Isolated Complete Heart Block in the Fetus.

Area of Science:

• Cardiology
• Maternal-Fetal Medicine
• Pediatric Electrophysiology

Background:

• Isolated congenital complete heart block (CCHB) is a rare condition with limited long-term outcome data.
• Fetal diagnosis is common, but prenatal treatment strategies for CCHB remain controversial.
• Understanding the natural history is crucial for managing CCHB and improving patient prognosis.

Purpose of the Study:

• To present the largest single-unit experience of prenatally diagnosed CCHB.
• To analyze long-term outcomes and survival rates in a conservatively managed cohort.
• To identify risk factors associated with intrauterine and postnatal mortality.

Main Methods:

• Retrospective analysis of 85 fetuses diagnosed with CCHB between 1981 and 2013.
• Data collection included maternal antibody status, antenatal treatments, delivery survival, and postnatal outcomes.
• Kaplan-Meier estimates were used to determine survival and time to pacemaker implantation.

Main Results:

• 74 out of 85 fetuses survived to delivery; fetal hydrops was the only significant risk factor for intrauterine death.
• 14 postnatal deaths occurred, with a 30-year survival estimate of 76.8%.
• Prematurity and hydrops were associated with increased postnatal mortality; dilated cardiomyopathy was uncommon.

Conclusions:

• Conservative management of prenatally diagnosed CCHB resulted in survival rates comparable to previous studies.
• Fetal hydrops is a critical predictor of poor intrauterine outcome in CCHB.
• This cohort provides valuable insights into the long-term natural history of congenital complete heart block.