RF catheter ablation of AVNRT in a patient with interrupted inferior vena cava anomaly with hemiazygos continuity with persistent left superior vena cava.

Intrahepatic interruption of the inferior vena cava (IVC) with continued hemizygous is a very rare abnormality and sometimes it may be accompanied by other cardiovascular abnormalities. Continuation of the hemizygous vein draining into the right atrium through the left superior vena cava (LSVC) is much rarer. In this paper, we have presented a patient who had simultaneous IVC interrupted with persistent LSVC and suffered from Atrioventricular nodal reentrant tachycardia (AVNRT). Finally, radiofrequencies (RF) catheter ablation for AVNRT was successfully performed through a left subclavian vein access.

[An intelligent model for classifying supraventricular tachycardia mechanisms based on 12-lead wearable electrocardiogram devices].

OBJECTIVE: To develop an intelligent model for differential diagnosis of atrioventricular nodal re-entrant tachycardia (AVNRT) and atrioventricular re-entrant tachycardia (AVRT) using 12-lead wearable electrocardiogram devices. METHODS: A total of 356 samples of 12-lead supraventricular tachycardia (SVT) electrocardiograms recorded by wearable devices were randomly divided into training and validation sets using 5-fold cross validation to establish the intelligent classification model, and 101 patients with the diagnosis of SVT undergoing electrophysiological studies and radiofrequency ablation from October, 2021 to March, 2023 were selected as the testing set. The changes in electrocardiogram parameters before and during induced tachycardia were compared. Based on multiscale deep neural network, an intelligent diagnosis model for classifying SVT mechanisms was constructed and validated. The 3-lead electrocardiogram signals from Ⅱ, Ⅲ, and Ⅴ1 were extracted to build new classification models, whose diagnostic efficacy was compared with that of the 12-lead model. RESULTS: Of the 101 patients with SVT in the testing set, 68 were diagnosed with AVNRT and 33 were diagnosed with AVRT by electrophysiological study. The pre-trained model achieved a high area under the precision-recall curve (0.9492) and F1 score (0.8195) for identifying AVNRT in the validation set. The total F1 scores of the lead Ⅱ, Ⅲ, Ⅴ1, 3-lead and 12-lead intelligent diagnostic models in the testing set were 0.5597, 0.6061, 0.3419, 0.6003 and 0.6136, respectively. Compared with the 12-lead classification model, the lead-Ⅲ model had a net reclassification index improvement of -0.029 (P=0.878) and an integrated discrimination index improvement of -0.005 (P=0.965). CONCLUSION: The intelligent diagnostic model based on multiscale deep neural network using wearable electrocardiogram devices has an acceptable accuracy for classifying SVT mechanisms.

Meta-Analysis of Genome-Wide Association Studies Reveals Genetic Mechanisms of Supraventricular Arrhythmias.

BACKGROUND: Substantial data support a heritable basis for supraventricular tachycardias, but the genetic determinants and molecular mechanisms of these arrhythmias are poorly understood. We sought to identify genetic loci associated with atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular accessory pathways or atrioventricular reciprocating tachycardia (AVAPs/AVRT). METHODS: We performed multiancestry meta-analyses of genome-wide association studies to identify genetic loci for AVNRT (4 studies) and AVAP/AVRT (7 studies). We assessed evidence supporting the potential causal effects of candidate genes by analyzing relations between associated variants and cardiac gene expression, performing transcriptome-wide analyses, and examining prior genome-wide association studies. RESULTS: Analyses comprised 2384 AVNRT cases and 106 489 referents, and 2811 AVAP/AVRT cases and 1,483 093 referents. We identified 2 significant loci for AVNRT, which implicate NKX2-5 and TTN as disease susceptibility genes. A transcriptome-wide association analysis supported an association between reduced predicted cardiac expression of NKX2-5 and AVNRT. We identified 3 significant loci for AVAP/AVRT, which implicate SCN5A, SCN10A, and TTN/CCDC141. Variant associations at several loci have been previously reported for cardiac phenotypes, including atrial fibrillation, stroke, Brugada syndrome, and electrocardiographic intervals. CONCLUSIONS: Our findings highlight gene regions associated with ion channel function (AVAP/AVRT), as well as cardiac development and the sarcomere (AVAP/AVRT and AVNRT) as important potential effectors of supraventricular tachycardia susceptibility.

The optimal slow pathway ablation site in atrioventricular nodal reentrant tachycardia cases with an inferiorly located His bundle.

INTRODUCTION: The optimal slow pathway (SP) ablation site in cases with an inferiorly located His bundle (HIS) remains unclear. METHODS AND RESULTS: In 45 patients with atrioventricular nodal reentrant tachycardia, the relationship between the HIS location and successful SP ablation site was assessed in electroanatomical maps. We assessed the location of the SP ablation site relative to the bottom of the coronary sinus ostium in the superior-to-inferior (SPSI), anterior-to-posterior (SPAP), and right-to-left (SPRL) directions. The HIS location was assessed in the same manner. The HIS location in the superior-to-inferior direction (HISSI), SPSI, SPAP, and SPRL were 17.7 ± 6.4, 1.7 ± 6.4, 13.6 ± 12.3, and -1.0 ± 13.0 mm, respectively. The HISSI was positively correlated with SPSI (R2 = 0.62; P < .01) and SPAP (R2 = 0.22; P < .01), whereas it was not correlated with SPRL (R2 = 0.01; P = .65). The distance between the HIS and SP ablation site was 17.7 ± 6.4 mm and was not affected by the location of HIS. The ratio of the amplitudes of atrial and ventricular potential recorded at the SP ablation site did not differ between the high HIS group (HISSI ≥ 13 mm) and low HIS group (HISSI < 13 mm) (0.10 ± 0.06 vs. 0.10 ± 0.06; P = .38). CONCLUSION: In cases with an inferiorly located HIS, SP ablation should be performed at a lower and more posterior site than in typical cases.

Voltage and propagation mapping: New tools to improve successful ablation of atrioventricular nodal reentry tachycardia.

INTRODUCTION: Mapping system is useful in ablation of atrioventricular nodal reentry tachycardia (AVNRT) and localization of anatomic variances. Voltage mapping identifies a low voltage area in the Koch triangle called low-voltage-bridge (LVB); propagation mapping identifies the collision point (CP) of atrial wavefront convergence. We conducted a prospective study to evaluate the relationship between LVB and CP with successful site of ablation and identify standard value for LVB. MATERIALS AND METHODS: Three-dimensional (3D) maps of the right atria were constructed from intracardiac recordings using the ablation catheter. Cut-off values on voltage map were adjusted until LVB was observed. On propagation map, atrial wavefronts during sinus rhythm collide in the site representing CP, indicating the area of slow pathway conduction. Ablation site was selected targeting LVB and CP site, confirmed by anatomic position on fluoroscopy and atrioventricular ratio. RESULTS: Twenty-seven consecutive patients were included. LVB and CP were present in all patients. Postprocedural evaluation identified standard cut-off of 0.3-1 mV useful for LVB identification. An overlap between LVB and CP was observed in 23 (85%) patients. Procedure success was achieved in all patient with effective site at first application in 22 (81%) patients. There was a significant correlation between LVB, CP, and the site of effective ablation (p = .001). CONCLUSION: We found correlation between LVB and CP with the site of effective ablation, identifying a voltage range useful for standardized LVB identification. These techniques could be useful to identify ablation site and minimize radiation exposure.

A Single Atrial Extrastimulation Resetting His Bundle During Supraventricular Tachycardia to Differentiate Atrial Tachycardia.

BACKGROUND: Catheter ablation is the curative treatment for paroxysmal supraventricular tachycardia (SVT). However, atrial tachycardia (AT) diagnosis is often challenging, especially when SVT is terminated by pacing. OBJECTIVES: This study sought to develop a novel method for AT diagnosis. METHODS: A total of 147 SVTs including 28 ATs, 87 atrioventricular nodal re-entrant tachycardias, and 32 orthodromic reciprocating tachycardias were prospectively studied. Single atrial extrastimulation was performed at the proximal coronary sinus from a coupling interval 20 milliseconds shorter than the tachycardia cycle length and gradually decreased until the His bundle (HB) was first reset and further until the SVT was terminated. The response of the SVT during the first HB resetting and the termination pattern were examined. RESULTS: In 27 of 28 ATs, tachycardia was unaffected when HB resetting whereas, in atrioventricular nodal re-entrant tachycardias or orthodromic reciprocating tachycardias (non-AT), tachycardia was simultaneously reset when HB resetting or was terminated with an atrio-Hisian block. When the coupling interval was further shortened for cases in which tachycardia persisted, all 33 SVTs with tachycardia termination with atrio-Hisian block were non-ATs, whereas 5 ATs and 7 non-ATs were terminated with Hisian-atrial block. The sensitivity, specificity, and positive and negative predictive values of the pattern of tachycardia that was unaffected when HB resetting for AT diagnosis were 96%, 100%, 100%, and 99%, respectively. Those of the pattern of tachycardia termination with atrio-Hisian block for non-AT diagnosis were 92%, 100%, 100%, and 42%, respectively. CONCLUSIONS: Single atrial extrastimulation from the proximal coronary sinus during tachycardia was useful and effective for AT diagnosis.

[Short history of the DC-Catheter-Ablation]. / Kurze Geschichte der Katheterablation mit DC-Schocks.

Direct current (DC) catheter ablation in 5 patients aiming to interrupt rapid atrioventricular (AV) conduction with atrial fibrillation and subsequent pacemaker implantation was first published by M. M. Scheinman et al. (San Francisco, CA, USA) in 1982. In Germany, L. Seipel, G. Breithardt, and M. Borggrefe reported their first experience with DC catheter ablation in 1984, followed by the group in Bonn (M. Manz and B. Lüderitz) in 1985. The first international DC catheter ablation registry, which also included four German centers, reported DC catheter ablation results of 127 patients in 24 centers in 1984. Complete AV block was achieved in 71% patients. In 1992, the Hannover group (H­J. Trappe, H. Klein and J. Huang) reported results of DC catheter ablation of AV conduction performed between 1983 and 1990 in 100 patients (86% with rapid atrial fibrillation, 14% with AV-node reentry tachycardias). The first successful DC catheter ablation in a patient with Wolff-Parkinson-White (WPW) syndrome was reported in 1985 by F. Morady et al. (San Francisco, CA, USA). In 1987, M. Borggrefe et al. were the first to report a switch from DC catheter ablation to a high-frequency (HF) catheter ablation procedure in a patient with WPW syndrome. The use of DC catheter ablation to treat ventricular tachycardia (VT) was described by G. O. Hartzler (Kansas City, MO, USA) in 3 patients in 1983. M. Borggrefe et al. (1989) reported on 24 patients who underwent DC catheter ablation for VT. Of those, 17 patients did not have VT recurrence within the following 14 months. In 1994, the Hannover group (H-J Trappe, H. Klein) published their 5­year long-term results of DC catheter ablation of VT in 51 patients. VT recurrence occurred in 57% patients and overall mortality was also high (16%). A comparison of DC catheter ablation with HF catheter ablation for recurrent VT was reported in 1994 by G. Gonska et al. (Göttingen, Germany). After 2 years follow-up, success rates were not found to be significantly different.

Cannon A wave validation as a diagnostic tool in paroxysmal supraventricular tachycardias.

OBJECTIVE: The presence of cannon A waves, the so called "frog sign", has traditionally been considered diagnostic of atrioventricular nodal re-entrant tachycardia (AVNRT). Nevertheless, it has never been systematically evaluated. The aim of this study is to assess the independent diagnostic utility of cannon A waves in the differential diagnosis of supraventricular tachycardias (SVTs). METHODS: We prospectively included 100 patients who underwent an electrophysiology (EP) study for SVT. The right jugular venous pulse was recorded during the study. In 61 patients, invasive central venous pressure (CVP) was registered as well. CVP increase is thought to be related with the timing between atria and ventricle depolarization; two groups were prespecified, the short VA interval tachycardias (including typical AVNRT and atrioventricular reciprocating tachycardia (AVRT) mediated by a septal accessory pathway) and the long VA interval tachycardias (including atypical AVNRT and AVRT mediated by a left free wall accessory pathway). RESULTS: The relationship between cannon A waves and AVNRT did not reach the statistical significance (OR: 3.01; p = .058); On the other hand, it was clearly associated with the final diagnosis of a short VA interval tachycardia (OR: 10.21; p < .001). CVP increase showed an inversely proportional relationship with the VA interval during tachycardia (b = -.020; p < .001). CVP increase was larger in cases of AVNRT (4.0 mmHg vs. 1.2 mmHg; p < .001) and short VA interval tachycardias (3.9 mmHg vs. 1.2 mmHg; p < .001). CONCLUSION: The presence of cannon A waves is associated with the final diagnosis of short VA interval tachycardias.

Validation of dual atrioventricular nodal physiology in dual atrioventricular nodal non-reentrant tachycardia via adenosine triphosphate injection during atrial pacing: A novel insight into the role of leftward inferior extension.

INTRODUCTION: Dual atrioventricular nodal non-reentrant tachycardia (DAVNNT) is a rare and challenging-to-diagnose arrhythmia, without previous reports associating it with a leftward inferior extension (LIE). METHODS: Diagnosis was made using adenosine triphosphate (ATP) injection during atrial pacing in a suspected DAVNNT patient. RESULTS: Ablation of the rightward inferior extension was unsuccessful in eliminating DAVNNT; however, subsequent ablation of the LIE successfully eradicated the arrhythmia. CONCLUSION: This unique case, marked by the first instance of DAVNNT caused by LIE, diagnosed through ATP injection, underscores the utility of this diagnostic approach and broadens the spectrum of our understanding and management of this condition.

High-density mapping of Koch's triangle during sinus rhythm and typical atrioventricular nodal re-entrant tachycardia, integrated with direct recording of atrio-ventricular node structure potential.

BACKGROUND: The mechanism of typical slow-fast atrioventricular nodal re-entrant tachycardia (AVNRT) and its anatomical and electrophysiological circuit inside the right atrium (RA) and Koch's Triangle (KT) are not well known. OBJECTIVE: To identify the potentials of the compact AV node and inferior extensions and to perform accurate mapping of the RA and KT in sinus rhythm (SR) and during AVNRT, to define the tachycardia circuit. METHODS: Consecutive patients with typical AVNRT were enrolled in 12 Italian centers and underwent mapping and ablation by means of a basket catheter with small electrode spacing for ultrahigh-density mapping and a modified signal-filtering toolset to record the potentials of the AV nodal structures. RESULTS: Forty-five consecutive cases of successful ablation of typical slow-fast AVNRT were included. The mean SR cycle length (CL) was 784.1 ± 6 ms and the mean tachycardia CL was 361.2 ± 54 ms. The AV node potential had a significantly shorter duration and higher amplitude in sinus rhythm than during tachycardia (60 ± 40 ms vs. 160 ± 40 ms, p < .001 and 0.3 ± 0.2 mV vs. 0.09 ± 0.12 mV, p < .001, respectively). The nodal potential duration extension was 169.4 ± 31 ms, resulting in a time-window coverage of 47.6 ± 9%. The recording of AV nodal structure potentials enabled us to obtain 100% coverage of the tachycardia CL during slow-fast AVNRT. CONCLUSION: Detailed recording of the potentials of nodal structures is possible by means of multipolar catheters for ultrahigh-density mapping, allowing 100% of the AVNRT CL to be covered. These results also have clinical implications for the ablation of right-septal and para-septal arrhythmias.

Local VA index for the differential diagnosis of supraventricular tachycardia.

BACKGROUND: Differentiating between atypical atrioventricular nodal reentrant tachycardia (AVNRT) and orthodromic reciprocating tachycardia utilizing a septal accessory pathway is a complex challenge. OBJECTIVE: The purpose of this study was to describe the "local VA index," a straightforward method based on signals from the coronary sinus catheter, to distinguish between these arrhythmias during tachycardia and entrainment. The ventriculoatrial (VA) interval on the coronary sinus catheter is measured during tachycardia and entrainment, at the site of earliest atrial activity. The difference between these 2 situations defines the "local VA index." We also propose a mechanism to clarify the limitations of historical pacing maneuvers, such as postpacing interval minus tachycardia cycle length (PPI-TCL) and stimulus-atrial interval minus ventriculoatrial interval (SA-VA), by examining nodal decrement and intraventricular conduction delay. METHODS: In a retrospective study of 75 patients referred for supraventricular tachycardia evaluation, 37 were diagnosed with atrioventricular reentrant tachycardia (AVRT) with orthodromic reciprocating tachycardia, and 38 with AVNRT (27 typical, 11 atypical). RESULTS: In comparison to AVRT patients, AVNRT patients exhibited longer PPI-TCL (176 ± 47 ms vs 113 ± 42 ms; P <.01) and SA-VA (138 ± 47 ms vs 64 ± 28 ms; P <.01). The AVRT group had mean local VA index of -1 ± 13 ms, whereas the AVNRT group had a significantly longer index of 91 ± 46 ms (P <.01). An optimal threshold for differentiation was a local VA index of 40 ms. Importantly, there was no significant correlation between pacing cycle length and nodal decrement as well as intraventricular delay related to pathway location. This interindividual variability might explain misleading interpretations of PPI-TCL and SA-VA. CONCLUSION: This novel approach is advantageous because of its simplicity and effectiveness, requiring only 2 diagnostic catheters. A local VA interval difference <40 ms provides a clear distinction for AVRT.

Ebstein's anomaly: an electrophysiological perspective.

Ebstein's anomaly of the tricuspid valve (EA) is an uncommon congenital cardiac malformation. It can present with atrioventricular tachycardia (AVRT), atrioventricular nodal re-entrant tachycardia (AVNRT), atrial arrhythmias, and rarely with ventricular tachycardia. The 12-lead electrocardiogram (ECG) is critically important and often diagnostic even prior to an electrophysiology study (EPS). Due to its complex anatomy, it poses particular challenges for mapping and ablation, even for an experienced electrophysiologist. In this review, we aim to provide insight into the electrophysiological perspective of EA and an in-depth analysis of the various arrhythmias encountered in diverse clinical scenarios.