Ablation of Atrioventricular Nodal Reentrant Tachycardia with Focal Cryoablation, Compared with Radiofrequency Ablation: Single-Center Experience. / Ablação de Taquicardia Reentrante Nodal Atrioventricular com Crioablação Focal, Comparada com Ablação por Radiofrequência: Experiência em Centro Único.

BACKGROUND: The ablation of atrioventricular nodal reentrant tachycardia (AVNRT) with cryoablation is an alternative to radiofrequency (RF) ablation in patients due to the low risk of total atrioventricular block. An increase in early-late recurrences after cryoablation is reported as an important disadvantage. OBJECTIVES: In this study, we aimed to compare the acute procedural success and the long-term recurrence rates of patients, with AVNRT who underwent methods. METHODS: 73 patients with AVNRT were included in the study: 32 with cryoablation and 41 with RF ablation. There was no statistically significant difference between acute procedural success in methods. The ablation procedure was performed by an operator experienced in arrhythmology. The choice of RF or cryoablation was made in the electrophysiology laboratory based on the material already available during the procedure. After the procedure, the patients were evaluated every 3 months for 2 years in polyclinic control. The significance level adopted in the statistical analysis was 5%. RESULTS: The 2 groups of patients were homogeneous. The fluoroscopy time (p<0.001) was shorter, but atrium-his (p=0.004) and his-ventricular (p=0.015) times were longer in the cryoablation group. There was no significant difference, in terms of acute procedural success, post-procedure jump without a single echo, and presence of echo and jump. CONCLUSIONS: Cryoablation requires less fluoroscopy time and is a safe non-inferior alternative to RF ablation in patients with AVNRT. The risk of AV block is a significant problem with the use of RF energy, making it less suitable for use in young and physically active patients.

FUNDAMENTO: A ablação da taquicardia por reentrada nodal atrioventricular (TRNAV) com crioablação é uma alternativa à ablação por radiofrequência (RF) em pacientes devido ao baixo risco de bloqueio atrioventricular total. Um aumento nas recorrências precoces e tardias após a crioablação é relatado como uma desvantagem importante. OBJETIVOS: Neste estudo, objetivamos comparar o sucesso do procedimento agudo e as taxas de recorrência em longo prazo de pacientes com TRNAV submetidos a métodos. MÉTODOS: Foram incluídos no estudo 73 pacientes com TRNAV: 32 com crioablação e 41 com ablação por RF. Não houve diferença estatisticamente significativa entre o sucesso agudo do procedimento nos métodos. O procedimento de ablação foi realizado por operador com experiência em arritmologia. A escolha entre RF ou crioablação foi feita no laboratório de eletrofisiologia com base no material já disponível durante o procedimento. Após o procedimento, os pacientes foram avaliados a cada 3 meses durante 2 anos em controle policlínico. O nível de significância adotado na análise estatística foi de 5%. RESULTADOS: Os dois grupos de pacientes foram homogêneos. O tempo de fluoroscopia (p<0,001) foi menor, mas os tempos his-átrio (p=0,004) e his-ventricular (p=0,015) foram maiores no grupo crioablação. Não houve diferença significativa em termos de sucesso agudo do procedimento, salto pós-procedimento sem eco único e presença de eco e salto. CONCLUSÕES: A crioablação requer menos tempo de fluoroscopia e é uma alternativa segura e não inferior à ablação por RF em pacientes com TRNAV. O risco de bloqueio AV é um problema significativo com o uso de energia de RF, tornando-o menos adequado para uso em pacientes jovens e fisicamente ativos.

Experience sharing of a case of dual atrioventricular nodal non-reentrant tachycardia: Case report.

RATIONALE: Tachycardia is a common arrhythmia in clinical practice, and its pathogenesis is mostly related to reentry. However, there are also a few tachycardia that are not related to reentry. Actively clarifying the pathogenesis of these non-reentry related tachycardia is of great significance for its treatment. PATIENT CONCERNS: A 55-year-old female patient presented with recurrent palpitations with a fastest heart rate of 180 beats/minute 10 years ago. DIAGNOSIS: Dual atrioventricular nodal non-reentrant tachycardia (DAVNNT). INTERVENTIONS: DAVNNT can be cured by radiofrequency ablation of atrioventricular nodal slow path modification. OUTCOMES: The tachycardia has stopped. CONCLUSION: DAVNNT is a rare disease in clinical practice. Its characteristic is not reentration-related arrhythmias, but the phenomenon of increased heart rate caused by electrical conduction down the double pathway of atrioventricular nodal tract and subsequent pathway. Electrophysiological examination helps to clarify the diagnosis and pathogenesis, and catheter ablation can cure the disease.

The impact of His bundle location and direction on the efficacy and safety of ablation.

BACKGROUND: The impact of the His bundle location and distance from the ablation site on ablation efficacy and complication risk remains unexplored. We determined the correlation between age, height, body mass index (BMI), and the His bundle location, and whether the distance between the His bundle and ablation target (DHIS-ABL) affects ablation safety and efficacy. METHODS: Overall, 346 patients with atrioventricular nodal re-entrant tachycardia (AVNRT) and 96 with atrioventricular re-entrant tachycardia (AVRT) were retrospectively analyzed. The distance between the His bundle and the coronary sinus ostium (DHis-CS), the height of the His bundle (HHIS), and DHIS-ABL were measured. Electrocardiograms were obtained 3 months post-ablation to assess recurrence and complications. RESULTS: Multiple linear regression showed that HHIS was negatively correlated with age in both groups. In AVNRT patients, DHIS-ABL was associated with age, height, and BMI; DHIS-CS was only negatively correlated with age. In AVRT patients, there was no significant correlation between the DHIS-ABL and age, height, or BMI. The recurrence rates in the AVNRT and AVRT groups were 0.9% and 8.7%, respectively. Subgroup analysis showed that patients with DHIS-ABL ≤ 10 mm had a higher recurrence rate than those with DHIS-ABL > 10 mm (p = .013). The incidence of third-degree atrioventricular block (AVB) complications was 0.2%. CONCLUSIONS: HHIS was negatively correlated with age but not with height and BMI. The DHIS-ABL correlated with age, height, and BMI in AVNRT patients. A short DHIS-ABL led to a higher rate of supraventricular tachycardia recurrence; whether this affects AVB risk warrants further studies with larger sample sizes.

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.

Upper common pathway analysis using late atrial premature depolarization in atrioventricular nodal reentry tachycardia.

BACKGROUND: Anatomic and electrophysiologic findings suggest that the actual circuit of atrioventricular nodal reentrant tachycardia (AVNRT) involves the perinodal atrium. However, occasional instances in which the atrium is dissociated from the AVNRT have led to the concept of an upper common pathway (UCP). OBJECTIVE: We aimed to assess the prevalence of UCP in AVNRT using a late atrial premature depolarization (LAPD) maneuver. METHODS: Patients who were diagnosed with typical AVNRT by electrophysiologic studies were enrolled. For evaluation of the presence of UCP, an LAPD was given at the coronary sinus ostium (osCS) during AVNRT, and then pacing was repeated incrementally every 10 ms. Electrograms in the earliest retrograde atrial activation site (ERAS) near the proximal His were mapped and recorded during the pacing. Results were interpreted as follows: absence of UCP-an LAPD from the osCS can reset the tachycardia without depolarizing the ERAS; presence of UCP-an LAPD from the osCS can depolarize the ERAS without resetting the tachycardia; and indeterminate-an LAPD from the osCS either resets the ERAS and tachycardia simultaneously or does not reset both. RESULTS: The LAPD maneuver was performed in 126 patients with AVNRT. It demonstrated an absence of UCP in 121 (96.0%) patients and the presence of UCP in 3 (2.4%) patients; the result was indeterminate in 2 (1.6%) patients. CONCLUSION: The LAPD maneuver revealed that the presence of UCP is indicated in only rare cases of AVNRT. In most AVNRT cases, the atrium is involved in the reentry circuit.

Ablation of accessory pathways in different anatomic locations using focal pulsed field ablation.

BACKGROUND: Ablation of accessory pathways (APs) is the cornerstone for treatment of patients with Wolff-Parkinson-White syndrome and manifestation of atrioventricular reentrant tachycardia. Pulsed field ablation (PFA) is a new type of nonthermal energy source delivered to the underlying tissue via the ablation catheter and used for ablation of arrhythmic substrates. OBJECTIVE: The purpose of this study was to determine the efficiency and long-term outcome of ablation of APs of different localizations using a focal pulsed electrical field. METHODS: Electrophysiological study was performed in patients with indication for AP ablation. An ablation catheter was used to map the position of AP insertion. Pulsed electric field was delivered through a standard ablation catheter. In left-sided APs, the first ablation attempt was within the coronary sinus (CS). Patient follow-up was scheduled 1-3 months after the ablation. Additional check-up was performed after 6 and 12 months. RESULTS: Fourteen 14 patients (3 pediatric) were treated. Termination of AP conduction was achieved in all procedures. The cohort consisted of 3 right free wall, 3 posteroseptal, and 8 left-sided APs. Ablation through CS was successfully used in 7 of 8 patients with left-sided APs. No complications were reported. Median follow-up was 5.5 months. Conduction recurrence through AP was documented in 1 patient. CONCLUSION: Focal PFA for AP shows promising results in terms of efficacy and safety. A high rate of successful termination of left-sided APs by ablation within CS may represent a new standard approach. The safety and efficacy profile of PFA seems to be transferable to the pediatric population.

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.

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.

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.