Which of the following is not true of Mahaim fibre tachycardia?
a) Left bundle branch block pattern
b) Normal baseline ECG
c) Mahaim fibres do not conduct retrogradely
d) Narrow QRS tachycardia
Correct answer: d) Narrow QRS tachycardia
Mahaim fibres do not conduct retrogradely. So Mahaim fibre tachycardia is always with wide QRS complexes – antidromic with LBBB pattern. Read more…