LEFT ANTERIOR FASCICULAR BLOCK (LAFB)/LEFT ANTERIOR HEMIBLOCK (LAHB):

An electrical delay or blockage in the conduction pathway that sends impulses down the left anterior fascicle of the left bundle.

•ECG Criteria:

•Prolonged QRS (0.08-0.11 sec).

•Left axis deviation (usually > -45 degrees).

•Leads 1 and aVL: small Q waves and tall R waves.

•Leads 2, 3 and aVF: small R waves and deep S waves.

•No other obvious cause of these findings (e.g. left ventricular hypertrophy or inferior wall myocardial infarction).