Cabrera’s sign


Cabrera’s sign is used to diagnose an acute myocardial infarction in the setting of a LBBB or paced rhythm. This ECG sign was first described by Cabrera & Friedland in 1953.

ECG features

It is defined as a prominent notching of at least 0.04 sec in the ascending limb of the S wave in any of leads V3-V4.

Although specificity is high, sensitivity for myocardial infarction is only 27% overall, 47% for anteroseptal MI. 

ECG 1 Cabrera sign in V3,V4


  1. Cabrera E, Friedland C. La onda de activacion ventricular en el bloqueo de rama izquierda con infarto: un nuevo signo electrocardiografico. Arch Inst Cardiol Mex 1953; 23: 441–460.