Complete heart block

Though apparently P wave is seen before each QRS complex, the PR interval is not constant suggestive of AV dissociation. The Atrial rate is 90, min and the ventricular rate is 45, min. Arrows indicate the P waves. There is a regular PP interval and a regular slower ventricular {RR interval}. The QRS complex is normal indicating the pacemaker is in AV node or a level higher than the bifurcation of the His bundle.
Impression - Complete heart block
Congenital complete heart block may be an isolated anomaly or may be associated with structural defects like L- transposition of great arteries. There is a frequent association of maternal SLE or other connective tissue diseases with CHB in offspring`s.
Asymptomatic children with CHB do not require pacemaker therapy until they become symptomatic Especially if their resting ventricular rate is more than 50 beats, min.
Surgically induced CHB may require pacemaker atleast temporarily in the immediate post operative period.

E-published: July 2007 Vol 4 Issue 7 Art # 29