Double-chambered right ventricle: a review

Effect of deletion of the protein kinase PRKD1 on development of the mouse embryonic heart

Congenital heart disease (CHD) is the most common congenital anomaly, with an overall incidence of approximately 1% in the United Kingdom. Exome sequencing in large CHD cohorts has been performed to provide insights into the genetic aetiology of CHD. This includes a study of 1891 probands by our group in collaboration with others, which identified three novel genes-CDK13, PRKD1, and CHD4, in patients with syndromic CHD. PRKD1 encodes a serine/threonine protein kinase, which is important in a variety of fundamental cellular functions. Individuals with a heterozygous mutation in PRKD1 may have facial dysmorphism, ectodermal dysplasia and may have CHDs such as pulmonary stenosis, atrioventricular septal defects, coarctation of the aorta and bicuspid aortic valve. To obtain a greater appreciation for the role that this essential protein kinase plays in cardiogenesis and CHD, we have analysed a Prkd1 transgenic mouse model (Prkd1em1) carrying deletion of exon 2, causing loss of function. High-resolution episcopic microscopy affords detailed morphological 3D analysis of the developing heart and provides evidence for an essential role of Prkd1 in both normal cardiac development and CHD. We show that homozygous deletion of Prkd1 is associated with complex forms of CHD such as atrioventricular septal defects, and bicuspid aortic and pulmonary valves, and is lethal. Even in heterozygotes, cardiac differences occur. However, given that 97% of Prkd1 heterozygous mice display normal heart development, it is likely that one normal allele is sufficient, with the defects seen most likely to represent sporadic events. Moreover, mRNA and protein expression levels were investigated by RT-qPCR and western immunoblotting, respectively. A significant reduction in Prkd1 mRNA levels was seen in homozygotes, but not heterozygotes, compared to WT littermates. While a trend towards lower PRKD1 protein expression was seen in the heterozygotes, the difference was only significant in the homozygotes. There was no compensation by the related Prkd2 and Prkd3 at transcript level, as evidenced by RT-qPCR. Overall, we demonstrate a vital role of Prkd1 in heart development and the aetiology of CHD.

Use of combined cutting balloon and high-pressure balloon technique for the treatment of double-chambered right ventricle or primary infundibular stenosis: a case series

Five dogs and two cats with a diagnosis of double-chambered right ventricle or primary infundibular stenosis were referred to undergo a combined cutting balloon and high-pressure balloon technique. At admission five cases were asymptomatic, one had a history of syncope and one had signs of right-sided congestive heart failure. Each patient underwent a complete transthoracic echocardiogram, thoracic radiographs, an angiogram and the combined interventional procedure. Median diameter of the right mid-ventricular stenosis was 4 mm (range 2-8.7 mm) in dogs, and it measured 1.9 and 2 mm in cats. Under general anesthesia initial dilation with an 8-mm × 2-cm cutting balloon was performed from a left external jugular vein approach followed by dilation with a high-pressure balloon (1.5:1 balloon diameter-right outflow tract diameter ratio). In one dog and the two cats the procedure was not completed due to technical issues. In the other four dogs the median intracavitary proximal chamber pressure decreased from 100 mmHg (range 70-150 mmHg) before the procedure to 57 mmHg (range 45-70 mmHg) post-dilation. Long-term follow-up (from six months to two years) showed complete or partial reverse remodeling of the proximal chamber with a median residual pressure gradient below 80 mmHg (range 46-75 mmHg) for all four dogs. This case series shows that this procedure should be considered in dogs with right ventricular outflow tract obstruction. In cats, the procedure might be feasible, if additional guidewire inventory were available.

Double-Chambered Right Ventricle in Adulthood: A Case Series

•DCRV is a rare cardiac anomaly leading to subvalvular RVOT obstruction. •DCRV is most frequently found in children but can occur in adults. •Adults with DCRV are often initially misdiagnosed. •Echocardiography is the first-line imaging modality to visualize this anomaly. •Providers should be aware of this condition and the associated image findings.

Double-Chambered Right Ventricle Presenting in Adulthood With Aortic and Pulmonic Valve Endocarditis

A 55-year-old woman admitted with symptoms of right heart failure received a diagnosis of double-chambered right ventricle and a ventricular septal defect with aortic and pulmonic valve endocarditis. This case highlights the use of multimodality imaging and importance of adult congenital heart disease expertise in the diagnosis and treatment of such patients. (Level of Difficulty: Intermediate.).

A case series of double-chambered left ventricle detected by cardiovascular magnetic resonance

Background

Double-chambered left ventricle (DCLV) is a rare congenital condition, and few case reports are mentioned in literature. Entity, clinical course, and prognosis remain unclear. Cardiovascular magnetic resonance (CMR) is often used for characterization of various congenital heart diseases and can be particularly useful for imaging rare phenomena.

Case summary

Three cases of DCLV were detected by CMR within 2 years in our CMR centre with and without associated congenital heart disease or hypertrabecularization. The patients did not suffer from cardiac symptoms despite the presence of premature ventricular complexes in one patient. Diagnosis of DCLV was made based on a first CMR study that was performed in adulthood, although some anatomical suspicion was already raised by previous echocardiography.

Discussion

Double-chambered left ventricle, synonymous with the terminus 'cor triventriculare sinistrum', has been previously perceived as a rare phenomenon compared with double-chambered right ventricle. It has to be distinguished from ventricular aneurysm or cardiac diverticulum and is characterized by an additional contractile septum with normal wall structure that divides the LV cavum into two (rather) same-sized chambers. The prognosis seems to be benign, since there is no restriction in functionality and no increased thrombogenicity until adulthood. Consequently, there is (presumably) no need for a tailored therapy-at least in the cases present here. Accordingly, we recommend follow-up CMR examinations for progress monitoring and recognize CMR's significant role for diagnosis and follow-up of cardiac abnormalities in orphan diseases. Due to its broader availability, we expect further cases of DLVC in the future.

Double-chambered left ventricle: diagnosis by CMR and review of the literature

BACKGROUND

A double-chambered left ventricle (DCLV) is an extremely rare congenital malformation. The exact prevalence of DCLV is not known, although studies have reported prevalence of 0.04-0.42%. This abnormality is characterized by the sub-division of left ventricle into two chambers, the main left ventricular chamber (MLVC) and the accessory chamber (AC) by a septum or muscle band.

CASE PRESENTATION

We are reporting two cases of DCLV, one in an adult male and an infant, who were referred for undergoing cardiac magnetic resonance (CMR) imaging. The adult patient was asymptomatic, whereas the infant had the diagnosis of left ventricular aneurysm on fetal echocardiography. On CMR, we confirmed the diagnosis of DCLV in both patients, as well as moderate aortic insufficiency in the adult patient. Both patients were lost to follow-up.

CONCLUSIONS

The double-chambered left ventricle (DCLV) is commonly detected in infancy or childhood. Although echocardiography can help detect double-chambered ventricles, MRI provides a better knowledge of this problem and can also be used to diagnose other related heart disorders.

An elderly case of aortic stenosis associated with double-chambered right ventricle

Double-chambered right ventricle (DCRV) caused by right ventricular outflow tract obstruction, is a developmental cardiac anomaly in which the anomalous muscle bundles divide the right ventricular cavity into two chambers. Few cases with DCRV coexisting with severe aortic stenosis (AS) have been reported. Moreover, adult cases are extremely uncommon.We report an elderly case of a heavy DCRV with severe AS detected by transthoracic echocardiography and catheterization study. An 85-year-old woman with dyspnea on effort and right-sided heart failure was diagnosed with DCRV and severe AS by echocardiography. She underwent a resection of the anomalous muscle of the right ventricle and aortic valve replacement. Her symptoms disappeared postoperatively and was discharged home. At 2 years postoperatively, she was generally well without recurrence of DCRV. In conclusion, the case of DCRV with AS is rare and surgery is useful to relieve the heart failure symptoms and improve the prognosis of both young and adult patients.

Learning objective

Double-chambered right ventricle (DCRV) is uncommon in the older population; however, clinicians should consider DCRV in patients with right-sided heart failure as a differential diagnosis. The case of DCRV with aortic stenosis is rare, surgical treatment is particularly useful for these patients to relieve the heart failure symptoms and improve the prognosis in young and adult cases.

Case report: Double-chambered right ventricle diagnosed in a middle-aged female with hypertrophic cardiomyopathy and atrial flutter: A rare case

Double-chambered right ventricle (DCRV) is a rare congenital heart defect in adults, manifesting with progressive right ventricular outflow tract obstruction. We describe the first case of DCRV coexisting with hypertrophic cardiomyopathy, which is complicated by atrial flutter. A middle-aged woman with recurrent symptomatic atrial flutter who had previously been diagnosed with biventricular hypertrophic cardiomyopathy was admitted to our department. Echocardiography and cardiac magnetic resonance revealed asymmetrical interventricular septal hypertrophy, and abnormal muscle bundles within the right ventricle, generating an obstructive gradient. Genetic testing detected a hypertrophic cardiomyopathy-associated mutation: MYH7, c.4135G > A, p. Ala1379Thr. A diagnosis of DCRV complicated by hypertrophic cardiomyopathy and atrial flutter was made. Surgical intervention was performed, which included radiofrequency ablation, removal of abnormal muscle bundles, and ventricular septal defect repair. Intraoperative transesophageal echocardiography demonstrated the well-corrected right ventricular outflow tract. Free of early postoperative complications, the patient was discharged in sinus rhythm on the 11th day after the surgery. Unfortunately, the patient died from a sudden death 38 days following the surgery. In conclusion, the coexistence of DCRV with hypertrophic cardiomyopathy in patients is an uncommon condition. The present case highlights the importance of diagnostic imaging in the management of this disorder.

An extremely rare association of coarctation of aorta with double chambered right ventricle: double-trouble causing bi-ventricular failure in a child

Double chambered right ventricle is a rare cardiac defect characterised by an obstructive hypertrophied muscle bundle in the right ventricle. The common associated lesions are ventricular septal defect followed by sub-aortic membrane. We report a child who had coarctation of aorta in association with double chambered right ventricle. This case is being reported for its rarity and challenges in management.

A six-chambered heart: cor triatriatum sinister with double-chambered right ventricle in association with ventricular septal defect

Background

Cor triatriatum has been described as a heart with three atria in which the left atrium (cor triatriatum sinistrum) or right atrium (cor triatriatum dextrum) is divided into two compartments by a fold of tissue, a membrane, or a fibromuscular band. Double-chambered right ventricle, on the other hand, is identified by the presence of an anomalous muscle bundle dividing the right ventricle into two chambers.

Case presentation

Here, we describe the case of a child who had a combination of both of these rare entities, effectively creating a heart with six chambers. The child underwent a successful intracardiac repair.

Conclusions

The association of CTS with DCRV forming a “6-chambered heart” is extremely rare. Awareness of its existence and accurate preoperative diagnosis has important implications in its surgical repair with all the components of this disease spectrum, further increasing the complexity of a successful surgical repair.

Anomalous right ventricular muscle bands obstructing a large apical muscular ventricular septal defect: From fetal to post-natal three-dimensional assessment

Anomalous right ventricle muscle bands and apical ventricular septal defect are two anomalies sometimes associated. We report a fetal diagnosis of a large apical ventricular septal defect, right intraventricular obstruction caused by anomalous muscle bands; consequently, the high right intraventricular pressure resulted in a right-to-left bulging of ventricular septum and moderate tricuspid regurgitation. Postnatal echocardiogram confirmed the fetal diagnosis and defined accurately the right ventricular anatomy through the three-dimensional echocardiographic assessment.

Diversity and determinants of the sigmoid septum and its impact on morphology of the outflow tract as revealed using cardiac computed tomography

BACKGROUND

The sigmoid septum has been generally evaluated subjectively and qualitatively, without detailed examination of its diversity, impact on the morphology of the left ventricular outflow tract (LVOT), and anatomical background.

METHODS

We enrolled 100 patients without any background cardiac diseases (67.5 ± 12.8 years old; 43% women) who underwent cardiac computed tomography. Basal septal morphology was evaluated using antero-superior and medial bulging angles (bidirectional angulation of the basal septum relative to the LVOT). The eccentricity index of the LVOT, area narrowing ratio (LVOT/virtual basal ring area), aortic-to-left ventricular axial angle (angulation of the aortic root relative to the left ventricle), and wedged height (non-coronary aortic sinus to inferior epicardium distance) were also quantified.

RESULTS

The antero-superior bulging, medial bulging, aortic-to-left ventricular axial angles, LVOT eccentricity index, area narrowing ratio, and wedged height were 76° ± 17°, 166° ± 27°, 127° ± 9°, 1.8 ± 0.5, 1.0 ± 0.2, and 41.2 ± 9.1 mm, respectively. Both bulging angles were correlated with each other and contributed to the narrowing and deformation of the LVOT. Angulated aortic root was not correlated with either bidirectional septal bulge or LVOT narrowing. Clockwise rotation of the aortic root rotation was an independent predictor of prominent antero-superior septal bulge. Deeper aortic wedging was a common independent predictor of bidirectional septal bulge.

CONCLUSIONS

The extent of septal bulge varies in normal hearts. Along with deep aortic wedging, the bidirectional bulge of the basal septum deforms and narrows the LVOT without affecting the virtual basal ring morphology.

Concomitant surgery for double-chambered right ventricle and coronary stenosis

BACKGROUND AND AIMS

The clinical data of coronary artery disease in patients with double-chambered right ventricle are limited. We report an adult double-chambered right ventricle case with three-vessel coronary artery disease that was successfully treated with concomitant double-chambered right ventricle repair and coronary artery bypass grafting.

MATERIALS AND METHODS

The patient case data was extracted from hospital records.

RESULTS

The patient was the case of a 60-year-old man with a double-chambered right ventricle and three-vessel coronary artery disease. He underwent concomitant surgery comprising double-chambered right ventricle repair and coronary artery bypass grafting. Achieving cardiac arrest allowed us to obtain a good surgical view of the heavy and severely hypertrophied heart. Postoperative computed tomography revealed a feasible running course of the sequential graft, indicating that the path of the sequential graft should be clockwise (aorto-right coronary-left circumflex artery) in this unusual anatomical condition.

DISCUSSION AND CONCLUSION

We report this rare disease combination and highlight the need for careful preoperative planning in such cases.

Double-chambered right ventricle masquerading as bipartite right ventricle

A 10-day-old neonate with pulmonary consolidation was referred for echocardiography to rule out CHD. At first glance, the morphology appeared to be a bipartite right ventricle with normal tricuspid and pulmonary valves. In-depth analysis, however, of the images showed a double-chambered right ventricle, in which the inlet and outlet portions of the right ventricle were isolated from the apical component of the right ventricle, which itself communicated with the left ventricle through a ventricular septal defect. There was a normal pulmonary valve and tricuspid annulus.

Long-term relief of obstruction in a dog with double-chambered right ventricle using combined cutting balloon and high-pressure balloon dilation

A 4-month-old intact female Golden Retriever dog was diagnosed with double-chambered right ventricle (DCRV) without infundibular stenosis, tricuspid valve dysplasia, and subsequent severe right atrial enlargement and was referred for combined cutting balloon and high-pressure balloon dilation. On presentation, these diagnoses were confirmed, and the peak systolic pressure gradient across the DCRV obstructive lesion assessed by continuous wave Doppler interrogation was 80 mm Hg. The obstructive lesion within the mid-right ventricle had a diameter of 6 mm through which blood flowed from the proximal right ventricular (RV) chamber to the distal RV chamber. The following day, general anesthesia was induced, and a minimally invasive balloon dilation was performed. A cutting balloon was inflated across the mid-RV obstructive lesion, followed by an inflation of a high-pressure balloon across this lesion. The high-pressure balloon catheter that was used had a diameter roughly 1.5 times the diameter of the pulmonary annulus. The following day, echocardiographic evaluation of the patient revealed a peak systolic pressure gradient across the DCRV obstructive lesion of 16 mm Hg, with a RV diameter at the level of obstruction of 11 mm. Twelve months later, the dog remains asymptomatic, right atrial size has decreased, and has a peak systolic pressure gradient across the DCRV lesion of 20 mm Hg.

Congenital, acquired, or both? The only two congenitally based, acquired heart diseases

Discrete subaortic stenosis (DSS) is a type of left ventricular outflow tract obstruction whereas double-chambered right ventricle is a form of right ventricular outflow tract obstruction. Both of these cardiac malformations share lots of similar characteristics which classify them as acquired developmental heart diseases despite their congenital anatomical substrate. Both of them are frequently associated to ventricular septal defects. The initial stimulus in their pathogenetic process is anatomical abnormalities or variations. Subsequently, a hemodynamic process is triggered finally leading to an abnormal subaortic fibroproliferative process with regard to DSS or to hypertrophy of ectopic muscles as far as double-chambered right ventricle is concerned. In many cases, these pathologies are developed secondarily to surgical management of other congenital or acquired heart defects. Moreover, high recurrence rates after initial successful surgical therapy, particularly regarding DSS, have been described. Finally, an interesting coexistence of DSS and double-chambered aortic ventricle has also been reported in some cases.

Double-chambered left ventricle: An unusual finding in a middle-aged woman

Double-chambered left ventricle (DCLV) is a rare congenital abnormality and is characterized by the subdivision of the left ventricle into two separate chambers by an abnormal septum or muscle band. This rare congenital entity is usually diagnosed in the neonatal or pediatric age. Nevertheless, it can be asymptomatic and incidentally found in the adulthood. A comprehensive multimodality imaging approach is crucial for the correct final diagnosis.

Two cases of six-chambered hearts

Double-chambered right ventricles (DCRV) and left ventricles are rare entities on their own. We present two cases with an unusual combination of double-chambered right as well as left ventricles. One was discovered in a 28-year-old female, while the other was found at birth in a female child. The differing nature of both the patient demographics as well as the presentation with a common morphological background is shown on both computed tomography and magnetic resonance imaging. The oldest description of an obstructive muscular band within the right ventricle was given in 1867. In the literature, there is ample description of the long-term prognosis and management guidelines for DCRV, but no inheritance patterns or risk factors have been identified except for associations with septal defects, tetralogy of Fallot and transposition of the great arteries. A combination of both double-sided left as well as right ventricles has been published in literature a few times with little details about management and prognosis. SIMILAR CASES PUBLISHED: Although many cases of DCRV and DCLV have been published, to our knowledge only 3 cases of combined DCRV and DCLV have been published in literature.

Early and late outcomes of surgical repair of double-chambered right ventricle: a single-centre experience

OBJECTIVE

Double-chambered right ventricle is characterised by division of the outlet portion of the right ventricle by hypertrophy of the septoparietal trabeculations into two parts. We aim to report our experiences regarding the presenting symptoms of double-chambered right ventricle, long-term prognosis, including the recurrence rate and incidence of arrhythmias after surgery.

METHODS

We retrospectively investigated 89 consecutive patients who were diagnosed to have double-chambered right ventricle and underwent a surgical intervention from 1995 to 2016. The data obtained by echocardiography, cardiac catheterisation, and surgical findings as well as post-operative follow-up, surgical approaches, post-operative morbidity, mortality, and cardiac events were evaluated.

RESULTS

Median age at the time of diagnosis was 2 months and mean age at the time of operation was 5.3 years. Concomitant cardiac anomalies were as follows: perimembranous ventricular septal defect (78 patients), atrial septal defect (9 patients), discrete subaortic membrane (32 patients), right aortic arch (3 patients), aortic valve prolapse and/or mild aortic regurgitation (14 patients), and left superior caval vein (2 patients). The mean follow-up period was 4.86 ± 4.6 years. In these patients, mean systolic pressure gradient in the right ventricle by echocardiography before, immediately, and long-term after surgical intervention was 66.3, 11.8, and 10.4 mmHg, respectively. There were no deaths during the long-term follow-up period. Surgical reinterventions were performed for residual ventricular septal defect (2), residual pulmonary stenosis (1), and severe tricuspid insufficiency (1).

CONCLUSION

The surgical outcomes and prognosis of double-chambered right ventricle are favourable, recurrence and fatal arrhythmias are unlikely in long-term follow-up.

Coronary-cameral fistula with double-chambered right ventricle: appearance on cardiac magnetic resonance imaging and 3D printed anatomic modeling

The present case illustrates cardiac magnetic resonance imaging (MRI) and three-dimensional (3D) printed anatomic model findings of a coronary-cameral fistula (CCF) and double-chambered right ventricle (DCRV). A pregnant woman presented with palpitations and near syncope. A non-contrast cardiac MRI showed CCF connecting to a DCRV. Post-delivery, the patient had a contrast-enhanced MRI and 3D printed anatomic model to better evaluate her aberrant anatomy.

Female Athlete With a Double-Chambered Right Ventricle

A 35-year-old female athlete presented with recent episodes of pre-syncope on exertion while exercising. An isolated double-chambered right ventricle was diagnosed by transthoracic echocardiography and cardiac magnetic resonance. This defect typically presents during infancy and/or early childhood, is rarely reported in adults, and is usually associated with other congenital defects. (Level of Difficulty: Advanced.)

Bacterial endocarditis presenting in an adult patient with undiagnosed double-chambered right ventricle

Double-chambered right ventricle (DCRV) is a rare congenital heart defect often associated with ventricular septal defect and pulmonary stenosis. Cardiac catheterization or magnetic resonance imaging can differentiate between DCRV and Tetralogy of Fallot when echocardiogram is inconclusive. Patients are at an increased risk for bacterial endocarditis.

Histological and anatomical variations of septomarginal trabecula in bovine hearts

The use of hearts from different animals as models in the experimental pharmacology and surgical clinic has led, in recent years, to an increase on interest of research with this organ. The heart's conducting system, from the septomarginal trabecula, presents several variations, which generates numerous controversies in the literature. So, the objective of the present study is to analyse the morphology of the septomarginal trabecula of bovine hearts, identifying possible macro- and microscopic variations. Thirty-four bovine hearts were analysed. Each trabecula was analysed macroscopically to obtain an anatomical description and measurements of its length and thickness. For histological and morphometric analysis, the samples were fixed in Bouin's solution and then subjected to histological processing. In all the analysed bovine hearts, the septomarginal trabecula presented itself as a smooth, tubular meaty structure of muscular consistency, with variable length and diameter. The anatomical variations observed included a trabecula with forked marginal fixation, and single septal fixation, in addition to a trabecula with extremely reduced or excessively thick caliber. The septomarginal trabecula consists of cardiac muscle fibres, connective tissue, vascular tissue and conduction myofibrils or Purkinje fibres. In the samples of smaller thicknesses, there was a predominance of connective tissue and scarce cardiac muscle tissue, whereas in the thicker samples the predominance was of cardiac striated muscle tissue. Therefore, there are significant macro- and microscopic differences between the bovine septomarginal trabecula concerning their diameter and constituent tissue, and that can lead to possible changes in cardiac physiology.

Origins and consequences of congenital heart defects affecting the right ventricle

Congenital heart disease is a major health issue, accounting for a third of all congenital defects. Improved early surgical management has led to a growing population of adults with congenital heart disease, including patients with defects affecting the right ventricle, which are often classified as severe. Defects affecting the right ventricle often cause right ventricular volume or pressure overload and affected patients are at high risk for complications such as heart failure and sudden death. Recent insights into the developmental mechanisms and distinct developmental origins of the left ventricle, right ventricle, and the outflow tract have shed light on the common features and distinct problems arising in specific defects. Here, we provide a comprehensive overview of the current knowledge on the development into the normal and congenitally malformed right heart and the clinical consequences of several congenital heart defects affecting the right ventricle.

An uncommon variant of double-chambered right ventricle masquerading as double-chambered left ventricle

We present a rare case of a double-chambered right ventricle masquerading as a double-chambered left ventricle, which was found incidentally on cardiac imaging in an adult female patient with atypical chest pain. The most common form of double-chambered right ventricle is characterized by compartmentalization of the right ventricle by muscular bands into 2 distinct chambers. The main features of this malformation are a pressure gradient between the 2 compartments, and the frequent (up to 90%) association with a membranous ventricular septal defect. In our case, the muscular band dividing the right ventricle was located in the inferoseptal part of the latter, creating a diminutive cavity that had no communication with the main right ventricle but communicated with the left ventricle creating the false impression of a double-chambered left ventricle. This constitutes a rare variant of double-chambered right ventricle with unknown clinical implications.

Double-chambered right ventricle in a 16-year-old patient with Williams syndrome

We present a case of double-chambered right ventricle diagnosed during preparation for colonoscopy due to gastrointestinal bleeding in a 16-year-old, mentally disabled boy with Williams syndrome. The patient was previously diagnosed with ventricular septal defect and mild pulmonary stenosis. Echocardiography performed under general anesthesia revealed hypertrophied muscular bundles in the right ventricle with the maximum gradient of 100 mmHg, causing severe outflow obstruction. This type of defect is extremely rare in patients with Williams syndrome, with only one case, which was diagnosed during invasive angiocardiography, described in world literature. A successful total surgical correction was performed based on echocardiography data.

Combined double chambered right ventricle, tricuspid valve dysplasia, ventricular septal defect, and subaortic stenosis in a dog

BACKGROUND

Double chambered right ventricle (DCRV) is a congenital heart anomaly where the right ventricle is divided into two chambers. We describe, for the first time, an unusual combination of DCRV combined with some other congenital heart defects.

CASE PRESENTATION

A 1.2-year-old Golden Retriever was presented with lethargy, exercise intolerance and ascites. Physical examination revealed an irregularly irregular pulse and a grade V/VI, systolic, right cranial murmur. Electrocardiography revealed widened and splintered QRS complexes with a right bundle-branch block pattern. Radiography demonstrated right-sided cardiomegaly. Two-dimensional echocardiography identified a DCRV with tricuspid valve dysplasia. The patient died despite abdominocentesis and 4 days of oral pharmacotherapy, and necropsy revealed an anomalous fibromuscular structure that divided the right ventricle into two compartments. Another finding was tricuspid valve dysplasia with hypoplasia of the posterior and septal leaflets. The anterior leaflet was prominent, being part of the anomalous structure that divided the right ventricle. Necropsy also identified a perimembranous ventricular septal defect and mild subaortic stenosis. Histopathological examination of the fibromuscular band that separated the right ventricle identified longitudinally oriented layers of dense fibrous connective tissue and myocardial cells arranged in a plexiform pattern. The muscular component was well represented at the ventral area of the fibromuscular band, and was absent in the central zone. Superficially, the endocardium presented areas of nodular hyperplasia covering mainly the fibrous part of the abnormal structure. The nodules were sharply demarcated and were composed by loosely arranged connective tissue with myxoid appearance, covered by discrete hyperplastic endocardium.

CONCLUSIONS

Concomitant cardiac malformations involving DCRV, tricuspid valve dysplasia, perimembranous ventricular septal defect and mild subaortic stenosis have not been previously described in veterinary medicine, and are reported here for the first time. Moreover, this is the first report of a canine patient with tricuspid valve dysplasia (TVD) and DCRV where the anterior leaflet is part of an anomalous structure dividing the right ventricle (RV) into two separate compartments.

An (In)Significant Ventricular Septal Defect and/or Double-Chambered Right Ventricle: Are There Any Differences in Diagnosis and Prognosis in Adult Patients

A double-chambered right ventricle (DCRV) is an uncommon congenital anomaly: the right ventricle (RV) is divided into two chambers due to the presence of an abnormally located muscular band or anomalous muscle hypertrophy in the subinfundibular part of RV outflow tract, with a variable degree of obstruction. Generally, DCRV is well recognized in childhood and misdiagnosed in adult patients. Transthoracic and/or transesophageal echocardiography are the mx0435;thods of choice for the diagnosis of DCRV. Due to limitations of echocardiography in adult patients, this entity may be missed, particularly if it presents concomitant with other congenital defects, and therefore additional imaging methods such as MRI or cardiac catheterization are required for a definitive diagnosis.

Correction of Double-Chambered Right Ventricle 40 Years after Pulmonary Valvuloplasty

Background Double-chambered right ventricle is a partial separation of the right ventricle by pathological tissue. This anomaly is described in infants and children but can also be diagnosed in young adults. Case Description A 47-year-old patient presented with chest pain and exercise intolerance. Further evaluation revealed a double-chambered right ventricle. During the surgical procedure, fibrotic tissue was transected, and a pulmonary valve replacement including enlargement of the main pulmonary artery was performed. Conclusion Subpulmonary obstruction of the right ventricle can be related to double-chambered right ventricle even in adulthood. Treatment options include surgical resection with pulmonary valve replacement.

Surgical Outcomes and Postoperative Prognosis Beyond 10 Years for Double-Chambered Right Ventricle

Double-chambered right ventricle (DCRV) is a rare condition. Stenosis of DCRV is progressive, and early surgical intervention is recommended for patients whose symptoms and/or pressure overload of right ventricular (RV) inflow are progressive. However, there are few data regarding the postoperative course of DCRV, and the surgical indications for asymptomatic patients remain to be determined. We retrospectively investigated 38 consecutive patients who were diagnosed with DCRV and underwent surgical intervention from 1981 to 2009. Moreover, we identified 29 patients in whom long-term follow-up transthoracic echocardiographic data were available and investigated the postoperative recurrence of DCRV by evaluating the systolic pressure of RV inflow before, immediately, and in the long term after surgical intervention. The mean follow-up period was 11.0 ± 8.8 years. There were no deaths and no surgical reinterventions during the long-term follow-up period. Among 29 patients with long-term follow-up echocardiographic data, there was no recurrence of DCRV. In these patients, the systolic pressure of RV inflow by echocardiography before, immediately, and long-term after surgical intervention was 80 ± 26, 30 ± 11, and 25 ± 6 mm Hg, respectively. In conclusion, the surgical outcomes and postoperative prognosis beyond 10 years of DCRV are favorable, and neither recurrence of DCRV nor fatal arrhythmias develop during the long-term follow-up period.

Bands, Chords, Tendons, and Membranes in the Heart: An Imaging Overview

Crests, bands, chords, and membranes can be seen within the different cardiac chambers, with variable clinical significance. They can be incidental or can have clinical implications by causing hemodynamic disturbance. It is crucial to know the morphology and orientation of normal structures, aberrant or accessory muscles, and abnormal membranes to diagnose the hemodynamic disturbance associated with them. Newer generation computed tomographic scanners and faster magnetic resonance imaging sequences offer high spatial and temporal resolution allowing for acquisition of high resolution images of the cardiac chambers improving identification of small internal structures, such as papillary muscles, muscular bands, chords, and membranes. They also help in identification of other associated complications, malformations, and provide a road map for treatment. In this article, we review cross-sectional cardiac imaging findings of normal anatomical variants and distinctive imaging features of pathologic bands, chords, or membranes, which may produce significant hemodynamic changes and clinical symptomatology.

Regional differences in WT-1 and Tcf21 expression during ventricular development: implications for myocardial compaction

BACKGROUND

Morphological and functional differences of the right and left ventricle are apparent in the adult human heart. A differential contribution of cardiac fibroblasts and smooth muscle cells (populations of epicardium-derived cells) to each ventricle may account for part of the morphological-functional disparity. Here we studied the relation between epicardial derivatives and the development of compact ventricular myocardium.

RESULTS

Wildtype and Wt1CreERT2/+ reporter mice were used to study WT-1 expressing cells, and Tcf21lacZ/+ reporter mice and PDGFRα-/-;Tcf21LacZ/+ mice to study the formation of the cardiac fibroblast population. After covering the heart, intramyocardial WT-1+ cells were first observed at the inner curvature, the right ventricular postero-lateral wall and left ventricular apical wall. Later, WT-1+ cells were present in the walls of both ventricles, but significantly more pronounced in the left ventricle. Tcf21-LacZ + cells followed the same distribution pattern as WT-1+ cells but at later stages, indicating a timing difference between these cell populations. Within the right ventricle, WT-1+ and Tcf21-lacZ+ cell distribution was more pronounced in the posterior inlet part. A gradual increase in myocardial wall thickness was observed early in the left ventricle and at later stages in the right ventricle. PDGFRα-/-;Tcf21LacZ/+ mice showed deficient epicardium, diminished number of Tcf21-LacZ + cells and reduced ventricular compaction.

CONCLUSIONS

During normal heart development, spatio-temporal differences in contribution of WT-1 and Tcf21-LacZ + cells to right versus left ventricular myocardium occur parallel to myocardial thickening. These findings may relate to lateralized differences in ventricular (patho)morphology in humans.