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 ?