[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.

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.

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.

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.

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.

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.

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.

Ultra-high-density mapping for safe and effective typical atrioventricular nodal reentrant tachycardia ablation.

Ultra-high-density mapping was used for potential-guided radiofrequency ablation for typical atrioventricular nodal reentrant tachycardia. The mapping detailed the spread of activation in the Koch's triangle and identified target potentials and tachycardia circuits. This mapping provides additional information to the slow pathway conventionally used for safe and effective ablation.

Zero-fluoro atrioventricular-nodal reentrant tachycardia ablation.

BACKGROUND: Atrioventricular-nodal reentrant tachycardia (AVNRT) is a common supraventricular tachycardia, particularly in younger patients. The treatment of choice is radiofrequency catheter ablation (RFCA), traditionally necessitating ionizing radiation for catheter guidance. OBJECTIVE: The authors aimed to demonstrate the feasibility and safety of zero-fluoroscopy RFCA of AVNRT using EnSite™ NavX™ as a three-dimensional (3D) electroanatomical mapping system (EAM). METHODS: The authors retrospectively analyzed 68 patients that underwent AVNRT-RFCA. One group was a priori allocated to conventional fluoroscopy mapping (convFluoro, n = 30). In 38 cases, the electrophysiologist chose to use 3D-EAM for ablation. Of these patients, 20 could be ablated without fluoroscopy use (zeroFluoro). In 18 cases that were initially intended as 3D-EAM, additional fluoroscopy use was necessary due to difficult anatomic conditions (convertedFluoro). Procedure duration, fluoroscopy duration and dose, as well as complications were analyzed. RESULTS: Procedure duration was similar for the convFluoro and zeroFluoro groups (74 ± 24 min vs. 80 ± 26 min, p = ns). The convertedFluoro group showed longer procedure duration compared to the convFluoro group (94 ± 30 min vs. 74 ± 24 min, p < 0.05). The use of 3D-EAM significantly reduced fluoroscopy duration comparing the convFluoro with the convertedFluoro group (12 ± 9 min vs. 7 ± 6 min, p < 0.05). The difference in fluoroscopy dose between convFluoro and convertedFluoro did not reach significance (169 ± 166 cGycm2 vs. 134 ± 137 cGycm2, p = ns). In zeroFluoro cases, no radiation was used at all. 3D-EAM-guided RFCA was primarily successful in all patients. Overall, there were only few minor complications in the different groups. No major complications occurred. CONCLUSION: Zero-fluoro RFCA in patients with AVNRT is feasible and safe. 3D-EAM can reduce radiation exposure in the majority of patients without prolonging procedure duration or increasing complications.

[Long-term results of catheter ablation for AV nodal reentry tachycardias and accessory pathways]. / Langzeitergebnisse der Katheterablation bei AV-Knoten-Reentry-Tachykardien und akzessorischen Leitungsbahnen.

Atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia in patients with accessory pathways (AP) are common supraventricular tachycardias. High long-term efficacy of about 97% (AVNRT) and 92% (AP) has been observed in children and adults. The risk of occurring atrioventricular block is low (0.4-0.8% during AVNRT, 0.1-0.2% for AP). Catheter ablation shows a lower efficacy of 87-93% and elevated atrioventricular block risk up to 10% in patient groups with complex congenital heart disease. Nonsynchronized ventricular activation during preexcitation or permanent reentrant tachycardias can induce heart failure, and remission of left ventricular function can be expected in > 90% after successful catheter ablation. Therefore, catheter ablation is the long-term therapy of choice for AVNRT and AP with high efficacy and safety for most patient populations.

Fast-slow atrioventricular nodal re-entrant tachycardia incorporating superior and inferolateral left atrial slow pathways.

BACKGROUND: A 70-year-old man revealed a rare type of atrioventricular nodal re-entrant tachycardia (AVNRT) involving distinct retrograde pathways, superior slow pathway, and inferolateral left atrial slow pathway. RESULT: Radiofrequency ablation was successfully performed on the noncoronary cusp and in the left atrium, respectively, to eliminate the tachycardias. DISCUSSION AND CONCLUSION: Due to the anomalous electrical conduction patterns, careful diagnosis and ablation strategies were necessary to avoid the risk of atrioventricular block. These findings underscore the diversity and complexity of AVNRT and highlight the importance of tailored therapeutic approaches.

Junctional rhythm during cryoablation for typical atrioventricular nodal reentrant tachycardia.

INTRODUCTION: Cryoablation is being used as an alternative to radiofrequency (RF) ablation for atrioventricular nodal reentrant tachycardia (AVNRT) owing to the lower risk of atrioventricular block (AVB) compared to RF ablation. Junctional rhythm often occurs during successful application of RF ablation for AVNRT. In contrast, junctional rhythm has rarely been reported to occur during cryoablation. This retrospective study evaluated the characteristics of junctional rhythm during cryoablation for typical AVNRT. METHODS AND RESULTS: This retrospective study included 127 patients in whom successful cryoablation of typical AVNRT was performed. Patients diagnosed with atypical AVNRT were excluded. Junctional rhythm appeared during cryofreezing in 22 patients (17.3%). These junctional rhythms appeared due to cryofreezing at the successful site in the early phase within 15 s of commencement of cooling. Transient complete AVB was observed in 10 of 127 patients (7.9%), and it was noted that atrioventricular conduction improved immediately after cooling was stopped in these 10 patients. No junctional rhythm was observed before the appearance of AVB. No recurrence of tachycardia was confirmed in patients in whom junctional rhythm occurred by cryofreezing at the successful site. CONCLUSION: Occurrence of junctional rhythms during cryoablation is not so rare and can be considered a criterion for successful cryofreezing. Furthermore, junctional rhythm may be associated with low risk of recurrent tachycardia.

Common Types of Supraventricular Tachycardia: Diagnosis and Management.

Supraventricular tachycardia (SVT) is an abnormal rapid cardiac rhythm that involves atrial or atrioventricular node tissue from the His bundle or above. Paroxysmal SVT, a subset of supraventricular dysrhythmias, has three common types: atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia, and atrial tachycardia. Presenting symptoms may include altered consciousness, chest pressure or discomfort, dyspnea, fatigue, lightheadedness, or palpitations. Diagnostic evaluation may be performed in the outpatient setting and includes a comprehensive history and physical examination, electrocardiography, and laboratory workup. Extended cardiac monitoring with a Holter monitor or event recorder may be needed to confirm the diagnosis. Acute management of paroxysmal SVT is similar across the various types and is best completed in the emergency department or hospital setting. In patients who are hemodynamically unstable, synchronized cardioversion is first-line management. In those who are hemodynamically stable, vagal maneuvers are first-line management, followed by stepwise medication management if ineffective. Beta blockers and/or calcium channel blockers may be used acutely or for long-term suppressive therapy. When evaluating patients for paroxysmal SVTs, clinicians should have a low threshold for referral to a cardiologist for electrophysiologic study and appropriate intervention such as ablation. Clinicians should use a patient-centered approach when formulating a long-term management plan for atrioventricular nodal reentrant tachycardia. Catheter ablation has a high success rate and is recommended as the first-line method for long-term management of recurrent, symptomatic paroxysmal SVT, including Wolff-Parkinson-White syndrome.