[Left ventricular false tendon: the most frequent cause of "innocent" murmur in childhood?]

The left ventricular false tendon (FT) is an anomalous fibrous or fibromuscular band stretching across the left ventricle. The false tendons extend from the septum to the left ventricular free wall or, more rarely, from the septum to a papillary muscle. The association between FT and innocent cardiac murmur has been pointed out. The aim of the present study was to assess the incidence of FTs in children with a murmur classified as innocent.

Two groups of subjects were selected. Group A consisted of 253 children with: 1) systolic ejection murmur; 2) normal electrocardiogram and 3) absence of clinical data suggesting cardiac disease. Group B consisted of 240 children clinically free of cardiac disease, and without any cardiac murmur. A FT was diagnosed by means of 2D echocardiogram whenever a linear band stretching across the left ventricular chamber was evident in at least two sections.

One hundred and sixty-one children of group A (63.6%) reflected a left ventricular FT; only in 3 patients out of 161 the FT was associated with a small ventricular septal defect, whereas in 158 children the FT was the only abnormal finding. A normal echocardiogram was observed in 71 children (28.1%) of group A; whereas in 21 patients (8.3%) a congenital heart disease was diagnosed. In group B, only 33 subjects (13.8%) had a FT. The different incidence of FT in the two groups (63.6% versus 13.8%) was statistically significant (p less than 0.01).

The study shows that about two thirds of children with innocent heart murmur reflect a left ventricular FT. Furthermore, FT is far more common in subjects with innocent cardiac murmur than in normal subjects. The relationship between FT and murmur thus appears very likely, although not definitely proven.