In a recent blog we looked at the use of the Sgarbossa criteria in the diagnosis of acute myocardial infarction in the setting of pre-existing left bundle branch block.
In this blog we're going to take a look at another useful diagnostic clue: Cabrera's sign, which can be used in the diagnosis of an old myocardial infarction in LBBB.
Cabrera's sign refers to a notch that occurs within the first 40 msec in the ascending portion of the S wave in lead V3 or V4:
|Cabrera's sign (arrowed)|
This ECG sign was first described by Cabrera & Friedland in 1953.
Although Cabrera's sign has a high specificity for the diagnosis of an old myocardial infarction in LBBB, it has a poor sensitivity.
More details about the original paper by Cabrera and Friedland can be found here: