Ignored Role of Paroxysmal Atrial Fibrillation in the Pathophysiology of Cryptogenic Stroke in Patients with Patent Foramen Ovale and Atrial Septal Aneurysm.

The association between cryptogenic stroke (CS) and patent foramen ovale (PFO) with or without atrial septal aneurysm (ASA) has been a debate for decades in terms of pathophysiologic processes and clinical courses. This issue has become more interesting and complex, because of the concerns associating the CS with so-called normal variant pathologies of interatrial septum, namely ASA and PFO. While there is an anatomical pathology in the interatrial septum, namely PFO and ASA, the embolic source of stroke is not clearly defined. Moreover, in patients with PFO and CS, the risk of recurrent stroke has also been associated with other PFOunrelated factors, such as hyperlipidemia, body mass index, diabetes mellitus, and hypertension, leading to the difficulty in understanding the pathophysiologic mechanism of CS in patients with PFO and/or ASA. Theoretically, the embolic source of cryptogenic stroke in which PFO and/or ASA has been involved can be categorized into three different anatomical locations, namely PFO tissue and/or ASA tissue itself, right or left atrial chambers, and venous vascular territory distal to the right atrium, i.e., inferior vena cava and lower extremity venous system. However, the possible role of paroxysmal atrial fibrillation associated with PFO and/or ASA as a source of cryptogenic stroke has never been mentioned clearly in the literature. This review aims to explain the association of cryptogenic stroke with PFO and/or ASA in a comprehensive manner, including anatomical, clinical, and mechanistic aspects. The potential role of paroxysmal atrial fibrillation and its contribution to clinical course have been also discussed in a hypothetical manner to elucidate the pathophysiology of CS and support further treatment modalities.

Association of atrial septal fenestration with outcomes after atrioventricular septal defect repair.

OBJECTIVE: During repair of atrioventricular septal defect (AVSD), surgeons might leave an atrial level shunt when concerned about postoperative physiology, or as part of routine practice. However, the association of fenestration with outcomes is unclear. We sought to determine factors associated with mortality after biventricular repair of AVSD. METHODS: We included 581 patients enrolled from 32 Congenital Heart Surgeons' Society institutions from January 1, 2012, to June 1, 2020 in the Congenital Heart Surgeons' Society AVSD cohort. Parametric multiphase hazard analysis was used to identify factors associated with mortality. A random effect model was used to account for possible intersite variability in mortality. RESULTS: An atrial fenestration was placed during repair in 133/581 (23%) patients. Overall 5-year survival after repair was 91%. Patients who had fenestration had an 83% 5-year survival versus 93% for those not fenestrated (P < .001). Variables associated with mortality in multivariable hazard analysis included institutional diagnosis of ventricular unbalance (hazard ratio [HR], 2.7 [95% confidence interval (CI): 1.5-4.9]; P = .003), preoperative mechanical ventilation (HR, 4.1 [95% CI, 1.3-13.1]; P = .02), atrial fenestration (HR, 2.8 [95% CI, 1.5-4.9]; P < .001), and reoperation for ventricular septal defect (HR, 4.0 [95% CI, 1.3-13.1]; P = .002). There was no difference in measures of ventricular unbalance for comparisons of fenestrated with nonfenestrated patients. No significant interinstitution variability in mortality was observed on the basis of the random effect model (P = .7). CONCLUSIONS: An atrial communication at biventricular repair of AVSD is associated with significantly reduced long-term survival after adjusting for other known associated factors, including unbalance. These findings might challenge the routine practice of fenestration.

Urgent neonatal balloon atrial septostomy in simple transposition of the great arteries: predictive value of fetal cardiac parameters.

OBJECTIVES: To investigate the impact of abnormal perinatal loading conditions on cardiac geometry and function in term fetuses and neonates with transposition of the great arteries with intact interventricular septum (simple TGA), and to explore the predictive value of fetal cardiac parameters for an urgent balloon atrial septostomy (BAS) after birth. METHODS: This was a prospective longitudinal follow-up study of women delivering at term, including both uncomplicated pregnancies with normal outcome and pregnancies affected by fetal simple TGA. Conventional, spectral-tissue Doppler and speckle-tracking echocardiographic parameters were obtained within 1 week before delivery and within the first few hours after delivery. Neonates with simple TGA that required urgent BAS were assessed after the procedure and before corrective arterial switch surgery. Cardiac parameters were normalized by cardiac cycle length, ventricular end-diastolic length or end-diastolic dimension, as appropriate. Fetal and neonatal cardiac parameters were compared between simple-TGA cases and controls, and perinatal changes in the simple-TGA group were assessed. Receiver-operating-characteristics (ROC)-curve analysis was used to assess the predictive value of fetal cardiac parameters for urgent BAS after birth in the simple-TGA group. RESULTS: A total of 67 pregnant women delivering at term were included in the study (54 normal pregnancies and 13 with a diagnosis of fetal simple TGA). Compared with normal term fetuses, term fetuses with simple TGA exhibited more globular hypertrophied ventricles, increased biventricular systolic function and diastolic dysfunction (right ventricular (RV) sphericity index (SI), 0.58 vs 0.54; left ventricular (LV)-SI, 0.55 vs 0.49; combined cardiac output (CCO), 483 vs 406 mL/min/kg; LV torsion, 4.3 vs 3.0 deg/cm; RV isovolumetric relaxation time (IVRT'), 127 vs 102 ms; P < 0.01 for all). Compared with normal neonates, neonates with simple TGA demonstrated biventricular hypertrophy, a more spherical right ventricle and altered systolic and diastolic functional parameters (RV-SI, 0.61 vs 0.43; RV myocardial performance index, 0.47 vs 0.34; CCO, 697 vs 486 mL/min/kg; LV-IVRT', 100 vs 79 ms; RV-IVRT', 106 vs 71 ms; P < 0.001 for all). Paired comparison of neonatal and fetal cardiac indices in the simple-TGA group showed persistence of the fetal phenotype, increased biventricular systolic myocardial contractility and CCO, and diastolic dysfunction (RV systolic myocardial velocity (S'), 0.31 vs 0.24 cm/s; LV-S', 0.23 vs 0.18 cm/s; CCO, 697 vs 483 mL/min/kg; LV torsion, 1.1 vs 4.3 deg/cm; P < 0.001 for all). Several fetal cardiac parameters in term fetuses with simple TGA demonstrated high predictive value for an urgent BAS procedure after birth. Our proposed novel fetal cardiac index, LV rotation-to-shortening ratio, as a potential marker of subendocardial dysfunction, for a cut-off value of ≥ 0.23, had an area under the ROC curve (AUC) of 0.94, sensitivity of 100% and specificity of 83%. For RV/LV end-diastolic area ratio ≥ 1.33, pulmonary-valve-to-aortic-valve-dimension ratio ≤ 0.89, RV/LV cardiac output ratio ≥ 1.38 and foramen-ovale-dimension-to-total-interatrial-septal-length ratio ≤ 0.27, AUC was 0.93-0.98, sensitivity was 86% and specificity was 83-100% for all. CONCLUSIONS: Simple-TGA fetuses exhibited cardiac remodeling at term with more profound alterations in these cardiac parameters after birth, suggestive of adaptation to abnormal loading conditions and possible adaptive responses to hypoxemia. Perinatal adaptation in simple TGA might reflect persistence of the abnormal parallel arrangement of cardiovascular circulation and the presence of widely patent fetal shunts imposing volume load on the neonatal heart. The fetal cardiac parameters that showed high predictive value for urgent BAS after birth might reflect the impact of late-gestation pathophysiology and progressive hypoxemia on fetal cardiac geometry and function in simple TGA. If these findings are validated in larger prospective studies, detailed cardiac assessment of fetuses with simple TGA near term could facilitate improvements in perinatal management and refinement of the timing of postnatal intervention strategies to prevent adverse pregnancy outcomes. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Congenitally corrected transposition and mitral atresia complicated by restrictive atrial septum.

Congenitally corrected transposition (ccTGA), also known as L-transposition of the great arteries (L-TGA), is a rare cardiac malformation accounting for approximately 0.05% of congenital heart disease, characterized by ventricular inversion, discordant ventriculo-arterial connections with a normal visceroatrial relationship. It was first described by Baron Rokitansky in 1875, and prenatal sonographic diagnosis can be difficult. Symptomatology and clinical presentation of this malformation are related to the associated intracardiac defects. We report a rare case of severe, complex cardiac disease: prenatally diagnosed ccTGA with atrial restriction, mitral atresia, Ebsteinoid tricuspid valve, and severe pulmonary valve stenosis, who subsequently developed left pulmonary vein stenosis.

Cierre de la comunicación interauricular por cateterismo intervencionista con dispositivo Amplatzer en pediatría / Atrial Septal defect closure by interventional catheterization with Amplatzer device in Pediatrics

Introducción: El cateterismo intervencionista corrige las cardiopatías complejas, donde el dispositivo Amplatzer es el más usado y está disponible en Cuba. Objetivo: Evaluar el cateterismo intervencionista con Amplatzer, en el cierre de la comunicación interauricular ostium secundum. Métodos: Estudio de evaluación, longitudinal y prospectivo en 92 pacientes. El cierre de la comunicación por cateterismo con Amplatzer, se realizó en el Cardiocentro Pediátrico William Soler (2010-2016). Se utilizaron variables demográficas, ecocardiográficas (transtorácicas y transesofágicas) antes, durante y al año del cateterismo. Se observaron las complicaciones. La evaluación clínica y ecocardiográfica se realizó al año poscateterismo. Los pacientes a quienes se les realizó el proceder en el 2016, se evaluaron a los 6 meses. Resultados: Se encontraron diferencias significativas en el sexo (p<0,05): femenino 64,1 por ciento con homogeneidad para la edad (p= 0,244): media 9,8 años ( 5 desviaciones estándar. Precateterismo: 28,3 por ciento eran desnutridos y 17,4 por ciento delgados; poscateterismo la desnutrición mejoró significativamente (p= 0,000): desnutridos 9,8 por ciento y delgados 8,7 por ciento. El diámetro medio del defecto por ecocardiografía transcateterismo fue significativo (p= 0,000). Transcateterismo: 98,9 por ciento con cierre de defecto, 16,3 por ciento con insuficiencia tricúspidea y 4,3 por ciento con insuficiencia mitral. Poscateterismo: 98,9 por ciento con Amplatzer bien colocado. Hubo complicaciones inmediatas en 8,7 por ciento (arritmias, derrame pericárdico y embolización). Al año se detectó cortocircuito residual pequeño (n= 1) e insuficiencias valvulares auriculoventriculares (n= 3). La evolución fue satisfactoria (n= 91). Conclusiones: La evolución del cierre de la comunicación interauricular ostium secundum con dispositivo Amplatzer es satisfactoria, con mejoras de la desnutrición(AU)

Introduction: The interventional catheterization corrects complex heart diseases, and the Amplatzer device is the most widely used and is available in Cuba. Objective: To assess the interventional catheterization with Amplatzer device in the ostium secundum atrial septal closure. Methods: Longitudinal and prospective evaluation study in 92 patients. The closure of the communication by Amplatzer catheterization was performed in the William Soler Pediatric Cardiocenter of (2010-2016). Demographic and echocardiographic (transthoracic and transesophageal) variables were used before, during, and at the year of the catheterization. Complications were observed. Clinical and echocardiographic assessment was made a year after catheterism. The patients who underwent the procedure in 2016 were evaluated at 6 months. Results: Significant differences were found in the sex (p< 0.05): Female 64.1 t percent with homogeneity of the age (p= 0.244): average 9.8 years ( 5 standard deviations. Pre-catheterism: 28.3 percent were malnourished and 17.4 percent thin; post-catheterism: malnutrition improved significantly (p= 0.000): 9.8 percent malnourished and 8.7 percent thin. The average diameter of the defect by transcatheter echocardiography was significant (p= 0.000). Transcatheter: 98.9 percent : with default closure, 16.3 percent with tricuspid insufficiency and 4.3 percent with mitral regurgitation. Post-catheterism: 98.9 percent with Amplatzer device correctly positioned. There were immediate complications in 8.7 percent (arrhythmia, pericardial effusion, and embolization). A year after, small residual short circuit was detected (n= 1), and atrioventricular valve regurgitation (n= 3). The evolution was satisfactory (n= 91). Conclusions: The evolution of ostium secundum atrial septal defect´s closure with Amplatzer device is satisfactory and improves malnutrition(AU)

The influence of iatrogenic atrial septal defect on the prognosis of patients with atrial fibrillation between cryoablation and radiofrequency ablation.

OBJECTIVE: The present study was to compare the incidence of septal defect (SD) in patients with atrial fibrillation (AF) who received radiofrequency ablation or cryoablation. METHODS: A total of 293 AF patients were performed with radiofrequency ablation and cryoablation. Cardiac ultrasonography was performed to calculate left atrial diameter (LAD), left atrial ejection fraction (LAEF%), strain rate (SR), left ventricular systolic (SRs), left ventricular diastolic (SRe), and left atrial systole (SRa) before surgery, 3 months and 1 year after surgery. The patients were followed up to observe statin and angiotensin-converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB) medication, AF recurrence, 6-min walk test, stroke, any symptoms caused by arrhythmia, and re-hospitalization. RESULTS: The levels of LAD and SD were higher, while SRe and SRa were lower in the cryoablation group in the comparison with the radiofrequency ablation group after surgery (P<0.05). LAEF was lower in the cryoablation group than the radiofrequency ablation group after 3 months (P<0.05). After 1-year follow-up, no right-to-left shunt occurred in all patients with SD. The AF recurrence rate in SD group was higher than that in the normal group (P<0.05). The use of statin and the application of ACEI/ARB were protective factors, whereas hypertension, LAD, left atrial operation time, and surgical plan were risk factors. CONCLUSION: SD affects left atrial function and increases the risk of AF recurrence. Hypertension, LAD, and left atrial operation time are risk factors for SD, whereas statin and ACEI/ARB drugs can reduce SD.

The mechanisms of recurrent atrial arrhythmias after second-generation cryoballoon ablation.

BACKGROUND: In patients with paroxysmal atrial fibrillation (PAF), 10%-15% of patients require repeat procedures after second-generation cryoballoon pulmonary vein isolation (CB-PVI). We sought to explore the mechanisms of recurrences after cryoballoon ablation. METHODS: The data of 122 PAF patients who underwent second procedures for recurrent arrhythmias 7.0 (4.0-12.0) months after the CB-PVI were analyzed. During second procedures, non-PV AF foci were explored with isoproterenol, adenosine, and repetitive cardioversions. RESULTS: In total, 378/487 (77.6%) PVs remained isolated, and reconnections were not observed in any PVs in 59 (48.4%) patients. PV reconnections were associated with recurrences in 38 (31.1%) patients, of whom 33 (86.8%) had reconnections of at least 1 upper PV. In 6 (4.9%) patients, non-PV AF foci were identified in the upper PV antra where cryoballoons cannot isolate but within the circumferential radiofrequency PVI line. Non-PV AF foci were identified in the superior vena cava, right atrial body, left atrial body, and atrial septum in 28 (23.0%), 18 (14.7%), 4 (3.3%), and 5 (4.1%) patients, respectively. Twelve (9.8%) patients had multiple non-PV AF foci. Four (3.3%), 3 (2.4%), and 8 (6.5%) patients underwent second procedures for atrioventricular nodal reentrant tachycardia, atrial flutter, and atrial tachycardias. During 16.0 (8.0-24.0) months of follow-up, freedom from any atrial arrhythmia at 1 year and 2 years after the second procedure was 79.2% and 60.6%. Nineteen (15.5%) patients had antiarrhythmic drug therapy at the last follow-up. CONCLUSIONS: Our study suggested that improvement in the upper PV PVI durability, eliminating arrhythmogenic superior vena cavae and coexisting atrial arrhythmias, and bonus cryoballoon applications at PV antra might improve the single procedure outcome in cryoballoon ablation.

Atrial septum biopsy for direct substrate characterization in atrial fibrillation.

INTRODUCTION: The aim of this study was to describe and illustrate the technique of performing interatrial septum biopsy and to demonstrate its use for direct histological substrate characterization in atrial fibrillation (AF). METHODS AND RESULTS: Biopsies were performed in four patients who underwent AF catheter ablation. Bipal 7 bioptome was directed through a steerable sheath directly onto the septum. Fluoroscopic views as well as echocardiography-guided techniques were utilized to confirm that the tip was oriented towards the interatrial septum. The bioptome was then placed on the right atrial (RA) septum and maneuvered to obtain the specimens (at least 1 mm in size) from the posterior septal region of the RA, adjacent to the fossa ovalis. Bioptome placement and sample acquisition were successful in all patients at the first attempt. No patient developed any minor or major complications during the procedure and hospital stay. All the biopsy specimens had proper qualities for histological assessments and revealed a variety of pathologies including fibrosis, inflammation, and fatty infiltration. CONCLUSION: Atrial septum biopsies could be safely performed guided by fluoroscopy and transesophageal echocardiography. The obtained specimens allowed for a detailed localized substrate characterization which is of great interest in AF.

Left atrial appendage isolation during ablation in the interatrial septum: Rapid recognition by continuous monitoring of appendage electrograms.

Extensive atrial ablation in the setting of atrial fibrillation (AF) and atrial tachycardia (AT) can affect interatrial connections. A 76-year-old man with a history of tachycardia-induced cardiomyopathy and nine ablation procedures for AF/AT over 15 years presented with highly symptomatic recurrent AT. Previous ablation lesions included pulmonary vein isolation, left atrial posterior wall isolation, mitral isthmus line, cavotricuspid isthmus line, and the ablation of areas of fractionated electrograms. Electroanatomical mapping found the pulmonary veins and the left atrial posterior wall to be silent, as was the posterior interatrial septum and the mitral isthmus area. Activation mapping showed progression of electrograms in the left atrial appendage (LAA) from the septal aspect posteriorly, and in the coronary sinus from proximal to distal; implying the existence of a septal circuit, where extensive fractionation was noted. This was targeted, while monitoring conduction into the LAA using a multielectrode catheter. Ablation led to prompt termination of tachycardia and simultaneous LAA isolation. Immediate cessation of ablation led to recovery of conduction into LAA. Additional lesions in the interatrial septum were required to render the tachycardia noninducible, accompanied by temporary isolation of LAA. The ablation lesion sets employed while ablating AF and left AT can block many interatrial pathways, rendering conduction dependent on muscle bundles in the interatrial septum and, therefore, vulnerable to block by lesions in this area. LAA isolation has been associated with high incidence of LAA thrombus formation and stroke despite oral anticoagulation. Continuous observation of LAA electrograms during ablation can help to avoid this complication.

Current Concepts of Anatomy, Electrophysiology, and Therapeutic Implications of the Interatrial Septum.

The interatrial septum (IAS), a fibromuscular structure separating the right (RA) and left (LA) atrium, plays an important role in both intra- and interatrial conduction. Electropathological changes in the IAS such as discordant activation of the right and left septal layer and conduction disorders may facilitate intraseptal re-entry and promote development of atrial tachyarrhythmias such as atrial fibrillation (AF). Various experimental studies have emphasized the importance of the IAS in AF initiation and perpetuation. Moreover, a thicker IAS has been associated with atrial tachyarrhythmias and a lower success rate of catheter ablation. Therefore, it is assumed that the septal interatrial connections, which may be more pronounced in patients with a thicker IAS, may furnish an anatomic pathway for re-entry and may explain failure of catheter ablation therapy. However, the exact role of the IAS in the treatment of AF still remains an enigma. More profound understanding of the role of the IAS in the pathophysiology of AF and other atrial tachyarrhythmias is necessary to improve success of current therapeutic options and develop new treatment modalities. This review outlines the current knowledge on the relationship between anatomic and electrophysiological properties of the IAS and discusses its involvement in atrial tachyarrhythmias.

Novel shunt modification with an adjustable stent-embedded "fenestrated" septal occluder in a patient with pulmonary hypertension.

A 60-year-old woman with progressive dyspnea and cyanosis, O2-dependent pulmonary hypertension despite optimal medical therapy and remote atrial septostomy presented with worsening cyanosis and right-to-left shunting. The creation of a "fenestrated" ASD closure device with the insertion of a peripheral stent through an AMPLATZER™ ASD closure device was deployed to minimize right to left shunting and allow for enlargement of the shunt if needed. This case demonstrates the benefit of diminishing a right to left shunt with a self-fabricated fenestrated AMPLATZER device to improve symptoms in pulmonary hypertension patients with a pre-existing ASD.

Percutaneous Closure of Persistent Atrial Septal Defects After Pulmonary Vein Isolation.

Pulmonary vein isolation (PVI) with radiofrequency or cryoballoon ablation to treat atrial fibrillation requires trans-septal puncture. This creates a small iatrogenic atrial septal defect (iASD). In most patients, the defect spontaneously closes after 3-6 months. However, persistent iASDs can cause hemodynamic changes and adverse consequences from inter-atrial shunting. Persistent post PVI iASDs that are clinically significant can be closed percutaneously. This diagnosis should be considered in patients with worsening dyspnea or fatigue after PVI. We present a case of post PVI iASDs causing immediate or late onset hemodynamic changes and clinical symptoms, which improved after ASD closure. We provide a review of previously reported cases and literature on post PVI ASD prevalence, risk factors and outcomes after ASD closure.

Demonstration of living anatomy clarifies the morphology of interatrial communications.

Inferences made regarding the postnatal anatomy of the atrial septum still tend to be based on developmental evidence. Although atrial septation is a well-defined process, it is remarkably complex and remains poorly understood. It is now established, however, that the process involves the conjugation of several myocardial structures and mesenchymal tissues of both intracardiac and extracardiac origin. The resultant postnatal morphology is equally complex, evidenced by the fact that, in the normal heart, only the floor of the oval fossa, along with its anteroinferior muscular buttress, are true anatomical septums. In this regard, septums can be defined as partitions that can be removed without creating communications with the extracavitary space. The true septal components are surrounded by grooves, which themselves largely represent infolding of the atrial walls. These anatomical features can now accurately be revealed using virtual dissection of CT data sets. These images, when carefully reconstructed, demonstrated the anatomy with as much accuracy as when hearts are dissected in the autopsy room. Such virtual dissection, furthermore, shows the components as they are seen within the chest, thus facilitating understanding for those intending to undertake interventional therapeutic procedures. By preparing such images, we show the complexity of the normal atrial septum and its surrounds. We show that it is only defects within the oval fossa, or the much rarer vestibular defects, which can appropriately be illustrated in the context of a normally constructed heart.