This study aimed to evaluate the characteristics, difficulties, and outcomes of patients who underwent transcatheter ablation treatment due to arrhythmia with a diagnosis of CHD. A total of 166 patients (189 substrates) with CHD who underwent catheter ablation between November 2013 and 2023 were evaluated retrospectively. EnSite™ (St Jude Medical Inc., St Paul, MN, USA) was used in all patients. The mean age was 14.8 ± 7.9 years (2.9-43 years). The most common CHD's were Ebstein anomaly (n: 40), tetralogy of Fallot (n: 31), atrial septal defect (n: 25), ventricular septal defect (n: 22), great artery transposition (D/L TGA, n: 12), and complex CHD in single ventricle physiology (n: 9). The most common arrhythmia mechanisms were Wolf-Parkinson-White syndrome (WPW, n: 50), intraatrial reentrant tachycardia (IART, n: 39), typical atrioventricular nodal reentrant tachycardia (AVNRT, n: 37), and ventricular tachycardia-ventricular extrasystoles (VT/VES, n: 23). There was more than one arrhythmia in 23 patients and multiple manifest accessory pathways in 10 patients. The average procedure time was 174 ± 69.3 minutes, and the average fluoro time was 8.3 minutes. While successful ablation was performed in 176/189 (acute success 93.1%) substrates, the procedure was unsuccessful in five patients and suboptimal in eight patients. Recurrence was observed in 11 patients (6.4%) during a mean follow-up period of 49.2 ± 30.1 months. A second ablation was performed on 13 patients. Acute success was achieved in all except one patient. A total of 11 patients are being followed up with medical treatment. Despite the complex anatomy, age, operations, and limited vascular access possibilities in patients diagnosed with CHD, transcatheter ablation treatment with advances in electrophysiology, the introduction of different energy types, special ablation catheters, multipolar mapping catheters, and 3D nonfluoroscopic mapping systems seems to be a safe and effective option.

Glob Acad J Med Sci, 2025; 7(6): DOI : https://doi.org/ Abstract PDF Full-Text e-Pub Purpose: This systematic review’s aim is to evaluate the role of autonomic markers in predicting supraventricular tachycardia (SVT) recurrence after catheter ablation. Understanding these markers can help to identify patients at higher risk of recurrence and improve post-procedural management. Methodology: A full literature review has been conducted using 12 electronic databases, such as PubMed, ScienceDirect, Springer, MDPI and Oxford Academic. It has covered studies in English from 1999 to 2025. The PRISMA 2020 guidelines for systematic reviews have been followed in the review. Studies have been chosen using the PICO framework: adult patients with SVT who undergo catheter ablation (Population), evaluation of autonomic markers like heart rate variability (HRV), baroreflex sensitivity (BRS), skin sympathetic nerve activity (SKNA), and P-wave alternans (Intervention), comparison with normal or baseline values (Comparator), and recurrence or non-recurrence of SVT as the outcomes (Outcome). Both qualitative and quantitative data were extracted, including statistical measures such as odds ratios, hazard ratios and predictive accuracy metrics. Findings: HRV is the most studied and widely applied autonomic marker. Early post-ablation HRV changes correlate with recurrence risk in AF studies, but evidence in SVT is limited and largely hypothetical. BRS, SKNA and PWA have showed potentiality but have been underexplored in SVT. Clinical and procedural factors, such as accessory pathway location and ablation strategy, is influencing the recurrence rates. In Bangladesh, HRV has been measured in tertiary centers, while other markers are not routinely applied due to resource constraints. Conclusion: Autonomic markers have promising potential to predict SVT recurrence, but no robust SVT-specific studies are there. Future research should focus on multicenter prospective studies with standardized measurement protocols and integration of clinical factors to develop reliable predictive models.

Background. In patients with Wolf-Parkinson-White (WPW) syndrome, localization of the site of accessory pathway using surface electrocardiography (ECG) is important step prior to any electrophysiological study and ablation. The purpose: to validate a new and simple stepwise algorithm to localize accessory pathway site from surface ECG during sinus rhythm. Materials and methods. It is prospective study enrolling patients with WPW syndrome scheduled for electrophysiological study and ablation in single center from January 2015 to February 2019. Surface ECG of patients with WPW syndrome one day prior to electrophysiological study was used to apply this algorithm to localize the site of accessory pathway and compare it with the results of electrophysiological study next day. Results. The total number of patients enrolled in the study was 121 patients, 73 males (60.3 %) and 48 females (39.7 %) with a mean age of 33 ± 12 years and range of 13–69 years. Overall sensitivity and specificity of this algorithm in detecting the site of accessory pathway using successful ablation site as a reference test are 94 and 98 %, respectively, the positive and negative predictive values were 90 and 99 %. There were six sites of accessory pathways detected by electro-physiological study (left lateral, left inferolateral, anteroseptal, posteroseptal, midseptal and right-sided), the sensitivity of this algorithm for each accessory pathway site was 91, 100, 100, 91, 100, 81 %, respectively, while the specificity was 100, 95, 99, 97, 99, 100 %. Conclusions. This new algorithm to localize the site of the accessory pathway in patients with WPW syndrome from surface ECG is easily applied and has good sensitivity and specificity.

The occurrence of a left free-wall (LFW) accessory pathway (AP) with concentric activation sequences in the coronary sinus (CS) during orthodromic atrioventricular reentrant tachycardia (OAVRT) is an uncommon phenomenon. Using three-dimensional (3D) mapping system in eight patients with LFW-AP (mean age 44±9.9 years), we systematically analyzed mitral annular (MA) activation during OAVRT. The primary location of the APs was in the left lateral region in seven patients. The tachycardia, characterized by varying CS sequences, remained sustainable in three patients and was inducible in four patients following the initial ablation at the earliest retrograde atrial insertions. The tachycardia cycle length (TCL) was comparable to the baseline TCL (345.4±94.2 vs. 345.6±93.4ms; p = 0.99). Moreover, the tachycardia was terminated by ablating the earliest retrograde atrial activation region adjacent to the initial ablation site. One patient with a history of left lateral AP ablation exhibited mitral isthmus (MI) block, and the left anterior AP was successfully ablated. Following a mean follow-up of 50.5 months, no recurrence of tachycardia was reported by any patient. LFW-AP with concentric CS activation sequences represents a distinctive electrophysiological entity, our study demonstrates detailed mapping in the vicinity of the MA is imperative to localize the secondary atrial insertion site of the AP or to identify multiple APs in close proximity to the initial ablation site. This retrospective study does not require clinical trial registration.

Accessory pathways (APs) are classified as typical or variant according to their atrial and ventricular insertions. Typical APs connect atrial and ventricular working myocardium directly across the annulus, whereas variant APs-including the atrio-Hisian pathway (AHP), fasciculoventricular pathway (FVP), nodofascicular pathway (NFP), and nodoventricular pathway (NVP) pathways-partially or fully engage the atrioventricular node-His (AVN-His) axis. Focusing on trans-annular APs in the right para-septal region, this review emphasizes how their anatomic course and spatial relationship to the AVN-His axis determine their electrocardiographic (ECG) and electrophysiologic (EP) manifestations. Accurate interpretation of these features requires detailed understanding of para-septal anatomy. By integrating anatomic, ECG, and EP correlations, a unified schematic model is proposed to describe the relative positions, insertion sites, and conduction relationships of typical and variant APs within the right para-septal region. This framework clarifies how subtle anatomic variations along the AVN-His axis account for the distinct yet overlapping ECG and EP features of these pathways.

Mitral isthmus block (MIB) complicating radiofrequency ablation (RFA) of orthodromic reciprocating tachycardia (ORT) using left - sided accessory pathways (APs) is poorly understood. Two cases and a systematic review of the literature of patients (pts) who developed MIB complicating left - sided ORT RFA is presented. Among 27 pts (34 ± 12 years old, 54% female, 68% concealed AP), 15 (56%) had ≥ 1 failed RFA procedure. One RF lesion caused MIB in 6 (22%) (≤ 3 lesions in 11 (41%)). MIB caused switch from eccentric to pseudo-concentric atrial activation (23/27 (85%)) without increasing septal ventriculo-atrial (VAHis) intervals/ ORT cycle lengths (17/18 (94%)). Recurrent ORT with "concentric" activation was misdiagnosed as atrio-ventricular nodal reentrant tachycardia (AVNRT) in 3 (11%) - 1 requiring pacemaker implantation after slow pathway (SP) RFA. By targeting earliest retrograde atrial activation on the high mitral annular free wall (1-3 o'clock (17/19 (89%)) above the line of block (LOB), successful AP RFA occurred in 23/23 (100%). Left free wall ORTs with RFA - induced MIB are (1) difficult ablations with > 50% requiring > 1 procedure, (2) can masquerade as AVNRT causing unnecessary SP RFA, and (3) are successfully ablated on the high mitral annular free wall predominantly between 1 and 3 o'clock and always superior to the LOB.

We develop a minimal whole-heart model that describes cardiac electrical conduction and simulate a basic three-lead electrocardiogram (ECG). We compare our three-lead ECG model with clinical data from a Norwegian athlete database. The results demonstrate a strong correlation with the ECGs recorded for these athletes. We simulate various pathologies of the heart's electrical conduction system, including ventricular tachycardia, atrioventricular nodal reentrant tachycardia, accessory pathways, and ischemia-related arrhythmias, showing that the three-lead ECGs align with the clinical data. This minimal model serves as a computationally efficient digital twin of the heart.

BackgroundCardiac electrophysiology has undergone significant advances in the therapeutic strategies of cardiac arrhythmias due to the implementation of invasive procedures as radiofrequency catheter ablation of arrhythmogenic substrates, foci and circuits. The Electrophysiology Council of the Argentine Society of Cardiology decided to create a registry of this procedure with free and anonymous participation of the main electrophysiology laboratories in our country. ObjectiveTo recognize the number of catheter ablation procedures, epidemiological data of patients, indications, outcomes and complications based on the information provided by the participant centers during the studied period. Material and MethodsBetween February 2000 and May 2008, 13 patients with this diagnosis had an We performed a prospective and consecutive registry of the procedures reported from November 2007 to March 2009 (16 months). A case report form was available at the SAC’s website in order to be completed on line. The information was transmitted through the Internet using optional users’ names and passwords to ensure the security and privacy of patients and participant centers. The information could also be submitted via mail or e-mail. ResultsA total of 30 centers provided information about 762 catheter ablation procedures (average: 47 procedures per month). Radiofrequency was used in 98.7% of patients (752/752) and cryothermia in 1.3% (10/162). Eighty four percent of procedures were made by operators who perform ± 50 procedures per year and 67.6% (515/762) by operators with up to 100 cases per year. The procedure was successful in 93.4% (709/762) of patients, and 3% had complications (23/762). Mean age was 42 years (5-94) and 56.3% were men. Most patients (76%) had no structural heart disease; 83.7% presented symptoms. Catheter ablation was indicated as primary therapy due to: symptoms, refractory medical treatment or high arrhythmic risk in 712 patients (93.5%); the procedure was performed due to recurrences in 20 cases (2.6%) and to failed ablation in 30 (3.9%). The arrhythmogenic substrates or circuits treated were: atrioventricular nodal tachycardia (30%; 237/786); atrial fibrillation (3.6%; 28/786); atrial flutter (21.5%; 171/786); atrial tachycardia (4.3%; 34/786); macroreentrant atrial tachycardia (0.8%; 7/786); manifest accessory pathway (24%; 186/786); concealed accessory pathway (8.6%; 68/786); idiopathic ventricular tachycardia (2.5%; 20/786); ischemic ventricular tachycardia (0.9%; 7/786); ventricular tachycardia associated with other heart diseases (0.9%; 7/786); AV node ablation (1.9%; 15/786) and ventricular premature beats (0.9%; 7/786). The complications were: complete AV block (n=2), pericardial effusion (n=2), hematoma at the puncture site (n=4), catheter entrapment, first degree AV block, traumatic LBB; aortic dissection, intolerance to the procedure, crural neuropathy, femoral artery pseudoaneurysm and deep venous thrombosis. ConclusionsThis first registry of catheter ablation in our country provides important and useful information about this procedure and shows an adequate immediate success rate (93.4%), similar to those reported by international registries, with low incidence of morbidity or non severe complications (3%). This procedure can be considered safe and efficient.

Left Superior Mahaim-Type Accessory Pathway With Latent Pre-Excitation: Diagnosis and Electrophysiological Characterization.

Spanish catheter ablation registry. 24th official report of the Heart Rhythm Association of the Spanish Society of Cardiology (2024).

A left-sided accessory pathway with bidirectional decremental conduction located at the aortomitral continuity

Pulsed field ablation (PFA) is a novel, non-thermal technique for atrial fibrillation ablation that is currently under early investigation for paroxysmal supraventricular tachycardia (PSVT). We conducted a meta-analysis to evaluate the efficacy and safety of PFA in this setting. We systematically searched PubMed, Embase, Cochrane Central, and Web of Science for studies on PFA in PSVT, including atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) with concealed or manifest accessory pathways. Outcomes included acute ablation success, success at 1, 3, and 6months, and procedural/postoperative adverse events (AEs). Proportions were pooled using a random-effects model with arcsine transformation to account for extreme values. Analyses were conducted using R (v4.3.2). Five prospective single-arm studies involving 202 patients were included. The pooled acute success rate was 99.98% (95% CI: 99.29-100), with sustained success at 1, 3, and 6months. Procedural and postoperative AE rates were low: 0.92% (95% CI: 0.00-4.88) and 0.06% (95% CI: 0.00-0.87), respectively. Subgroup analysis showed 100% acute success in AVNRT and in AVRT with concealed pathways, with high sustained success at 6months. In AVRT with manifest pathways, acute success was 97.5% (95% CI: 84.74-100), maintained through follow-up. In this systematic review and meta-analysis, PFA demonstrated excellent safety and efficacy for the treatment of PSVT. Randomized controlled trials are warranted to establish the outcomes of PFA in this setting relative to thermal ablation.

Supraventricular tachycardia is the most common sustained arrhythmia in childhood. It is characterized by a rapid heart rhythm originating above the ventricles, usually caused by an accessory pathway or a nodal reentry mechanism. In infants, it may present with irritability, poor feeding, or signs of heart failure; in older children, with palpitations or dizziness. We present the case of a 7-year-old girl who attended the emergency department, referred from her health center due to an episode of palpitations. An electrocardiogram was performed, showing findings consistent with supraventricular tachycardia. The patient was hemodynamically stable, and the episode initially resolved with vagal maneuvers. During her stay in the emergency department, she experienced recurrent and persistent supraventricular tachycardia episodes that required intravenous adenosine administration up to 0.2 mg/kg on two occasions. The baseline electrocardiogram obtained after resolution of the tachycardia showed sinus rhythm with signs of ventricular preexcitation (delta wave and short PR interval), findings consistent with Wolff-Parkinson-White syndrome. Our aim is to highlight the importance of early detection of this condition and, through this clinical case, to focus on the fundamental aspects of its etiology, diagnosis, and therapeutic management.

Background/Objectives: The stellate ganglion (SG), formed by the fusion of the inferior cervical and first thoracic sympathetic ganglia in approximately 80% of individuals, plays crucial roles in cardiac innervation, pain management, and autonomic regulation. This review examines the anatomical variations, histological structure, clinical applications, and therapeutic implications of the SG and stellate ganglion block (SGB), presenting original high-resolution magnetic resonance imaging (MRI) evidence of SG visualization, an underutilized approach in autonomic nervous system research. Methods: We conducted a comprehensive literature review of anatomical, physiological, and clinical studies on the SG, incorporating original anatomical dissections and high-resolution MRI. Contemporary research on SGB applications, complications, and mechanisms of action was analysed and correlated with imaging characteristics. Results: The SG demonstrates significant anatomical variability, including the presence of intermediate ganglia, accessory nerve pathways, and variable relationships with surrounding vascular structures. Our original MRI imaging consistently identified the SG at the thoracic inlet, anterior to the neck of the first rib, lateral to the longus colli muscle, and posterior to the vertebral artery, demonstrating that advanced imaging can reliably visualize this critical autonomic structure and its anatomical variants. Histologically, it contains typical sympathetic architecture, comprising postganglionic neurons, satellite glial cells, and specialized SIF cells that modulate ganglionic transmission. SGB shows therapeutic efficacy across diverse conditions, including cardiac arrhythmias, chronic pain syndromes, post-traumatic stress disorder, sleep disorders, and immune dysfunction. The procedure's mechanisms involve both direct sympathetic blockade and complex neuroimmune pathways that affect central autonomic centers and lymphoid organs. Complications include vascular injury, pneumothorax, and nerve blocks affecting the recurrent laryngeal and phrenic nerves. Conclusions: The SG represents a critical autonomic structure with expanding clinical applications. This work advances the field by demonstrating that high-resolution MRI can consistently and non-invasively visualize the SG and its anatomical variations, knowledge previously mostly limited to cadaveric studies. Understanding these imaging-defined anatomical variations is essential for optimizing therapeutic interventions. Advanced imaging guidance integrated with comprehensive anatomical knowledge is crucial for maximizing efficacy while minimizing complications in stellate ganglion block procedures.

To develop a machine learning (ML) model to identify fiducial points on canine ECGs to localize right-sided accessory pathways as posterior or anterior during ventricular preexcitation (VPE). ECG recordings with VPE and documented accessory pathway locations were preprocessed for a 1-dimensional U-net algorithm. A web-based platform (https://setpsi.com/AccessoryPathways/) was created. Training used approximately 70% of pooled beats from 16 of 27 dogs. Testing used approximately 30% of pooled beats from 11 of 27 dogs to assess accurate diagnosis of posterior versus anterior accessory pathways. Vectorcardiograms and mean electrical axis (MEA) were calculated to validate the ML model. Fiducial boundary correctness and beat identification accuracy were assessed with receiver operator characteristic curves and reported as area under the curve (AUC; 95% CI). A Mann-Whitney test was used to compare MEA methods (median; IQR). The ML algorithm was trained on 3,405 beats and tested on 1,984 beats. The model identified fiducial points P wave to delta wave (AUC, 0.957; 95% CI, 0.957 to 0.958) and delta wave/QRS (AUC, 0.965; 95% CI, 0.964 to 0.966), classified individual beats as posterior (AUC, 0.917; 95% CI, 0.915 to 0.920) and anterior (AUC, 0.948; 95% CI, 0.947 to 0.949), and determined pathway location in 82% (9 of 11) of test dogs. Vectorcardiograms of posterior pathways showed oval or elliptical loops with superior leftward vectors, while anterior pathways displayed complex figure-eight loops with inferior leftward vectors. The MEA differed (P < .01) between posterior (-23.7°; IQR, 39.5°) and anterior (61.1°; IQR, 9.8°) pathways. Both methods validated the ML model. The ML model accurately localized accessory pathways in canine VPE. ML will advance the ability to accurately diagnose VPE.

Background: Social determinants of health (SDOH) contribute to disparities in cardiovascular care and outcomes. In pediatric Wolff-Parkinson-White (WPW) syndrome, timely access to risk stratification by electrophysiology study (EPS) and possible ablation can prevent sudden cardiac death. The impact of SDOH on the management of pediatric supraventricular tachycardia has been evaluated but has not been investigated in patients with WPW specifically. Hypothesis: We hypothesize that patients with WPW who are non-white, primarily Spanish-speaking, publicly insured, and have lower childhood opportunity index (COI) are less likely to undergo EPS and have longer waits from diagnosis to EPS. Methods: This single-center, retrospective cohort study identified patients aged 5 to 18 years old with WPW pattern by ECG between 2014 and 2024. Patients diagnosed before 5 years of age and patients with intermittent WPW pattern were excluded. Demographic, clinical, and insurance data were extracted via chart review; census tract level COI was obtained from a validated public database. The primary outcome was the time from first diagnostic ECG to EPS. Risk stratification, accessory pathway, and procedural success data were collected from EPS reports. Odds ratio and time interval comparisons were made using 2-sample t, chi-squared, ANOVA, and Kruskal-Wallis tests. Results: Of 363 included patients, 174 (48%) are female, 222 (61%) are non-white, 58 (16%) are primarily Spanish-speaking, and 181 (50%) are publicly insured. Two hundred thirty-four (64%) underwent an EP study with a median time from ECG to EPS of 68 (IQR 41, 182) days (Table 1). Hispanic patients were less likely to undergo EPS compared to non-Hispanic whites ( P =0.049), and Spanish speaking patients were less likely compared to English speaking ( P =0.03). Patients with public insurance were less likely to undergo EPS compared to those with private insurance ( P =0.02). Patients with lower COI levels were less likely to undergo EPS compared to those with very high COI. There was no significant difference in time from ECG to EPS or from EPS to follow-up based on demographic variables (Table 2). Conclusion: In this diverse pediatric WPW cohort, Hispanic ethnicity, primarily Spanish-speaking, and public insurance were associated with lower likelihood of undergoing EPS. These findings identify potential barriers to timely EPS and highlight a need for targeted interventions to promote equitable care in this population.

Introduction: Pulsed Field Ablation (PFA) is becoming popular for Atrial Fibrillation (AF) ablation due to its improved safety profile. However, there are situations where a combination of PFA and Radiofrequency Ablation (RFA) may be indicated. We herein report two cases where PFA was followed by RFA, resulting in cardiac perforation. Case #1: A 36-year-old male underwent catheter ablation (CA) for a highly symptomatic AF and supraventricular tachycardia. A concealed Left Lateral Accessory Pathway (LLAP) was diagnosed. Because of incessant degeneration to AF during the study, ablation of AF was undertaken first with wide area Pulmonary Vein Isolation (PVI) and Posterior Wall Ablation (PWA) using PFA. Subsequently, the LLAP was ablated using RFA. Suddenly, an acute impedance rise was noted (Image 1) . The patient became hemodynamically unstable and had a large pericardial effusion. Case #2: A 72-year-old male was referred for CA of AF. After PVI and PWA with PFA, refractory atrial flutter developed due to mitral annular flutter. To avoid giving high-dose nitroglycerin (NTG) to prevent coronary spasm in PFA, RFA was used to create a linear lesion from the left inferior PV down to the mitral valve. During RFA, an impedance spike was noted (Image 2). The patient’s blood pressure dropped, and Intracardiac echo revealed a large pericardial effusion. Discussion: PFA creates myocardial lesions with minimal thermal effects and has properties of myocardial tissue specificity as compared to RFA. However, there may be situations where RFA is desired as well; for our first case, we wished to use a focal RF catheter to ablate an accessory pathway; in the second case, RF was chosen to avoid PFA on the mitral annulus that would have required high-dose prophylactic NTG administration. PFA changes tissue characteristics, and it can create larger lesions with subsequent RFA. Although this synergistic effect may be quite useful, especially in the ventricles where larger/deeper lesions may be desired, it may also be fraught with a higher risk of cardiac perforation. It is of interest that both cases reported here involved RFA on the mitral annulus subsequent to PFA lesions delivered for PVI. However, it remains unclear how close in proximity to PFA lesions RFA lesions need to be delivered to produce a synergistic effect. Conclusion: Based on the discussion above, caution is warranted when using both forms of energy during catheter ablation of atrial arrhythmias.

Unusual electrophysiological features of fasciculoventricular accessory pathway

Long RP supraventricular tachycardia poses a significant diagnostic challenge because of overlapping electrophysiological features among differential diagnoses. Detailed evaluation with an electrophysiological study is essential for accurate diagnosis and effective management, particularly when initial ablation attempts fail to eliminate inducibility. A 40-year-old Southeast Asian male with a 5-year history of recurrent palpitations was referred for evaluation. Baseline echocardiography was normal. During symptomatic episodes, electrocardiography demonstrated long RP tachycardia. Electrophysiology study revealed eccentric atrial activation with decremental conduction, with the earliest A recorded at DD9-10 (coronary sinus ostium/left posteroseptal region). Tachycardia cycle length was 410 ms, with a VA interval of 215 ms, AH interval of 93 ms, HA interval of 332 ms (AH/HA < 1), a VAV response during ventricular entrainment, PPI-TCL of 225 ms, and SA-VA of 194 ms. Ventricular reset did not terminate the arrhythmia and showed no atrial delay or advancement. Ablation at the coronary sinus ostium terminated the tachycardia but did not prevent reinduction. A subsequent slow pathway ablation was performed, during which slow junctional rhythm was observed. Post-ablation testing demonstrated crossover at 320ms, while supraventricular tachycardia remained easily inducible with atrial S1 pacing at 400ms. Given persistent inducibility, medical therapy was optimized and the patient was scheduled for advanced three-dimensional mapping and ablation. The leading differential diagnoses were atypical atrioventricular nodal reentrant tachycardia (fast-slow variant) with a bystander accessory pathway and permanent junctional reciprocating tachycardia with coexisting dual AV nodal physiology. This case illustrates the diagnostic complexity and management challenges of long RP supraventricular tachycardia, particularly in distinguishing atypical atrioventricular nodal reentrant tachycardia from permanent junctional reciprocating tachycardia. When initial ablation does not achieve full arrhythmia control, a stepwise strategy involving detailed electrophysiological evaluation, cautious ablation, and advanced mapping may be required to guide definitive therapy.

Background: Fetal tachyarrhythmias occur in less than 0.1% pregnancies, with atrial flutter accounting for one-third of cases. Atrial flutter results from a reentrant circuit within the atrium with atrial rates in fetal atrial flutter ranging from 300 to 540 beats per minute. The fetal atrial flutter is most often an isolated finding; however, it may also be associated with maternal diabetes, neonatal macrosomia, cardiac rhabdomyoma, maternal substance use, Turner syndrome, congenital heart disease, and the presence of accessory pathways. The majority of cases of atrial flutter in the neonatal period are isolated; however, only a few cases of recurrent atrial flutter have been described. Methods: This is a single-institution, retrospective chart review of neonates with recurrent atrial flutter. Results: Four neonates with recurrent atrial flutter were identified, each linked either to a correctable trigger or to an underlying substrate, guiding individualized therapy. When no clear trigger was present, antiarrhythmic medication was required. Conclusions: These cases highlight the importance of the recognition of potential triggers of recurrent neonatal atrial flutter, tailoring therapy accordingly and considering antiarrhythmic agents when necessary.