• Mechanism of the Delta Wave
• ECG and Delta Wave
• Wolf-Parkinson-White (WPW) Syndrome
• Mahaim Syndrome

Mechanism of the Delta Wave

• In WPW syndrome, there is a accessory pathway (Bundle of Kent)
• Bundle of Kent activates one ventricle earlier than the impulse from the AV junction
• The impulse from the Bundle of Kent creates a delta wave on the ECG
• Delta Wave
• Widening of the QRS complex
• Shortening of the PQ interval
  
  
• Fusion beat (fusion contraction)
• 1st impulse activates the ventricles via the AV junction (QRS complex)
• 2nd impulse activates the ventricles via the Bundle of Kent (Delta wave)
• Fusion beat can also occur in ventricular tachycardia

Wolf-Parkinson-White (WPW) Syndrome

Kent Bundle and WPW Syndrome

• WPW syndrome features a Kent bundle
• Connects the atria and ventricles, bypassing the AV junction (Atrio-Ventricular bypass)
• Delta wave
• Impulse through the Kent bundle activates the ventricles earlier and widens the lower part of the QRS complex
• Shortened PQ interval < 0.12s
• Widened base of the QRS complex shifts towards the P wave

Delta Wave and WPW Syndrome

• There are 3 ECG recordings from different patients shown
• Each shows WPW syndrome
• Delta wave
• Shortened PQ interval < 0.12s

Delta Wave and WPW Syndrome (Type B)

• Delta wave and widened QRS approximately 0.15s
• Shortened PQ interval < 0.12s
• Negative QRS (V1)
  • This indicates that the Kent bundle is in the right atrium
• Dominant R wave in V4-V6
  • This is not left ventricular hypertrophy
  • This is not left bundle branch block
  • This is a sign of WPW syndrome