# Left ventricular outflow tract obstruction caused by abnormal mitral valve tendinous Chordae manifesting in the extremely remote period after surgery for partial atrioventricular septal defect: a case report

## TL;DR

A rare case of heart obstruction caused by abnormal heart chords was found years after a heart surgery, requiring further surgery to resolve.

## Contribution

Reports a rare long-term complication of partial AVSD surgery involving abnormal chordae causing LVOTO.

## Key findings

- LVOTO occurred 35 years post-pAVSD surgery due to abnormal chordae causing systolic anterior motion.
- Surgical resection of the abnormal chordae resolved the obstruction and symptoms.
- Late-onset LVOTO can arise from anatomical anomalies unrelated to typical postoperative timelines.

## Abstract

Atrioventricular septal defect (AVSD) is a congenital heart disease characterized by intracardiac shunting due to septal defects, often associated with left ventricular outflow tract obstruction (LVOTO) caused by myocardial anomalies. Surgical intervention is recommended for AVSD if needed. This case report presents a rare case of LVOTO developing in the extremely remote period after partial Atrioventricular septal defect (pAVSD) surgery.

A 35-year-old man with a history of intracardiac repair for pAVSD presented with worsening exertional dyspnoea. Transoesophageal echocardiography led to the diagnosis of LVOTO caused by systolic anterior motion (SAM) of an abnormal chordae without myocardial hypertrophy and mitral valve prolapse. Medical therapy was attempted but proved completely ineffective, so surgical resection of the abnormal chordae causing SAM was performed via open-heart surgery. Postoperatively, the LVOTO resolved, and the patient’s symptoms disappeared.

AVSD has anatomical characteristics that allow it to be associated with LVOTO in various forms; however, much remains unknown about the modes of onset and the progression of the condition. It is reported that most cases of LVOTO after intracardiac repair of AVSD occur within five years postoperatively; however, rare cases can present in the late postoperative period. Among these are cases in which symptoms become apparent due to rare anatomical features such as chordal SAM, or haemodynamic changes associated with lifestyle modifications.