Atrioventricular Nodal Reentry Research Articles

PO-05-229 DEEP LEARNING CLASSIFICATION OF PAROXYSMAL SUPRAVENTRICULAR TACHYCARDIA TYPES USING SINUS RHYTHM ELECTROCARDIOGRAMS

Only sinus rhythm electrocardiograms (ECGs) are often available in patients with paroxysmal supraventricular tachycardia (PSVT). However, sinus rhythm ECGs have a limited value in classifying PSVT types. We aimed to investigate the deep learning approach of classifying Atrioventricular Nodal Reentry Tachycardia (AVNRT) from concealed Atrioventricular Reentry Tachycardia (AVRT) using sinus rhythm ECGs. We collected the patients with AVNRT or conceald AVRT, and their 12-lead ECGs with sinus rhythm. The diagnosis of each patient was validated with an electrophysiology study. ResNet-34 was used for the deep learning model, and it was trained to classify sinus rhythm ECGs with underlying AVNRT and conceald AVRT. Due to the limited training dataset, transfer learning was performed by pre-training of an open-source ECG database (PhysioNet/CinC Challenge 2021). Ten-fold cross-validation was used to validate deep learning performance. Integrated gradient analysis was used to visualize which ECG segment is important for the model to classify the two arrhythmias. A total of 696 patients with AVNRT and 305 patients with conceald AVRT were analyzed. Compared to the AVNRT group, the conceald AVRT group was significantly younger and had a higher male proportion; age 48 vs. 51 years (p<0.001); male 63.3 vs. 34.3% (p<0.001). After the pre-training, the deep learning performance was significantly improved; AUROC 0.73 (95% CI 0.69-0.76) vs. 0.67 (0.62-0.72) for with and without pre-training; p<0.001 (Figure A). Deep learning showed modest performance for classifying the two arrhythmias; AUPRC, F1-score, sensitivity, and specificity were 0.84 (0.81-0.87), 0.75 (0.70-0.80), 0.68 (0.61-0.75), and 0.71 (0.65-0.77), respectively. Deep learning focused on PR intervals and T waves for identifying AVNRT, and P-waves for concealed AVRT (Figure B). Deep learning classification of AVNRT and conceald AVRT was feasible with sinus rhythm ECGs.

PO-05-232 SAFETY AND EFFICACY OF ATRIOVENTRICULAR NODAL REENTRY TACHYCARDIA ABLATION USING AN IRRIGATED CONTACT FORCE CATHETER

Atrioventricular Nodal Reentry Tachycardia (AVNRT) ablation is a common procedure in contemporary electrophysiology practice. Traditionally ablation for AVNRT has been performed with non-irrigated catheters, guided by fluoroscopy and intracardiac electrograms. Increasingly electroanatomic mapping systems are utilized to allow for low or zero fluoroscopy procedures. Contact force catheters can provide information on tissue contact and stability that can be helpful in patients with challenging anatomy. Available contact force catheters are irrigated and concern has existed for using irrigated tip ablation catheters for AVNRT ablation due to the potential to create lesions that are too deep and could increase the risk for AV block. To describe the safety and efficacy for the use of irrigated contact force catheters for ablation of AVNRT Review of procedural data from patients undergoing radiofrequency ablation for AVNRT using electroanatomical mapping combined with irrigated contact force catheter. Fifty patients from 4 regions across Australia were included. Procedures were performed by 9 experienced electrophysiologists. No periprocedural complications occurred. Procedural success was achieved in 96%. Median lesion contact force (25-75 centile) was 4.0(2-6)g. Peak power was set at 50W, median baseline irrigation was at 2ml/min and 6ml/min during ablation. Median number of lesions was 9(4.5-17.5); with total ablation time of 203(95-366) seconds. 60% of the cases were performed without fluoroscopy. Ablation of AVNRT using an irrigated contact force catheter on low irrigation setting is safe and effective. Contact force catheters using low irrigation settings may safely improve success rates in AVNRT with challenging anatomy or ablation of other substrate in close proximity to vital structures.

Radiofrequency Catheter Ablation of Mahaim Tachycardia in Adult Patients

Mahaim pathways causing reentrant tachycardia are rare but potentially dangerous arrhythmia. Catheter ablation is the definitive treatment option for individuals with this kind of tachycardia. Objective: To evaluate the efficacy and safety of radiofrequency catheter ablation of mahaim tachycardia in adult patients. Methods: A retrospective study investigated total of 40 adult patients referred to the Cardiac Electrophysiology Department of Hayatabad medical Complex Peshawar from 4th January 2017 to 21st September 2022 were enrolled. Patient’s age (20-68 years) of both male and female genders referred for radiofrequency ablation of mahaim tachycardia were studied. The tachycardia was invariably antidromic, resulting from anterograde conduction via the Mahaim pathway. All the cases were followed for complications. Results: The overall mean age was 43.60 ± 12.4 years. The mean ablation and flouro time was 9.44± 6.93 minutes and 20.64 ± 9.77 minutes respectively. Hypertension and diabetes were found in 11 (27.5%) and 6 (15%) patients respectively. The successful ablation was achieved in 31 (77.5%) patients whereas 1 case was abandoned. During follow-up, one patient developed femoral hematoma as a complication. Typical Atrioventricular nodal reentry tachycardia (AVNRT) and atrial fibrillation were other tachycardia found in 3 (7.5%) and 4 (10%) respectively. The incidence of congenital anomalies such as ASD Secundum, HOCM, DCM, and Ebstein Anomaly was 2 (5%), 1 (2.5%), 1 (2.5%), and 1 (2.5%) respectively. Conclusion: The present study found that Radiofrequency ablation is effective and safe for treating Mahaim tachycardia. The success rate of RFA was 77.5%.

Combination of slow pathway late activation maps and voltage gradient maps in guidance of atrioventricular nodal reentrant tachycardia cryoablation

The optimal strategy for electroanatomic mapping-guided cryoablation of atrioventricular nodal reentry tachycardia (AVNRT) remains unclear. The purpose of this study was to investigate the effectiveness of slow pathway late activation mapping (SPLAM) and voltage gradient mapping for AVNRT cryoablation. From June 2020 to February 2022, all consecutive patients with AVNRT underwent SPLAM to define the wave collision point and voltage gradient mapping to define the low-voltage bridge (LVB). Conventional procedures performed from August 2018 to May 2020 served as control. The study and control groups comprised 36 patients (age 16.5 ± 8.2 years) and 37 patients (age 15.5 ± 7.3 years), respectively. Total procedural times were comparable, and acute success rates were 100% in both groups. Compared to controls, the number of cryomapping attempts (median 3 vs 5; P = .012) and cryoablation applications (median 1 vs 2; P <.001) were significantly lower in the study group. At median follow-up of 14.6 and 18.3 months, recurrence rates were 5.6% (2 patients) and 10.8% (4 patients) in the study and control groups (P = .402), respectively. Mapping of the Koch triangle took 11.8 ± 3.6 minutes, during which 1562 ± 581 points were collected. In SPLAM, wave collision points were defined and compatible with the final successful lesion sites in all patients, including those with multiple slow pathways. LVB could not be defined in 6 patients (16.7%), and LVB was not compatible with the final successful lesion in another 6 (16.7%). For AVNRT cryoablation, SPLAM could effectively guide the localization of slow pathway ablation sites and was particularly beneficial in patients with multiple slow pathways.

Evaluation of the Quantity and Duration of Junctional Rhythm during Successful Radiofrequency Ablation among Patients with Atrioventricular Nodal Re-Entry Tachycardia

Objectives: To evaluate the quantity and duration of junctional rhythm during radiofrequency ablation among atrioventricular nodal reentry tachycardia (AVRNT) patients. Methodology: A Cross sectional study was conducted at Punjab Institute of cardiology from May – July, 2022. Ablations of slow pathway were executed on 50 patients who fulfilled the inclusion criteria using ablation catheters of 4-mm tip. Power output was kept between 35- 40 Watt with a temperature control at 60 °C depending upon the occurrence of junctional rhythm. The target end points of radio frequency ablation (RFA) were inability to either induce or spontaneously demonstrate clinical tachycardia. Presence of more than one atrio-ventricular (AV) nodal echo beat was the criteria to continue further ablations as it was considered indicator residual slow pathway. Data was entered in SPSS software version 21.0 and were presented as mean ± SD were used. Results: The mean age of the patients was 36.50 ± 7.129 years. Ablation power was titrated between 35-40 watts (Mean 39.6 ± 1.37). The average amount of junctional beats in each patient was 57.34 ± 9.71 (73-38) with mean duration of junctional rhythm was 29.20 ± 3.47 sec. Successful ablation mean was 54.25 + 8.45 as compared to unsuccessful attempts of 44.32 ± 5.77 and was statistically significant (p&lt;0.001). Conclusion: The study concluded that RFA had high success rate and a low recurrence rate with less complication. Junctional rhythm is a sensitive predictor of successful ablation and is a safe and effective way of permanent termination of AVNRT.

Usefulness of wearable electrocardiography devices in patients experiencing paroxysmal cardiac-related symptoms: A case series of the “CardioSecur” system

BackgroundElectrocardiograms (ECGs) recorded with wearable devices and additional smartphone apps play an increasing role in cardiology. Case summariesWe present two cases in which it was possible to record an ECG during cardiac-related symptoms using the patients' smartphones. Previous standard resting and 24-hour ECGs had revealed no pathologies. In one case, AV nodal reentry tachycardia was detected and treated accordingly. In the second case, ischemic ECG changes were recorded in a young woman without cardiovascular risk factors during a chest pain episode. Suspecting a coronary vasomotion disorder, an invasive diagnostic procedure was performed. The acetylcholine spasm provocation test revealed coronary microvascular spasm and appropriate therapy was initiated. DiscussionSmartphone-based ECG systems which can be used by the patient independently while experiencing cardiac-related symptoms are a modern diagnostic tool. Considering the use of these systems is beneficial for early diagnosis and appropriate treatment for paroxysmal arrhythmias and coronary vasomotion disorders.

AVNRT cryoablation in children

The recently published "electrophysiologically guided low-voltage bridge (LVB) strategy" is effective in the ablation of atrioventricular nodal re-entry tachycardia (AVNRT) in children. This study aimed to evaluate its efficacy and safety in children <26kgs. Fourteen children [64% males, median age 6.5 years (IQR 6-8 years), median weight 25.5kg (IQR 24-26kg)] with AVNRT were treated. In all patients, we detected a LVB associated to a typical slow pathway potential. The acute success rate was 100% with a mean of 5.5 cryoablation deliveries. All procedures were performed with near-zero fluoroscopic exposure (median time 0.15 min, IQR 0-0.7 min), in six patients fluoroscopy was 0 min. There were no complications or recurrences during the follow-up (median 20.91 months, IQR 11.7-26.7 months).

Long-term follow-up in preschool children after radiofrequency catheter ablation of arrhythmias.

Radiofrequency ablation (RFA) is the standard method of treatment for tachyarrhythmias in school children, and it leads to complete recovery in children without structural heart disease. However, RFA in young children is limited by the risk of complications and unstudied remote effects of radiofrequency lesions. To present the experience of RFA of arrhythmias and the results of follow-up of younger children. RFA procedures (n=255) were performed in 209 children with arrhythmias from 0 to 7 years old. The arrhythmias were presented with atrioventricular reentry tachycardia withWolff-Parkinson-White(WPW) syndrome (56%), atrial ectopic tachycardia (21.5%), atrioventricular nodal reentry tachycardia (4.8%), and ventricular arrhythmia (17.2%). The overall effectiveness of RFA, considering the repeated procedures performed due to the primary ineffectiveness and recurrencies, was 94.7%. There was no mortality associated with RFA in patients, including young patients. All cases of "major" complications are associated with RFA of the left-sided accessory pathway and tachycardia foci and are represented by the mitral valve damage in three patients (1.4%). Tachycardia and preexcitation recurred in 44 (21%) patients. There was a correlation between recurrences and parameters of RFA (odds ratio 0.894; 95% confidence interval: 0.804-0.994; p=.039). Reducing the maximum power of effective applications in our study increased the risk of recurrence. The use of the minimum effective parameters of RFA in children reduces the risk of complications, but increases arrhythmia recurrence rate.

Pseudo-Kussmaul's Sign in Atrioventricular Nodal Reentry Tachycardia: A Prospective, Cohort Study.

To study the respiratory variation of right atrial (RA) pressures at baseline and during atrioventricular nodal reentry tachycardia (AVNRT). Of the 23 patients screened, 16 participants with typical AVNRT were included in the study. After ensuring adequate hydration, baseline RA pressures were measured as the height of 'a' and 'v' waves. The patients were asked to take deep breaths, and the measurements were taken in both inspiration and expiration. Of the 16 participants, 14(87.5%) showed a normal fall in the height of 'a' and 'v' waves with inspiration, 1(6.25%) showed no change and 1(6.25%) showed a rise in height at baseline, p <0.01. During induced AVNRT, the 'a' and 'v' wave heights increased in 8(50%), remained same in 6(37.5%) and showed a normal fall in 2(12.5%), p = 0.07 for 'a' waves and p = 0.09 for 'v' waves. When the magnitude and direction of change in 'a' and 'v' wave height at baseline was compared with AVNRT, it showed a significant difference with 13(81.25%) participants demonstrating positive Pseudo-Kussmaul's sign, p <0.01. Mean age was numerically higher in those with a more considerable inspiratory rise in RA pressures but was not statistically significant, χ2(2) = 3.1, p = 0.21. Pseudo-Kussmaul's sign does occur in a substantial number of patients during AVNRT. Clinical appreciation of this phenomenon is possible in half to three-fourth of patients, provided the mean RA pressures are low enough for the variation to be visible in the neck.

Empiric Slow Pathway Cryoablation in Symptomatic Children Without Documented Supraventricular Tachycardia.

In symptomatic children without documented supraventricular tachycardia (SVT) and non-inducible atrioventricular nodal reentry tachycardia (AVNRT) the benefit of empiric slow pathway (SP) ablation is unknown. We evaluated 62 symptomatic patients without documented SVT that underwent electrophysiology study (EPS). The purpose of this study was to determine if symptoms improved after empiric SP ablation in children without documented SVT and without inducible AVNRT. Sixty-two symptomatic patients without previously documented SVT underwent EPS; 31 (50%) had inducible AVNRT and underwent SP ablation, 20 (32%) were non-inducible and underwent empiric SP ablation, 11 (18%) were non-inducible and had no ablation. After a mean follow-up of 23 ± 18months there was no significant difference in freedom from symptoms within the non-inducible cohort regardless of whether empiric SP ablation was performed (p = 0.135). There was a significant improvement in symptoms at follow-up after SP ablation when comparing inducible and non-inducible patients (p = 0.020). During follow-up no patients had documented SVT. Symptomatic children without documented SVT do not benefit from empiric SP ablation when AVNRT cannot be induced.

Three faces of one paroxysmal supraventricular tachycardia

Fragments of a transesophageal electrophysiological study of a 35-year-old patient with induction of paroxysmal atrioventricular nodal re-entry tachycardia occurring with three different electrocardiographic patterns are presented.

Common Supraventricular and Ventricular Arrhythmias in Children.

The most common pediatric arrhythmias are tachycardias, and the most common type is supraventricular tachycardia, originating from or above the atrioventricular node and HIS bundle. Ventricular tachycardias are less common but more dangerous. Supraventricular tachycardias usually cause a narrow complex tachycardia unless there is a basal bundle branch block or rate-dependent aberration. A wide QRS tachycardia should be treated as ventricular tachycardias unless proven to be an supraventricular tachycardia with aberration. Diagnosis of both tachyarrhythmia types depends mainly on 12-lead electrocardiography. The most common supraventricular tachycardia type in newborns and infants is atrioventricular reentry tachycardia, related to manifest or concealed accessory pathways and in adolescent atrioventricular nodal reentry tachycardia, whereas focal atrial tachycardias consist of 10%-15% of supraventricular tachycardias during all ages. Supraventricular tachycardias have a low risk of morbidity, and ablation therapy is successful in most types with success rates over 90%. Ventricular tachycardias can be monomorphic or polymorphic, nonsustained or sustained, and can cause more hemodynamic instability than supraventricular tachycardias, requiring more close monitoring and urgent therapies. If hemodynamically unstable, synchronized cardioversion must be performed. Polymorphic ventricular tachycardias are very dangerous and often associated with primary ion channel defects (channelopathies), which can cause sudden cardiac death.

Randomized comparison of atrioventricular node re-entry tachycardia and atrial flutter catheter ablation with and without fluoroscopic guidance: ZeroFluoro study.

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.

Electrocardiographic and electrophysiological characteristics of fasciculoventricular fibers in children.

Fasciculoventricular fiber (FVF) that does not cause tachyarrhythmia is a rare form of ventricular preexcitation, which is important to distinguish from Kent fibers. Although, adenosine and some electrocardiographic features are important in the differentiation of Wolff Parkinson White (WPW) than FVF, a clear distinction may not always be possible without an electrophysiological study (EPS). In this study, we aimed to present the clinical and electrophysiological features of our pediatric patients with fasciculoventricular fiber. Between October 2013 and September 2021, 565 patients who underwent electrophysiological studies due to ventricular preexcitation in our clinic were screened in the study, and 27 (4.7%) patients with fasciculoventricular fiber were included. The data of the patients were obtained from the file records using the electronic internet database system Filemaker® . Electrophysiological study age, weight, gender, symptom, and presence of congenital heart disease of the patients were obtained from the file records. Accessory pathway localization was evaluated according to the modified Arruda algorithm in pre-procedural electrocardiography. In addition, delta wave amplitudes were measured in the first 40ms from the surface ECG. PR interval, QRS interval, and delta wave amplitude were recorded before and after ablation in patients with additional accessory pathways. Post-procedure values were included in the FVF group. The mean age of the patients was 11.47±4.25 years. All 70.4% of the reasons for admission were symptoms such as palpitations and syncope. Two patients had hypertrophic cardiomyopathy and 1 patient had ccTGA. In the electrophysiological study, additional manifest WPW was found in 9 (33%) patients (3 patients with high risk, 6 patients with orthodromic supraventricular tachycardia), focal atrial tachycardia in a patient, and atrioventricular nodal reentry tachycardia in a patient. While the delta wave amplitude was found to be 2.56±1.38(1-5.5) mm in the first 40ms in surface electrocardiography in 9 patients with additional accessory pathway, it was found to be 1.64±0.67(0.5-3) mm in the FVF group. There was no statistically significant difference between the 2 groups (p=.398). Delta wave amplitude>3.5mm was not detected in any patient with isolated FVF. Interestingly, delta wave amplitude was<3.5mm in 7 (78%) of 9 patients who were identified and ablated with an additional accessory pathway. Total 19 of the patients (59.3%) were adenosine-responsive (18 isolated FVF, 1 manifest AP+FVF adenosine-responsive. 8 patients with other manifest AP + FVF had no pre-procedural adenosine-asystole response, and all of them QRS were expanded). Although, the fasciculoventricular fibers themselves are not the cause of tachyarrhythmia, the accessory pathway and other tachyarrhythmia substrate frequency accompanying these cases are quite high (approximately 40%) in EPS. The delta wave characteristics of ablated patients are very similar to FVF patients. While all patients with isolated FVF were adenosine responsive, most of those with additional manifest WPW were unresponsive. Therefore, performing EPS in patients with suspected FVF based on surface ECG features seems to be important for the detection of additional tachyarrhythmias and risky accessory pathways.

Deep-Learning-Based Detection of Paroxysmal Supraventricular Tachycardia Using Sinus-Rhythm Electrocardiograms.

Background: Paroxysmal supraventricular tachycardia (PSVT) is a common arrhythmia associated with palpitation and a decline in quality of life. However, it is undetectable with sinus-rhythmic ECGs when patients are not in the symptomatic onset stage. Methods: In the current study, a convolution neural network (CNN) was trained with normal-sinus-rhythm standard 12-lead electrocardiographs (ECGs) of negative control patients and PSVT patients to identify patients with unrecognized PSVT. PSVT refers to atrioventricular nodal reentry tachycardia or atrioventricular reentry tachycardia based on a concealed accessory pathway as confirmed by electrophysiological procedure. Negative control group data were obtained from 5107 patients with at least one normal sinus-rhythmic ECG without any palpitation symptoms. All ECGs were randomly allocated to the training, validation and testing datasets in a 7:1:2 ratio. Model performance was evaluated on the testing dataset through F1 score, overall accuracy, area under the curve, sensitivity, specificity and precision. Results: We retrospectively enrolled 407 sinus-rhythm ECGs of PSVT procedural patients and 1794 ECGs of control patients. A total of 2201 ECGs were randomly divided into training (n = 1541), validation (n = 220) and testing (n = 440) datasets. In the testing dataset, the CNN algorithm showed an overall accuracy of 95.5%, sensitivity of 90.2%, specificity of 96.6% and precision of 86.0%. Conclusion: Our study reveals that a well-trained CNN algorithm may be a rapid, effective, inexpensive and reliable method to contribute to the detection of PSVT.

Anatomy for ablation of atrioventricular nodal reentry tachycardia and accessory pathways.

The atrioventricular (AV) valve plane and the central septum are of particular importance for electrophysiological diagnosis and interventional therapy of supraventricular tachycardias because accessory electrical connections of various types may be present in addition to the specific conduction system. Although modern 3D electroanatomic reconstruction systems including high-density mapping can be of great assistance, detailed knowledge of the anatomic structures involved, their complex three-dimensional arrangement, and their electrical properties in conjunction with electrophysiological features of supraventricular arrhythmias is essential for safe and efficient electrophysiological treatment. The aim of this article is to present current anatomical, topographical, and electrophysiological findings against the background of historical, seminal, and still indispensable literature.

Zero-fluoroscopy catheter ablation of supraventricular tachycardias in pediatric population

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation (CA) of supraventricular tachycardias (SVTs) in pediatric patients is conventionally performed with the aid of X-ray fluoroscopy. Usage of the three-dimensional (3D) electro-anatomical mapping (EAM) system and the intracardiac echocardiography (ICE) enables zero-fluorscopy ablation, eliminating the harmful effects of the radiation (1-3). Purpose We retrospectively analyzed the feasibility, effectiveness and safety of zero-fluoroscopy radiofrequency and cryoablation of various types of SVTs in pediatric patients. Methods In this retrospective study, we analyzed consecutive pediatric patients who underwent CA procedure due to SVT in our institution from April 2014 to October 2021. All procedures were performed completely without the use of fluoroscopy. A 3D EAM system and ICE were used as the principal modes of catheter visualisation. Left-sided procedures were done with ICE guided transseptal approach. Radiofrequency was the principal energy source, while cryoablation was used for arrhythmia substrates in the proximity of the conduction system. Results The study included 174 consecutive patients (69/174 (66%) female; 12.5 ± 3.9 years; 19.2 ± 3.6 kg/m2). Altogether 176 SVTs were diagnosed and treated. Atrio-ventricular nodal reentry tachycardia (AVNRT) was diagnosed in 45% of cases (80/176), atrio-ventricular reentry tachycardia (AVRT) in 47% (82/176), focal atrial tachycardia (AT) in 7% (13/176), typical atrial flutter (AFL) was treated in only one patient, while 2 patients had multiple arrhythmias (AVNRT and AVRT). In total, 202 procedures were performed. Radiofrequency ablation was performed in 76% (154/202), cryoablation in 20% (40/202) and both in 4% (8/202) of procedures. The acute procedural success rate was 96% (195/202). Procedural success rate was 99% (79/80) for AVNRT, 94% (77/82) for AVRT, 92% (12/13) for AT, and 100% (1/1) for AFL, respectively. There were no major complications in our study group. Follow-up was complete in 99% (172/174) of patients. During the follow-up period of a median of 316 days (181 - 747), 98% of patients were arrhythmia free. On average, 1.16 procedures per patient were performed with the long-term success rate of 99% (79/80), 98% (80/82), 100% (13/13) and 100% (1) for AVNRT, AVRT, AT, and AFL, respectively. Conclusion Zero-fluoroscopy CA of various types of SVTs in pediatric population is a feasible, effective, and safe treatment option.

Negative SA-VA difference during entrainment of a supraventricular tachycardia: a new criterion for the diagnosis of focal atrial tachycardia

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Ventricular overdrive pacing during tachycardia is one of the most common and useful maneuvers to assess de differential diagnosis of supraventricular tachycardia (SVT). Focal atrial tachycardia (FAT) usually presents long ventriculo-atrial (VA) interval, which is a passive interval since FAT is not an atrio-ventricular reentry. Therefore, during ventricular entrainment of a FAT, the stimulus-atrial (SA) interval will depend solely on the retrograde VA conduction time, if retrograde conduction exists. This retrograde conduction time is usually shorter than the VA Interval during tachycardia, thus being able to cause a negative SA-VA difference. This does not occur in other types of SVT, where the SA-VA difference helps to differential diagnosis, but positive values have been described. Purpose Our aim was to analyze whether the SA-VA value discriminates FAT from the other types of SVT, in patients with SVT and VA conduction when stimulating the ventricle during tachycardia. Methods Multicenter data of SVT entrainment were collected retrospectively, including FAT, atrioventricular nodal reentry tachycardia (AVNRT), and atrioventricular reciprocating tachycardia (AVRT). The numeric value of SA-VA difference was calculated for each case. The best SA-VA cut-off point for the diagnosis of TAF was determined, evaluating the sensitivity and specificity of this value for the diagnosis of TAF with respect to the gold standard (classical criteria). Results Continuous ventricular pacing during tachycardia succeeded in accelerating the atrium to the pacing rate in 80 cases out of the total studied cases: 32 (40%) AVNRT, 28 (35%) AVRT and 20 (25%) FAT. All FAT cases had a negative SA-VA value and all AVNRT and AVRT cases obtained positive SA-VA (Figure 1). SA-VA value lower than 0 ms was the best cut-off point (using ROC curve, Figure 2) with an area under the curve of 1. SA-VA difference lower than 0 ms (or negative SA-VA difference) showed 100% sensitivity and specificity for the diagnosis of FAT. Conclusions Negative SA-VA difference is a new and accurate criterion for the diagnosis of focal atrial tachycardia.

Catheter ablation of atrioventricular nodal reentry tachycardia and quality of life

Abstract Funding Acknowledgements Type of funding sources: None. Objective To present the results of radiofrequency catheter ablation of patients with atrioventricular nodal reentry tachycardia (AVNRT). Materials and methods Catheter ablation was performed in 488 patients with AVNRT. The age of patients is from 14 to 66 (mean age 40.2±14.7 years). Comorbidities such as ischemic heart disease and hypertension were in 234 (48%) patients, in 83 (17%) patients chronic myocarditis was detected. No organic pathology from the cardiovascular system was detected in 171 (35%) patients. In the anamnesis, tachycardia attacks were observed from 2 to 29 years (on average, 18.7 ± 4.9 years). After confirming the diagnosis of typical "slow-fast" AVNRT on the intracardiac electrophysiological investigation, an ablation catheter was inserted into the heart of the patient. Then radiofrequency ablation of "slow paths" of AV-connection was performed. Traditionally, the quality of life associated with health is considered as an integral characteristic of a person’s physical, mental (emotional) and social well-being, based on his subjective perception of these attributes. We assessed the quality of life of patients with AVNRT using the SF-36 questionnaire and The Hospital Anxiety and Depression Scale (HADS) before and after performing of catheter radiofrequency ablation. Results In 488 patients, the criteria for the effectiveness of the destruction of the "slow pathways" were obtained and the effectiveness of the procedure was 99.38%. During the study of indicators of QOL according to the SF-36 questionnaire, wich was obtained 6 months after Radiofrequency Ablation (RFA), the most significant improvement was noted in terms of role functioning RF (by 48.6%), physical functioning PF (by 25.5%) and GH general health (19.7%). The BP bodily pain index, although increased (by 13.8%), but not reliably. After 12 months, we observed a significant improvement in QOL in all indicators of the physical component of health, which did not differ from those in the control group. Clinically manifested anxiety was observed in a reliably larger number of patients (63.6%). The total indicator of the anxiety level was 11.1±2.4 points and corresponded to clinically manifested anxiety. The majority (66.7%) of patients had a subclinical form of depression. The total value of the depression level was 9.8±1.8 points and corresponded to the indicator of subclinically manifested disorders. Testing on the hospital anxiety and depression assessment scale after 12 months showed that all patients had no significant symptoms of anxiety and depression. The total score of anxiety was -2.8±1.1 points (p&amp;lt;0.0001), depression - 2.4±1.4 (p&amp;lt;0.0001). Conclusions Radiofrequency catheter ablation is an effective, drastic and safe method of treating AVNRT, the effectiveness of the procedure reaches up to 100% and allows patients to improve their quality of life, get rid of the lifelong intake of antiarrhythmic drugs.

Arrhythmia burden, rhythm interventions and outcome in a large Swiss multicenter population of d-TGA patients with atrial switch

Abstract Funding Acknowledgements Type of funding sources: None. Background Patients with dextro-transposition of the great arteries (d-TGA) and atrial switch face a high life-time risk of arrhythmias. Purpose To describe the incidence of arrhythmias, associated cardiac interventions and outcome in a large Swiss population of patients with d-TGA and atrial switch. Methods In this multicenter analysis we included all consecutive patients with d-TGA and atrial switch treated at three Swiss tertiary care hospitals. The primary outcome was survival free from left ventricular assist device (LVAD), heart transplantation (HTx) and death. The secondary outcome was survival free from ventricular tachycardia, ventricular fibrillation and sudden cardiac death. Results We identified 207 patients (34% females; median age at last follow-up 35 years) with d-TGA and atrial switch. Arrhythmias occurred in 97 patients (47%) at a median age of 22 years. A pacemaker or an implantable cardioverter/defibrillator was implanted in 39 (19%) and 13 (6%) patients, respectively, and 33 (16%) underwent a total of 51 ablation procedures to target 60 intra-atrial reentry tachycardias, 4 AV nodal reentry tachycardias and one atrial fibrillation (Figure 1). The primary outcome occurred in 21 patients (10%) and the secondary outcome in 18 (9%) (Figure 2). Primary and secondary outcomes were more common in patients with concomitant ventricular septum defect (VSD) than in those without (hazard ratio [HR] 3.06; 95% confidence interval [CI] 1.29-7.27, p=0.011; and HR 3.62; 95% CI 1.43-9.18, p=0.007, respectively). Conclusions At a median age of 35 years, arrhythmias occur in almost half of patients with d-TGA and atrial switch and associated rhythm interventions are frequent. One in ten patients does not survive free from LVAD and HTx and outcome is worse in patients with concomitant VSD.