Rate:

• Take 300 divided by the number of big boxes OR

• Count down 300 | 150 | 100 | 75 | 60 | 50 for each big box

Rhythm: Is it sinus?

• Is there a P before each QRS? QRS after each P?

• Are P waves upright in leads I and II, inverted in aVR?

• Are the PR intervals constant

• Are the QRS complexes narrow (< 100 ms wide or approximately 3 small boxes)

Intervals:

Ischemia

• Look for Q waves (deeper or wider than1 small box (1 mm) or >1/3 QRS amplitude)

• Look for ST depressions, ST elevations, and T wave inversions

• Scan EKG for contiguous leads. Findings are only real if they occur in 2 or more contiguous leads

  • Inferior leads: II, III, aVF

  • Anterior leads: V1 - V4 (make sure the inverted T wave in V1 gradually becomes positive)

  • Lateral leads: V5, V6, I, aVL

Waves: