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Poor R Wave Progression

Poor R Wave Progression (PRWP)

Pathological R Wave

• Physiologically, the main vector in 3D space is directed
• From lead aVR (Negative S wave, Q wave)
• Toward the lateral leads (aVL, I, V5, V) (Dominant R wave)
  
  
• The following R wave conditions require increased attention:
• Dominant R in V1
• The R wave in V1 lead should not be dominant
• Dominant R in aVR
• The R wave in aVR lead should not be dominant
• Decreased R Wave Progression
• The height of the R wave does not increase from V1 to V5
• QRS Alternans
• The height of the R wave changes from beat to beat

Causes of Decreased R Wave Progression

• Old Antero-septal Infarction
• (Most common cause of decreased R wave progression)
• Left Ventricular Hypertrophy
• Switched ECG leads V1 with V3
• Dilated Cardiomyopathy
• Left Tawar's Bundle Block
• WPW Syndrome
• Dextrocardia
• It may be a normal variant

Decreased R Wave Progression and Left Ventricular Hypertrophy

• Left Ventricular Hypertrophy
• Positive Sokolow index (R in V2 + R in V6 > 35mm)
• Left ventricular hypertrophy creates a massive main vector
• Which directs towards lead V5, so the highest R wave is in V5
• R wave in V3 < 4mm
• Main vector of the hypertrophied left ventricle directs away from leads V1-V3 (towards leads V5-V6)
• Therefore, in leads (V1-V3) the QRS complex is predominantly negative

Decreased R Wave Progression and Dilated Cardiomyopathy

• Dilated Cardiomyopathy
• Biatrial Hypertrophy
• Left Ventricular Hypertrophy
• Positive Sokolow index (R in V2 + R in V6 > 35mm)
• Right Ventricular Hypertrophy
• Not visible because the right ventricular vector is "covered" by the massive left ventricular vector
• R wave in V3 < 4mm
• Massive left ventricular vector directs away from leads V1-V3
• Sometimes a pathological Q wave can even appear in leads V1-V3
• Hypertrophy and chamber dilation produce the same ECG pattern
• Because electrical vectors are increased in both hypertrophy and dilation
• On echocardiography, the patient had dilation of both atria and ventricles

WPW Syndrome Type B

• WPW Syndrome (Type B)
• Shortened PQ interval < 0.12s
• Delta wave
• Widened lower part of the QRS, best visible in (I, II, V4-V6)
• Type B (The Kent bundle is in the right ventricle, leading to a negative QRS in V1)
• R wave in V3 < 4mm
• The ventricles are activated through 2 pathways (via the AV node and the Kent bundle)
• The ventricles begin to activate through the right ventricle (Kent bundle) towards the left ventricle
• From (V1-V3) to (V5-6)