Non-sinus bradyarrhythmias in very low birth weight infants.

Transient bradycardias occur frequently in preterm infants with apnea of prematurity. However, occurrence of non-sinus bradyarrhythmias in very low birth weight (VLBW) infants has received very little attention. This case series documents transient bradyarrhythmias in VLBW infants. Most frequently observed arrhythmia was a non-sinus atrial rhythm followed by junctional escape rhythm. Ventricular rhythm with wide QRS complexes occurred rarely. The majority of these episodes occurred in the absence of oxygen desaturation. Increase in vagal tone is presumed to mediate this response.