Cor Triatriatum Sinister Presenting as Cardioembolic Stroke in a Young Woman

Cor triatriatum dexter as an incidental finding due to symptomatic bicuspid aortic valve stenosis

Cor triatriatum is a rare congenital heart defect in which a thin, fibro-muscular membrane divides the left or right atrium into two chambers resulting in a triatrial heart. Subdivision of the left atrium named cor triatriatum sinister (CTS), is the more common form, whereas the right atrial equivalent called cor triatriatum dexter (CTD) is rarer. They account for up to 0.4% and 0.025% of the burden of congenital heart disease respectively. We present the case of CTD found incidentally with transthoracic echocardiography for a patient who underwent aortic valve replacement for symptomatic bicuspid aortic valve stenosis.

Clinical case of Cor triatriatum sinister, a dilemma of anticoagulation: A case report and literature review

Cor triatriatum is a rare congenital heart abnormality in which a membrane separates the left atrium (LA; sinister) or the right atrium (dexter) into two compartments. It is also a long-forgotten cause of atrial fibrillation (AF) and substantially higher rates of blood stagnation, particularly proximal to the additional septum in the LA. In this case report, we faced a CHA2DS2-VASc score of 1 in patients with non-valvular AF due to Cor triatriatum sinister (CTS). The decision to start anticoagulants in this particular case was controversial, so we reviewed the literature to assess and address it. We present our case and discuss the indication of anticoagulants in this unique clinical scenario, accompanied by a literature review. Facing this dilemma of starting anticoagulants in special cases of CTS and AF should be individualized and need more investigation. However, till this moment, based on similar reports, it seems to be rational to consider CTS Per se as an additional risk stratification marker beyond the CHA2DS2-VASc score start anticoagulant until the surgical resection. Considering CTS as the sole indication of anticoagulant in patients with normal sinus rhythm is a complex matter that needs further investigation.

Discovery and functional investigation of BMP4 as a new causative gene for human congenital heart disease

OBJECTIVE

Aggregating evidence highlights the strong genetic basis underpinning congenital heart disease (CHD). Here BMP4 was chosen as a prime candidate gene causative of human CHD predominantly because BMP4 was amply expressed in the embryonic hearts and knockout of Bmp4 in mice led to embryonic demise mainly from multiple cardiovascular developmental malformations. The aim of this retrospective investigation was to discover a novel BMP4 mutation underlying human CHD and explore its functional impact.

METHODS

A sequencing examination of BMP4 was implemented in 212 index patients suffering from CHD and 236 unrelated non-CHD individuals as well as the family members available from the proband carrying a discovered BMP4 mutation. The impacts of the discovered CHD-causing mutation on the expression of NKX2-5 and TBX20 induced by BMP4 were measured by employing a dual-luciferase analysis system.

RESULTS

A new heterozygous BMP4 mutation, NM_001202.6:c.318T>G;p.(Tyr106*), was found in a female proband affected with familial CHD. Genetic research of the mutation carrier's relatives unveiled that the truncating mutation was in co-segregation with CHD in the pedigree. The nonsense mutation was absent from 236 unrelated non-CHD control persons. Quantitative biologic measurement revealed that Tyr106*-mutant BMP4 failed to induce the expression of NKX2-5 and TBX20, two genes whose expression is lost in CHD.

CONCLUSION

The current findings indicate BMP4 as a new gene predisposing to human CHD, allowing for improved prenatal genetic counseling along with personalized treatment of CHD patients.

Discovery of BMP10 as a new gene underpinning congenital heart defects

OBJECTIVE

Aggregating evidence convincingly establishes the predominant genetic basis underlying congenital heart defects (CHD), though the heritable determinants contributing to CHD in the majority of cases remain elusive. In the current investigation, BMP10 was selected as a prime candidate gene for human CHD mainly due to cardiovascular developmental abnormalities in Bmp10-knockout animals. The objective of this retrospective study was to identify a new BMP10 mutation responsible for CHD and characterize the functional effect of the identified CHD-causing BMP10 mutation.

METHODS

Sequencing assay of BMP10 was fulfilled in a cohort of 276 probands with various CHD and a total of 288 non-CHD volunteers. The available family members from the proband harboring an identified BMP10 mutation were also BMP10-genotyped. The effect of the identified CHD-causative BMP10 mutation on the transactivation of TBX20 and NKX2.5 by BMP10 was quantitatively analyzed in maintained HeLa cells utilizing a dual-luciferase reporter assay system.

RESULTS

A novel heterozygous BMP10 mutation, NM_014482.3:c.247G>T;p.(Glu83*), was identified in one proband with patent ductus arteriosus (PDA), which was confirmed to co-segregate with the PDA phenotype in the mutation carrier's family. The nonsense mutation was not observed in 288 non-CHD volunteers. Functional analysis unveiled that Glu83*-mutant BMP10 had no transactivation on its two representative target genes TBX20 and NKX2.5, which were both reported to cause CHD.

CONCLUSION

These findings provide strong evidence indicating that genetically compromised BMP10 predisposes human beings to CHD, which sheds light on the new molecular mechanism that underlies CHD and allows for antenatal genetic counseling and individualized precise management of CHD.

Cor Triatriatum: A Review

Cor triatriatum is a rare congenital cardiac anomaly, characterized by a fibromuscular partition dividing the left (cor triatriatum sinister) or, rarely, the right atrium (cor triatriatum dexter). Occurring in 0.1-0.4% of congenital heart disease cases, it exhibits diverse clinical presentations, often mimicking mitral stenosis and left-sided heart failure, while occasionally remaining asymptomatic into adulthood. The embryological origin of cor triatriatum remains controversial. Recent years have seen the emergence of new classification systems that offer enhanced prognostic insights. Transthoracic echocardiography is the diagnostic cornerstone. Surgical resection, preferably under cardiopulmonary bypass, is the mainstay treatment, and is associated with favorable long-term outcomes.