Relationship between heart rate on atrioventricular node reentrant tachycardia sustaining and slow path position during procedure of slow path modified ablation using three-dimensional mapping system / 中国介入影像与治疗学

Objective: To observe the relationship between heart rate on atrioventricular node reentrant tachycardia (AVNRT) sustaining and slow path position during procedure of slow path modified ablation using three-dimensional mapping system. Methods: Modified ablation of slow pathway under three-dimensional mapping system was performed in 98 patients with slow-fast (S-F) AVNRT confirmed by invasive electrophysiology examination. The successful target (the site of slow-pathway) and standard His bundle were marked using three-dimensional mapping system, and the distance (Distance A) between the successful target and standard His bundle was measured. The relationship between heart rate in AVNRT and Distance A was analyzed. Results: Distance A was successfully obtained in 96 patients, including 64 tachycardia induced without infusion of isoproterenol, the heart rate was (179.77±29.22)bpm and relevant Distance A was (13.56±5.06)mm, also 32 tachycardia induced with infusion of isoproterenol, the heart rate was (174.91±17.41)bpm and relevant Distance A was (12.43±3.70)mm. No obvious correlation between heart rate and slow path position was found among the above 96 patients (rs=0.048, -0.190; P=0.705, 0.298). Conclusion: There was no obvious correlation between patient's heart rate on AVNRT sustaining and slow path position druing the procedure of slow path modified ablation using three-dimensional mapping system.

3D electronic anatomy mapping guided radiofrequency catheter ablation in 95 children with atrioventricular nodal reentrant tachycardia / 中华儿科杂志

Objective@#To investigate the clinical features and evaluate the efficacy of radiofrequency catheter ablation (RFCA) guided by 3D electronic-anatomy mapping system (CARTO3 System) in children with atrioventricular nodal reentrant tachycardia (AVNRT).@*Methods@#This was a retrospective case-controlled study. Data were collected from 95 children with AVNRT who underwent RFCA using CARTO3 System in the first hospital of Tsinghua University from January 2014 to December 2017. The onset age, characteristic of electrophysiology and anatomy feature of Koch triangle were analyzed. The efficacy and safety of ablation and X-ray fluoroscopy were compared with control 135 children with AVNRT who underwent RFCA without using CARTO3 System. The t test or the chi-square test was used for group comparison. Linear regression equation was established for correlation analysis.@*Results@#The onset age of the 95 children (male 55, female 40; the average age (8.0±3.6) years) with AVNRT was (0.2-17.0) years and 23(24.2%) children were less than 3 years old. Electrophysiologic study showed that 84.2% (80 cases) was AVNRT-slow fast (SF), 11.6% (11 cases) AVNRT-slowslow and 4.2%(4 cases) AVNRT-fast slow. The phenomena of atrio-Hisian(AH) jump occurred in 65.3% and the interval of AH jump was (73.0±10.6) ms. The height of Koch triangle (CSo-His) was (22.3±5.8) mm and related with the weight of children (Y=0.171X+ 16.660, r2=0.224, P<0.001).The distance between the successful ablation target and the lowest point of His zone (ABL-His) was (11.7±2.6) mm. And there was no relation with the body weight(Y=-0.005X + 11.650, r2=0.001, P=0.780) and CSo-His (Y=0.072X+9.914, r2=0.030, P=0.171). The acute success rate was 97.9% (93/95) and recurrent rate was 5.4% (5/93) during follow-up. No obvious complication was reported. Compared with control group, the fluoroscopy time ((3.3±2.5) vs. (10.7±5.8) min, t=13.190, P<0.05), radiation dose ((5.4±4.9) vs. (15.5±6.3) mGy, t=13.660, P<0.05), and dose area product (514±445) vs. (2 478±415) mGy·cm2, t=33.850, P<0.05) were decreased significantly.@*Conclusions@#AVNRT-SF was the most common type of AVNRT. AVNRT incidence in infant and toddlers is lower than that in elder children. CSo-His is correlated with the body weight. ABL-His is relatively fixed. There is no correlation between ABL-His and the body weight and also no correlation between ABL-His and CSo-His. RFCA of AVNRT in children using the CARTO3 system is safe, effective and minimizes X-ray fluoroscopy.

Study on the three-dimensional mapping to reduce the X-ray exposure dose of interventional doctors in radiofrequency catheter ablation of atrioventricular nodal reentry tachycardia / 中华劳动卫生职业病杂志

Objective@#To explore the advantage of radiofrequency catheter ablation under the three-dimensional mapping in the treatment of atrioventricular nodal reentrant tachycardia (AVNRT) in reducing the X-ray exposure dose of interventional doctors.@*Methods@#79 patients with AVNRT, in the first hospital of Shanxi Medical University from January 2015 to June 2016, performed to do radiofrequency catheter ablation treatment were selected, and according to the random number method were divided into two-dimensional mapping group and three-dimensional mapping group. The two-dimensional mapping group was mapped the ablation target at the X-ray, while the ablation target was mapped by CARTO 3 system in the three-dimensional mapping group. Compare the X-ray fluoroscopy time, success rate, complications rate and doctor’s X-ray exposure dose between the two groups.@*Results@#Compared with the two-dimensional mapping group, acute success rate and complication rate of the three dimensional mapping group were not statistically significant (P>0.05) , while the X-ray fluoroscopy time and the X-ray dose of the three-dimensional mapping group decreased significantly, the difference was statistically significant (P<0.05) .@*Conclusion@#Three-dimensional mapping can significantly reduce the X-ray irradiation time and interventional doctor’s X-ray exposure dose in radiofrequency catheter ablation of AVNRT patients and the potential hazards of ionizing radiation on the human body.

Spontaneous Transition of Double Tachycardias with Atrial Fusion in a Patient with Wolff-Parkinson-White Syndrome

Among patients with Wolff-Parkinson-White syndrome, atrioventricular reciprocating tachycardia (AVRT) and atrioventricular nodal reentrant tachycardia (AVNRT) can coexist in a single patient. Direct transition of both tachycardias is rare; however, it can occur after premature atrial or ventricular activity if the cycle lengths of the two tachycardias are similar. Furthermore, persistent atrial activation by an accessory pathway (AP) located outside of the AV node during ongoing AVNRT is also rare. This article describes a case of uncommon atrial activation by an AP during AVNRT and gradual transition of the two supraventricular tachycardias without any preceding atrial or ventricular activity in a patient with preexcitation syndrome.

Pitfalls of Atrial Advancement Using a Ventricular Extra-stimulus During Supraventricular Tachycardia

The delivery of single His-refractory ventricular extra-stimulus during supraventricular tachycardia is useful to identify the mechanism of the tachycardia. We present the different responses based on the ventricular extra-stimulus site. Our findings demonstrate that the atrial activation via an accessory pathway was not advanced based on the ventricular pacing site. Therefore, atrioventricular tachycardia could masquerade as atrioventricular nodal reentrant tachycardia.

Fibrilação atrial durante taquicardia por reentrada nodal atrioventricular: achado sugestivo da presença de via superiorcomum nodal / Atrial fibrillation during atrioventricular nodal reentry tachycardia: a suggestive finding favoring the presence of the upper common nodal pathway

Na taquicardia por reentrada nodal atrioventricular, a necessidade do átrio para a manutenção da taquicardia é controverso. Descrevemos um caso de fibrilação atrial ocorrendo durante taquicardia por reentrada nodal atrioventricular sem afetar o ciclo da arritmia, e discutimos as evidências favorecendo a presença de umavia comum superior.

In Atrioventricular Nodal Reentry Tachycardia the requirement of the atrium for the maintenance oftachycardia is controversial. We describe a case of atrial fibrillation that occurred during Atrioventricular Nodal Reentry Tachycardia without affecting the arrhythmia cycle, and discuss the evidences favoring the presence ofan upper common pathway.

Correlation between connexins and atrioventricular node / 心血管康复医学杂志

Atrioventricular node is responsible for conducting impulse from atria to ventricles.Connexin within atri-oventricular junction play a key role in conducting function of atrioventricular junction;because it presents diversi-fied expression,so its conducting junction is diversified in different areas of atrioventricular junction.Knowing ex-pression type of connexins can approximately determine conductive function in atrioventricular junction area.

Effective analysis on cool-tipped catheter ablation of epicardial accessory pathway / 重庆医学

Objective To investigate the efficacy and safety of cool-tipped saline-irrigated catheter ablation of epicardial accesso-ry pathway in the patients after failure of conventional radiofrequency ablation .Methods 30 patients with epicardial accessory path-way after failuer of conventional radiofrequency ablation were included in this study ,among them ,25 cases of the left accessory pathway and 5 cases of the right accessory prathway used the cool-tipped catheter for conducting ablation through the endocardium (ventricular side or atrial side) or coronary sinus .Results All patients achieved success ,no intraoperative and postoperative related complications occurred .Conclusion The cool-tipped saline-irrigated catheter ablation of epicardial accessory pathway is effective and safe in the patients after failure of conventional radiofrequency ablation ,which may improve the success rate of epicardial acces-sory pathway ablation .

Successful Ablation of Resistant Left Lateral Accessory Pathway and Coexisting Atypical Atrioventricular Nodal Reentrant Tachycardia

A 41-year-old male was presented with drug-resistant supraventricular tachycardia. Electrophysiological study confirmed that the supraventricular tachycardia was caused by dual atrioventricular nodal pathways and a left lateral accessory pathway (AP). The left lateral AP was resistant to traditional endocardial ablation, but was successfully eliminated by radiofrequency ablation via the intracoronary sinus approach.

Radiofrequency current catheter ablation combined with multiple X-ray projecting angles in the treatment of atrioventricular nodal reentrant tachycardia patients / 中国医师进修杂志

Objective To investigate the therapy efficiency and complication prevention in patients undergoing radiofrequency current catheter ablation combined with multiple X-ray projecting angles.Methods Two hundred and six atrioventricular nodal reentrant tachycardia (AVNRT) patients were involved in this study. The distance between the tip of His and the ostium of coronary sinus were measured under different X-ray projecting angles respectively, including posterior anterior (PA), right anterior oblique 30° (RAO 30° ) and left anterior oblique 45° (LAO 45° ) in each patient, and mapping was proceeding under the corresponding X-ray projecting angles with the longest distance. The distance between ablating catheter and His was confirmed again before powering by the other two X-ray projecting angles. Results The longest distance between the tip of His and the ostium of coronary sinus were obtained in 66,75 and 65 patients under PA,RAO 30° and LAO 45° respectively(P＞ 0.05 ),and the data were (2.94 ± 0.87), (2.98 ± 0.76)and (2.91 ± 0.52) cm(P＞ 0.05). Transient first or second degree of atrioventricular blocking was observed in 4 cases among 22 high risk patients in which the powering sites were above the medium level of the distance between the tip of His and the ostium of coronary sinus under three kinds of X-ray projecting angles obviously.However,only 1 case was observed in other 184 patients(P＜ 0.01 ). All patients were cured successfully and no permanent atrioventricular blocking occurred. Conclusion Radiofrequency current catheter ablation combined with multiple X-ray projecting angles is helpful to increasing the successful rate and preventing complication in ablating therapy.

Hemodynamic Effects of Simulated Ventricular Tachycardia and Supraventricular Tachycardia in Dogs

BACKGROUND AND OBJECTIVES: Tachycardias have various clinical features according to the heart rate, the left ventricular systolic function, the site of origin and the mechanisms of the tachycardias. The primary purpose of this study was to evaluate the role of the origin site and cycle length on the ventricular tachycardia (VT) hemodynamics. Our secondary purpose was to explore the possible hemodynamic differences between the two common supraventricular tachycardias (SVT). MATERIALS AND METHODS: VT was simulated in 18 dogs that had there chests opened by using ventricular pacing (VP) at 3 different sites: the left ventricular apex (LVA), the right ventricular outflow tract (RVOT), and the right ventricular apex (RVA). The mean arterial pressure (MAP), the mean left atrial pressure (MLAP) and the mean pulmonary artery pressure (MPAP) were monitored during VP. To simulate SVT, the right atrial appendage and the right ventricular basal septum were stimulated at different cycle lengths with different ventriculo-atrial (VA) time intervals in another 11 dogs that had their chests opened. The arterial pressure, the pulmonary capillary wedge pressure and the cardiac output was observed during simulated atrial tachycardia (Group I), AVRT (Group II) and AVNRT (Group III). RESULTS: In the VT study, at the same pacing site as of the VP, the MAP was significantly decreased with the VP, and the deltaMAP was significantly increased as the length of the VP cycle shortened. At the same pacing cycle length of the VP, the deltaMAP was significantly greater at the RVA or RVOT than at the LVA. At the same pacing site of the VP, the MLAP and the deltaMLAP were significantly increased as the VP cycle length shortened. In the SVT study, MAP was highest in Group I and it decreased with the decreasing VA interval, but this was not significant. The systolic arterial pressure was significantly higher in Group II than in Group III. The CO was higher in Group I than in the other two groups, with a significant difference, and the CO decreased with shortening of the VA interval, but this was not significant. CONCLUSION: The above results suggest that in addition to the tachycardia rate, the origin site could be an independent factor of the VT hemodynamics. Episodes of AVRT and AVNRT may have a different hemodynamic impact that probably originates from the different timing of the ventricular and atrial contraction.

Significance of Atrio-Ventricular Block Following Atrio-His Jump in the Diagnosis of Dual Atrioventricular Nodal Physiology with Adenosine Infusion

BACKGROUND AND OBJECTIVES: Atrioventricular block (AVB) is frequently seen following atrio-His (AH) interval lengthening after adenosine injection during sinus rhythm when both the fast and slow pathways are blocked in patients with dual atrioventricular nodal physiology (DAVNP). However, the condition also occurs in patients without DAVNP. Therefore, an AH jump may not indicate DAVNP if AVB is accompanied. The goal of this study was to use a low dose (6-9 mg) of adenosine to determine whether an AH jump truly represents DAVNP when the presence or absence of AVB following the AH jump is taken into consideration. SUBJECTS AND METHODS: This study included 78 patients (male:female=47:31, age 40.0+/-15.7 years, DAVNP group, n=46, control group, n=32). Adenosine (6-9 mg) was administered intravenously during sinus rhythm. The inclusion criteria of DAVNP were either induced AVNRT (n=37:common type, n=35, uncommon, n=2) or identification of AH jump (n=9) during elctrophysiology study (EPS). The control group consisted of patients without evidence of DAVNP and noninducible AVNRT on EPS. In all subjects, the electrophysiologic parameters of the AV nodal properties were tested. In the DAVNP group, intravenous adenosine during sinus rhythm resulted in an AH jump without AVB (8/46, 17.4%), an AH jump followed by AVB (9/46, 19.6%), an AH jump accompanied by induced AVNRT (1/46, 2.1%), or no significant changes in the AH interval (28/46, 60.9%). In the control group, none of the subjects showed an AH jump without AVB, however an AH jump with subsequent AVB was observed in 4 of 32 subjects (12.5%). If the finding of an AH jump without AVB alone was considered as a positive criteria of DAVNP, its specificity (87.5% to 100%) and positive predictive value (81.8% to 100%) increased compared to the criteria defined by an AH jump regardless of the presence or absence of AVB, however, its sensitivity decreased from 39.1% to 19.6%. CONCLUSION: AH jump induced by adenosine injection may not indicate DAVNP if AVB follows.

Radiofrequency Catheter Ablation of Atrioventricular Nodal Re-entrant Tachycardia in a Patient with Dextrocardia Associated with Atrial Septal Defect

It is known that tachyarrhythmias in patients with congenital heart defects have a potentially high impact on quality of life, morbidity and mortality. Conventional treatment with antiarrhythmic drugs may have untoward results including recurrence of tachyarrhythmia and its adverse effects. Therefore, radiofrequency catheter ablation is increasingly used for the treatment of supraventricular tachycardias in patients with congenital heart diseases, although abnormal anatomy and atypical conduction systems have the potential to complicate catheter ablation procedures. This report describes our experience with the successful radiofrequency catheter ablation of atrio-ventricular nodal reentrant tachycardia (AVNRT) in a patient with dextrocardia with situs solitus (isolated dextrocardia).

Cellular electrophysiology of fast pathway ablation of rabbit atrioventricular node

Discrete radiofrequency lesion at the atrial insertion site of the tendon of Todaro in the perfused rabbit preparation lengthens A-H interval, mimicking fast pathway input ablation. This study attempts to define the cellular electrophysiology of the ablation region prior to and after the elimination of fast AV node conduction. In six superfused rabbit AV node preparations, the cellular electrophysiology around the region of the atrial insertion to the tendon of Todaro was recorded using standard microelectrode technique prior to and after ablation. Before ablation, the action potentials recorded in the area of proposed lesion were exclusively from atrial or AN cells. At postablation, the superior margin of the lesion was populated with atrial or AN cells. AN, N, or NH cells bordered the lower part of the lesion. Electrophysiology of surviving cells at the edges of the lesion showed no significant changes in their Vmax, APD50 or APD90 and MDP from preablation values. Fast AV node pathway input ablation in the rabbit heart can be accomplished with a singular lesion around the atrial insertion site of the tendon of Todaro, involving atrial or AN cells. The results of the studies imply that inputs to the compact node may act as a substrate for successful ablation of AV node reentry tachycardia.

Successful radiofrequency ablation of atrioventricular nodal reentrant tachycardia at the mitral annulus / 中国介入心脏病学杂志

Objective To analyze the electrophysiological characteristics of atrioventricular nodal reentrant tachycardia(AVNRT) requiring ablation at the mitral annulus.Methods Ablation was carried out at the mitral annulus by mapping the slow pathway with resetting method in order to acquire the electrophysiological parameters needed for successful ablation of AVNRT.Results Three cases with AVNRT who had prior failed ablation were successfully ablated by targeting the slow pathway located at the mitral annulus.The location of the left-sided slow pathway was selected by a positive resetting response and verified by junctional automaticity elicited by radiofrequency application and elimination of tachycardia.Conclusion AVNRT refractory to ablation of slow pathway at the posteroseptal area may require ablation at the mitral annulus.Resetting response may help to locate the slow pathway along the mitral annulus.

Radiofrequency ablation of atrioventricular nodal re-entrant tachycardia guided by the CARTO electroanatomic mapping system / 解放军医学杂志

0.05), while when the CARTO technology was used, the mean fluoroscopy time was significantly shorter (6.3?2.6min vs 16.2?7.0min,P