Case report of a double-wave re-entry atrial flutter in a patient with atrial cardiomyopathy.

Background: Double-wave macrore-entry is a rare mechanism of atrial tachycardia with limited documentation in the literature. We present a three-dimensional documentation of a double-wave 'typical' atrial flutter in a patient with extensive atrial cardiomyopathy. Case summary: A 78-year-old female with a history of atrial cardiomyopathy and dual-chamber pacemaker for sinus node disease presented with palpitations and incessant atrial flutter. Electrophysiological study revealed a regular tachycardia with a cycle length (TCL) of 230 ms, with proximal to distal coronary sinus (CS) activation. Three-dimensional mapping identified two independent wavefronts circulating the cavotricuspid isthmus (CTI), each with a TCL of 460 ms. Cavotricuspid isthmus ablation resulted in conversion into a distinct tachycardia with left atrial roof origin. Linear ablation in this location slowed the TCL to 435 ms with concentric CS activation and another CTI dependent atrial flutter was mapped, this time with only one wavefront of activation. Further ablation with a second, more lateral, line in the CTI led to tachycardia interruption. Given the extensive atrial scarring and high arrhythmic recurrence risk, atrioventricular node ablation was performed. Discussion: Double-wave re-entrant tachycardias were primarily observed in experimental models, precipitating acceleration of ventricular and supraventricular tachycardias via extrastimulation. In our case, there is documentation of a spontaneous double-wave of activation around the CTI, representing the first documented double-wave 'typical' atrial flutter. Unlike other cases in the literature, the two wavefronts were equidistant, which resulted in a regular tachycardia with TCL that was half of the single-wave cycle length. Three-dimensional propagation mapping was essential to visualize the two distinct wavefronts.

Successful catheter ablation of atrial tachycardia initiated with orthodromic capture of superior vena cava potentials.

A case of successful catheter ablation of paroxysmal atrial fibrillation and atrial tachycardia is reported. After pulmonary vein isolation, atrial tachycardia was induced by the use of isoproterenol and burst pacing from the catheter in the right atrium. An attempt was made to create a three-dimensional (3D) map of the atrial tachycardia, but the atrial tachycardia was terminated in the middle of the mapping. The 3D map was insufficient but indicated that the superior vena cava was involved in the circuit. When the intracardiac electrograms were reviewed, it was found that the atrial tachycardia was initiated with orthodromic capture of superior vena cava potentials and it was considered that the atrial tachycardia involved the superior vena cava-right atrium junction. Accordingly, superior vena cava isolation was performed. After that, atrial fibrillation and atrial tachycardias were not induced by the use of isoproterenol and burst pacing. In this case, an intracardiac electrogram at the time of induction of the tachycardia was helpful for understanding the circuit of the tachycardia.

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.

Characterization of conduction system activation in the postinfarct ventricle using ripple mapping.

BACKGROUND: Three-dimensional (3D) mapping of the ventricular conduction system is challenging. OBJECTIVE: The purpose of this study was to use ripple mapping to distinguish conduction system activation to that of adjacent myocardium in order to characterize the conduction system in the postinfarct left ventricle (LV). METHODS: High-density mapping (PentaRay, CARTO) was performed during normal rhythm in patients undergoing ventricular tachycardia ablation. Ripple maps were viewed from the end of the P wave to QRS onset in 1-ms increments. Clusters of >3 ripple bars were interrogated for the presence of Purkinje potentials, which were tagged on the 3D geometry. Repeating this process allowed conduction system delineation. RESULTS: Maps were reviewed in 24 patients (mean 3112 ± 613 points). There were 150.9 ± 24.5 Purkinje potentials per map, at the left posterior fascicle (LPF) in 22 patients (92%) and at the left anterior fascicle (LAF) in 15 patients (63%). The LAF was shorter (41.4 vs 68.8 mm; P = .0005) and activated for a shorter duration (40.6 vs 64.9 ms; P = .002) than the LPF. Fourteen of 24 patients had left bundle branch block (LBBB), with 11 of 14 (78%) having Purkinje potential-associated breakout. There were fewer breakouts from the conduction system during LBBB (1.8 vs 3.4; 1.6 ± 0.6; P = .039) and an inverse correlation between breakout sites and QRS duration (P = .0035). CONCLUSION: We applied ripple mapping to present a detailed electroanatomic characterization of the conduction system in the postinfarct LV. Patients with broader QRS had fewer LV breakout sites from the conduction system. However, there was 3D mapping evidence of LV breakout from an intact conduction system in the majority of patients with LBBB.

Termination of slow-fast atrioventricular reentrant tachycardia by a single cryoablation of the slow pathway guided by a fractionation map.

This is a slow-fast atrioventricular nodal reentrant tachycardia (AVNRT) case wherein the fractionation map-guided cryoablation of the slow pathway (SP) successfully terminated the tachycardia. In this case, the Advisor™ HD Grid catheter and fractionation map in the EnSite™ X EP system with relatively high-sensitive settings were useful for detecting the target SP area. Direct AVNRT termination by cryomapping at the fractionated potential area might be a quick and safe ablation strategy, which may provide a new workflow for SP ablation.

Experience of left ventricular outflow tract arrhythmia ablation in paediatric patients using limited fluoroscopy and three-dimensional mapping technique.

OBJECTIVE: The left ventricular outflow tract is an important source of ventricular arrhythmias. Up to one-third of all idiopathic ventricular arrhythmias in patients with structurally normal hearts may arise from this region. We would like to share the results of our left ventricular outflow tract ablation using three-dimensional mapping and limited fluoroscopy. MATERIALS AND METHODS: This is a single-centre retrospective cohort study. Forty-six consecutive patients who underwent left ventricular outflow tract ablation procedures between January 2015 and June 2023 were included in the study. The EnSite Precision System (Abbott, St. Paul, MN, USA) was used to facilitate mapping and to reduce or eliminate the need for fluoroscopy. RESULTS: The study group comprised 29 males and 17 females, with a mean age of 13.4 ± 4.5 years. The most common location for arrhythmias was the left coronary cusp (n : 21). Other locations, in sequence, included the junction of the right and left coronary commissure (n : 10), right coronary cusp (n : 10), left ventricular outflow tract endocardium (n:4), aorto-mitral junction (n : 1), and great cardiac vein (n : 1). Nine of these patients had previously undergone unsuccessful right ventricular outflow tract ablation at another centre. Cryoablation was performed in three patients, irrigated radiofrequency ablation in three patients, and conventional radiofrequency ablation in the remaining patients. The acute success rate was 100%, and no recurrences were observed. The mean follow-up period was 49.6 ± 24.4 months. All patients were asymptomatic and were being followed without antiarrhythmic medication. CONCLUSION: Although left ventricular outflow tract ablations pose a risk for coronary artery and heart valve complications, they can be performed successfully and safely with the guidance of three-dimensional mapping.

Left ventricular endocardial activation maps during right ventricular pacing in pediatric patients.

BACKGROUND: Cardiac pacing from right ventricular (RV) sites may cause electromechanical ventricular dyssynchrony. Invasive and noninvasive mapping studies showed left ventricular (LV) activation sequence in adults. Aim of this study was to seek out the LV endocardial activation (LVEA) in pediatric patients who underwent RV pacing. METHODS: Single-center, prospective study conducted on pediatric patients who underwent left sided catheter ablation of accessory pathways with the Carto Univu mapping system. After successful ablation procedures, LVEA was recorded by the ablation catheter during sinus rhythm (SR) and during para-hisian (PHP), midseptum (MSP), and apical (RVAP) pacing. RESULTS: Seventeen patients, 13 males, aged 12 (10-15) years, registered LV activation maps and times (LVAT). SR showed significantly shorter LVAT than during pacing. LVAT of PHP was shorter than MSP, while there were not significant differences among PHP and MSP versus RVAP. In SR initial LV endocardial activation occurred in two midseptum sites, inferior-posterior and superior-anterior. During PHP, initial activation occurred at parahisian basal septum, rapidly followed by midseptum as in SR. During MSP and RVAP initial activation occurred at midseptum and apex, respectively. From all initial sites, the excitation spreads toward the base of the lateral LV free wall. A mild linear correlation was found between QRS duration and LVAT for MSP and for PHP. CONCLUSIONS: In pediatric patients LVEA maps during RV pacing showed that the shortest LVAT was obtained with PHP. The LV activation pattern seemed similar in sinus rhythm, PHP and MSP, from midseptum to LV lateral base.

Chinese expert consensus on the construction of the fluoroless cardiac electrophysiology laboratory and related techniques.

Transcatheter radiofrequency ablation has been widely introduced for the treatment of tachyarrhythmias. The demand for catheter ablation continues to grow rapidly as the level of recommendation for catheter ablation. Traditional catheter ablation is performed under the guidance of X-rays. X-rays can help display the heart contour and catheter position, but the radiobiological effects caused by ionizing radiation and the occupational injuries worn caused by medical staff wearing heavy protective equipment cannot be ignored. Three-dimensional mapping system and intracardiac echocardiography can provide detailed anatomical and electrical information during cardiac electrophysiological study and ablation procedure, and can also greatly reduce or avoid the use of X-rays. In recent years, fluoroless catheter ablation technique has been well demonstrated for most arrhythmic diseases. Several centers have reported performing procedures in a purposefully designed fluoroless electrophysiology catheterization laboratory (EP Lab) without fixed digital subtraction angiography equipment. In view of the lack of relevant standardized configurations and operating procedures, this expert task force has written this consensus statement in combination with relevant research and experience from China and abroad, with the aim of providing guidance for hospitals (institutions) and physicians intending to build a fluoroless cardiac EP Lab, implement relevant technologies, promote the standardized construction of the fluoroless cardiac EP Lab.

Electrographic flow mapping guided catheter ablation offers advantages for patients with persistent atrial fibrillation.

BACKGROUND: Catheter ablation (CA) remains challenging due to suboptimal success rates in persistent atrial fibrillation (AF). Existing mapping technologies cannot reliably distinguish sources in this patient population. Recently, the novel electrographic flow (EGF) mapping system was developed using a modified Horn-Schunk optical flow algorithm to detect and quantify patterns of electrical wavefront propagation in the atria. OBJECTIVES: To test the hypothesis that targeted source ablation based on EGF mapping is superior to empiric AF ablation. METHODS: We included all consecutive patients undergoing EGF guided ablation for persistent AF. All patients underwent pulmonary vein isolation (PVI) and were treated with the same EAM system (CARTO). The outcome of PVI+EGF guided CA was compared with data of PVI-only procedures (PVI-only group) and PVI plus additional empiric adjunctive linear and substrate ablations (PVI+LINES group). 12-months outcome as freedom from AF and atrial tachycardia/flutter (AT/AFL), procedural safety and efficiency characterized by procedure duration, fluoroscopy use, radiofrequency applications and duration, were analyzed. Both intention-to-treat and per protocol analysis were conducted. RESULTS: A total number of 70 patients (39 in PVI+EGF, 16 in PVI-only and 15 patients in PVI+LINES group) were enrolled. Intention-to-treat analysis showed fewer AF recurrences in PVI+EGF as compared with the PVI-only or PVI+LINES groups at 12 months (25.6% vs. 62.5% vs. 53.3%, p = .02). There were no differences in AT/AFL recurrence (17.9% vs. 37.5% vs. 20.0%, p = .37). Procedure times were longer in PVI+EGF group (p < .01), and there were no differences in fluoroscopy use (p = .67). CONCLUSION: Our data suggest that patients treated with EGF-guided CA developed fewer AF recurrences. Although the procedure times are longer, it seems to be safe and offers a more targeted, patient-specific ablation strategy beyond PVI than adjunctive empiric lines and substrate ablation in this complex group of patients.

Nanoscale Three-Dimensional Charge Density and Electric Field Mapping by Electron Holographic Tomography.

The operation of nanoscale electronic devices is related intimately to the three-dimensional (3D) charge density distributions within them. Here, we demonstrate the quantitative 3D mapping of the charge density and long-range electric field associated with an electrically biased carbon fiber nanotip with a spatial resolution of approximately 5 nm using electron holographic tomography in the transmission electron microscope combined with model-based iterative reconstruction. The approach presented here can be applied to a wide range of other nanoscale materials and devices.

Three-dimensional mapping in cardiac implantable electronic device - a feasible and effective alternative to fluoroscopy.

BACKGROUND: During the last decade, three-dimensional mapping technology has substantially aided the development of cardiac implanted electronic devices (CIEDs). This article intends to present an outline of the use and benefits of three-dimensional (3D) mapping systems in CIEDs. RESULT: As an alternative to fluoroscopy, 3D mapping greatly minimizes radiation exposure and eliminates the need for contrast dye during the implantation of CIEDs. Based on the visualization of the pacing lead tip and accurate anatomic reconstruction of the chamber of interest and a specialized mapping technique, 3D mapping technology dramatically improves the efficacy and success of the advanced cardiac implantable devices' placement. Additionally, it provides a superior option for those with complex medical conditions. CONCLUSION: The use of 3D mapping technology in CIEDs has been proven feasible and effective by accumulating evidence. It is fair to anticipate that it will be widely used in CIED implantation in the future.

Imaging Real-Time Coronary Anatomy Using a Three-Dimensional Electrophysiology Mapping System.

The aim of this study is to evaluate the feasibility of creating fast three-dimensional maps of coronary arteries and to develop a bipolar coronary guidewire in vitro and determine whether it can be localised accurately within the model.A total of five patients were recruited, and EnSite Precision was utilised to create 3D coronary anatomy. A water bath to accommodate a 3D-printed coronary model was developed to test the performance of the bipolar angioplasty wire.Successful guidewire localisation and 3D reconstruction of coronary anatomy were achieved in all the cases. No complications. The bipolar wire was able to collect point clouds, and localisation of the distal tip was excellent when tested in the water bath.Our study demonstrates the feasibility and safety of utilising EAMS to collect coronary anatomy. Real-time tracking with a bipolar catheter is accurate when tested in vitro.

Placement of catheters without magnetic sensors in the coronary sinus without fluoroscopic guidance: Feasibility and safety evaluation.

Background: A three-dimensional (3D) mapping system is essential to reduce radiation exposure during catheter ablation. When using the CARTO 3D mapping system, only the catheter with magnetic sensor can visualize its location. However, once target chamber matrix is created using the catheter, even the catheters without magnetic sensors (CWMS) can enable visualization. We aimed to investigate the feasibility and safety of placing a CWMS in the coronary sinus (CS) without fluoroscopic guidance. Methods: The study group comprised 88 consecutive patients who underwent catheter ablation. CWMS placement was performed without fluoroscopic guidance in 47 patients and with fluoroscopic guidance in 41 patients. Placement without fluoroscopic guidance was performed after creating a visualization matrix of the CS, right atrium, and superior vena cava using a catheter with a magnetic sensor. Feasibility and safety were compared between the two groups. Results: Successful catheter placement was achieved in all patients without fluoroscopic guidance, with no inter-group difference in the median procedure time: with guidance, 120.0 [96.0-135.0] min, and without guidance, 110.0 [97.5-125.0] min; p = .22. However, radiation exposure was significantly shorter, and the effective dose was lower without fluoroscopic guidance (0 [0-17.5] s and 0 [0-0.004] mSv, respectively) than with fluoroscopic guidance (420.0 [270.0-644.0] s and 0.73 mSv [0.36-1.26], respectively); both p < .001. Conclusions: CWMS placement without fluoroscopic guidance is feasible, safe to perform, and does not involve complications. Our technique provides an option to decrease radiation exposure during catheter ablation and electrophysiological testing.

Three-dimensional mapping of junctional beats during atrioventricular nodal reentrant tachycardia cryoablation.

Cryoablation of slow pathway doesn't usually cause junctional beats. If this occurs, the nearness to AV compact node is supposed. 3d electroanatomical mapping during this unusual finding may help to clarify the relationship between junctional beats (JBs) during cryomapping/cryoablation and Koch's triangle.

Successful Ablation of a Biatrial Tachycardia from the Superior Vena Cava after a Senning Operation for Complete Transposition of the Great Arteries.

The Senning operation used to be widely performed for an intracardiac repair in a complete transposition of the great arteries. During the long-term follow-up, supraventricular tachycardia (SVT) is often observed because of the complex suture lines. The typical mechanism of a Senning-related SVT is cavo-tricuspid isthmus-dependent atrial flutter. On rare occasions, complex SVTs (e.g., biatrial tachycardia (BiAT)) whose diagnosis and treatment are challenging, may occur. We report a rare case of a BiAT following a Senning operation that was successfully ablated from the superior vena cava, and the local activation time histogram module (CARTO3 V7 module [Biosense Webster, Irvine, CA, USA]) was crucial for analyzing the complex circuit.

Prediction of PR interval prolongation after catheter ablation of incisional atrial tachycardia.

A three-dimensional (3D) mapping system is safe and effective for catheter ablation of incisional atrial tachycardia (IAT). Prolongation of the PR interval is occasionally observed after this procedure. Although a first-degree atrioventricular block is typically benign, an excessively prolonged PR interval can indicate a worse prognosis. Currently, a method to predict the PR interval after ablation therapy for IAT is lacking. We report the case of a 70-year-old woman with paroxysmal atrial tachycardia, in which our maneuver using a 3D mapping system and the electrophysiological findings enabled us to preoperatively predict the post-ablation PR interval. We believe that this method is useful for determining treatment strategies for IAT. Learning objective: Three-dimensional (3D) mapping systems can clearly visualize macro-reentrant circuits and enable the creation of precise ablation lines. When creating ablation lines for incisional atrial tachycardia, attention should be paid to the prolongation of the PR interval, because an excessively prolonged PR interval may indicate a worse prognosis. Herein, we have presented a method for predicting the post-ablation PR interval using a 3D mapping system and electrophysiological findings.

Utilising electroanatomic mapping during ablation in patients with CHD to reduce radiation exposure.

BACKGROUND: Patients with CHD can be exposed to high levels of cumulative ionising radiation. Utilisation of electroanatomic mapping during catheter ablation leads to reduced radiation exposure in the general population but has not been well studied in patients with CHD. This study evaluated the radiation sparing benefit of using three-dimensional mapping in patients with CHD. METHODS: Data were retrospectively collected from the Catheter Ablation with Reduction or Elimination of Fluoroscopy multi-institutional registry. Patients with CHD were selected. Those with previous ablations, concurrent diagnostic or interventional catheterisation and unknown arrhythmogenic foci were excluded. The control cohort was matched for operating physician, arrhythmia mechanism, arrhythmia location, weight and age. The procedure time, rate of fluoroscopy use, fluoroscopy time, procedural success, complications, and distribution of procedures per year were compared between the two groups. RESULTS: Fifty-six patients with congenital heart disease and 56 matched patients without CHD were included. The mean total procedure time was significantly higher in patients with CHD (212.6 versus 169.5 minutes, p = 0.003). Their median total fluoroscopy time was 4.4 minutes (compared to 1.8 minutes), and their rate of fluoroscopy use was 23% (compared to 13%). The acute success and minor complication rates were similar and no major complications occurred. CONCLUSIONS: With the use of electroanatomic mapping during catheter ablation, fluoroscopy use can be reduced in patients with CHD. The majority of patients with CHD received zero fluoroscopy.