Search

In humans, septal defects are among the most prevalent congenital heart diseases, but their cellular and molecular origins are not fully understood. We report that transcription factor Tbx5 is present in a subpopulation of endocardial cells and that its deletion therein results in fully penetrant, dose-dependent atrial septal defects in mice. Increased apoptosis of endocardial cells lacking Tbx5, as well as neighboring TBX5-positive myocardial cells of the atrial septum through activation of endocardial NOS (Nos3), is the underlying mechanism of disease. Compound Tbx5 and Nos3 haploinsufficiency in mice worsens the cardiac phenotype. The data identify a pathway for endocardial cell survival and unravel a cell-autonomous role for Tbx5 therein. The finding that Nos3, a gene regulated by many congenital heart disease risk factors including stress and diabetes, interacts genetically with Tbx5 provides a molecular framework to understand gene-environment interaction in the setting of human birth defects.

Lipomatous hypertrophy of the interatrial septum is a rare benign pathology characterized by fatty deposits in the septum and is mostly diagnosed incidentally. This accumulation mostly causes a globular thickening of the interatrial septum, commonly sparing the fossa ovalis. We report on a 65-year-old female patient who underwent successful transcatheter closure of atrial septal defects (ASD) accompanied by lipomatous hypertrophy of the septum. Both transthoracic and transesophageal echocardiography showed enlargement of the right heart cavities, thickening of the interatrial septum (16 mm) with bright echogenicity, and two separate secundum ASDs measuring 17 mm and 4 mm, respectively. Transcatheter closure of the defects was performed using a 24-mm Amplatzer septal occluder. There was no residual shunt and Holter monitoring was normal after the procedure. During a three-year follow-up, no complications were observed pertaining to the procedure or lipomatous tissue.

A 52-year-old man with left atrial tachycardia underwent radiofrequency catheter ablation. A steerable 4-mm-tip ablation catheter was advanced into the left atrium through a patent foramen ovale without transseptal puncture. However, the tip of the catheter was stuck in a structure. A pull-back maneuver rendered the catheter free and the procedure was cancelled. Transthoracic and transesophageal echocardiograms obtained immediately after the procedure showed intimal layer dissection in the interatrial septum and intramural hematoma formation throughout the anterior left atrial wall. The patient was in stable condition. Therefore, he was followed-up conservatively with serial echocardiographic examinations. The dissected intimal layer disappeared in 10 days and the hematoma underwent near-complete resolution in three months. This case highlights a rare complication of catheter ablation procedure that all interventionists should be familiar with.

Atrial arrhythmias can occasionally be associated with atrial structural abnormalities that may require sophisticated diagnostic imaging for management. Lipomatous hypertrophy of the intraatrial septum is generally considered a benign fatty infiltrative process usually limited to the atrial septum. We present a rare case of lipomatous hypertrophy of the intraatrial septum associated with atrial flutter and right atrial inflow obstruction in which atrial reconstruction alleviated not only the obstruction but also helped control a challenging arrhythmia., (Copyright (c) 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

We report a case of a 70-year-old woman admitted with symptoms of decompensated heart failure. Magnetic resonance imaging revealed lipomatous hypertrophy of the interatrial septum with partial upper right atrial inflow obstruction, partial obstruction of the right ventricular outflow tract, and excessive accumulation of adipose tissue in the pericardial space. The patient underwent excision of the septal lipomatous mass, which relieved the right ventricular outflow obstruction.

Background: The primary objective of this study was to develop an image-guided, noninvasive procedure to create or enlarge an atrial septal defect for the treatment of neonates with hypoplastic left heart syndrome and an intact or restrictive atrial septum. Histotripsy is an innovative ultrasonic technique that produces nonthermal, mechanical tissue fractionation through the use of high-intensity ultrasound pulses. This article reports the pilot in vivo study to create an atrial septal defect through the use of extracardiac application of histotripsy in an open-chest canine model., Methods and Results: In 10 canines, the atrial septum was exposed to histotripsy by an ultrasound transducer positioned outside the heart. Ultrasound pulses of 6-microsecond duration at a peak negative pressure of 15 MPa and a pulse repetition frequency of 3.3 kHz were generated by a 1-MHz focused transducer. The procedure was guided and monitored by real-time ultrasound imaging. In 9 of 10 canines, an atrial septal defect was produced, and shunting across the atrial septum was visualized. Pathology of the hearts showed atrial septal defects with minimal damage to surrounding tissue. No damage was found on the epicardial surface of the heart or other structures., Conclusions: Under real-time ultrasound guidance, atrial septal defects were successfully created with extracardiac histotripsy in a live canine model. Although further studies in an intact animal model are needed, these results provide promise of histotripsy becoming a valuable clinical tool.

Patent foramen ovale (PFO) occurs in up to 30% of the population, making it the most common site for intra-cardiac shunting. The passage of thrombus across a PFO is typically transient, thus is rarely proven. We describe a rare case of a 79-year-old man with thrombus entrapped across a PFO providing a source for ongoing pulmonary and systemic thromboembolism, despite systemic anticoagulation. There is a paucity of literature to guide primary management of this condition. Management options include surgical thrombectomy with PFO closure, thrombolysis and systemic anticoagulation. The role of percutaneous PFO closure devices for secondary prevention of thromboembolic complications is currently under investigation., (Copyright (c) 2009. Published by Elsevier B.V.)

In order to study anatomical and functional characteristics of patent foramen ovale (PFO) in patients with cryptogenic stroke and with other stroke subtypes we examined 56 stroke patients (male--35, female--21, age 46.7 +/- 16.5 years) with PFO and ischemic stroke. Diagnosis of PFO was made by transesophageal echocardiography (TEE), contrast transcranial Doppler monitoring (C-TCD), contrast transthoracic echocardiography (C-TTE). Group 1 was made up of patients with definite stroke cause (cardioembolic, lacunar, atherotrombotic) (n=40), and group 2--of patients with cryptogenic stroke (n=16). Patients in group 2 were younger than patients in group 1 (38.7 +/- 13.4 and 50.4 +/- 16.5 years, p < 0.05) and had slight neurological symptoms. These patients also more frequently had avalvular, or "window-like" anatomic types of PFO (2 [13%] and 4 [27%] patients, respectively), combination of large anatomic size (3 mm and larger) and functional level of PFO (3 degree of the right-to-left shunt by C-TCD) (p < 0.05).

Background: Patent foramen ovale (PFO) has been investigated in several conditions apart from cryptogenic ischemic stroke. Contrast transesophageal echocardiography (cTEE) is the gold standard for the diagnosis, although it has some known limitations. Contrast transcranial Doppler (cTCD) allows a semiquantitative estimation of right-to-left shunt (RLS) volume. The aims of our study were to confirm the diagnostic accuracy of cTCD in PFO diagnosis and to compare the abilities of cTCD and cTEE to detect a RLS and PFO, respectively, under normal breathing. The latter could represent an important feature for its clinical significance., Methods: A total of 100 consecutive patients (59 women and 41 men, age 46 +/- 12 years) were evaluated after stabilized ischemic stroke/transient ischemic attack, migraine, and lacunae, and before neurosurgery in sitting position. All patients undertook cTEE and cTCD, at rest and under Valsalva maneuver (VM). cTEE under VM was the reference standard. A categorization of patients and a semiquantitative cTCD classification were proposed., Results: In all, 63 of 100 patients had PFO diagnosed by cTEE. A general concordance of up to 90% between both techniques was found. cTCD sensitivity and specificity were 96.8% and 78.4%, respectively. In 17 of 100 patients with cTEE-proven PFO under VM, cTCD and cTEE detected RLS at rest in 75% (95% confidence interval [CI] 62%-85%) and 48% (95% CI 35%-61%) of cases, respectively (P < .001). cTEE disclosed RLS at rest in about 71% (95% CI 9%-42%) of cTCDs showing a "shower-curtain" pattern and only in about 22% (95% CI 52%-85%) of those cTCDs without that pattern., Conclusions: In diagnosing PFO, cTCD has a good accuracy compared with cTEE. To detect a RLS at rest, cTCD appears to be more sensitive than cTEE. The latter resulted positive under normal breathing, mostly in cases of significant RLS at cTCD. Our results point out the impact of cTCD in the evaluation of RLS volume, thus aiding, in association with the anatomic details by cTEE, in the prevention of the occurrence or recurrence of paradoxical embolism in individuals with and without cerebrovascular diseases. The combination of cTEE and cTCD could be considered the real gold standard for PFO in the near future.

Atrial septal defects are a common congenital heart defect in humans. Although mutations in different genes are now frequently being described, little is known about the processes and mechanisms behind the early stages of atrial septal development. By utilizing morpholino-induced knockdown in the chick we have analysed the role of alpha myosin heavy chain during early cardiogenesis in a temporal manner. Upon knockdown of alpha myosin heavy chain, three different phenotypes of the atrial septum were observed: (1) the atrial septum failed to initiate, (2) the septum was initiated but was growth restricted, or (3) incorrect specification occurred resulting in multiple septa forming. In addition, at a lower frequency, decreased alpha myosin heavy chain was found to give rise to an abnormally looped heart or an enlarged heart. Staining of the actin cytoskeleton indicated that many of the myofibrils in the knockdown hearts were not as mature as those observed in the controls, suggesting a mechanism for the defects seen. Therefore, these data suggest a role for alpha myosin heavy chain in modelling of the early heart and the range of defects to the atrial septum suggest roles in its initiation, specification and growth during development.

Management of cardiac tumours depends mainly on their localisation and histological type. Cardiac magnetic resonance (CMR) imaging is a robust technique in diagnosis of cardiac tumors. It enables precise localisation of a mass and its tissue characteristics. We present a case of a lipomatous hypertrophy of the interatrial septum diagnosed by CMR.

Lipomatous hypertrophy of the interatrial septum is generally a benign disorder characterized by lipid accumulation in the interatrial septum. A 56-year-old asymptomatic woman with a history of hypertension and hyperlipidemia was referred to echocardiographic examination. Transthoracic echocardiography showed left ventricular hypertrophy, normal left ventricular systolic function, and left ventricular relaxation disturbance. The apical four-chamber view showed a hyperechogenic mass in the interatrial septum. Lipomatous hypertrophy was suspected and transesophageal echocardiography was performed. A dumbbell-shaped hypertrophy of 22 mm thickness was noted in the interatrial septum, which did not involve the fossa ovalis. There was no decrease in flow velocities of the superior and inferior vena cava nor a flow disturbance in the pulmonary veins. Cardiac magnetic resonance imaging showed lipomatosis and thickening in the interatrial septum and subepicardial region.

Primary cardiac tumors are rare and are diverse in histology and anatomic origin. Approximately 75% are benign, and nearly 50% of these are myxomas. Herein, we report concurrent myxoma and papillary fibroelastoma, which tumors were found attached to the left atrial septum and aortic valve, respectively. Concurrent primary cardiac tumors of differing histology and origin are rare, and, to our knowledge, this is one of the few such cases reported in the medical literature.

Hypoplastic left heart syndrome (HLHS) with intact atrial septum (IAS) is a severe congenital cardiac malformation with little possibility of postnatal survival, unless an intra-atrial connection is created promptly after delivery. The timing of that intervention is often dictated by logistic restrictions, such as the proximity of the delivery room to the cardiac catheterization laboratory. This report details the use of a hybrid cardiac catheterization suite to expedite the delivery, transfer, and initial treatment of a fetus with HLHS/IAS. The mother underwent cesarean delivery in one hybrid room, and the newborn infant was transferred directly into an adjoining room where successful atrial septal stenting was performed without delay via a percutaneous, transhepatic approach., (Copyright 2008 Wiley-Liss, Inc.)

Platypnea orthodeoxia is a rare syndrome that describes breathlessness on standing that resolves on lying flat. We present a previously healthy patient who developed platypnea orthodeoxia in her eighth decade of life. Cardiovascular imaging demonstrated an atrial septal defect, extensive Chiari network and atrial septal hypertrophy. We propose the development of lipomatous atrial septal hypertrophy led to altered atrial compliance and a baffle to direct flow preferentially to the left heart on standing.

We present the echocardiographic images of a patient with transient ischaemic attack with double atrial septum and persistent interatrial space as probable source of thrombus. A patent foramen ovale could be excluded and a communication between left atrium and interatrial space could be demonstrated.

Background: Technical developments in the management of atrial arrhythmias revived interest into the detailed knowledge of atrial anatomy. The atrial septum (AS), known for its complex structure, has been particularly difficult to study, and our knowledge of the muscular bundles providing routes for intra-atrial and interatrial conduction within the AS remains limited., Objective: The purpose of this study was to describe myocardial arrangement within the AS and adjacent parts of atrial walls for delineation of possible substrates for interatrial and intra-atrial conduction., Methods: Human heart specimens from 84 postmortem studies were studied using conventional morphometric assessment, blunt dissection, and light microscopy of serial histological sections of AS., Results: Interatrial muscular connections are present anteriorly, posteriorly between right pulmonary veins, and inferiorly between the coronary sinus and the right inferior pulmonary vein. The inferior connections can be more prominent than the Bachmann bundle. Atrial musculature in the fossa ovalis consists of muscular bands isolated by fatty tissue from the endocardium of the right and left atrium. They are arranged along the anterior-posterior axis and have connections with left atrial myocardium. Myocardial fascicles in the posterior-inferior and superior portions of the muscular rim of fossa ovalis originate on the right atrial side and can be traced toward the atrioventricular node., Conclusion: The general myocardial arrangement in the AS and adjacent regions of atrial walls are important for understanding propagation of atrial activation for selection of the optimal treatment strategy.

Background: Atrial septal defect (ASD) flow can be measured indirectly by velocity-encoded cardiovascular magnetic resonance (veCMR) of the pulmonary artery and aorta. Imaging the secundum ASD en face could potentially enable direct flow measurement and provide valuable information about ASD size, shape, location, and proximity to other structures., Methods and Results: Forty-four patients referred for possible transcatheter ASD closure underwent a comprehensive standard evaluation, including transesophageal and/or intracardiac echocardiography and invasive oximetry. CMR was performed in parallel and included direct en face veCMR after an optimal double-oblique imaging plane was determined that accounted for ASD flow direction and cardiac-cycle interatrial septal motion. ASD flow measured by direct en face veCMR correlated better with invasive oximetry than indirect (pulmonary artery and aorta) veCMR (r=0.80 versus r=0.66). Additionally, 95% limits of agreement were narrower (+/-3.9 versus +/-5.1 L/min). En face veCMR determined that defects usually were eccentrically shaped (major/minor axis length >1.5) rather than circular, with 16% having extreme eccentricity (major/minor >2.0). Overall, ASD size by both veCMR and intracardiac echocardiography correlated with final device size; however, in small to medium defects (<3 cm(2)) and extremely eccentric defects, veCMR correlated better with final device size than did intracardiac echocardiography. Importantly, CMR identified additional information in 9 patients (20%) that altered clinical management. Specifically, en face veCMR detected additional defects (n=3), large ASD with insufficient rim tissue (n=2), and sinus venosus defect with anomalous pulmonary vein (n=1). Cine and/or morphological imaging detected interrupted inferior vena cava (n=2) and sinus of Valsalva aneurysm (n=1)., Conclusions: En face veCMR with an optimized imaging plane can determine ASD flow, size, and morphology. CMR provided information incremental to comprehensive standard evaluation that altered clinical management in 20% of patients.

Understanding of right ventricular (RV) remodeling is needed to elucidate the mechanism of RV dysfunction in the overloaded right ventricle, but is hampered by the chamber's complex shape. We imaged 15 patients with repaired tetralogy of Fallot (TOF) and 8 normal subjects by magnetic resonance imaging in long- and short-axis views. We reconstructed the right ventricles in 3 dimensions using the piecewise smooth subdivision surface method. Shape was analyzed from cross-sectional contours generated by intersecting the right ventricle with 20 planes evenly spaced from apex to tricuspid annulus. Patients with TOF had dilated right ventricles compared with normal (end-diastolic volume index 216 +/- 99 vs 81 +/- 16 ml/m(2), p <0.001) but near-normal function (ejection fraction 40 +/- 9% vs 48 +/- 12%, respectively, p = NS). RV shape in patients with TOF differed from normal subjects in several ways. First, the right ventricle had a larger normalized cross-sectional area in patients with TOF (p <0.01 in apical planes). Second, the cross-sectional shape was rounder in patients with TOF (p <0.05 in apical planes). Also, the interventricular septum underwent relatively less enlargement so that it comprised only 27 +/- 4% of total RV surface area in patients with TOF, compared with 33 +/- 2% in normal subjects (p = 0.0001). In addition, the right ventricle in patients with TOF exhibited bulging basal to the tricuspid valve (4 +/- 4% of total RV length), unlike normals (1 +/- 2%, p <0.001). This basal bulging was amplified by tilting of the tricuspid annulus (29 +/- 11 degrees vs 15 +/- 7 degrees , respectively, p <0.005). In conclusion, the right ventricle remodels in several directions rather than following a shape continuum. Characterization of RV remodeling from 3-dimensional reconstructions provides novel insights.

Background: Clinical practice is discrepant regarding routine enlargement of the interatrial communication (IAC) in patients with right-sided atrioventricular valve atresia. We determined the percentage and risk factors of those who develop a restrictive IAC., Methods: Medical records were reviewed for patients treated from 1985 to 2006, including those admitted in the first 6 weeks of life (group A), and those referred at a later age (group B), some of whom had routine atrial septal procedures. In group A, we analyzed the initial postnatal echocardiogram., Results: Group A consisted of 79 patients, 16 of whom had an atrial septectomy as part of the initial surgical procedure. Of the remaining 63 patients, 9 (14%) developed atrial septal restriction. In group A, an atrial septal aneurysm (ASA) (OR 16, P = .006) and IAC diameter < 5 mm (OR 13, P = .009) were associated with atrial septal restriction. Atrial septal restriction occurred in 80% of patients with both features, 20% with IAC > or = 5 mm and ASA, 18% with IAC < 5 mm and no ASA, and 2% with neither feature. Group B consisted of 95 patients, 27 of whom had an atrial septal procedure. Of the remaining 68 patients, 11 (16%) developed atrial septal restriction., Conclusion: Routine enlargement of the IAC is not necessary in patients with right-sided atrioventricular valve atresia. Patients with ASA or IAC < 5 mm are at increased risk for development of atrial septal restriction.

Lipomatosis of interatrial septum is a rare benign disorder characterized by fat accumulation into interatrial septum. It may cause atrial arrhythmias and hemodynamic complications. For this reason, it should be considered in differential diagnosis of other cardiac masses. We report the typical case of lipomatosis of interatrial septum and atrial flutter.

The objective of the study was to assess differences in proportion of large right-to-left shunt (RLS) and atrial septal characteristics between migraineurs and non-migraineurs referred for transcatheter closure of patent foramen ovale (PF0). This retrospective study took place in a large metropolitan medical centre. The patients were migraineurs with aura (n=52), migraineurs without aura (n=19) and non-migraineurs (n=149). RLS was evaluated before closure using bilateral power m-mode transcranial Doppler at rest and after calibrated, sustained Valsalva manoeuvre, and graded with a validated 0-5 scale. Intracardiac echocardiography was used to assess atrial septal characteristics. Migraineurs had a higher proportion of large RLS (Grade IV or V) than nonmigraineurs at rest and after calibrated Valsalva (rest, p=0.04; Valsalva, p=0.01). Atrial septal characteristics were similar between groups. Migraine is associated with larger RLS at rest and strain; however migraine status does not predict PFO characteristics.