[False chordae tendineae].

False tendons (FT) are fibrous or fibromuscular structures which cross the ventricular cavity with no connections with valvular leaflets. They were considered for a long time as normal structures but now cardiologists are interested because of the possible association with the so-called innocent murmur, and even more so for the role they can have in eliciting ventricular arrhythmias. Some Authors believe that arrhythmias can arise from the false tendons because they contain not only fibrous tissue but also muscular and conduction tissue. Arrhythmias can be triggered either by stretching of the Purkinje fibers or by distortion of the ventricular wall, where false tendons arise. At the same time they can act as reentry circuits due to their non-homogeneous structure. Due to the fact that false tendons may arise anywhere from the ventricular cavity, they have been classified according either to anatomic or echocardiographic criteria: the latter being more complex and difficult than the former for the difficulty in locating the attachment areas. In our echocardiographic laboratory we simply distinguish two types of false tendons: type I which parallel the interventricular septum or bridges from the postero-basal portion of the septum to the posterior left ventricular wall; type II which crosses the ventricular cavity more distally, towards the apex. In the anatomic studies the prevalence of the FT is rather homogeneous, ranging from 46 to 54.9%, while it is extremely variable in the echocardiographic studies, ranging from 0.2 to 71%. This is possibly due not only to the examiner's skills, or the equipment's quality but also to the population studied. Among the patients referred to our cardiac paediatric unit we have found false tendons in 80 (29.3%) out of 273 children without cardiac disease, age ranging from i day to 13 yrs. Males were affected twice more than females, 63.7% vs 36.3%.(ABSTRACT TRUNCATED AT 250 WORDS)