A 45-year-old man presented with frequent palpitations. Clinical examination and electrocardiogram were unremarkable. Transthoracic echocardiography suggested asymmetrical septal hypertrophy, although the acoustic windows were poor. Transoesophageal echocardiography revealed a broad false tendon within the left ventricle, extending from the basal septum to the apical lateral wall (Figure). Holter monitoring showed frequent premature ventricular complexes, indicating right bundle branch block morphology.

The incidence of false tendons — fibromuscular intracavitary bands anatomically distinct from the valvular cusps — is 0.4% to 3.0%.1 They may be associated with malignant ventricular arrhythmias, which should be excluded before making a diagnosis of benign premature ventricular complexes in a healthy patient.1

Transoesophageal echocardiogram: the arrow shows the false tendon from the basal septum to the apical lateral wall of the left ventricle (LV).