@misc{cogprints5239, volume = {6}, number = {3}, month = {July}, author = {Mohammad Alasti and Abolfath Alizadeh and Amirfarjam Fazelifar and Mohammad Ali Sadr-Ameli}, editor = {Balbir Singh and Yash Lokhandwala and Johnson Francis and Anup Gupta and Joydeep Ghosh}, title = {Infra-His Block in a Normal Heart }, publisher = {Indian Pacing and Electrophysiology Group}, year = {2006}, journal = {Indian Pacing and Electrophysiology Journal}, pages = {184--185}, keywords = {His-purkinje system; infra-his block }, url = {http://cogprints.org/5239/}, abstract = {A 55 year old man with history of palpitation was referred for electrophysiologic study. Baseline ECG, physical examination and transthoracic echocardiographic study were normal. Electrophysiologic study revealed normal AH and HV intervals. Pacing of right atrium with a cycle length of 300 msec showed 2:1 AV block. AH interval was 252 msec and the block was infra-his (Figure 1). With continual of right atrial pacing, one to one AV conduction with increasing AH interval to 282 msec and QRS widening (LBBB pattern) were being observed. HV intervals during 2:1 block and during 1:1 AV conduction were normal. What is the mechanism? Is it an abnormal finding in this patient? } }