False tendons(FT), also referred to as pseudotendons or bands, are fibrous strings that pass from two papillary muscles and insert elsewhere except mitral valve leaflets. They can be classified into six types according to sites of attachment to the left ventricular wall and thickness. FT have been generally considered to be common normal structural variants with no clinical significance. But, these may be misinterpreted echocardiographically as left ventricular endocardium of the ventricular septum or mural thrornbus, since the echo from the tendon might mimic these structures. Moreover they have been reported to be a cause of functional ejection murmur. Some investigators have suggested that FT rnight be an etiologic factor in the genesis of ventricular arrhythmias in the autopsy and the clinical studies.

We evaluated the prevalence of the false tendons in consecutive 263 patients for 2 month period in routine echocardiographic method. In cases with FT, we examined their attachment and thickness accurately by tilting and rotating the echo probe, and classified them. In possible 9 cases, 24 hour ambulatory ECG monitoring was performed and evaluated the existence of ventricular arrhythmias.

FT were found in routine echocardiographic views in 15 patients(male 11, female 4) out of 263 patients(prevalence 5.7%). The pye of FT were longitudinal type 7 cases(thin 3 cases, thick 4 cases) most commonly, diagonal type 3 cases(thin 2 cases, thick 1 cases), transverse thin type 4 cases and apical thin type 1 case. In 24 hour ambulatory ECG monitoring, ventricular premature contractions were detected in all 9 patients. Interestingly in one patient(case 5) visited with dyspnea and repetitive long period of palpitation, suggestive ILVT(idiopathic left ventricular tachycardia) and FT(longitudinal thick type) were coexisted.

FT are common normal variants, but may be confused with other normal structures. Clinically in apparently healthy subjects with symptomatic idiopathic ventricular arrhythmias(ventricular premature contractions, ILVT and so on), the echocardiography would be performed carefully for the existence of FT and could be helpful for the evaluation of etiologies.