Two Neonatal Cases of Pacemaker Implantation in Congenital Complete Atrioventricular Block

Congenital complete atrioventricular heart block(CCAVB) is a rare disease of the newborn that carries significant mortality and has a heterogenous etiology. It may occur as a result of the presence of maternal autoantibodies that are transferred to the fetus and affect the fetal heart or be associated with a congenital structural abnormality of the heart. Infants with CCAVB are at risk of diminished cardiac output and the subsequent development of congestive heart failure. We report two cases of CCAVB in newborns treated with pacemaker implantation after birth. The first case revealed CCAVB with patent ductus arteriosus and anti- Ro(SS-A) antibody in both of the mother and the newborn. The second case was accompanied with mitral regurgitation and tricuspid regurgitation, but anti-Ro(SS-A) antibody was absent in both of the mother and the newborn. Pacemaker implantation was performed for both cases and the result was favorable. We concluded that our experience supports that the pacemaker implantation in the newborn is feasible and beneficial in the treatment of CCAVB.

Estudo do comportamento autonômico dos ritmos de escape no bloqueio atrioventricular congênito / Study of the Autonomic Behavior of the Escape Rhythms in Complete Congenital Heart Block

PURPOSE--To study the autonomic behavior of the escape rhythm in congenital complete heart block (CCHB), using heart rate variability (HRV). METHODS--A group of 10 asymptomatic patients with CCHB and narrow QRS was studied, 7 females; mean age = 14 +/- 9 years. The following time domain indexes were analyzed from a 24 hour Holter monitoring. The mean of all RR intervals (NN); the standard deviation of the mean (CLV5); the mean of all standard deviations (SDNN); the percent of successive differences longer than 50 ms (pNN50); the shortest cycle (CC) and the longest cycle (CL). The results were compared with a control group, using the Wilcox test for statistical analysis. RESULTS--The results were: NN = 1016 +/- 276 ms in CHB and 725 +/- 121 ms in control (p < 0.01); CLV5 = 184 +/- 97 ms in CHB and 125 +/- 38 ms in control (p = NS); SDNN = 102 +/- 32 ms in CHB and 88 +/- 29 ms in control (p = NS); rMSSD = 113 +/- 69 ms in CHB and 78 +/- 28 ms in control (p = NS); pNN50 = 43 +/- 26 per cent in CHB and 33 +/- 12 per cent in control (p = NS); CC = 582 +/- 129 ms in CHB and 333 +/- 49 ms in control (p = 0.05). CONCLUSION--No statistical difference was noted by comparing HRV indexes in CHB with control subjects, showing that the autonomic behavior of the escape rhythm in CCHB is similar to the sinus node in asymptomatic patients. The differences in NN, CC and CL are probably related to intrinsic properties of each command