Prolonged PR Interval at Birth Predicting the High Occurrence of Fatal Atrioventricular Block in Hypoplastic Left Heart Syndrome.

Infants with hypoplastic left heart syndrome (HLHS) are at high mortality especially when they are associated with bradyarrhythmias. However, the risk factor of developing high-grade atrioventricular block (HAVB) is still unclear. Seventy-three patients with HLHS in our institutions from 2002 to 2011 were enrolled. The survival rate was assessed by the anatomical types, treatments, occurrence of HAVB, severe tricuspid regurgitation (TR), and restrictive atrial septal defect (ASD) along with electrocardiogram findings at birth. There were 23 (32%) cardiogenic and 7 (10%) non-cardiogenic deaths. The occurrence rate of HAVB but not severe TR or restrictive ASD was higher in 30 deceased patients than in 43 survived patients [7 (23%) vs. 1 (2.3%), p = 0.0038]. The overall mortality rate was higher in patients with HAVB than in those without it (p = 0.0002). Of 7 deceased patients with HAVB, 6 HAVB occurred within 10 days post-surgery, and 3 HAVB led to the early death. The mortality rate of patients with prolonged PR (≥ 0.15 s) but not wide QRS (> 0.08 s) or prolonged QTc (> 0.43 s) at birth was higher than each without it (p = 0.0106). Multivariate analysis indicated that prolonged PR but no other variables was independently associated with the mortality (hazard ratio: 2.948, p = 0.0104). Prolonged PR at birth in HLHS infants predicts the development of fatal HAVB.