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Objectives: The atrial septal pouch was first recognised in humans in 2006 and, since 2010, has been described in more detail. The first reports on the left-sided atrial septal pouch linked its occurrence with a higher risk of thromboembolic stroke resulting from left atrial thrombus formation. However, subsequent studies have challenged this theory; therefore, the consequences of septal pouch occurrence remain disputed. Currently, in veterinary species, septal pouch occurrence and morphology have been described in sheep and pigs, showing species-related differences. No studies have been conducted on cats. As cats show a species-related risk of aortic thromboembolic disease resulting from left atrial thrombus formation, we aimed to describe the interatrial septum anatomical variations as the first step in the investigation of the relationship between the septal pouch presence and left atrial thrombus formation., Methods: The study was conducted on hearts collected post mortem from 80 cats. After formalin fixation and dissection, a detailed anatomical description of the interatrial septum for all cases was followed by a histopathological analysis of the heart in 25 cases. After dissection, the specimens were embedded in paraffin blocks and stained with haematoxylin and eosin, Masson-Goldner trichrome, Picrosirius Red and Movat pentachrome in a routine manner and evaluated via light microscopy., Results: Our study showed a very high prevalence (95%) of the left-sided septal pouch in cats with a lower incidence (29%) of the right-sided septal pouch. We noted a high morphological variety of the left-sided septal pouch and described anatomical variants not previously reported in the literature., Conclusions and Relevance: The septal pouch is a common anatomical variation of the interatrial septum in cats. Although, based on the current study, we cannot draw further conclusions on the relationship between the left-sided septal pouch and thromboembolic events in cats, the high prevalence of this anatomical entity points to a need of further studies on the topic., Competing Interests: Conflict of interestThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Incomplete or irregular fusion of the interatrial septum may result in several anatomic variants, including atrial septal pouches and ridges, whose knowledge and recognition are still poorly widespread in clinical practice. An educational review focused on the definition, clinical significance and diagnostic work-up of these anatomic findings was performed using PubMed, MEDLINE, Embase and Cochrane Central databases up to June 2023. Atrial septal pouches and ridges have been associated with an increased difficulty of catheter-based interventions requiring a transseptal approach, due to procedural challenges for transseptal puncture and the restricted motion of guidewires and catheters through the transseptal access. Additionally, left atrial septal pouch may serve as a thrombogenic nidus and a source of systemic embolism, mostly in the presence of factors leading to higher left atrial pressure and/or atrial blood stasis, which increase the risk of thrombus formation and embolic events, rather than for the only presence of left atrial septal pouch itself. Further investigations are needed in order to better elucidate the implications of such anatomic findings in daily clinical practice, and to provide the most appropriate decision-making strategies., Competing Interests: Declaration of competing interest The authors declare they have no conflicts of interest, financial or otherwise to disclose., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Abstract: Lipomatous hypertrophy of the interatrial septum (LHIS) is a rare but benign cardiac tumor that can be found on cardiac imaging such as echocardiogram, or during surgery or an autopsy. Cardiac MRI is the best imaging modality to determine the borders of the tumor and its extension into the intraventricular septum and ventricular free wall. Patients require close monitoring because LHIS may cause right or left outflow tract obstruction or superior vena cava obstruction, requiring cardiac surgical intervention. This article describes a patient with LHIS who underwent cardiac surgery because of her increasing symptomatology., (Copyright © 2024 American Academy of Physician Associates.)

Background: Primary cardiac synovial sarcoma is a rare condition with limited treatment options for advanced stages. Surgery and chemotherapy are currently the mainstay treatments; however, survival rates remain low., Case Presentation: A 64-year-old woman presenting with symptoms of chest tightness and shortness of breath was found to have an obstructive right atrial mass, along with pulmonary infarction and metastasis. She was ultimately diagnosed with advanced primary cardiac synovial sarcoma. Following surgery, the patient's symptoms improved, and she underwent chemotherapy and anti-angiogenic therapy, but unfortunately, her survival time was only 8 months., Conclusion:  This case report aims to enhance clinicians' understanding of the diagnosis and treatment of primary cardiac synovial sarcoma. Enhancing both survival outcomes and quality of life in individuals with primary cardiac synovial sarcoma continues to present a significant challenge., (© 2024. The Author(s).)

Background: Cardiac hemangiomas are very uncommon benign primary tumors. They are usually located preferentially in the right atrium and their location in the interatrial septum is extremely rare., Case Presentation: We report the case of a 41-year-old patient who was admitted due to a stroke. The transthoracic echocardiogram revealed a large mass in the right atrium adhered to the interatrial septum. Suspecting an atrial myxoma, surgical intervention was performed confirming that the mass extended within the thickness of the interatrial septum, protruding into the right atrial cavity. The histologic report confirmed a hemangioma., Conclusions: Cardiac hemangiomas are rare primary tumors and are usually misdiagnosed as other cardiac tumors. Histopathological examination is essential for a definitive diagnosis., (© 2024. The Author(s).)

Background: The left atrial septal pouch (LASP) is a small anatomical septal recess in the heart that has been linked with cardioembolic events. A systematic appraisal of the existing literature is necessary to establish a better understanding of the risk as studies continue to indicate a correlation between LASPs and cryptogenic strokes., Objectives: To determine the level of association between the presence of LASP and the risk of developing cryptogenic stroke., Methods: We searched PubMed, EMBASE and Scopus for studies comparing the prevalence of LASP in patients with cryptogenic stroke against non-cryptogenic stroke control groups from inception till December, 2023. The Newcastle Ottawa scale was used for quality assessment and Comprehensive Meta-Analysis Version 3.3 was used for data analysis with odds ratio (OR) as the effect measure., Results: Our review included a total of 10 retrospective, observational studies published between 2010 to 2022. A total of 683 cases of cryptogenic strokes were identified, out of which 33.1 % (n = 271) were associated with a LASP. Among the non-cryptogenic stroke controls (n = 2641), LASP was present in 20.6 % cases (n = 476). The aggregate OR for cryptogenic stroke was 1.618 times greater than non-cryptogenic stroke (p < 0.001) among LASP cases, CONCLUSION: The presence of a septal pouch in the left atrium is significantly linked to a higher risk of developing cryptogenic strokes. As a potential site of thrombus formation and subsequent dislodgement, further large-scale studies are necessary to establish the guidelines for management and prophylaxis to prevent embolic events., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

The relative simplicity of the clinical presentation and management of an atrial septal defect belies the complexity of the developmental pathogenesis. Here, we describe the anatomic development of the atrial septum and the venous return to the atrial chambers. Experimental models suggest how mutations and naturally occurring genetic variation could affect developmental steps to cause a defect within the oval fossa, the so-called secundum defect, or other interatrial communications, such as the sinus venosus defect or ostium primum defect., (© 2024. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

The antemortem diagnosis of secondary cardiac involvement by lymphoma remains suboptimal. Prognosis is worse with delayed diagnosis as the tumor burden increases with the multicompartment participation. Chemotherapy may improve survival, but there is a risk of mortality due to treatment-related complications, such as myocardial rupture and fatal arrhythmias. Modified chemotherapy regimens may prevent such complications, but the data are limited. We report the case of a 72-year-old woman diagnosed with diffuse large B-cell lymphoma with cardiac involvement, where early diagnosis prevented cardiac complications from the disease and its treatment as well. The aim of this case report is to highlight the fact that cardiac involvement in lymphoma is frequent and can be easily missed, leading to complications. Treatment requires an individualized approach., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Abstract: Lipomatous hypertrophy of the interatrial septum is a rare lesion of the heart. CT and cardiac MR are often sufficient to determine the benign lipomatous nature of the tumor and can avoid the need for histological confirmation. Lipomatous hypertrophy of the interatrial septum contains variable amounts of brown adipose tissue, resulting in different degrees of 18 F-FDG uptake in PET. We report the case of a patient with an interatrial lesion suspected of malignancy, discovered on CT and failing cardiac MR, with initial 18 F-FDG uptake. Final characterization was made thanks to 18 F-FDG PET with β-blocker premedication, avoiding an invasive procedure., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Abstract: Lipomatous hypertrophy of the interatrial septum (LHIS) is a benign anomaly with low prevalence. Lipomatous hypertrophy of the interatrial septum is asymptomatic in most of the cases and rarely leads to atrial arrhythmias, obstructive flow symptoms, or sudden death. It is mostly diagnosed as an incidental finding in cross-sectional imaging and echocardiography, and increased 18F-FDG uptake on LHIS has been described. We present a case of repeated increased 18F-PSMA uptake in LHIS. Although very rare, familiarity with the typical features and prevalence of LHIS in PET/CT can avoid misinterpretation for metastatic disease., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Cardiac myxomas (CMs) are the most common primary tumors of the heart, said to be derived from pluripotent cardiac stem cells. They are most often attached to the left side of the inter-atrial septum (IAS) and a feature noted at the site of attachment is a conglomeration of thick-walled vessels that has been noted to precede the development of myxomas., Aims: The present study was conducted to compare histology of the normal inter-atrial septa to the septal flap excised with the myxomas and to evaluate the significance of this 'vascular tangle' in the histogenesis of these tumors., Materials and Methods: In a 10-year retrospective analysis of all surgically excised CMs, tumors with attached septal sleeves were selected. This histology was compared to the serial sections of 25 normal age-matched septa obtained from normal hearts at autopsy., Results: Of the 56 myxomas seen in 10 years, 38 tumors (all left atrial in location) were received with a flap of the IAS. All of these cases, irrespective of the sizes of the tumor, showed the presence of conglomeration of thick-walled blood vessels, many of which showed abrupt myxoid change in their walls. Another noteworthy feature in many vessels in all flaps was migration of the myxoid tissue through the vascular walls and the endocardium to mushroom out into the atrial lumen. Such vascular channels were not seen in any of the normal IAS., Conclusions: Based on these findings, we propose a two-step hypothesis: an initial step that stimulates the pluripotent cells toward vasculogenesis with endothelial and smooth muscle differentiation, and a subsequent step leads to production of abundant mucopolysaccharides that splay apart the smooth muscle cells, which would explain rings, cords or nests of myxoma cells around endothelial lined spaces.

Introduction : A patent foramen ovale (PFO) is highly prevalent among the adult population. It allows shunting of blood through the inter-atrial septum and has been associated with cryptogenic stroke, transient ischemic attack, platypnea-orthodeoxia syndrome, decompression sickness (e.g. deep-water divers), and migraines. Areas Covered : In this manuscript, we will review the anatomy of PFO with particular emphasis on the factors associated with increased risk of paradoxical embolization, as well as the different modalities for the diagnosis of PFO. We will discuss medical, surgical, and transcatheter therapy for secondary prevention in patients with PFO and cryptogenic stroke, and summarize the data from observational studies, randomized controlled trials (RCTs), and meta-analysis of RCTs that have established the beneficial effect of transcatheter PFO closure in this patient population. Finally, we will provide a brief overview of the role of transcatheter PFO closure in patients with migraine. Expert Opinion : Transcatheter closure is the preferred treatment option in young (<60 years) patients with PFO and cryptogenic stroke. A multi-disciplinary approach with input from clinical cardiologist, neurologist, hematologist, cardiac surgeon, and interventional cardiologist provides the best therapeutic plan for each patient taking into account the available data, but also medical, social, and occupational considerations.

We explored the significance of the L-Arginine/asymmetric dimethylarginine (L-Arg/ADMA) ratio as a biomarker of endothelial dysfunction in stroke patients. To this aim, we evaluated the correlation, in terms of severity, between the degree of endothelial dysfunction (by L-Arg/ADMA ratio), the methylene tetrahydrofolate reductase (MTHFR) genotype, and the interatrial septum (IAS) phenotype in subject with a history of stroke. Methods and Results: L-Arg, ADMA, and MTHFR genotypes were evaluated; the IAS phenotype was assessed by transesophageal echocardiography. Patients were grouped according to the severity of IAS defects and the residual enzymatic activity of MTHFR-mutated variants, and values of L-Arg/ADMA ratio were measured in each subgroup. Of 57 patients, 10 had a septum integrum (SI), 38 a patent foramen ovale (PFO), and 9 an ostium secundum (OS). The L-Arg/ADMA ratio differed across septum phenotypes ( p ≤ 0.01), and was higher in SI than in PFO or OS patients ( p ≤ 0.05, p ≤ 0.01, respectively). In the PFO subgroup a negative correlation was found between the L-Arg/ADMA ratio and PFO tunnel length/height ratio ( p ≤ 0.05; r = - 0.37; R 2 = 0.14). Interestingly, the L-Arg/ADMA ratio varied across MTHFR genotypes ( p ≤ 0.0001) and was lower in subgroups carrying the most impaired enzyme with respect to patients carrying the conservative MTHFR ( p ≤ 0.0001, p ≤ 0.05, respectively). Consistently, OS patients carried the most dysfunctional MTHFR genotypes, whereas SI patients the least ones. Conclusions: A low L-Arg/ADMA ratio correlates with impaired activity of MTHFR and with the jeopardized IAS phenotype along a severity spectrum encompassing OS, PFO with long/tight tunnel, PFO with short/large tunnel, and SI. This infers that genetic MTHFR defects may underlie endothelial dysfunction-related IAS abnormalities, and predispose to a cryptogenic stroke. Our findings emphasize the role of the L-Arg/ADMA ratio as a reliable marker of stroke susceptibility in carriers of IAS abnormalities, and suggest its potential use both as a diagnostic tool and as a decision aid for therapy.

Objective: To compare length of stay of the initial neonatal hospitalization and mortality across multiple stages of surgical palliation for infants with left-sided obstructive lesions and severely restrictive or intact atrial septum (I/RAS)., Methods: Retrospective cohort study of patients prenatally diagnosed with left-sided obstructive lesions and I/RAS, defined by fetal pulmonary venous Dopplers., Results: We identified 76 fetal patients with 59 live born intending to pursue intervention. Those with I/RAS had longer durations of mechanical ventilation (P = .031) but no difference in intensive care unit or total length of stay. Survival to discharge from neonatal hospitalization was 41.7% in the I/RAS group and 80.7% in the unrestrictive group (P = .001). There was a higher proportion of deaths between stage 1 and stage 2 in the I/RAS group - 5/9 (55.6%) vs 9/50 (18%) in the unrestrictive group (P = .027). Beyond stage 2 palliation there was trend toward a difference in overall mortality (66.7% in I/RAS vs 35.7% in unrestrictive, P = .05) but no statistically significant difference in transplant-free survival (33.3% in I/RAS vs 53.5% in unrestrictive, P = .11)., Conclusion: The survival disadvantage conferred by prenatally diagnosed severe atrial septal restriction is most pronounced in the neonatal and early infancy period, with no detectable difference in late midterm transplant-free survival in our cohort., (© 2020 John Wiley & Sons, Ltd.)

The atrial septum enables efficient oxygen transport by separating the systemic and pulmonary venous blood returning to the heart. Only in placental mammals will the atrial septum form by the coming-together of the septum primum and the septum secundum. In up to one of four placental mammals, this complex morphogenesis is incomplete and yields patent foramen ovale. The incidence of incomplete atrial septum is unknown for groups with the septum primum only, such as birds and reptiles. We found a low incidence of incomplete atrial septum in 11 species of bird (0% of specimens) and 13 species of reptiles (3% of specimens). In reptiles, there was a trabecular interface between the atrial septum and the atrial epicardium which was without a clear boundary between left and right atrial cavities. In developing reptiles (four squamates and one crocodylian), the septum primum initiated as a sheet that acquired perforations and the trabecular interface developed late. We conclude that atrial septation from the septum primum only results in a low incidence of incompleteness. In reptiles, the atrial septum and atrial wall develop a trabecular interface, but previous studies on atrial hemodynamics suggest this interface has a very limited capacity for shunting., (© 2019 The Authors. Evolution & Development published by Wiley Periodicals, Inc.)

Although bronchogenic cysts are the most common primary mediastinal cysts, intracardiac bronchogenic cysts are extremely rare. We report a case of a bronchogenic cyst of the interatrial septum in a 42-year-old woman who presented with recent onset of dyspnea on exertion. Cardiac investigations including transthoracic echocardiography and computed tomography revealed a cystic homogeneous mass in the interatrial septum. The patient underwent surgical resection, and the resultant atrial septal defect was repaired using an autologous pericardial patch. Histopathological examination of the resected specimen revealed findings consistent with a benign bronchogenic cyst. Although bronchogenic cysts are extremely rare, they should be considered in the differential diagnoses of intracardiac tumors. Complete resection of bronchogenic cysts is recommended primarily for diagnostic and potentially therapeutic purposes.

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., (© 2019 Wiley Periodicals, Inc.)

There are many different congenital abnormalities and acquired pathologies involving the interatrial septum. Differentiation of these pathologies significantly affects patient management. We have reviewed the various interatrial septal pathologies and discussed their congenital associates, clinical significance, and management. After reading this article, the reader should be able to better characterize the interatrial septal pathologies using the optimal imaging tools, and have a better understanding of their clinical significance and management., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background and Aim: Recently, a clear evidence suggests that nonalcoholic fatty liver disease (NAFLD) is associated with an increased risk of incident atrial fibrillation (AF). Yet, the underlying pathogenesis is speculative. Thereby, we aimed to investigate the hypothesis that, interatrial thickness (IAST) and left atrial stiffness (LASt) might have mechanistic links between NAFLD and AF., Methods: Echocardiography and speckle-tracking assessment of left atrial function, transient elastography (TE) of the liver, basal ECG, and Holter monitoring were performed in 180 patients with (NAFLD) and 80 subjects without NAFLD., Results: Patients with NAFLD had higher values of IAST (P < 0.001), LASt (<0.001), and E/e' ratio (<0.003) compared with controls. IAST was correlated with LASt (r = 0.413; P < 0.001). 15.6% of patients with NAFLD had AF. More so, patients with increased IAST/LASt had a higher incidence of AF (25%) vs 3.8% in those with normal IAST/LASt. The LASt and IAST increased significantly in those with AF compared with those without (P < 0.001). Patients who experienced AF had higher values (P < 0.01) of TE (kPa). The degree of liver stiffness TE (kPa) was correlated with both IAST and LASt (r = 461, r = 0.535; P < 0.001). Furthermore, multivariate regression analysis showed that LASt and IAST were independent predictors of incident AF in subjects with NAFLD., Conclusions: Our data suggest that increased IAST and LASt index are independently associated with incident atrial fibrillation in patients with NAFLD. Increased IAST and LASt index might provide mechanistic links between NAFLD and incident atrial fibrillation., (© 2018 Wiley Periodicals, Inc.)

Smooth septum interatrial septum, patent foramen ovale (PFO) channel and atrial septal pouches (SPs) are commonly described variants in humans. Recent discoveries on the clinical significance of left-sided SP may encourage the creation of new strategies and devices for the management of SPs. However, these strategies may first be tested in the ovine model before implementation in humans. Unfortunately, little is known about the presence of SPs in ovine. In this study a total of 60 ovine (Ovis aries) hearts were examined. The interatrial septum morphology was assessed and the PFO channel and SPs were measured. The most commonly occurring variant were PFO channels (25.0%) with channel lengths of 5.4±2.3 mm. Smooth septums were observed in 18.3% of hearts. In the remaining cases, septums had a left septal ridge (15.0%), left SP (11.7%), left septal bridge (10.0%), right SP (10.0%), or had both a right SP and left septal ridge (10.0%). No double SPs were observed. The mean right SP depth was 3.4 ± 1.2 mm, and its mean ostium width and height were 7.9±1.8 mm and 2.8±1.0, respectively. For the left SP, the mean depth was 6.0±1.7mm, the ostium width was 7.9±2.4mm, and the ostium height was 4.1±1.6mm (range: 2.3-6.4mm). In conclusion the interatrial septum of ovine hearts exhibit morphologies that are more similar to humans than they are to swine, which should be taken into account during experimental studies. The presence of a left SP in sheep hearts make ovine models a promising alternative to the human heart for developing left-sided SP management devices and techniques., Competing Interests: The authors have declared that no competing interests exist.

Background: Partial anomalous pulmonary venous return is a rare congenital cardiac anomaly that usually involves the right pulmonary vein and an atrial septal defect. Isolated partial anomalous pulmonary venous return with an intact atrial septum is even rarer, and this condition is usually treated surgically in younger patients. We describe isolated partial anomalous pulmonary venous return in a 65-year-old woman who was treated by caval division with pericardial patch baffling through a surgically created atrial septal defect and reconstruction of the superior vena cava using a prosthetic graft., Case Presentation: A 65-year-old Asian woman who presented with exertional dyspnea was diagnosed with isolated partial anomalous pulmonary venous return. The surgical indications and strategy were controversial because of the rarity of this pathology. She had an indication for surgery because she was symptomatic and had a high ratio of pulmonary to systemic blood flow. We considered that surgical procedures should avoid postoperative stenosis of a reconstructed flow tract, sinus node dysfunction, and thrombogenesis. We created a caval division with pericardial patch baffling through a surgically created atrial septal defect and reconstructed the superior vena cava using a prosthetic graft for the isolated partial anomalous pulmonary venous return. She has since remained free of exertional dyspnea, arrhythmia, and thrombotic complications. This surgical strategy is safe and effective for treating isolated partial anomalous pulmonary venous return in older symptomatic adults., Conclusions: The long-term outcome of surgical repair of partial anomalous pulmonary venous return with an intact atrial septum in our patient, a symptomatic 65-year-old woman, was excellent.

Aims: The aim of this study is to characterize the arrhythmogenic substrate for peri-mitral atrial flutter (PMAFL), thereby determining a personalized ablation strategy to treat PMAFL., Methods and Results: Thirty-six consecutive PMAFL patients (mean age: 63.8 ± 11.3, 23 males) underwent detailed three-dimensional electroanatomic mapping in left atrium (LA). The LA was divided into septal-anterior wall (SAW), posterior inferior wall (PIW), and mitral isthmus (MI) region, respectively. Ablation strategy was determined based on the endocardial bipolar voltage map. Based on electrophysiological substrates, 10, 17, and 9 cases were classified into iatrogenic, spontaneous, and no-substrate PMAFL, respectively. The mean voltage in SAW was significantly lower in spontaneous PMAFL (iatrogenic: 1.07 ± 0.66 mV; spontaneous: 0.65 ± 0.44 mV; no-substrate: 1.60 ± 0.53 mV, P <0.001), while iatrogenic PMAFL patients had the lowest voltage in MI (0.51 ± 0.23 mV vs. 1.55 ± 0.78 mV, 1.61 ± 0.56 mV, P <0.001). No low-voltage or slow conduction zone was found in the no-substrate PMAFL group. Fifteen spontaneous PMAFLs were successfully terminated by modified septal-anterior (9/10) or conventional anterior ablation line (6/7). Eight iatrogenic PMAFLs (8/10) were terminated by reinforcing the previous ablation areas. Cardioversion without PMAFL ablation was done in no-substrate PMAFL patients. After a median follow-up of 12 (7-39) months, two spontaneous PMAFL patients received redo procedures for recurrence due to "gap" conduction., Conclusions: The ablation strategy for PMAFL patients should be based on the arrhythmogenic substrate, but not the indiscriminate MI ablation. No-substrate PMAFLs during AF ablation could be monitored after cardioversion and might not need further ablation.

Background: The left-sided atrial septal pouch (SP), a recently re-discovered anatomical structure within the human interatrial septum, has emerged as a possible source of thrombi formation and a trigger for atrial fibrillation, thereby potentially increasing the risk for ischemic stroke. In many studies, the swine interatrial septum has been used as model of the human heart. Also, possible new strategies and devices for management of the SPs may first be tested in this pig model. Therefore, in this study, we aimed to evaluate swine interatrial septum morphology and to compare it with the human analog, especially in the light of SP occurrence., Methods: A total of 75 swine (Sus scrofa f. domestica) hearts were examined. The interatrial septum morphology was assessed, and SPs were measured., Results: The most common variant of the interatrial septum was smooth septum (26.6%) followed by the patent foramen ovale channel and right SP (both 22.7%). No left or double SPs were observed. In 28.0% of all cases the fold of tissue (left septal ridge) was observed on the left side of the interatrial septum in the location where the left-sided SP should be expected. The mean length of the patent foramen ovale channel was 7.1±1.5mm. The mean right SP depth was 6.3±2.2mm, and its ostium width and height were 5.8±1.2 and 5.3±1.6mm, respectively., Conclusions: There are significant differences between human and porcine interatrial septum morphology that should be taken into account during experimental studies. The absence of the left SP in swine results in the inability to use porcine heart as an experimental model for left-sided SP management., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

Benign lipomatous lesion of the heart includes  an heterogeneous group of entities including neoplastic, congenital and reparative phenomena. Among these lipomas and lipomatous hypertrophy of the atrial septum ( LHIS) represent the most common lesion. Patients suffering from LHIS are often asymptomatic, however atrial fibrillation, congestive heart failure and supraventricular tachycardia are typical findings. Here we present a rare case of LHIS symptomatic  for asthenia and dyspnea.

Background: Subaortic septal myectomy is usually performed to mitigate obstruction in patients with the obstructive form of hypertrophic cardiomyopathy (HCM) or in those with congenital subaortic stenosis. Moreover, it is combined with aortic valve replacement in patients with severe aortic valve stenosis (SAS) and asymmetrical septal hypertrophy causing concomitant left ventricular outflow tract obstruction. When both conditions coexist, it is conceptually difficult to identify a cardiomyopathy beyond an adaptive myocardial hypertrophy, strictly related to pressure overload. Myectomy histopathology might be useful to enlighten the cause of the obstruction and establish the diagnosis., Aim: The aim was to describe the pathological findings of surgical septal myectomy specimens obtained from a group of patients with diverse clinical diagnosis, including HCM, severe aortic stenosis, and asymmetrical septal hypertrophy., Methods: This was a retrospective study of 56 patients undergoing septal myectomy along a 10-year period at a tertiary cardiac surgical center. Clinical, interventional, and anatomopathological findings between patients with and without a preoperative diagnosis of HCM were analyzed and compared., Results: Mean age at intervention was 67.5±20.5 years; 37 (66.1%) were female Preoperative diagnosis of sarcomeric obstructive HCM was assumed in 23 (41.1%) patients. All the other patients (58.9%) were referred for surgery with preoperative diagnosis of asymmetric septal hypertrophy, mainly in the context of severe aortic stenosis (24 patients). Twenty-seven (48.2%) patients had a greater than 30 mmHg intraventricular gradient at rest. Patients with presumed HCM were significantly younger (56.5±15.8 vs. 70.2±13.3 years, P<.001), had higher prevalence of significant intraventricular obstruction at rest [20 (87.0%) vs. 8 (34.8%), P<.001], and more frequently had moderate or severe mitral regurgitation [9 (39.1%) vs. 5(15.1%), P=.043]. All patients with aortic valve stenosis underwent both aortic valve replacement and septal myectomy. Twelve (52.1%) of the patients with obstructive HCM had isolated septal myectomy, while in the remaining 11, the procedure was combined with intervention on the mitral valve. Histopathological final diagnosis was of nonspecific reactive myocardial hypertrophy in all but 4 (92.2%) patients. In those, 2 (3.6%) had the final diagnosis of HCM and 2 (3.6%) the diagnosis of congenital subaortic membranous stenosis with reactive myocardial hypertrophy. Different grades of subendocardial fibroelastosis and myocardial fibrosis, mainly interstitial, were present [27 (48.2%) and 18 (32%) patients, respectively]. When microscopic data were compared between patients with or without a preoperative clinical diagnosis of HCM, no significant differences were found., Conclusion: In patients submitted to surgical septal myectomy, histology was mostly indistinctive among different clinical entities. Since different myocardial hypertrophy etiologies may share similar pathological expression, there is a need for detailed clinical assessment when trying to define the best strategy for clinical management., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background and purpose Previous studies have suggested that atrial septal aneurysm is a potential risk factor for cerebral embolism. However, the association between the level of atrial septal protrusion and cerebral embolism is still unclear. The purpose of the present study was to assess the association between the maximal distance of atrial septal protrusion and cryptogenic stroke. Methods A total of 588 consecutive acute ischemic stroke patients (70 ± 11 (mean ± SD) years, 401 men) who underwent transesophageal echocardiography were enrolled. The maximal distance of atrial septal protrusion into the right or left atrium was measured. Atrial septal aneurysm was diagnosed when the maximal distance of atrial septal protrusion was >10 mm. Cryptogenic stroke was defined as non-lacunar ischemic stroke without >50% proximal artery stenosis or occlusion, cardioembolic sources, ≥4 mm atherosclerotic plaques in the aortic arch, or carotid or vertebral artery dissection. Results The rate of cryptogenic stroke increased with the increasing maximal distance of atrial septal protrusion. The maximal distance of atrial septal protrusion (multivariate-adjusted odds ratio (OR) per 1 mm, 1.14; 95% confidence interval (CI), 1.04-1.24; P = 0.003) and atrial septal aneurysm (multivariate-adjusted OR, 4.32; 95% CI, 1.22-20.39; P = 0.022) was independently associated with cryptogenic stroke. Conclusions The maximal distance of atrial septal protrusion was independently associated with cryptogenic stroke.

The article discusses anatomical and clinical judgements on atrial septal aneurysm (ASA) as a primary cardiac structural abnormality. It presents current approaches to the classification of ASA and its echocardiographic diagnosis. Special attention is focused on the clinical significance of ASA as an isolated anomaly and concurrent with other structural abnormalities of the heart, especially from the standpoint of a risk of cardioembolic stroke.

Background: A significant proportion of ischemic strokes are cryptogenic. In this context, the clinical pertinence of patent foramen ovale (PFO) with and without atrial septum aneurysm (ASA) remains controversial. The aim of this study was to identify how PFO +/-ASA and cryptogenic stroke are associated in a representative sample of stroke patients., Methods: We enrolled all patients (n = 909) with ischemic stroke or transient ischemic attack admitted to the certified stroke unit or neurological intensive care unit of our university medical center who underwent transesophageal echocardiography (TEE) between 2012 and 2014. The baseline characteristics, cardio-/neurovascular risk factors, clinical parameters and TEE findings were analyzed., Results: PFO was present in 26.2%, and PFO was combined with an ASA in 9.9%. In cryptogenic stroke, the prevalence of PFO was higher compared to other etiologies (30.9 vs. 21.9%; p < 0.002). Patients with PFO had lower National Institute of Health Stroke Score (NIHSS) values at admission than those without (2 [0-5] vs. 3 [1-7]; p = 0.001; 95% CI [0.62-0.88]). No difference was found in NIHSS values of PFO patients with or without ASA (2 [0-5] vs. 2 [0-5]; p = 0.683; 95% CI 0.94 [0.68-1.28])., Conclusions: Our study indicates that a detected PFO +/-ASA could exhibit a stroke-relevant finding, if classical risk factors for the stroke were lacking., (© 2017 S. Karger AG, Basel.)

A 33-day-old infant with obstructed cor triatriatum sinister and partial anomalous pulmonary venous drainage presented with respiratory distress and fever. Her suprasystemic pulmonary hypertension was relieved by opening the connection to the right atrium using balloon atrial septoplasty and septostomy, and to the inferior chamber using balloon dilation of a fenestration in the dividing membrane. This enabled extubation and discharge, with elective surgical repair at 2 months. To our knowledge, this is the youngest patient to receive a catheter intervention for obstructed cor triatriatum sinister, providing relief of pulmonary hypertension and postponement of surgical repair., (Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: The atrial septal pouch (SP) is a new anatomical entity within the interatrial septum. The left-sided SP may be the source of thrombus and contribute to ischemic stroke. The aim of this study was to provide a detailed morphometric description of the SP., Methods: Two hundred autopsied hearts (23% deriving from females) with a mean age of 46.7±19.1years were investigated. We assessed the morphology of the interatrial septum. We obtained measurements and casts of the SPs, and we conducted histological staining of the left-sided SPs., Results: Patent foramen ovale was observed in 25% of hearts. We found a left SP in 41.5%, right in 5.5% and a double SP in 5.5% of hearts. We found the patent foramen ovale (PFO) more often in younger hearts, and the SP and smooth septum were more prevalently found in older hearts (p=.0023). The mean volume of the left-sided SP was 0.31±0.11ml, which represented 13.6±9.4% (range: 3.1-44.9%) of the left atrial appendage volume. The SP shape resembled a cone or a cylinder with some smaller diverticula originating from the main body. The SP free wall was composed of two layers of endocardium, transverse muscle fibers and connective tissue., Conclusions: A left-sided SP was present in 47% of individuals. The SP arises as a result of PFO channel closure. The anatomy of left-sided SP may promote blood stasis and thrombus formation. The universal formula for SP volume was calculated., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Lipomatous atrial septal hypertrophy (LASH) is a histologically benign cardiac lesion characterized by excessive fat deposition in the region of the interatrial septum that spares the fossa ovalis. The etiology of LASH remains unclear, though it may be associated with advanced age and obesity. Because of the sparing of the fossa ovalis, LASH has a pathognomonic dumbbell shape. LASH may be mistaken for various tumors of the interatrial septum. Histologically, LASH is composed of both mature and brown (fetal) adipose tissue, but the role of brown adipose tissue remains unclear. In interventional procedures requiring access to the left atrium, LASH may interfere with transseptal puncture, as traversing the thickened area can reduce the maneuverability of catheters and devices. This may cause the needle to enter the epicardial space, causing dangerous pericardial effusions. LASH was once considered a contraindication to percutaneous device closure of atrial septal defects because of an associated increased risk for incorrect device deployment. However, careful attention to preprocedural imaging and procedural intracardiac echocardiography enable interventional cardiologists to perform procedures in patients with LASH without serious complications. In this review article, the authors describe anatomic and functional aspects of LASH, with emphasis on their roles in percutaneous interventions., (Copyright © 2016 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)

Lipomatous hypertrophy of the interatrial septum (LHIS) is characterized by excessive accumulation of adipose tissue within some segments of the interatrial septum. Only one published case so far describes fever as a presenting feature of LHIS. On the other hand, systemic symptoms including anemia and fever are well-known clinical presentations of cardiac myxomas. We report an unusual case of a 79-year-old woman who was thoroughly but unsuccessfully investigated for recurrent fever and anemia in several specialized departments over the course of 4 years. Computed tomography scan showed a pathological mass localized in the interatrial septum and spreading to ascending aorta. Histological analysis of the biopsy samples from surgery revealed the unexpected diagnosis of regressively changed LHIS. We discuss the clinical and pathologic features of this lesion suggesting that its regressive changes may be associated with inflammation and can cause systemic symptoms such as fever and anemia., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Patent foramen ovale (PFO) is the most common congenital heart abnormality of fetal origin and is present in approximately ∼25% of the worldwide adult population. PFO is the consequence of failed closure of the foramen ovale, a normal structure that exists in the fetus to direct blood flow directly from the right to the left atrium, bypassing the pulmonary circulation. PFO has historically been associated with an increased risk of stroke, the mechanism of which has been attributed to the paradoxical embolism of venous thrombi that shunt through the PFO directly to the left atrium. However, several studies have failed to show an increased risk of stroke in asymptomatic patients with a PFO, and the risk of stroke recurrence is low in patients who have had a stroke that may be attributed to a PFO. With the advent of transoesophageal and transthoracic echocardiography, as well as transcranial Doppler, a PFO can be routinely detected in clinical practice. Medical treatment with either antiplatelet or anticoagulation therapy is recommended. At the current time, closure of the PFO by percutaneous interventional techniques does not appear to reduce the risk of stroke compared to conventional medical treatment, as shown by three large clinical trials. Considerable controversy remains regarding the optimal treatment strategy for patients with both cryptogenic stroke and PFO. This Primer discusses the epidemiology, mechanisms, pathophysiology, diagnosis, screening, management and effects on quality of life of PFO.

We report herein a case of benign cardiac schwannoma in the interatrial septum. A 42-year-old woman was transferred from a clinic because of cardiomegaly as determined by chest X-ray. A transthoracic echocardiography and chest computed tomography examination revealed a huge mass in the pericardium compressing the right atrium, superior vena cava (SVC), left atrium, and superior pulmonary vein. To confirm that the tumor originated from either heart or mediastinum, cine magnetic resonance imaging was performed, but the result was not conclusive. To facilitate surgical planning, we used 3D printing. Using a printed heart model, we decided that tumor resection under cardiopulmonary bypass (CPB) through sternotomy would be technically feasible. At surgery, a huge tumor in the interatrial septum was confirmed. By incision on the atrial roof between the aorta and SVC, tumor enucleation was performed successfully under CPB. Pathology revealed benign schwannoma. The patient was discharged without complication. 3D printing of the heart and tumor was found to be helpful when deciding optimal surgical approach.

Lipomatous hypertrophy of the interatrial septum (LHIS) is an uncommon cause of superior vena cava syndrome (SVCS). Fibrosing mediastinal lymphadenopathy is another cause of SVCS. We present a 65-year-old female patient with a history of tuberculosis (TB) and the coexistence of LHIS and fibrosing mediastinitis due to TB of the lung. Fibrosing or sclerosing mediastinitis is a rare entity with few cases published in the western literature. She presented with mild symptomatology of SVCS and she underwent on transthoracic and transesophageal echocardiography, computed tomography scan, magnetic resonance imaging, and venography. Due to the development of an abundant collateral venous system seen on venography and her negation for any treatment, she did not undergo yet on any intervention. To our knowledge, this is the first case reported in the international bibliography in which LHIS and sclerosing lymphadenopathy are simultaneously diagnosed in the same patient.