Anomalous left atrial chord as a rare cause of mitral regurgitation

A 16-year-old patient with an unremarkable medical history was referred for echocardiography due to a systolic murmur grade 1–2/6.

The two-dimensional transthoracic echocardiogram demonstrated a mildly thickened anterior mitral valve leaflet (AMVL) and a band-like structure on the left atrial site attached to the AMVL which measured approximately 3 cm in length.

Three-dimensional echocardiography confirmed the presence of a linear band, from A2 scallop of the AMVL to the left upper pulmonary vein. The pulmonary venous drainage was unobstructed. This finding was consistent with the diagnosis of an anomalous mitral chord in the left atrium (Figure 1 and Supplementary material).

Figure 1.

Three-dimensional transthoracic echocardiogram showing the aberrant chord, a band-like structure, extending from the atrial site of the A2 scallop of the anterior leaflet to the left-upper pulmonic vein. CHORD, aberrant chord; LA, left atrium; LV, left ventricle; MV, mitral valve; PV, pulmonic vein; RV, right ventricle.

As the patient was asymptomatic and the mitral regurgitation was mild, no intervention was required.

Anomalous left atrial chordae are an extremely rare finding with an incidence of about four cases in 6500 autopsies. There are only a few reports in the literature describing this congenital malformation.

The embryology of this anomaly is not completely known, but it is likely related to a defect during embryogenesis between 14 and 17th weeks of gestation when atrial chordae and papillary muscles are developed.

The incidental finding of an anomalous left atrial chord should be considered as a benign congenital abnormality of no clinical significance, but when the chord is attached to mitral valve, it may be associated with valve dysfunction or flow obstruction.

Supplementary material

Supplementary material is available at European Heart Journal - Case Reports online.

Consent: The author/s confirm that written consent for submission and publication of this case report including image(s) and associated text has been obtained from the patient in line with COPE guidance.

Conflict of interest: none declared.