Active clinical trials for "Tachycardia, Atrioventricular Nodal Reentry"

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common supraventricular tachycardia inducible during an electrophysiological study. Although ablative therapy proved to be the treatment of choice, little is known about the components of the tachycardia circuit. The aim of this study is to detect the presence and patterns of specific electrograms representing slow pathway (SP) potentials and to explore Koch's triangle pattern activation during sinus rhythm and/or atrial extraestimulus with a high-density mapping catheter in an attempt to clarify a fast and safety catheter ablation strategy. We hypothesized that, in patients with dual atrioventricular nodal physiology, during sinus rhythm (SR), high-density mapping (HDM) catheters could identify the SP signals, making possible to delineate small areas of slow conduction associated to abnormal electrograms on Koch's triangle. On a second step, radiofrequency (RF) applications safety guided by the HDM obtained with this method, should interrupt the circuit far from the His region. Finally, SP signals should disappear after the RF procedure when performing a new 3D HDM. A control group of patients without AVN dual physiology should show absence of fragmented/slow conduction zones.

The FAST Trial Registry is a prospective observational cohort study of fetuses with a new diagnosis of atrial flutter (AF) or supraventricular tachycardia (SVT) that is severe enough to consider prenatal treatment (see eligibility criteria below). Aims of the Registry include to establish a large clinical database to determine and compare the efficacy and safety of different prenatal treatment strategies including observation without immediate treatment, transplacental antiarrhythmic fetal treatment and direct fetal treatment from the time of tachycardia diagnosis to death, neonatal hospital discharge or to a maximum of 30 days after birth.

The aim of the present work is to analyze the capacity of high resolution mapping systems to determine the precise location of the AV node and peri-nodal slow-conducting pathways, using standard recording parameters, but also off-line additional filter changes and additional techniques (conduction velocities, isochrones and dV/dt). The investigative team plan a prospective monocentric study. Detailed high resolution mapping of the Koch triangle and neighboring areas will be collected through the RHYTHMIA HDx 3D electro-anatomical mapping system and the multipolar ORION catheter. This sample will consist of 2 groups of patients: the first will include patients referred for AVNRT ablation and the second will include control patients (without AVNRT), referred for another indication requiring similar mapping system. If visualized, position of the slow pathway and AV node will be compared with the ablation areas, which will be set conventionally under fluoroscopy.

The purpose of this study is to determine/identify what mechanisms/factors are involved with regard to AV nodal reentrant tachycardia.

The WATER ATTAC study aims at multicentric, longitudinal, perspective evaluation of safety and efficacy of atrioventricular nodal reentrant tachycardia (AVNRT) performed combining irrigated ablation catheter and three-dimensional electroanatomic mapping system. Efficacy and rate of complications will be evaluated over medium and long term follow-up.

Atrioventricular nodal reentry tachycardia is best treated with catheter ablation aimed at disruption of conduction of the slow pathway. There are currently two possible options for this ablation: radiofrequency ablation and cryoablation. The first seems to result in superior success rate, however carries a small risk of collateral damage of the heart conduction system, specifically the atrioventricular (AV) node. Cryoablation seems less effective, but safer as AV nodal damage can be avoided. The aim of this study is to prospectively test possible improved efficcacy of cryoablation of the slow pathway with the use intraprocedural intracardiac echocardiography.

Study protocol To prepare for the electrophysiologic study, antiarrhythmic drugs were discontinued at least five half-lives before the procedure and were under conscious sedation using midazolam ± fentanyl while fasting. ICE-guided ablation group In patients randomized to ICE-guided ablation group, catheter placement was initially performed using fluoroscopy guidance, after local anesthesia. A decapolar steerable catheter was placed in the coronary sinus (CS), a quadripolar electrode catheter was positioned in the right ventricular apex and an ablation catheter was inserted to record the His bundle electrogram. Twelve-lead electrocardiogram and intracardiac electrograms were recorded and saved on a digital recording system using a band pass filter of 30 to 500 Hz. Electrical stimulation techniques were used to test atrioventricular nodal conduction and induce AVNRT, with the S2 coupling interval being gradually shortened after each drive-train until tachycardia was induced, AV conduction block occurred, or the atrial refractory period was reached. If tachycardia was not inducible, isoprenaline infusion was given to increase the heart rate by at least 20%, and the same stimulation protocol was repeated during both the infusion and washout phases. The diagnosis of AVNRT was made using established electrophysiologic criteria and pacing maneuvers. This involved assessing the A-(H)-V response after ventricular overdrive pacing, with an SA-VA interval greater than 85 ms, and a corrected postpacing interval minus tachycardia cycle length greater than 110 ms. After confirmation of the diagnosis of AVNRT through the diagnostic EP study, the quadripolar electrode catheter was removed and replaced with an 8F ICE catheter for mapping and SP ablation. The echo-transducer was positioned in the low right atrium at the 6 o'clock position and rotated clockwise towards the septum to allow for visualization of the anatomic landmarks. The proximity of the ablation catheter to the compact AV node was determined by the distance from the aortic valve, which marks the recording site of a proximal His potential. In cases of ineffective ablation, the catheter was moved closer to the aortic valve, but always maintaining a distance of at least 0.5 cm, and RF application was attempted again. RF energy was delivered starting just below the CS with a power output of 30 W and a preset temperature of 55°C. Effective applications were continued for 30 to 60 s and considered successful when junctional rhythm appeared. RF application was immediately halted if there was catheter displacement, sudden impedance rise, prolongation of PR interval, anterograde AV or retrograde VA block. Electroanatomical mapping system -guided ablation group An ablation catheter was inserted into the heart to create an anatomical map by CARTO of the right atrium after local anesthesia, and the location of the His bundle was tagged. Decapolar and quadripolar diagnostic catheters were positioned thereafter into appropriate position as described above. After confirming the diagnosis of AVNRT, mapping of the slow pathway was started by NAVISTAR catheter guided by EAMS and aiming at an atrial-to-ventricular electrogram amplitude ratio of 1:3-1:5. If the ablation endpoint was not reached after 8 radiofrequency (RF) applications, patients in the EMAS-guided ablation group were allowed to crossover to an ICE-guided procedure. The ablation procedure was deemed successful if, following a 20-minute waiting period, the arrhythmia failed to be induced and there were no instances of more than one echo beat observed, both in the presence and absence of isoprenaline. The procedure time was measured from the initial femoral puncture until the withdrawal of the catheters. The mapping plus ablation time was calculated from the start of the SP mapping until the end of the last attempted ablation. Fluoroscopy time, radiation dose, and dose-area product (DAP) were automatically recorded by the fluoroscopy system. The ablation data, including the total number of RF applications, sum of delivered RF energy in Watts, and the total ablation time in seconds, were calculated and stored by the EP recording system (CardioLab, GE Healthcare).

ICY-AVNRT (Intracardiac CrYoablation for AtrioVentricular Nodal Reentrant Tachycardia) is a prospective multi-center, nonrandomized, single arm, controlled, unblinded, investigational clinical study. The purpose of this clinical study is to demonstrate the safety and effectiveness of the Freezor® Xtra Cardiac CryoAblation Catheter for the cryoablation of the conducting tissues of the heart in the treatment of patients with atrioventricular nodal reentrant tachycardia (AVNRT) using an endocardial approach.

The MAGMA-AVNRT study compares two different methods of handling the ablation catheters for av-node-reentry-tachycardia with regard to x-ray dose, safety and success: manually guided vs magnetically navigated RF-catheter.

In this randomized study, two energy sources for the ablation of AV nodal reentry tachycardia are compared: The standard technique of radiofrequency energy delivery is compared with the new approach of cryo-energy application.