Cabrera Sign

Cabrera sign is defined as the presence of a prominent, shelf-like or downward notching, of >0.04 second duration, at the ascending limb of the S wave.

Cabrera and Friedland in 1953 found that late notching of the up-slope of the S wave, occurring aſter 0.04 ms in leads V3–V5, is highly sensitive and specific for the diagnosis of old MI in LBBB. This electrocardiographic marker  is a well-described sign of anteroseptal MI in the setting of LBBB and Wackers et al. estimated its sensitivity to 47% and a specificity to 87%. Hands et al. in 1989 determined the sensitivity and specificity of Cabrera’s sign to be 29% and 91% respectively. Furthermore, Barold et al. have reported that Cabrera’s sign, is the most useful single ECG criterion for the diagnosis of an old anterior, or anteroseptal MI during RV pacing with sensitivity 23–50% depending on the size of the MI, and specificity 97–100% if the notching is properly defined, findings, that are in accordance with many other studies.

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Image reproduced from Barold SS, Herweg B (2006) Electrocardiographic diagnosis of myocardial infraction during left bundle branch blck. Cardiol Clin 24:377-385

  • Specific Cabrera cariants:
    • Small, narrow r wave deforming the terminal QRS
    • Series of tiny notches giving a serrated appearance along the ascending S wave
    • Series of late notches on QRS during epicardial pacing
  • False Cabrera’s sign
    • Slight notching of the ascending S wave in V leads is normal during RV apical pacing. It is usually confined to 1 lead, shows a sharp upward direction on the S wave and has a duration typically
    • Ventricular fusion beats
    • Early retrograde P waves deforming the late portion of the QRS complex masquerading as an intrinsic component of the QRS complex

Table reproduced from Herweg B, Marcus MB, Barold SS. Diagnosis of myocardial infarction and ischemia in the setting of bundle branch block and cardiac pacing. Herzschrittmachertherapie + Elektrophysiologie 2016;27(3):307–22.
References:
1. CABRERA E, FRIEDLAND C. Wave of ventricular activation in left branch block with infarct; new electrocardiographic sign. Arch Inst Cardiol Mex 1953;23(4):441–60.
2. Herweg B, Marcus MB, Barold SS. Diagnosis of myocardial infarction and ischemia in the setting of bundle branch block and cardiac pacing. Herzschrittmachertherapie + Elektrophysiologie 2016;27(3):307–22.
3. Barold SS, Herweg B. Electrocardiographic diagnosis of myocardial infarction during left bundle branch block. Cardiol Clin 2006;24:377–385
4. Wackers FJ. The diagnosis of myocardial infarction in the presence of left bundle branch block. Cardiol Clin 1987;5:393–401
5. Hands MECE, Stone PH et al. Electrocardiographic diagnosis of myocardial infarction in thepresence of complete left bundle branch block. AmHeart J 1998;116:23–31
6. Kochiadakis GE, Kaleboubas MD, Igoumenidis NE et al. Electrocardiographic appearance of old myocardial infarction in paced patients. Pacing Clin Electrophysiol 2002;25:1061–1065.
7. Tzeis S, Andrikopoulos G, Asbach S, et al. Electrocardiographic identification of prior myocardial infarction during right ventricular pacing – Effect of septal versus apical pacing. Int J Cardiol 2014;177(3):977–81.
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