel endocardial activation–derived predictor for focal paraseptal atrial tachycardias: Evidence from a multicenter cohort study

BackgroundThe electrocardiogram-based algorithm for predicting paraseptal atrial tachycardia (PSAT) is limited by the significant overlaps in P-wave morphology originating from various paraseptal sites. ObjectivesThe goals of this study were to investigate the endocardial activation characteristics of PSAT and to seek an endocardial activation–derived predictor for the ablation site. MethodsForty-four patients [11 men (25%); mean age 62.6 ± 14.7 years] with PSAT ablation in 4 tertiary medical centers were assigned to 3 groups according to the ablation site: right atrial (RA) para-Hisian region (group 1, n = 10), noncoronary cusp (NCC) (group 2, n = 13), and left atrial (LA) paraseptal area (group 3, n = 21). Multiple-chamber activation mapping was performed guided by a 3-dimensional navigation system. The discrepancies in the earliest activation time between 2 of 3 chambers (ΔRA-LA, ΔRA-NCC, and ΔLA-NCC) were calculated in each group and used for pairwise comparisons. ResultsThere was a significant difference in ΔRA-LA, ΔRA-NCC, and ΔLA-NCC among the 3 groups. ΔRA-LA was the only parameter that could consistently predict the ablation site of PSAT with good accuracy (area under the curve 1.000, sensitivity 100% and specificity 100%, and cutoff value 7 ms for predicting right para-Hisian or NCC ablation; area under the curve 0.974, sensitivity 92.3% and specificity 95.2%, and cutoff value −4 ms for predicting NCC or left paraseptal ablation). Based on 2 cutoff values, a 2-step algorithm was developed to predict the ablation site of PSAT with a positive predictive value of 95.4% and a negative predictive value of 97.0%. ConclusionΔRA-LA is a useful endocardial activation–derived parameter for predicting the successful ablation site of PSAT.

Electrophysiological assessment of atrial tachycardia substrates in patients with repaired tetralogy of Fallot

Abstract Introduction Adults with repaired tetralogy of Fallot (rToF) are most often referred to Adult Congenital Heart Disease centers for atrial tachycardia (AT) and radiofrequency catheter ablation (RFCA) is often required. A systematic evaluation of the mechanisms and recurrences of arrhythmias in these patients is lacking. Methods 28 patients with rToF referred for catheter ablation to the Interventional Electrophysiology Unit of our center between January 2013 and January 2023 were evaluated. Pts underwent electrophysiologic study (EPS) with 3D electroanatomic high density mapping. Evaluation of right atrial bipolar voltage and activation mapping of the AT was performed. Intra-atrial re-entrant tachycardias (IART), focal AT (FAT), other. Activation mapping was performed to identify the critical isthmus for IART. FATs were localized according to the earliest unipolar signal. Whenever possible, all the induced tachycardias were treated besides the arrhythmia which represented the clinical indication to EPS. RFCA was aimed at the earliest activation point for FAT and at the critical isthmus for IART, anchoring lesion to fixed obstacles (valve annuli or atriotomy scar). All patients provided written informed consent for participating in the study. Results Among 28 adult (age 47±13 years) patients (females n=14, 50%), 53 AT were documented: 34 (64%) IART, 11 (21%) FAT and 8 (15%) atrial fibrillation (AF). Mean tachycardia cycle length (excluding AF) was 307±95 ms. At least 2 ATs were induced in 12 pts during index EPS. Among IARTs, incisional IART (IARTinc, atriotomy and superior and inferior vena cava orifices, SVC and IVC, respectively) was the prevalent critical part of the circuit (n=22, 52%), while CTI was the second mechanism (n=20, 48%). In three pts, due to non-inducibility, a pre-emptive lesion set comprising in one case CTI and in two cases CTI+SVC-atriotomy-IVC line was performed. 2 patient underwent scheduled pulmonary veins isolation and CTI ablation. Among FAT, in 3 cases the AT was mapped in the coronary sinus, in two at the tricuspid annulus, in the remaining at the crista terminalis, at the right appendage base, at the posterolateral incision scar or between atriotomy and SVC. In 6 patients AF was induced but not ablated. During a median follow up of 23 months (interquartile range, 6-37) recurrence occurred in 8 pts (18% of pts, 15% of tachycardias). Patients with recurrences were younger (43±7 vs. 48±17 y, p=0.04); no differences were found according to critical isthmus location (4 CTI and 4 IARTinc, 50%, p=ns). Conclusions Among rToF pts with AT, IART is the prevalent mechanism and atriotomy scar is the prevalent critical isthmus. FAT location is much more variable. Atrial fibrillation burden is not negligible. Long-term freedom from AT in this clinical setting is encouraging.

Feasibility of catheter ablation with zero-fluoroscopy in congenital heart disease

Abstract Background Catheter ablation (CA) with zero and near-zero fluoroscopy has been shown to be safe and effective in patients (pts) without structural heart disease, but there are limited data regarding CA in congenital heart disease (CHD). Aim Our aim was to compare the safety and outcome of zero-fluoroscopy (ZF) and fluoroscopy (non-ZF) CA of CHD pts. Methods This is a single-center retrospective study of CHD pts who underwent CA at our center between 2006-2020. The ZF and non-ZF groups were compared for the complexity of anatomy, arrhythmia substrate, difficulties of vascular access, transseptal or transbaffle puncture, intracardiac pacemaker/ICD, procedural parameters, complications, and acute outcome. Near-ZF CAs (effective dose ≤1 mSv) were assigned to the ZF group. Results The ZF group included 22 pts (age: 22±13 years) and the non-ZF group 48 pts (age: 31±12 years). The distribution of CHD anatomical complexity (mild/moderate/severe) was 18.2%-68.2%-13.6% in the ZF group and 14.6%-68.7%-16.7% in the non-ZF group. Arrhythmia diagnoses were focal atrial tachycardia (ZF: 4.6%), atrial flutter (ZF: 45.4%, non-ZF: 75.0%), atrioventricular reentry tachycardia (AVRT) via manifest accessory pathway (AP) (ZF: 31.8%, non-ZF: 10.4%), AVRT via concealed AP (ZF: 4.6%, non-ZF: 8.3%), and atrioventricular nodal reentry tachycardia (ZF: 13.6%, non-ZF: 6.3%). Difficulties in vascular access occurred in 4.5% of the ZF group and 18.8% of the non-ZF group (p=0.10). The rate of transseptal/transbaffle puncture was significantly higher in the non-ZF group (22.9% vs. 4.6%, p=0.04). In the ZF group 13.6% and in the non-ZF group 20.8% of pts had pacemaker or ICD (p=0.22). Electroanatomical mapping was used in all CAs in both groups. There was no significant difference in procedure time, ablation time and the number of radiofrequency applications (ZF group: 169±53 min, 1205±906 sec, 28±15 vs. non-ZF group: 203±74 min, 1459±940 sec, 34±16, p>0.05). The acute success rate was 100% in both groups. No complications occurred in any group. Conclusion Zero fluoroscopic CA was feasible in 1/3 of the pts with CHD and as safe and effective as fluoroscopic ablation. No significant differences were found in the non-fluroscopy related procedural data between the two groups.

Implementation of near zero fluoroscopy in supraventricular tachycardia ablation procedures: a single center experience

Abstract Background Supraventricular tachycardia (SVT) are common cardiac arrhythmias, and catheter ablation has proven to be a very effective treatment, but exposes patients and healthcare providers to radiation. "Near Zero Fluoroscopy" (NZF) techniques, utilizing advanced imaging, aim to reduce radiation exposure while maintaining efficacy. Purpose To present an analysis of near-zero fluoroscopy in SVT ablation procedures, in a tertiary center, since its implementation. Methods We prospectively enrolled 446 SVT-diagnosed patients for this study. All of them underwent NZF procedures using the same specific 3D mapping system, between January/19 and December/22. Patients with atrial fibrillation or macroreentrant atrial tachycardias or when a different mapping system was used, were excluded. All patients provided informed consent. Results Our population had 266 (60%) females and a median age of 39 (IQR 24-51) years. AVNRT was the most frequent arrhythmia documented (229 cases, 51%), followed by Accessory Pathways (AP) (201 cases, 45%) and focal atrial tachycardia (AT) (16 cases, 4%). The ablation success rate was high (405/418, 97%). There was no ablation attempt in 12 patients (9 APs and 3 ATs) and the unsuccessful ablations (7/418 cases, 1,67%) were APs. Overall, fluoroscopy time was 1.1 minutes (IQR 0-2.6). There was no statistically significant difference in the distribution of fluoroscopy time among the types of SVT based on the Kruskal-Wallis test (p 0.14). Observing trends of fluoroscopy use through time, we acknowledge the presence of a learning curve, leading towards shorter times of X-ray during procedures along the first 3 years of implementation of a near-zero strategy. Median times (IQR) of fluoroscopy were as follows: 2019 – 2.25 (0.45-3.4) min; 2020 – 1 (0-2.5) min; 2021 – 0 (0-1.9) min; 2022 – 0.55 (03.05) min. (see BoxPlot) Pairwise comparisons using the Wilcoxon rank-sum test with continuity correction revealed statistically significant differences in medians between all pairs of years, with p-values adjusted for multiple comparisons using the Bonferroni method (p<0.01). In 2022, fluoroscopy time increased, when compared to 2021. We believe this finding can be explained by the fact that in 2022, our department received a new fellow and a young EP consultant (coming from a center where NZF was not the standard for SVT ablation), both being in the lab on a daily basis, explaining this upward trend in fluoroscopy time. There were no acute complications requiring hospital admission or active treatment. Conclusion Our results emphasize the potential of near-zero fluoroscopy techniques to enhance safety and reduce radiation exposure while maintaining a high level of procedural efficacy in the treatment of SVT cases. Absence of acute complications highlighted the safety of these approaches.

Slow pathway ablation in pediatric patients: long-term outcomes in a high-volume center according to baseline electrophysiologic characteristics

Abstract Background Slow pathway ablation (SPA) in pediatric patients with documented paroxysmal supraventricular tachycardia (PSVT) has been proven safe and effective. Arrhythmia induction is often difficult in the pediatric population. Accordingly, empirical SPA is frequently adopted in this population. Real-world data about long-term outcomes of slow pathway ablation (SPA) in relation to tachycardia inducibility and electrophysiologic characteristics in pediatric patients with PSVT in a high-volume center are lacking. Purpose To compare long-term clinical outcomes of SPA in pediatric patients with and without intraprocedural documentation of DAVP and AV nodal reentrant tachycardia induction. Methods In this retrospective sigle-center study, all SPA procedures performed on pediatric patients (under 18 years) at our Institution since 2016 were considered. All patients had documented PSVT with short RP interval, no evidet ventricular pre-excitatio on surface ECG and normal echocardiography. Baseline EPS was performed to exclude the presence of concealed accessory pathway and isoproterenol infusion was used to exclude focal atrial tachycardias. According to intraprocedural EP characteristics, three group of patients were identified: Group 1 with AVNRT induction; Group 2 with dual atrioventricular nodal physiology (DAVP) and no tachycardia induction; Group 3 without DAVP. According to previous documentation of a short RP PSVT and after discussion with patients’ families, SPA was performed in all patients. The endpoint of the ablation was to eliminate slow pathway conduction and AV node re-entrant beat. Follow up visits were scheduled three and twelve months after ablation for all patients. Results 1734 patients underwent SPA since 2016 at our Institution. 1092 patients (73.4%) showed AVNRT induction during EPS (Group 1). 433 patients (14.2%) showed DAVP without tachycardia induction (Group 2). 209 patients (12.4%) didn’t show DAVP at EPS (Group 3). Age and gender were similar among the three groups. SPA was performed with acute procedural success in all patients. After 36-month median follow-up, freedom from palpitations was 98.5% in Group 1, 97.1% in Group 2 and 92.3% in Group 3. A survival analysis showed the best outcomes in group 1 and no significant difference in recurrence rate among the groups 2 and 3 (Figure 1). No permanent heart blocks, neither other major complication was observed. Conclusions When performed by experienced operators and in high-volume centers, SPA is a safe and effective procedure in pediatric patients with documented short RP PSVT. Success rate is highest with AVNRT induction and good without AVNRT induction, regardless of AV node dual conduction at baseline EPS. Such high success rate depends on careful exclusion of others arrhythmia mechanisms (i.e., focal atrial tachycardias, AV re-entrant tachycardias) that, although infrequent in children, are the main determinants of arrhythmia recurrences.

Ultra-high density mapping and ablation of localized microreentrant tachycardias: insight from the CHARISMA registry

Abstract Background The optimal criteria for distinguishing microreentrant atrial tachycardias (mAT) from macroreentrant atrial arrhythmias (MAT) in clinical practice have not been definitively established. Recent advancements in ultra-high-density mapping featuring automated functionalities, has enhanced our understanding of mAT circuits and the precise localization of foci. Purpose Our intent was to observe the diagnostic support provided by high density mapping and Lumipoint algorithm in mAT as well as the ablation outcomes. Methods Consecutive patients eligible for atrial tachycardia (AT) ablation in 22 Italian centres were prospectively enrolled. all ATs were comprehensively mapped in either the left or right atrium utilizing the Rhythmia mapping system and the 64-pole Orion basket catheter. A mAT was defined as an AT characterized by slow, continuous, low fragmented potentials covering a minimum of 50% of the tachycardia cycle length (CL) within a confined area (defined as a circuit within < 1 cm2), enclosed by a couple of closed splines of the Orion catheter, and exhibiting a centrifugal activation pattern to the rest of the atria. The Lumipoint tool was systematically employed to confirm electrogram fragmentation within this defined area. Results Among 159 ATs analysed, 97 (61.0%) were identified as MAT, 50 (31.4%) as focal atrial tachycardias and 12 (7.5%) as mAT. Of these latter, 6 patients (50%) had a previous history of atrial ablation procedure. Concerning the mAT group, the predominant origin site was the left atrium (10 mAT, 83,3%); the targeted activity was localized in the anterior wall in 4 cases (33.3%), in proximity to PVs in 3 cases (25%), along the left ridge in 2 cases (16.6%) and at the roof in 1 case (8,3%). In the remaining right mAT, the foci were found in the free wall and along the CTI in 1 case (8.3% each). The electrical activity spanning the whole CL was detected by 2.7±1.8 pairs of close bipoles of the Orion catheter, was confined to a region of 0.36±0.3cm2 with the longest component of fractionated EGM per spline equal to 64.7±17% of the CL. Low voltage areas (<0.1 mV) were detected in all mAT cases and colocalized with the origin site. Voltage level was 0.2±0.1mV at the site of longest duration of the fragmented potential. A single shot RF delivery terminated each arrhythmia at targeted location. Consolidative RF ablations were then delivered in the adjacent area. Over a median of 288 [248-349] days of follow-up, 5 (3.1%) patients suffered from an AT/AF arrhythmia recurrence and of these, 3 (3.1%) were in the MAT group, 1 (2%) in the focal AT and 1 (8.3%) in the mAT group. No complications were observed. Conclusions A novel automated algorithm for microreentrant atrial tachycardia identification, coupled with the identification of matched areas of electrogram fractionation by the Orion catheter, may restrict the extent of required ablation and result in a low arrhythmia recurrence.

Electrophysiological characteristics of tachyarrhythmia and effects of catheter ablation in patients with Fontan circulation

Abstract Introduction Incidence of arrhythmia in complex congenital heart disease is higher than general population. Characteristics of arrhythmia in patients with functional single ventricle is not known. Methods Total 18 patients (age, 22.1 8.5 years, 9 men) with Fontan circulation who had undergone catheter ablation for tachyarrhythmia were retrospectively consecutively included. Characteristics of congenital heart disease, mechanisms of tachyarrhythmia, and efficacy and safety of catheter ablation were analyzed. Results Congenital heart diseases of the patients were as follows: double outlet right ventricle, 9; common atrioventricular septal defect, 5; and pulmonary atresia, 4. Fontan types were as follows: lateral tunnel Fontan, 9; extracardiac conduit Fontan 9. Fontan conduit puncture was successful in all patients. Mechanisms of tachyarrhythmia were as follows: intraatrial macroreentrant tachycardia, 8; focal atrial tachycardia, 4; atrioventricular nodal reentrant tachycardia, 3; twin atrioventricular nodal reciprocating tachycardia, 2; unknown, 2. Success rate of catheter ablation, recurrence rate, and complication rate were 16 of 18 patients, 2 of 18 patients, and 0 of 18 patients, respectively. Conclusion Intraatrial macroreentrant tachycardia is the most common tachycardia mechanism in patients with Fontan circulation. Catheter ablation for tachyarrhythmia is effective and safe in these population.

Focal atrial tachycardias originating from the aorta-mitral continuity: Anatomical and electrophysiological characteristics

BackgroundThe aorta-mitral annulus conjunction (AMC) is an uncommon site of origin of focal atrial tachycardias (ATs). Hence, the electrophysiological and ablation target characteristics are poorly described. ObjectiveThe purpose of this study was to describe the characteristics of AMC ATs in detail. MethodsThe study enrolled 650 patients with ATs, 21 (3.2%) of whom had ATs originating from the AMC. A comprehensive evaluation, including electrocardiography, electrophysiology study, computed tomography scan, and intracardiac echocardiography, was performed. ResultsThe majority (19, 90.5%) of ATs occurred spontaneously. The mean age of this group was 48.9 ± 21.6 years, with 12 being female (57.1%). Seventeen patients had a typical biphasic P wave with a prominent positive component. The earliest activation site in the right atrium was near the His bundle, with average activation −10.3 ± 6.0 ms preceding the P wave. The successful ablation targets were distributed as follows: 1 case at 9 o’clock, 6 cases at 10 o’clock, 7 cases at 11 o’clock, 6 cases at 12 o’clock, and 1 case in the left coronary cusp. The local AMC potential differed from the commonly perceived annular potential and was characterized by a prominent A wave and a smaller V wave (atrial-to-ventricular ratio > 1). The angle of encroachment on the left atrial anterior wall, compressed by the left coronary cusp, was significantly smaller in the AMC ATs group than in the control group consisted of 40 patients who underwent coronary artery CT scans because of the chest pain but without atrial arrhythmias were randomly selected, which may have contributed to the arrhythmia substrate (141.7° ± 11.5° vs 155.2° ± 13.9°; P = .026). ConclusionA new strategy for mapping AMC ATs has been introduced. The ablation target should have an atrial-to-ventricular ratio of >1.

Comparison of safety and effectiveness of different sheaths in ablation of focal atrial tachycardia: a retrospective study.

A novel visualized steerable sheath, referred to as the Vizigo sheath, has been utilized in clinical interventions. The objective of this study was to evaluate and contrast the efficacy and safety of the Vizigo sheath with other sheaths in the catheter ablation (CA) for focal atrial tachycardia (FAT). A retrospective cohort study was conducted on consecutive patients with CA for FAT from March 2019 to February 2022. Objectives were to assess the impact of the Vizigo sheath on acute and long-term ablation success rates, procedural and fluoroscopy times, and contact force (CF). A total of 164 patients, mean age 50±15 years, 97 (59.1%) women, underwent CA of FAT using the Vizigo sheath (N=42), non-visualized steerable sheath (N=36), or other conventional sheath (N=86). Age, sex, body mass index (BMI), presence of hypertension, heart failure, and diabetes mellitus were not significantly different among the three groups. The acute success rate of 94.0% was similar among the three groups. Over a follow-up of 14±2 months, the Vizigo sheath was associated with superior arrhythmia-free survival (88.1%) when compared to non-visualized steerable (69.4%; P=0.04) and other conventional (72.1%, P=0.046) sheaths. Procedural duration, number of ablation lesions, and ablation times were similar among the three groups. However, the Vizigo sheath was associated with lower fluoroscopy times (e.g., 145 vs. 250 s with Vizigo versus non-visualized steerable sheaths, P=0.03) and higher CF (e.g., average CF 12.0 versus 8.0 g with Vizigo versus non-visualized steerable sheaths, P=0.003). The application of Vizigo sheath can improve the long-term success rate of FAT and reduce the radiation exposure of patients and medical staff in our single-center limited sample study. More research may be needed in the future to confirm our findings.

Predictors of nonpulmonary vein triggers for atrial fibrillation: A clinical risk score

BackgroundTargeting non-pulmonary vein triggers (NPVTs) after pulmonary vein isolation may reduce atrial fibrillation (AF) recurrence. Isoproterenol infusion and cardioversion of spontaneous or induced AF can provoke NPVTs but typically require vasopressor support and increased procedural time. ObjectiveThe purpose of this study was to identify risk factors for the presence of NPVTs and create a risk score to identify higher-risk subgroups. MethodsUsing the AF ablation registry at the Hospital of the University of Pennsylvania, we included consecutive patients who underwent AF ablation between January 2021 and December 2022. We excluded patients who did not receive NPVT provocation testing after failing to demonstrate spontaneous NPVTs. NPVTs were defined as non-pulmonary vein ectopic beats triggering AF or focal atrial tachycardia. We used risk factors associated with NPVTs with P <.1 in multivariable logistic regression model to create a risk score in a randomly split derivation set (80%) and tested its predictive accuracy in the validation set (20%). ResultsIn 1530 AF ablations included, NPVTs were observed in 235 (15.4%). In the derivation set, female sex (odds ratio [OR] 1.40; 95% confidence interval [CI] 0.96–2.03; P = .080), sinus node dysfunction (OR 1.67; 95% CI 0.98–2.87; P = .060), previous AF ablation (OR 2.50; 95% CI 1.70–3.65; P <.001), and left atrial scar (OR 2.90; 95% CI 1.94–4.36; P <.001) were risk factors associated with NPVTs. The risk score created from these risk factors (PRE2SSS2 score; [PRE]vious ablation: 2 points, female [S]ex: 1 point, [S]inus node dysfunction: 1 point, left atrial [S]car: 2 points) had good predictive accuracy in the validation cohort (area under the receiver operating characteristic curve 0.728; 95% CI 0.648–0.807). ConclusionA risk score incorporating predictors for NPVTs may allow provocation of triggers to be performed in patients with greatest expected yield.

Case report: Para Hisian Atrial Tachycardia

Case report: Para Hisian Atrial Tachycardia

Focal Pulsed Field Ablation for Atrial Arrhythmias: Efficacy and Safety under Deep Sedation.

Focal pulsed field ablation (PFA) is a novel technique for treating cardiac arrhythmias. It has demonstrated positive results in initial studies and has a good safety profile. In recent studies, PFA was often utilized for first-time pulmonary vein isolation (PVI) and was performed under general anesthesia. In our study, we assessed the feasibility, safety, acute procedural efficacy, and efficiency of focal PFA under deep sedation in patients, 80% of whom had undergone at least one left atrial ablation previously. We treated 30 patients (71 ± 7, 46% male) using the CENTAURI system for various atrial arrhythmias, including atrial fibrillation, typical and atypical atrial flutter, and focal atrial tachycardia. The average procedure and fluoroscopy times were 122 ± 43 min and 9 ± 7 min, respectively. A total of 83.33% of patients received additional line ablations beyond PVI, specifically targeting the posterior box and anterior mitral line. All ablations were successfully performed in deep sedation with only one major and one minor complication observed. The major complication was a vasospasm of the right coronary artery during ablation of the cavotricuspid isthmus, which was treated successfully with intracoronary nitroglycerin. All patients could be discharged in sinus rhythm. Moreover, adenosine appears effective in identifying dormant conduction in some patients after focal PFA. In conclusion, focal PFA is an effective approach for complex left atrial ablations under deep sedation, offering both high efficacy and efficiency with a reliable safety profile. Studies on long-term outcomes are needed.

Catheter ablation of supraventricular tachycardia and atrial flutter with no or minimal use of fluoroscopy: the initial experience of a single Bulgarian center

Introduction: Catheter ablation (CA) is an established therapy for most arrhythmias. Non-&amp;#64258; uoroscopic three-dimensional (3D) electroanatomic mapping systems allow ablation of supraventricular tachycardia (SVT) and atrial &amp;#64258; utter (AFL) with zero or near-zero &amp;#64258; uoroscopy (ZF/NZF). The current study aims to report our initial experience with ZF/NZF in SVT or AFL CA. Material and methods: We conducted a single-center prospective registry enrolling consecutive patients referred for CA of SVT or AFL. ZF/NZF CA was attempted in all patients using a commercially available 3D mapping&amp;nbsp;system. Fluoroscopy use was allowed at any point of the procedure. Procedural characteristics and long-term outcome were analyzed. The learning curve effect was also studied. Results: Sixty-three patients (age 53.5 &amp;plusmn; 14.1, 57% males) with SVT or AFL were enrolled. According to arrhythmia type typical AVNRT was diagnosed in 36 (57.1%) cases, right atrial &amp;#64258; utter in 25 (39.7%) cases, left-sided accessory pathway in 1 (1.6%) and focal right atrial tachycardia in 1 (1.6%) case. Three patients (4.8%) had two arrhythmia substrates. The procedure was performed with ZF in 49/63 cases (77.8%), while NZF was necessary in 14 (22.2%) patients with a &amp;#64258; uoroscopy time of 220 &amp;plusmn; 169 sec and a dose-area product of 7556 &amp;plusmn; 5886 mGy*cm2. Median procedural time was 88 (IQR 25-75 percentile 71.5-116) min with 22 (IQR 25-75 percentile 16-31) min of mapping time. Acute procedural success was accomplished in all patients with no periprocedural complications. Over a follow-up of 12 &amp;plusmn; 3 months, all patients remained arrhythmia-free. There was a learning curve effect with a signi&amp;#64257; cant reduction of procedural time (P = 0.025) and a signi&amp;#64257; cant difference (P = 0.019) in the rate of &amp;#64258; uoroscopy use among different periods of the study duration. Conclusion: ZF/NZF CA of SVT and AFL is associated with high ef&amp;#64257; cacy and safety. Entirely &amp;#64258; uoroless CA can be performed in the vast majority of patients. It is a feasible approach associated with a detectable learning curve effect.&amp;nbsp;

Identification of the Ectopic Foci of Focal Atrial Tachycardia (FAT) by Using Electrocardiogram (ECG) Signal Analysis

Identification of the Ectopic Foci of Focal Atrial Tachycardia (FAT) by Using Electrocardiogram (ECG) Signal Analysis