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

Post Myocardial Infarction Complications

Ischemic Complications

• Infarct Expansion
• Reinfarction
• Post MI Angina

Mechanical Complications

• Heart Failure
• Cardiogenic Shock
• Cardiac Rupture
• Mitral Valve Dysfunction
• Aneurysm

Arrythmic Complications

• Atrial and Ventricular Arrhthmias
• Sinus or atrioventricular node Dysfunction

Embolic Complications

• CNS Embolization
• Periphral Embolization

Inflammatory Complication

• Pericarditis

Cheyne-Stokes Respiration

This form of respiration is also known as periodic breathing which is characterized by cycles of shallow respirations that increase in depth and rate causing severe hyperpnea. Hyperpnea is followed by decreasing depth and rate of respiration and then the period of apnea that lasts foe almost 15 seconds. This type of respiration is a symptom of congestive heart failure and some CNS diseases. The respiration most often occurs during sleeep and often reported by others because patient is not aware of cheyne stokes respiration.

Causes of Dyspnea

Dyspnea is commonly defined as labored or difficult respiration. Dyspnea can be also defined as unpleasant awareness of one`s breathing.

Causes of Chronic Dyspnea

• Heart Failure
• Pulmonary Disease
• Anxiety
• Obesity
• Poor Physical Fitness
• Pleural Effusions
• Asthma

Causes of Acute Dyspnea

• Airway Obstruction
• Pneumonia
• Pulmonary Embolism
• Pneumothorax
• Hyperventilation
• Acute Pulmonary Edema

Causes of Dyspnea on Exertion

• Congestive Heart Failure
• Physical Deconditioning
• Chronic Pulmonary Disease