Differential Diagnosis of Q waves on the Electrocardiogram

1. Positional or Physiological Q waves on the ECG

A. Normal Variant Septal Q waves
B. Normal Variant Q Waves in Leads V1, V2, AVL, III and AVF
C. Acute Loss of lateral R wave progression in case of Left sided Pneumothorax.
D. Chronic loss of lateral R wave progression in case of Dextrocardia.

2. Q waves in case of Myocardial infiltration and injury

A. Acute processes

•  Myocardial Infacrtion or Ischemia
• Myocarditis
• Hyperkalemia

B. Chronic Processes

• Myocardial Infarction
• Myocarditis
• Idiopathic Cardiomyopathy
• Amyloid
• Sarcoid
• Tumor

3. Ventricular Hypertrophy or Enlargement

A. Slow R wave progression in case of left ventricular Hypertrophy

B. Reversed R wave progression in Case of  Right Ventricular Hypertrophy

C. Slow R wave progression in case of chronic obstructive lung disease.

D. Hypertrophic Cardiomyopathy can also simulate anterior, inferior, posterior or lateral infarcts.

4. Conduction Abnormalities

A. Slow R wave progression in case of Left Bundle Branch Block

B. Wolff Parkinson White Pattern