View source for Wide Complexes Intervening Regular Sinus Rhythm - 4

{{NHJ|
|mainauthor= '''A.A.M. Wilde'''
|edition= 2008:05,175
}}
[[Image:Puzzle_2008_05_01.jpg|Figure 1|thumb]]

A 55-year-old male without cardiac history is
complaining of an irregular heartbeat. Physical
examination and an echo reveal no abnormalities. His
ECG (extremity leads only) is shown in figure 1.

'''What is your diagnosis?'''

[[Answer 2008_05|Answer]]