Normal Sinus Rhythm-Sinus Bradycardia is Common in Young Children Post-extracardiac Fontan

Area of Science:

• Pediatric Cardiology
• Cardiac Surgery
• Electrophysiology

Background:

• The extracardiac Fontan procedure is a palliative surgery for complex congenital heart disease.
• Sinus bradycardia, a heart rate below normal limits, can have various causes and implications.
• Understanding heart rhythm post-Fontan surgery is crucial for long-term patient management.

Purpose of the Study:

• To investigate the prevalence of normal sinus rhythm with sinus bradycardia in children following extracardiac Fontan surgery.
• To compare heart rates in post-Fontan children with a healthy control group.

Main Methods:

• Ambulatory 24-hour Holter monitoring was used to assess heart rate in 33 children post-extracardiac Fontan.
• Patients with significant arrhythmias (e.g., sinus pauses, junctional rhythm) were excluded.
• Heart rate data was compared to a control group of similarly aged children.

Main Results:

• The average 24-hour heart rate in post-extracardiac Fontan children was 78 ± 12 beats per minute (bpm).
• This heart rate was statistically significantly lower than the control group's average of 90 ± 10 bpm (p < 0.01).
• Exclusion criteria ensured the observed bradycardia was within normal sinus rhythm.

Conclusions:

• Normal sinus rhythm with sinus bradycardia is a common finding in children after extracardiac Fontan surgery.
• This bradycardia is a distinct physiological finding, not solely attributable to other arrhythmias.
• Further research may explore the clinical significance and management of this bradycardia.