Systemic Venous Atrium Research Articles

Contemporary Management Strategies of Baffle Leaks in Adults with a Failing Systemic Right Ventricle Late after Atrial Switch: A Case Series and Literature Overview

Baffle leaks are a frequently encountered and often overlooked complication after the atrial switch procedure for transposition of the great arteries. Baffle leaks are present in up to 50% of non-selected patients, and while they initially may not cause clear symptoms, they can complicate the hemodynamic course and influence the prognosis in this complex patient group. A shunt from the pulmonary venous atrium (PVA) to the systemic venous atrium (SVA) can lead to pulmonary overflow and subpulmonary left ventricular (LV) volume overload, while a shunt from the SVA to the PVA can result in (exercise-associated) cyanosis and paradoxical embolism. We report three cases of baffle leaks in patients with systemic right ventricular (sRV) failure late after the atrial switch procedure. Two symptomatic patients who presented with exercise-associated cyanosis due to SVA to PVA shunting over the baffle leak underwent successful percutaneous baffle leak closure with a septal occluder device. One patient with overt sRV failure and signs of subpulmonary LV volume overload due to PVA to SVA shunting was managed conservatively, as baffle leak closure was expected to lead to an increase in sRV end-diastolic pressure and aggravation of sRV dysfunction. These three cases illustrate the considerations made, challenges faced, and necessity of a patient-tailored approach when addressing baffle leaks.

Imaging characteristics and associations of left atrioventricular valve atresia and patent aortic root with lateralized atrial chambers on multidetector CT.

To study the imaging characteristics and the associations of left atrioventricular valve atresia with patent aortic root and lateralized atrial chambers on multidetector computed tomography (CT) angiography. We retrospectively evaluated all the CT angiography studies performed for the evaluation of various congenital heart diseases at our center from January 2014 to December 2021. Cases with left atrioventricular valve atresia and patent aortic root with lateralized atrial chambers were identified. The types of cardiovascular involvement as identifiable on CT angiography were studied and compiled. A total of 38 patients with left atrioventricular valve atresia and patent aortic root were included (median age: 5 months, males: 31). A total of 89.5% had usual atrial arrangement and 10.5% had mirror imagery of atria. Normal drainage of right and left superior caval veins and inferior caval vein into systemic venous atrium was seen in 77.8%, 61.5%, and 86.6%, respectively. Anomalous pulmonary venous drainage was seen in 3 (7.9%) patients. Atrial and ventricular septal defects were the most common associations. Imperforate left atrioventricular membrane was seen in 9 (23.7%) patients and absent left atrioventricular connection in 27 (71.1%). Discordant right atrioventricular connection was seen in 5 (13.1%) patients. While a double outlet right ventricle (76.3%) was the most common ventriculoarterial connection, discordant ventriculo-arterial connection (transposition) in 4 (10.5%). Most patients had good sized pulmonary arteries. Patent arterial duct and right aortic arch were seen in 29% and 21%, respectively. Aberrant right subclavian artery was the most common arch vessel anomaly. Coronary anomalies were seen in 7 patients (19%); single coronary artery being the most common. Majority of the patients with left atrioventricular valve atresia and patent aortic root with lateralized atrial chambers have usual atrial arrangement, normal right atrioventricular connections and a double outlet configuration of the right ventricle. Absent left atrioventricular connection is a more common than imperforate left atrioventricular valve membrane. Atrial and ventricular septal defects are the most common associations. Comprehensive CT based evaluation of vascular and nonvascular thoracic structures is imperative before surgery or interventions in patients with mitral atresia.

Transbaffle/transconduit puncture using a simple CARTO-guided approach without echocardiography in patients with congenital heart disease.

Catheter ablation (CA) of atrial tachyarrhythmias (ATs) in patients with complex congenital heart disease (CHD) often requires technically challenging transbaffle or transconduit puncture. The aim was to assess the feasibility and safety of transbaffle/transconduit puncture based on computed tomography (CT) three-dimensional (3D) reconstruction merged with electro-anatomical mapping (EAM) without per-procedure echocardiographic guidance. We included 18 consecutive CHD patients in two centers who had atrial-switch or Fontan surgery and underwent CA of AT by an antegrade approach requiring intracardiac puncture. Twelve patients with atrial-switch surgery and six patients with extracardiac Fontan surgery were referred for CA of AT. Cardiac CT with 3D reconstruction was performed before the procedure. The 3D volume of the systemic venous atrium or extracardiac conduit acquired by EAM was merged with the corresponding CT 3D reconstruction. The ablation catheter was positioned at the optimal puncture site. Under fluoroscopic guidance, the needle was positioned next to the ablation and the puncture was performed. Balloon expansion of the puncture site was performed in every case of transconduit puncture and in two (17%) cases of transbaffle puncture. Overall, 17 intra-atrial reentrant tachycarrythmias and 9 focal ATs were successfully ablated, with no acute complications. The median time to access the pulmonary atrium was 78.5 minutes (range, 55-185) and total median fluoroscopy time was 23 minutes (range, 7-53). Transbaffle and transconduit punctures can be performed safely in CHD patients by using a simple technique relying on CT 3D reconstruction and EAM.

P921Feasibility of multipoint, high-definition mapping with grid cathether of SVTs in patients with D-Transposition of the great arteries treated with atrial switch surgery

Abstract Introduction Patients with D-transposition of the great arteries (TGA) treated with Senning or Mustard surgery develop supraventricular tachycardias (SVTs) that require treatment with ablation. The use of multipoint, high-density, wavefront-activation-orientation independent mapping catheters hasn’t been reported in literature. Purpose To describe the feasibility of using a specific mapping catheter in SVTs in this set of patients. Methods Prospective observational study in patients with history of SVT and atrial switch surgery, that underwent EP study and electroanatomic (EA) mapping with a new 8Fr deflectable, multipoint (16 equidistant electrodes along 4 splines), with magnetic sensor, wavefront-activation-orientation independent catheter, in a third level hospital since April 2018 until May 2019, with medium-term follow-up. Results A total of 8 EPS (electrophysiologic studies) were performed in 7 patients (clinical data in Table 1). One patient had a tachycardia recurrence, accounting for a second EPS. The pulmonary venous atrium (PVA) was mapped in all procedures, whereas the systemic venous atrium (SVA) was mapped only in 75% of them, A total of 15 EA maps were obtained, with a ratio of 1.9 maps/patient, and an average of 20 375 ± 13 045 total points per patient. In all cases, PVA mapping was performed via retrograde transaortic approach, without transbaffle puncture. Tachycardia was induced in 5 out of 8 procedures, obtaining 6 different tachycardias (4 CTI dependent macro-reentry: 3 w/anticlockwise activation; 1 localized re-entry in SVA; 1 focal AT in SVA). No arrhythmia was induced in the other 3 procedures, however, in a patient with a previous CTI ablation, evidence of a gap in the ablation line on the voltage map was found. Ablation was performed with an irrigated, contact force, 3.5 mm catheter in 6 of the 8 procedures (75%). A retrograde transaortic approach was used in 3 of CTI dependent macro-reentries (75%). In one patient (who underwent two procedures) ablation was performed through a baffle leak. We report an acute success rate of ablation of 100%, and a recurrence rate of 20% on medium-term follow up. There were no major complications; nonetheless, one patient with history of morbid obesity had a minor vascular complication on the femoral puncture site treated medically. Conclusions it’s feasible and safe to use this new mapping catheter in patients with history of atrial switch surgery, both via retrograde and anterograde approach on the PVA and SVA respectively. The most frequent tachycardia observed in this study was anticlockwise CTI-dependent atrial flutter. Abstract Figure. Patient characteristics

2398Efficacy of remote controlled catheter ablation for atrial arrhythmias in patients with atrial switch

Abstract Introduction Since arterial switch procedure replaced the Mustard and Senning (M/S) operations for D-transposition of great arteries (TGA) in 1980s, there are many M/S survivors who are now over 30 yrs old. Atrial arrhythmias are common in these patients and catheter ablation is a valid alternative to medical treatment. Purpose Assess the efficacy of atrial arrhythmia ablation using remote magnetic navigation (RMN) in M/S patients. Methods All ablations performed on patients with M/S by a single operator in a tertiary center over a 10 year period (2008–2019) were reviewed and analyzed. All documented sustained recurrences were recorded. Results Twenty-eight patients (57% M, age 41 [33–44] yrs, 2 Senning), underwent 41 procedures, 40 of which consisted of ablation for atrial tachycardia (AT, 36, 91%: 81% in PVA, 8% SVA, 11% in PVA+SVA), atrio-ventricular nodal re-entry tachycardia (1, 1%) or atrial fibrillation (AF 3, 8%). All procedures were carried out using remote navigation, electroanatomical mapping and 3D image integration. Pre-procedure echo showed at least moderately impaired systemic ventricle in 68% and moderate or severe tricuspid regurgitation in 58% of patients. Access to pulmonary venous atrium (PVA) was gained retrogradely in all cases while to access systemic venous atrium (SVA) either via femoral, subclavian or jugular veins. All except one procedure (98%) were acutely successful. At 1 and 3 years, 82% and 74% of patients were free from recurrent arrhythmia. Multiple procedures were required to control arrhythmias in 10 (36%) patients ablated for AT (60% in PVA, 30% in PVA+SVA). After the 2nd ablation 60% of these patients were in sinus rhythm at 3 years. On multivariate Cox analysis, Senning repair was associated with a higher recurrence risk after ablation compared to patients undergone a Mustard procedure (HR 1.47, p=0.01). Overall median procedural duration was 210 [155–265] min with a median fluoroscopy time of 0.9 [0.4–1.5] min and fluoroscopy exposure of 60 [43–120] μGy·m2. Conclusions Remote magnetic navigation represents a valid treatment for atrial arrhythmias in patients post M/S operation, with good short and longer-term results. Moreover, it allows the retrograde approach sparing the transbaffle puncture and enables a low fluoroscopy exposure.

Ablation of Atrial Arrhythmias After the Atriopulmonary Fontan Procedure: Mechanisms of Arrhythmia and Outcomes.

This study sought to describe atrial arrhythmia mechanisms, acute outcomes, and long-term arrhythmia burdens following catheter ablation in adult atriopulmonary (AP) Fontan patients. Atrial arrhythmias are a significant cause of morbidity and mortality in the AP Fontan population. Sixty consecutive atrial arrhythmia ablations were reviewed in 42 AP Fontan patients (31 ± 8 years of age), performed between 1998 and 2017. The number of induced and ablated tachycardias was recorded for each case, as wellas the ability to ablate the suspected clinical tachycardia. Longer-term arrhythmia burden was assessed by using a 12-point clinical arrhythmia severity score. Intra-atrial re-entrant tachycardia (IART) was induced in 93% of cases (n= 56), atrioventricular re-entrant tachycardia in 2 (3%) and atrioventricular nodal re-entrant tachycardia in a single case. The mean number of tachycardias induced per case was 2.3. The critical isthmus for IART was mapped to the lateral (n= 10), inferolateral (n= 8), posterior/posterolateral (n= 16), or septal (n= 10) systemic venous atrium, or to the pulmonary venous atrium (n= 4). Ablation of all inducible tachycardias was achieved in 62%, ablation of at least one (but not all) inducible tachycardias in 25%, with failure to ablate any tachycardias in 13%. The suspected clinical arrhythmia was ablated in 50 cases (83%). Catheter ablation resulted in a significant reduction in arrhythmia score at 3 to 6, 12, and 24 months, irrespective of whether all inducible tachycardias were ablated, or the suspected clinical arrhythmia only. Twelve patients (29%) underwent at least one repeat ablation procedure, with a mean time between ablations of 2.7 ± 3.0 years. There were no cases of periprocedural death, stroke or cardiac tamponade. Catheter ablation can be a safe and effective intervention that will significantly reduce arrhythmia burden in the AP Fontan patient.

Transbaffle catheter ablation of atrial re-entrant tachycardia within the pulmonary venous atrium in adult patients with congenital heart disease.

Catheter ablation of atrial re-entrant tachycardia in patients after atrial switch procedure for transposition of the great arteries or with a Fontan circulation is technically challenging if the critical part of the re-entry circuit is located within the pulmonary venous atrium (PVA). We report our experience in transbaffle access (TBA) to the PVA for ablation of atrial re-entrant tachycardia focusing on technical details. In eight patients, six after Mustard procedure and two with a Fontan circulation, endocardial mapping of atrial re-entrant tachycardia revealed the critical part of the re-entry circuit within the PVA. A total of 10 ablation procedures were performed. Detailed angiographic assessment of the anatomy of the systemic and pulmonary venous atria was performed prior to baffle puncture. Transbaffle access was successfully established with a standard transseptal needle in 9 of 10 procedures. No major complications occurred. At the end of the procedure and the removal of the transseptal sheath, there was no residual shunt in any patient. Transbaffle access to the PVA for ablation of atrial re-entrant tachycardia is feasible, less invasive than alternative approaches and can be safely applied in patients after Mustard procedure or with a Fontan circulation. However, the rigidity of prosthetic material may preclude baffle puncture at least in a subset of those patients.

Catheter ablation of tachycardia arising from the pulmonary venous atrium after surgical repair of congenital heart disease.

Tachycardia arising from the pulmonary venous atrium (PVA) has not been adequately characterized in the setting of surgically repaired congenital heart disease (CHD). The purpose of this study was to determine the mechanisms, approach, and outcomes of catheter ablation of PVA tachycardia after CHD repair. The adult CHD procedural database was searched for consecutive ablation procedures over a 4-year period. Procedural characteristics of the population with tachycardia arising from the PVA were compared to those without PVA tachycardia. Groups were classified as (1) biventricular CHD, (2) single ventricle, or (3) d-transposition of the great arteries (DTGA)-baffle. Complete 3-dimensional mapping was possible for 113 of 124 sustained tachycardias during 81 procedures. Of these, 31 (19%) arose from the PVA, including 11 (15%) tachycardias in biventricular CHD, 8 (31%) in single ventricle, and 12 (80%) in DTGA-baffle procedures. Intra-atrial reentrant tachycardia was less frequently observed in the PVA vs the systemic venous atrium (SVA) (P = .012). Independent predictors of PVA tachycardia were absence of biventricular CHD (odds ratio 0.19, confidence interval 0.05-0.64, P = .010) and ipsilateral atrial surgery (odds ratio 15.7, confidence interval 4.8-59.9, P <.001). PVA procedure duration was greater than SVA-only procedures (median 5.3 hours vs 4.0 hours, P = .012), but acute success was similar (87% vs 82%, respectively, P = NS). PVA tachycardia is not unusual after surgical repair of CHD. Predictors include ipsilateral atrial surgery and absence of biventricular CHD. Such procedures involve increased complexity and unique tachycardia substrates but appear equally amenable to catheter ablation.

Novel catheter‐interventional strategy for intracardiac connecting of total anomalous pulmonary venous return in newborns with hypoplastic left heart‐syndrome prior to hybrid approach

Total anomalous pulmonary venous return (TAPVR) associated with hypoplastic left heart-syndrome (HLHS) is a rare condition, and from the therapeutical point of view associated with a high Aristotle score and thus increased mortality. We report two newborns with HLHS, one with a supracardiac type of TAPVR and mildly obstructed left vertical vein, and the other with a supracardiac type of TAPVR in association with cor triatriatum and severely obstructed left-sided vertical vein. In both patients, radio frequency perforation from the pulmonary venous confluence to the systemic venous atrium was performed with consecutive gradual balloon dilatation, followed by stent placement in one. Hybrid stage I, and comprehensive stage II were successfully performed thereafter. Currently, both are awaiting their Fontan completion. Transcatheter intracardiac connecting of supracardiac type of TAPVR in newborns with HLHS is feasible and might render these children suitable candidates for further hybrid approach.

The safety and efficacy of trans-baffle puncture to enable catheter ablation of atrial tachycardias following the Mustard procedure: A single centre experience and literature review

Targets for catheter ablation of atrial tachyarrhythmias (AT) in post-Mustard procedure patients are often located in the pulmonary venous atrium (PVA). Traditional access to this chamber is retrograde via the aorta. However trans-baffle puncture may be a key determinant of successful ablation in many cases. All AT ablations performed in patients late after Mustard and Senning operations by a single operator from 2007 to 2012 were reviewed. Nine procedures were identified. In total, 12 ATs were treated, seven persistent, the remainder induced, consisting of counterclockwise cavotricuspid isthmus dependent flutter (5), macroreentrant with isthmus in the systemic venous atrium (SVA) (2), macroreentrant with isthmus in the PVA (1), focal from the PVA (3), and focal from the SVA (1). Ablation within the PVA was required in all procedures to treat AT. Retrograde access in one patient was impossible due to the presence of a Bjork-Shiley tricuspid valve replacement; retrograde access in another two patients was attempted but catheter manipulation was ineffective and AT could not be mapped and ablated. Trans-baffle puncture was performed with transoesophageal echocardiographic guidance in all cases without complications and resulted in successful ablation of AT. Access to the pulmonary venous atrium is essential for successful ablation of AT in many Mustard patients. Trans-baffle puncture remains a relevant technique to modern practice and can be performed safely and effectively.

Percutaneous atrial septal defect closure in a child with interrupted inferior vena cava: Successful femoral venous approach

Interrupted inferior vena cava (IVC) with azygous continuation to the superior vena cava (SVC) is a relatively common systemic venous anomaly. This anomaly can occasionally complicate transcatheter intervention by rendering more difficult the usual direct route to the systemic venous atrium afforded by femoral venous access. We report our experience with successful transcatheter closure of a large residual atrial septal defect (ASD) using the femoral venous route in a 3-year-old patient with heterotaxy syndrome of left isomerism type, dextrocardia, partial atrioventricular canal defect, and interrupted IVC with azygous continuation to the SVC.

Anatomical Perspective on Radiofrequency Ablation of AV Nodal Reentry Tachycardia after Mustard Correction for Transposition of the Great Arteries

A case of radiofrequency catheter ablation of atrioventricular (AV) nodal reentry tachycardia, in a patient with transposition of the great arteries after venous rerouting according to Mustard, is described. An electroanatomical map of the His and AV nodal region was created from inside the systemic venous atrium. Retrograde mapping of the pulmonary venous atrium was performed and the arterial catheter retracted to a position in close proximity to the venous catheter inside the intraatrial baffle. This position was chosen to deliver radiofrequency current.

Utility of Intracardiac Echocardiography for Atrial Baffle Leak Closure in Repaired Transposition of the Great Arteries

A 27-year-old male with dextro-transposition of great arteries had Senning atrial switch repair in childhood and dual-chamber pacemaker placement for sinus node dysfunction in adulthood. Transthoracic echocardiography showed a lead in the systemic (anatomic right) ventricle. Multidetector computed tomography showed the lead perforating the baffle in the region of the body of the systemic venous atrium into the systemic ventricle. The lead was extracted, and a new lead was placed in the pulmonary (anatomic left) ventricle. A bidirectional baffle shunt persisted. The iatrogenic baffle leak was percutaneously closed with an Amplatzer septal occluder device using both intracardiac echocardiography (ICE) and three-dimensional transesophageal echocardiography (3D-TEE). We report the first use of ICE for baffle leak closure, which provided a good definition of the complex anatomy and guided the procedure.

Real-Time Integration of Intracardiac Echocardiography to Facilitate Atrial Tachycardia Ablation in a Patient With a Senning Baffle

This case report concerns a 10-year-old boy who previously underwent a Senning operation for transposition of the great arteries with an intramural course of the coronary arteries. The patient had recurrent episodes of atrial tachycardia with 1:1 atrioventricular conduction that caused, in combination with dysfunction of the systemic right ventricle, hemodynamic instability. Unresponsive to antiarrhythmic drug treatment, the patient was referred to our institution for an electrophysiological study and radiofrequency catheter ablation. The procedure was performed under general anesthesia. Because the atrial tachycardia caused hemodynamic instability, the mapping procedure was aimed at identification of the arrhythmogenic substrate and critical isthmus of a presumed macro-reentrant circuit with only brief episodes of induced tachycardia. First, a registered 3D shell of the cardiac anatomy was created on an electroanatomic mapping system (Cartosound, Biosense Webster, Diamond Bar, Calif), using intracardiac echocardiography (ICE). By positioning the ICE catheter inside the systemic venous atrium, the entire cardiac anatomy could be visualized, including structures that form a potential area of conduction block such as the caval veins, the tricuspid valve annulus, and surgical suture lines (eg, atrial baffle suture line) (Figure 1). Second, bipolar voltage mapping of the systemic venous atrium was performed during sinus rhythm to further evaluate the …

Simplified Demonstration of Cavotricuspid Isthmus Block After Catheter Ablation in Patients After Mustard's Operation

The Mustard operation is a complex atrial rerouting performed in patients with transposition of the great arteries (TGA). Cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) is an important problem in these patients. While catheter ablation (CA) is successful, three-dimensional (3D) mapping is necessary to prove block at the CTI. 3D mapping, however, requires baffle puncture. We tested a simplified concept to prove isthmus block after CA for AFL in Mustard patients. During electrophysiology study, catheters were placed in the high and low systemic venous atrium (HSVA and LSVA) and in the low pulmonary venous atrium (LPVA). LPVA and then LSVA were paced while recording in the HSVA and the alternate site. While pacing from one low site, the time taken to activate the other low site and the HSVA was compared before and after successful ablation. Three patients with Mustard operation and AFL underwent successful CA. Involvement of the CTI in AFL was proved by entrainment mapping. AFL was terminated during ablation and no longer inducible after ablation in all. LSVA pacing showed LPVA activation preceded HSVA activation preablation and activation pattern reversal after ablation. Likewise, LPVA pacing showed LSVA activation preceding HSVA preablation with reversal after ablation. This study provides a simple method to demonstrate bidirectional block at the CTI in patients with CTI-based AFL after Mustard operation for TGA.

Mapping of Intraatrial Reentrant Tachycardias by Remote Magnetic Navigation in Patients with d‐Transposition of the Great Arteries After Mustard or Senning Procedure

Remote Magnetic Mapping After Mustard/Senning Procedure. Mapping of intraatrial reentrant tachycardia (IART) still presents a challenge in complex congenital heart disease. The goal of this work was to present our initial experience with remote magnetic navigation (RMN) for mapping of IART in four patients after the atrial switch procedure (Mustard n = 1, Senning n = 3) for d-transposition of the great arteries. Three-dimensional (3D) mapping of the systemic venous atrium and the pulmonary venous atrium (PVA) was performed using RMN (Niobe) in conjunction with 3D mapping (CartoRMT). The maps were fused with a CT-based 3D anatomy. All patients had cavotricuspid isthmus-dependent IART with a mean atrial cycle length of 305 ms. Mapping of both atria (PVA retrogradely by passing the aortic and tricuspid valve) was feasible and safe. The procedure time for IART mapping ranged from 210 to 320 minutes with a mean of 251 minutes. The fluoroscopy time for IART mapping ranged from 15.8 to 45.0 minutes (mean 31.6 minutes) for patients, and ranged from 12.3 to 24.3 minutes with a mean of 19.5 minutes for physicians. No procedural complications occurred. Precise mapping of IART in the complex anatomical structures after an atrial switch procedure was feasible and safe using RMN. The maneuverability of the catheter was possible even with a retrograde access crossing two valves. Further reduction of procedural and fluoroscopy times for both patients and physicians seems possible.

Transvenous Pacing via a Disconnected Superior Vena Cava in a Patient with Transposition of the Great Arteries

We describe successful implantation of a permanent pacemaker via the right subclavian vein in a 28-year-old man with operated transposition of the great arteries where the superior vena cava is completely disconnected from the systemic venous atrium following a previous Glenn procedure.

Baffle puncture guided by transoesophageal echocardiography in a patient with dextrocardia and Mustard correction

A baffle puncture is a challenging procedure but can be safely done using direct visualization of the region of interest. To our knowledge, however, it has never been performed in a patient with dextrocardia. We present a 62-year-old male with dextrocardia, right isomerism, congenitally corrected transposition of the great arteries, persistent left-sided superior and inferior caval veins, atrial septum defect, and pulmonary valve stenosis. The atrial septum defect was surgically closed with a Teflon patch, a variant Mustard operation was performed, and also a prosthetic tricuspid valve was implanted. The patient developed multiple episodes of atrial tachycardia leading to acute heart failure on many occasions. An electrophysiological study was undertaken in order to create a bi-atrial electro-anatomical map. Owing to the presence of a prosthetic tricuspid valve, the femoral venous access was used and a baffle puncture was performed using continuous monitoring with fluoroscopy and transoesophageal echocardiography (TEE). The baffle puncture was successful and the tachycardia was ablated in the systemic venous atrium. To our knowledge, we present the very first case report demonstrating a successful baffle puncture in a patient with dextrocardia and Mustard correction. Direct imaging using TEE seems to be a very useful tool for guiding the puncture.

Site of Coronary Sinus Drainage Does Not Significantly Affect Coronary Flow Reserve in Patients Long Term After Fontan Operation

This study was designed to investigate the impact of postoperative coronary sinus drainage pressure on coronary flow reserve (CFR) assessed by Doppler guidewire in patients long term after Fontan operation. Twenty-nine patients (median age, 17.4 years female, 11) at a median of 10.6 years after Fontan operation were examined with intracoronary Doppler guidewire during cardiac catheterization. Fourteen patients had coronary sinus (CS) drainage to the systemic venous atrium and 15 patients had CS drainage to the pulmonary venous atrium after Fontan operation. Median CS drainage pressure was significantly higher in systemic venous CS drainage compared to pulmonary venous CS drainage (11 vs 5 mmHg, p < 0.0001). Median CFR values for the right and left coronary artery did not differ significantly with respect to CS drainage. There was a positive correlation between coronary flow reserve and pulmonary arteriolar resistance (p < 0.05) in multivariate regression analysis. The site of coronary drainage into the systemic atrium or the pulmonary venous atrium did not significantly affect CFR. Our data do not support a surgical strategy of elective redirection of coronary sinus blood to a low-pressure compartment but support an early staged approach. The positive correlation between CFR and pulmonary resistance demands further evaluation.

The electrophysiology of atrioventricular nodal reentry tachycardia following the Mustard or Senning procedure and its radiofrequency ablation

We describe the electrophysiological studies undertaken in four patients with atrioventricular nodal reentry tachycardia in the setting of concordant atrioventricular and discordant ventriculo-arterial connections (transposition). Radiofrequency ablation was attempted in three, all with success. Clear evidence of dual antegrade pathways through the atrioventricular node was present in only one of the four, but other characteristics of discrete fast and slow pathways into the atrioventricular node were present in all. Atrioventricular nodal reentry tachycardia was inducible in all. In the three patients in whom ablation was attempted, the application of radiofrequency energy to the low medial regions of the systemic venous atrium (morphologically left) consistently caused junctional accelerated rhythm, but these lesions were not successful in eliminating the tachycardia. Successful radiofrequency ablation required a retrograde approach to the region of the slow pathway in the pulmonary venous atrium (morphologically right).