Poor R Wave Progression (PRWP) refers to an abnormal finding on an electrocardiogram (ECG or EKG), where the normal pattern of R wave growth across the chest (precordial) leads (V1 to V6) does not occur as expected.
Normal R Wave Progression:
- In a healthy heart, the R wave (the positive deflection) gradually increases in amplitude from leads V1 to V4, reaching a maximum in leads V4 or V5, and then slightly decreasing by V6.
- Poor R wave progression means this gradual increase is either absent or less pronounced.
Causes of Poor R Wave Progression:
- Myocardial Infarction (MI): Often, an anterior MI can cause damage to the left ventricle, leading to abnormal R wave progression.
- Left Ventricular Hypertrophy (LVH): Enlarged heart muscle can alter the electrical patterns, causing PRWP.
- Chronic Obstructive Pulmonary Disease (COPD): Lung diseases can shift the heart’s position or affect the electrical patterns in the heart.
- Electrolyte Imbalances: Abnormal potassium or calcium levels can alter the electrical activity of the heart.
- Bundle Branch Block: A blockage in one of the bundle branches (especially the left bundle branch) can cause PRWP.
- Lead Placement Errors: Improper placement of ECG leads can sometimes give a false appearance of poor R wave progression.
- Obesity or Increased Chest Wall Thickness: These factors can affect how the heart’s electrical activity is detected on the ECG.
Clinical Significance:
- PRWP is not always indicative of a serious condition and may sometimes be a normal variant, but it can also point to underlying heart or lung pathology.
- If PRWP is noted, further investigations like echocardiography or more detailed imaging might be needed, especially if the patient has symptoms such as chest pain, shortness of breath, or a history of heart disease.
Evaluation of PRWP should always be done in conjunction with clinical findings and other diagnostic tests.