FASCICULAR (HEMI-) BLOCKS


n.b. concepts below may not be quite valid, but do provide a useful theoretical framework

I. Left anterior fascicular block

  1. EKG features--see "Electrocardiography"
  2. Associated with LAD occlusion
  3. Can occur with RBBB (a type of bifascicular block); you see RBBB and marked LAD; this can progress to complete heart block if LPF gets affected. Pacemaker indicated only if symptomatic

II. Left posterior fascicular block

  1. Much rarer then LAFB because LPF is bigger
  2. Associated with either RCA or LAD occlusion
  3. EKG features--see "Electrocardiography"