Comprehensive rhythm evaluation in a large contemporary Fontan population

Area of Science:

• Pediatric Cardiology
• Cardiac Surgery
• Electrophysiology

Background:

• Rhythm disturbances are a significant cause of morbidity in patients with Fontan circulation.
• Current surgical techniques for total cavopulmonary connection include intra-atrial lateral tunnel (ILT) and extracardiac conduit (ECC).

Purpose of the Study:

• To evaluate rhythm abnormalities in a contemporary cohort of Fontan patients.
• To compare the incidence of arrhythmias between ILT and ECC surgical techniques.

Main Methods:

• A cross-sectional multicentre study involving 115 Fontan patients (age 12.5 ± 3.1 years).
• Rhythm evaluation included ECG, exercise testing, Holter monitoring with heart rate variability analysis.
• Medical history was reviewed for documented episodes of arrhythmia.

Main Results:

• Sinus node dysfunction (SND) was observed in 29% of patients, with no difference between ILT and ECC groups.
• Sinus pauses occurred exclusively in the ILT group.
• Atrial arrhythmias were more prevalent in ILT patients (15% vs 1%, P = 0.004), particularly with baffle ILT.
• Heart rate reserve and recovery were significantly lower in ILT patients compared to ECC patients.

Conclusions:

• The overall incidence of arrhythmia in this cohort was low, though SND is frequent in both Fontan surgical groups.
• ILT patients, especially those with baffle techniques, experienced more atrial arrhythmias and sinus pauses.
• The clinical significance of asymptomatic ventricular arrhythmias in young Fontan survivors requires further investigation.