ecg: reciprocating tachycardia

ECG OF THE WEEK

Prof.Dr.MAHESH KUMAR’s unitDr.T. Balamurugan, PG

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

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)

DIAGNOSIS

Narrow complex tachycardia

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

PAROXYSMAL TACHYCARDIAS IN WPW SYNDROME

AV junctional re-entry

tachycardia

•AV Junctional using anamolous pathway- 1) Orthodromic 2) antidromic•Intra nodal pathway (micro re-entry)•AV junctionl re-entry involving two anamolous pathways•Macro entry involving two anamolous pathways

Atrial tachyarrhythmi

a

•Atrial tachycardia•Atrial flutter•Atrial fibrillation

Ventricular tachycardia

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)

activation front on reaching ventricles, conducted retrogradely, activating

atria retrogradely

Retrograde P’ wave

Inverted P’ wave in L2,3,aVF

Returning reciprocal impulse, after reaching atria

Conducted anterogradely through normal AV nodal conduction, activating

ventricles

Re-enter bypass once again, activating atria……………

Reciprocating tachycardia

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’

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