1. ECG of the week Prof.Dr.MAHESH KUMAR’s unit Dr.T. Balamurugan, PG

2. 46 year old female, admitted in ICCU with c/o palpitation----------- 4 hrs

4. ECG Heart rate- 190 Rhythm regular QRS duration- 60 ms R-R interval –regular & 320 ms P’ visible after QRS complexes R-P’ interval 80 ms (shortened)

5. Diagnosis Narrow complex tachycardia

7. Heart rate- 72/min Rhythm- regular QRS duration- 130 ms Slurred upstroke of QRS complex (delta wave) P-R interval –90 ms (shortened) Q-T interval –480 ms

8. Paroxysmal tachycardias in WPW syndrome

10. Mechanism of reciprocating tachycardia in WPW syndrome Sinus impulse activating atria (normal P wave) conduction of sinus impulse through bypass may be blocked, but conducted in usual manner through AV node, activating ventricles (normal QRS wave)

11. activation front on reaching ventricles, conducted retrogradely, activating atria retrogradely Retrograde P’ wave Inverted P’ wave in L2,3,aVF

12. Returning reciprocal impulse, after reaching atria Conducted anterogradely through normal AV nodal conduction, activating ventricles Re-enter bypass once again, activating atria…………… Reciprocating tachycardia

13. Since anterograde conduction to the ventricles occurs through normal pathway, pre-excitation doesn’t take place & delta waves not recordable When ECG recorded during this phase, manifestations of WPW syndrome not evident in ECG ‘Concealed WPW syndrome’

15. THANK YOU