Catheter ablation of supraventricular tachycardia in patients with dextrocardia and situs inversus.

The safety and effectiveness of radiofrequency catheter ablation (RFCA) for supraventricular tachycardia (SVT) in young children was investigated. Ninety-five children who underwent RFCA procedures were stratified according to age (group 1, 0-4 years, n = 24; group 2, 5-9 years, n = 71) and were evaluated retrospectively. Among the 95 patients, atrioventricular reentrant tachycardia was 78.9%, atrioventricular nodal reentrant tachycardia was 10.5%, and ectopic atrial tachycardia was 8.4%. The acute success rate of RFCA was 97.9% and the recurrence rate was 11.6%. RFCA was performed for different main reasons in each group, including drug-resistant tachycardia (37.5% in group 1 vs 7% in group 2; P = 0.001) and symptomatic tachycardia (4.2% in group 1 vs 57.7% in group 2; P < 0.001). There was no significant difference in success rate, recurrence rate, and procedure and fluoroscopy duration between the two groups. The acute success rates did not differ significantly between patients with a single accessory pathway (AP) and those with multiple APs; however, failure or recurrence was more common in the patients with multiple APs (38.5% vs 11.5%; P = 0.01). The multiple APs were found frequently on the right side (P = 0.005). Septal dyskinesia with left ventricular dysfunction in Wolff-Parkinson-White syndrome and tachycardia-induced cardiomyopathy improved after RFCA. RFCA was found to be effective and safe for SVT in young children.

Electrophysiological features and radiofrequency catheter ablation of supraventricular tachycardia in patients with persistent left superior vena cava

Influence of age and gender on the mechanism of supraventricular tachycardia

Two hearts beating out of time: Mapping and ablation of concurrent atrial fibrillation and macroreentrant left atrial flutter in a transplanted heart

0037: Is the risk of atrial fibrillation dependent on the mechanism of tachycardia in patients with history of paroxysmal supraventricular tachycardia?

Various forms of supraventricular tachycardia (SVT) occur in patients with severe pulmonary hypertension (PH). Despite the high efficacy of radiofrequency catheter ablation (RFCA) for SVT, insufficient data exist regarding patients with PH. Thirty SVTs in 23 PH patients (age 47 [35–60] years; mean pulmonary artery pressure 44 [32–50] mmHg) were analyzed. Procedural success rate, short- and long-term clinical outcomes, were evaluated during a median follow-up of 5.1 years. Single-procedure success rate was 83%; 94% (17/18) in typical atrial flutter, 73% (8/11) in atrial tachycardia (AT), and 100% (1/1) in atrioventricular nodal reentrant tachycardia. Antiarrhythmic drugs, serum brain natriuretic peptide levels and number of hospitalizations significantly decreased after RFCA than that before (p = 0.002, 0.04, and 0.002, respectively). Four patients had several procedures. After last RFCA, 12 patients had SVT and 8 patients died. Kaplan–Meier curves showed that patients with SVT after the last RFCA had a lower survival rate compared to those without (p = 0.0297). Multivariate analysis identified any SVT after the last RFCA as significant risk factor of mortality (hazard ratio: 9.31; p = 0.016). RFCA for SVT in patients with PH is feasible and effective in the short-term, but SVT is common during long-term follow-up and associated with lower survival.

This paper reviews the anatomical substrates responsible for the induction and maintenance of supraventricular tachycardia and discusses the ECG findings associated with these tachycardias. The normal anatomy of the supraventricular conducting system, particularly within the atria, is complex with conduction proceeding along preferential pathway, which are in turn determined in part by the anisotropic properties of the atrial myocardium. There appear to be at least dual inputs to the atrioventricular node, a posteriorly situated slow pathway and an anterior fast pathway. It is sometimes possible to relate ECG findings directly to anatomical substrates; for example, in some cases of atrial tachycardia the site of the atrial focus (left or right, superior or inferior) can be determined by the polarity of the P wave. The anatomical substrates responsible for intra-atrial re-entry, atrial flutter and atrial fibrillation relate to anatomical barriers to impulse propagation and areas of slow conduction. In atrial flutter the crista terminalis, Eustachian valve, inferior vena cava, coronary sinus os, and tricuspid annulus have been identified as anatomical barriers to conduction around which a macro re-entrant circuit within the right atrium may conduct, usually in a counter-clockwise direction. Clockwise direction of conduction, and other mechanisms of tachycardia, occur in some of the less typical forms of atrial fluter. Atrial fibrillation is caused by multiple wavelets which randomly conduct through the atrial myocardium and are responsible for the irregular 'fibrillation waves' on the ECG. Supraventricular tachycardia presents as a narrow complex tachycardia unless pre-existing or rate-related bundle branch block is present. Less common causes for a broad complex tachycardia occurring in supraventricular tachycardia include an accessory atrioventricular or atriofascicular pathway conducting antegradely during tachycardia, or accessory pathway participation as a bystander during supraventricular tachycardia. ECG features which can help to distinguish between atrioventricular nodal re-entrant tachycardia and atrioventricular re-entrant tachycardia include: (1) the presence of a delta wave during sinus rhythm which is highly suggestive of atrioventricular re-entrant tachycardia as the mechanism of supraventricular tachycardia; (2) the finding of a pseudo s (lead II) or pseudo r' (lead V1) during tachycardia in atrioventricular nodal re-entrant tachycardia; (3) lengthening of the tachycardia cycle length in cases of atrioventricular re-entrant tachycardia when bundle branch block occurs ipsilateral to the accessory pathway and (4) the finding of QRS alternans during tachycardia which is suggestive of atrioventricular re-entrant tachycardia. "Long RP' tachycardia may be caused by an atrial tachycardia due to an inferiorly situated area of abnormal automaticity, atypical atrioventricular nodal re-entrant tachycardia with slow retrograde conduction, or atrioventricular re-entrant tachycardia with an accessory pathway conducting slowly from ventricle to atrium during tachycardia.

To analyse outcomes of supraventricular tachycardia (SVT) ablations performed within a prospective German Ablation Quality Registry. Data from 12566 patients who underwent catheter ablation of SVT between January 2007 and January 2010 to treat atrial fibrillation (AFIB, 37.2% of procedures), atrial flutter (AFL, 29.9%), atrioventricular nodal re-entrant tachycardia (AVNRT, 23.2%), atrioventricular re-entrant tachycardia (6.3%), and focal atrial tachycardia (AT, 3.4%) were prospectively collected. Patients were followed for at least 1 year. The periprocedural success rate was 96.3%, ranging from 84.3% (focal AT) to 98.9% (AVNRT). Kaplan-Meier mortality estimate at 1 year was 1.4% overall, and as high as 2.6% in the AFL group and 2.8% in the focal AT group. Recurrence of ablated or another symptomatic SVT was observed in 3783 (32.6%) of patients, ranging from 17.2% (AVNRT) to 45.6% (AFIB). Repeat ablation was performed in 12.0% of patients. After 1 year, 74.1% of survivors perceived ablation therapy as successful, 15.7% as partly successful, and 9.6% as unsuccessful. Even in those patients with arrhythmia recurrence, 76.0% perceived ablation as successful or partly successful and 89.6% would still undergo repeat ablation in the same institution. Ablation therapy for SVT is a safe procedure bringing symptomatic improvement and satisfaction to three quarters of patients after 1 year. Even in patients with arrhythmia recurrence, a high satisfaction level and adherence to the ablating institution could be documented. Strikingly high mortality and stroke rates in follow-up were observed in AFL patients, who apparently need consistent long-term anticoagulation and more medical attention.

The use of non-fluoroscopic systems (NFS) to guide radiofrequency catheter ablation (RFCA) for the treatment of supraventricular tachycardia (SVT) is associated with lower radiation exposure. This study aimed to determine if NFS reduces fluoroscopy time, radiation dose and procedure time. We prospectively enrolled patients undergoing RFCA for SVT. NFS included EnSiteTM NavXTM or CARTO® mapping. We compared procedure and fluoroscopy times, and radiation exposure between NFS and conventional fluoroscopy (CF) cohorts. Procedural success, complications and one-year success rates were reported. A total of 200 patients over 27 months were included and RFCA was guided by NFS for 79 patients; those with atrioventricular nodal reentrant tachycardia (AVNRT), left-sided atrioventricular reentrant tachycardia (AVRT) and right-sided AVRT were included (n = 101, 63 and 36, respectively). Fluoroscopy times were significantly lower with NFS than with CF (10.8 ± 11.1 minutes vs. 32.0 ± 27.5 minutes; p < 0.001). The mean fluoroscopic dose area product was also significantly reduced with NFS (NSF: 5,382 ± 5,768 mGy*cm2 vs. CF: 21,070 ± 23,311 mGy*cm2; p < 0.001); for all SVT subtypes. There was no significant reduction in procedure time, except for left-sided AVRT ablation (NFS: 79.2 minutes vs. CF: 116.4 minutes; p = 0.001). Procedural success rates were comparable (NFS: 97.5% vs. CF: 98.3%) and at one-year follow-up, there was no significant difference in the recurrence rates (NFS: 5.2% vs. CF: 4.2%). No clinically significant complications were observed in both groups. The use of NFS for RFCA for SVT is safe, with significantly reduced radiation dose and fluoroscopy time.

A remote magnetic navigation system (MNS) has been developed for mapping and catheter ablation of cardiac arrhythmias. The present study evaluates the safety and feasibility of this system to perform radiofrequency (RF) ablation in patients with supraventricular tachycardias (SVT). A total of 32 patients (22 female; mean age 44 +/- 16 years) with documented SVT underwent mapping and ablation using Helios II (a 4-mm-tip magnetic catheter), under the guidance of the MNS (Niobe II, Stereotaxis, Inc.). Catheter ablation procedure with MNS was successful in 30/32 (94%) patients including all patients (27/27, 100%) with atrioventricular nodal reentrant tachycardia (AVNRT) and three of five patients (60%) with atrioventricular reentrant tachycardia (AVRT) without any complication. The procedural successful rate in patients with AVNRT was significantly higher than those in patients with AVRT (P < 0.001). Overall, the medium number of RF application using the MNS was 2 (mean 2.7 +/- 1.6, range 1 to 7), and the medium numbers of RF for AVNRT and AVRT were 2 and 3, respectively. There was no significant difference in the mean procedural time between patients with AVNRT and AVRT (126.3 +/- 38.6 vs. 138.0 +/- 40.3 min, P = 0.54). However, the mean fluoroscopy time was significantly shorter in patients with AVNRT than those with AVRT (5.7 +/- 3.0 vs. 16.5 +/- 2.5 min, P < 0.001). Among those patients with AVNRT, the mean procedural time (139.3 +/- 45.0 vs. 112.3 +/- 24.9 min, P = 0.07) and fluoroscopic time (3.2 +/- 1.0 vs. 8.0 +/- 2.2 min, P < 0.001) were shorter for the later 13 patients than the first 14 patients, suggesting a learning curve in using the MNS for RF ablation. The Niobe MNS is a new technique that can allow safe and effective remote-controlled navigation and minimize the need for fluoroscopic guidance for ablation catheter of AVNRT. However, further improvement is required to achieve a higher successful rate for treatment of AVRT.

Interventional cardiology procedures may expose patients and staff to considerable radiation doses. We aimed to assess whether exposure to ionizing radiation during catheter ablation of supraventricular tachycardia (SVT) can be completely avoided. In this prospective randomized study, patients with SVT (atrioventricular re-entrant tachycardia n = 94, typical atrial flutter n = 29) were randomly assigned in a 1:1 ratio to catheter ablation with conventional fluoroscopic guidance (CF group) or with the EnSite Precision mapping system [zerofluoro (ZF) group]. Acute procedural parameters, increased stochastic risk of cancer incidence and 6-month follow-up data were assessed. Between May 2019 and August 2020, 123 patients were enrolled. Clinical parameters were comparable. Median procedural time was 60.0 and 58.0 min, median fluoroscopy time and estimated median effective dose were 240 s vs. 0 and 0.38 mSv vs. 0 and arrhythmia recurrence was 5% and 7.9% in the CF and ZF groups, respectively. The acute success rate was 98.4% in both groups. No procedure-related complications were reported. At an average age of 55.5 years and median radiation exposure of 0.38 mSv, the estimate of increased incidence was approximately 1 in 14 084. The estimated mortality rate was 1 per 17 857 exposed persons. The procedural safety and efficacy of the zero-fluoroscopic approach are similar to those of conventional fluoroscopy-based ablation for atrioventricular nodal re-entrant tachycardia and atrial flutter. Under the assumption of low radiation dose, the excessive lifetime risk of malignancy in the CF group due to electrophysiology procedure is reasonably small, whilst totally reduced in zero fluoroscopy procedures.

Objective To investigate the success rate, factors associated with recurrence, safety and effect of age on results of radiofrequency catheter ablation(RFCA) for different types of tachyarrhythmias in children. Methods A thousand children diagnosed as tachyarrhythmias underwent electrophysiological study(EPS), with mean age (7.6±3.8)years old(0.33-16.50 years old). RFCA methods and results for different kinds of tachyarrhythmias along with recurrence and complications were analyzed.RFCA results for different age groups were compared. Results A thousand children underwent EPS.The number of atrioventricular reentrant tachycardia(AVRT) was 560(56%), atrioventricular nodal reentrant tachycardia(AVNRT) was 210(21%), ventricular tachycardia/ventricular premature contraction(VT/PVC)was 159(15.9%), focal atrial tachycardia(FAT)was 49(4.9%), and atrial flutter/incisional reentrant atrial tachycardia (AF/IRAT)was 22(2.2%). Totally 958 children underwent RFCA, among whom success rate was 96.2% and recurrence rate was 8.1%.EPS performed on recurred cases showed restoration of primary pathway/origin was 5.3%, while appearance of new pathway/origin was 2.8%.Five hundred and thirty-three AVRT cases underwent RFCA, among whom success rate was 98.0%, recurrence rate was 8.4%, restoration of primary pathway was 4.0%, and appearance of new pathway was 4.4%.Success rate of right anterior/mid septal pathway was relatively low(85.3%), but its rate of restoration of primary pathway was high(31.0%), as 205 cases of AVNRT underwent RFCA, among whom success rate was 100%, recurrence rate was 5.9%, and restoration of primary origin was 4.9%, while 22 cases of AF/IRAT underwent RFCA, among whom success rate was 95.5% with no recurrence, 46 cases of FAT underwent RFCA, in which success rate was 84.8%; success rates for two-dimensional mapping group and three-dimensional mapping combined with cool-tip ablation group were 62.5% and 96.7% respectively and the difference was significant(P<0.05), as 10 cases recurred in which 7 originated from atrial appendages, and these 7 cases were successfully cured by appendectomy, 152 cases of VT/PVC underwent RFCA, in which success rate was 89.5%, recurrence rate was 6.6%, restoration of primary origin was 5.9%.There was no difference in success rate between different age groups.The gross success rates and success rates for different types of arrhythmias between early and late periods were not different, while recurrence rates for AVNRT and left anterior pathways in early periods were significantly higher than late periods(P<0.05). There were totally 8 cases with complications(0.84%), including 2 cases of complete atrioventri-cular block and 1 case of anesthetic accident which happened in early period.The other 5 were vascular complications, and there was no death. Conclusions RFCA can be safely used as frontline treatment to cure some kinds of tachyarrhythmias in children with high success rate and low recurrence rate.There is no difference in rates of success, recurrence and complication between younger and older children, while difficulty for procedure increased for the former so that caution should be made for selection of patients.Application of three-dimensional mapping for difficult arrhythmias can increase success rate for ablation.Proficient experience and skillful manipulation are the main factors to avoid complications. Key words: Tachyarrhythmias; Electrophysiology; Radiofrequency catheter ablation; Child

Little is known about the long-term outcomes of catheter ablation of supraventricular tachycardia (SVT) using remote magnetic navigation system (RMN). One hundred twenty patients underwent catheter ablation of SVTs with RMN (Niobe, Stereotaxis, USA): atrioventricular nodal re-entrant tachycardia (AVNRT; n = 59), atrioventricular re-entrant tachycardia (AVRT; n = 45), and focal atrial tachycardia (AT, n = 16). The outcome of AVRT with right free wall accessory pathway was compared with those of a group of 26 consecutive patients undergoing manual ablation. Mean follow-up period was 2.2 ± 1.4 years. Overall arrhythmia-free survival was 86%; AVRT (77%), AVNRT (96%), and focal AT (71%). After the learning period (initial 50 cases), procedural outcomes had improved for AVRT and AVNRT (91% in overall group, 90% in AVRT group, 100% in AVNRT group, and 68% in focal AT group). The recurrence-free rate was higher for the free wall accessory pathways than those of the other sites (92 vs. 73%, log-rank P = 0.06). Furthermore, when it is confined for the right free wall accessory pathway, RMN showed excellent long-term outcome (7/7, 100 %) compared to the results of manual approach (18/26, 69.2%, log-rank P = 0.07). RMN showed favorable long-term outcomes for the ablation of SVT. In our experience, RMN-guided ablation may be associated with a higher success rate as compared to manual ablation when treating right-sided free wall pathways.

AimTo compare patient characteristics, safety and efficacy of catheter ablation of supraventricular tachycardia (SVT) in patients with and without structural heart disease (SHD) enrolled in the German ablation registry.Methods and resultsFrom January 2007 until January 2010, a total of 12,536 patients (37.2% with known SHD) were enrolled and followed for at least one year. Patients with SHD more often underwent ablation for atrial flutter (45.8% vs. 20.9%, p < 0.001), whereas patients without SHD more often underwent ablation for atrioventricular nodal reentrant tachycardia (30.2% vs. 11.8%, p < 0.001) or atrioventricular reentrant tachycardia (9.1% vs. 1.6%, p < 0.001). Atrial fibrillation catheter ablation procedures were performed in a similar proportion of patients with and without SHD (38.1% vs. 36.9%, p = 0.21).Overall, periprocedural success rate was high in both groups. Death, myocardial infarction or stroke occurred in 0.2% and 0.1% of patients with and without SHD (p = 0.066). Major non-fatal complications prior to discharge were rare and did not differ significantly between patients with and without SHD (0.5% vs. 0.4%, p = 0.34). Kaplan–Meier mortality estimate at 1 year demonstrated a significant mortality increase in patients with SHD (2.6% versus 0.7%; p < 0.001).ConclusionPatients with and without SHD undergoing SVT ablation exhibit similar success rates and low major complication rates, despite disadvantageous baseline characteristics in SHD patients. These data highlight the safety and efficacy of SVT ablation in patients with and without SHD. Nevertheless Kaplan–Meier mortality estimates at 1 year demonstrate a significant mortality increase in patients with SHD, highlighting the importance of treating the underlying condition and reliable anticoagulation if indicated.

Objective To analysis the impact of age and gender on the mechanism of paroxysmal supraventricular tachycardia(PSVT). Methods Using the data from interventional treatment of arrhythmias database platforms, analyzing the impact of age and gender on the mechanism of PSVT. Results Four thousand seven hundred and thirty-two patients accepted catheter ablation for PSVT, the mechanisms were classified as atrioventricular reentrant tachycardia(AVRT)and atrioventricular nodal reentrant tachycardia(AVNRT). The mean age was(45.9±15.7 )years, and the majority were women(n=2 397, 50.66%), AVNRT was the predominant mechanism(n=2 458, 51.94%). The diagnosis of AVNRT was significantly determined by age(the area under the ROC curve was 0.613, standard error was 0.008, P<0.001). Logistic regression analysis showed that age(OR=1.279 6, 1.231 6-1.329 6)and female(OR=2.131 9, 1.894 0-2.399 7)were the determined factor for the diagnosis of AVNRT. Conclusion The distribution of age and gender were significant difference between patients with AVRT and AVNRT, PSVT mechanism was determined by gender and age. Key words: Paroxysmal supraventricular tachycardia; Atrioventricular reentrant tachycardia; Atrioventricular nodal reentrant tachycardia; Gender; Age