Electrocardiography

Approach (a systematic approach is vital)

  • Rate (? tachy or brady) and rhythm (? P waves, regularity, P & QRS relationship)
  • Intervals (PR, QRS, QT) and axis (? LAD or RAD)
  • Chamber abnormality (? LAA and/or RAA, ? LVH and/or RVH)
  • QRST changes (? Q waves, poor R-wave progression V1–V6, ST ↑/↓ or T-wave ∆s)
Figure 1-1 QRS axis

Left axis deviation (LAD)

  • Definition: axis beyond –30° (S > R in lead II)
  • Etiologies: LVH, LBBB, inferior MI, WPW
  • Left anterior fascicular block (LAFB): LAD (–45 to 90°)