Quick ECG revision

Common ECG Patterns:

1. Myocardial Infarction (MI):

   • Inferior MI: Look for ST elevation in leads II, III, and aVF, with reciprocal ST depression in leads I and aVL.
   • Anterior/Septal MI: ST elevation in leads V1-V4, with possible reciprocal ST depression in leads II, III, and aVF.
   • Lateral MI: ST elevation in leads I, aVL, V5, and V6, with reciprocal ST depression in leads II, III, and aVF.

2. Pulmonary Embolism (PE):

   • Commonly presents with sinus tachycardia.
   • Look for the S1Q3T3 pattern: prominent S wave in lead I, Q wave, and inverted T wave in lead III.
   • T-wave inversions in right precordial leads (V1-V4) and inferior leads (II, III, aVF).
   • Right bundle branch block (RBBB) pattern can be seen.

3. Digoxin Toxicity:

   • Characterized by a “sagging” ST segment (Salvador Dali effect).
   • Down-sloping ST depression, T-wave flattening, and shortened QT interval.
   • Possible atrial tachycardia with block.

4. Hyperkalemia:

   • Look for peaked T waves, widened QRS complexes, and eventually a sine wave pattern if severe.
   • ST depression and T-wave inversion can also be seen.

5. Acute Pericarditis:

   • Diffuse ST elevation across many leads, not confined to anatomical regions.
   • PR segment depression, most notable in lead II.
   • Concave ST elevation (saddle-shaped).

6. Atrial Fibrillation (AF):

   • Absence of P waves, replaced by fibrillatory waves.
   • Irregularly irregular rhythm on the ECG.

7. Atrial Flutter:

   • Sawtooth pattern of flutter waves, best seen in leads II, III, and aVF.
   • Often presents with a variable block (e.g., 2:1 or 3:1).

When presenting these findings in the exam, focus on what you see: describe the positive findings, link them to the history, and conclude with your diagnosis. Avoid detailing every component of the ECG unless necessary.