KEYWORDS
Concealed conduction, Parahisian pathway, Resetting, Echo beat
25 year male with repeated episodes of palpitation and structurally
normal heart was admitted for electrophysiology study. 12 lead
electrocardiograph during EP study showed the following rhythm. ECG
below is showing groups of 3 beats followed by a pause followed by
initiation of narrow complex regular tachycardia. In a group first
complex is narrow followed ba a wide complex and then a norrow complex
but with a prolonged PR interval. Then there is a pause before start of
another froup of 3 beats. So what the explanation for this type of
rhythm ?