ECG Library


Infarcts and Ischemia ECG 3

  1. Normal sinus rhythm
  2. Left bundle branch block
  3. First-degree AV block
  4. Cabrera’s sign - possible myocardial infarction

Cabrera’s sign is used to diagnose an acute myocardial infarction in the setting of a left bundle branch block and consists of notching at 40 milliseconds in the upslope of the S wave in leads V3 and V4. This has a poor sensitivity of 27% for MI.

Historically, it has been taught that detecting myocardial ischemia is not possible on an ECG in the setting of a LBBB; however, three different changes that can be seen in this setting could suggest an acute myocardial infarction. These include the Sgarbossa criteria, Chapmans sign and Cabreras sign.