Left posterior fascicular block
Diagnostic criteria include:
- Right axis deviation (>110)
- QRS < 120ms
- qR in III and aVF
- rS in I and aVL
LAFB vs LPFB
|Axis||Left axis deviation||Right axis deviation|
|I and aVL||Upright QRS||Downgoing QRS|
|III||Downgoing QRS||Upright QRS|
- Usually associated with disease
- Isolated LPFB associated with MI
- Exclude other causes of RAD (PE, COPD, RVH, Lat MI)
- Surawicz B, et al. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part III: intraventricular conduction disturbances. Journal of the American College of Cardiology. 2009; 53(11): 976–981.
- Mattu A and Brady WJ. ECG's for the Emergency Physician. BMJ Books. Sep 19, 2003.
- Godat FJ and Gertsch M. Isolated left posterior fascicular block: a reliable marker for inferior myocardial infarction and associated severe coronary artery disease. Clin Cardiol. 1993; 16(3):220-226.