Heart Block
Basic Information
Definition
Complete heart block (CHB) is a bradycardic rhythm caused by failure of impulse conduction from the atria to the ventricles with complete atrioventricular dissociation. The atrial rate is usually higher than the ventricular rate.
Synonyms
Unless bradycardia is concurrent, atrioventricular dissociation is not an acceptable synonym because this entity may exist with normal rates of at least one pacemaker (e.g., sinus bradycardia with an appropriate junctional rate) and with ventricular tachycardias.
Epidemiology & Demographics
• The incidence of surgically induced CHB has progressively decreased and is currently quite low (less than 5%), seen most commonly in the setting of complex cardiac malformation repairs.
• Congenital CHB caused by fetal exposure to anti-Ro (SSA/Ro) and anti-La (SSB/La) occurs in only 1% to 5% of mothers with collagen vascular disease, but the recurrence rate for subsequent pregnancies is 20%.
