Heart rate variability in children with Fontan circulation - lateral tunnel and extracardiac conduit
Objective: The technique in Fontan surgery has developed from lateral tunnel towards extracardiac conduit in order to reduce long-term complications. Earlier studies have shown lower heart rate variability (HRV) in patients with Fontan circulation palliated with lateral tunnel (LT) as compared to healthy controls. This study also investigates HRV parameters in children with Fontan circulation palliated with extracardiac conduit (EC).
Methods: 102 patients (61 LT and 41 EC) and 64 healthy controls underwent Holter-ECG. Analysis included RR-intervals and power spectrum analysis of HRV (Total power TP, Low frequency LF, high frequency HF).
Results: The mean age at Holter for the whole study group was 9.1 years, LT 9.9 years and EC 7.1 years. Children with Fontan circulation (both LT and EC) showed significantly longer RR-interval as compared to controls (p= 0,0015). Furthermore, the children with Fontan circulation showed significantly lower total power (p=0,0076) (Fig), LF (p=0,0013) and HF (p=0,00023) as compared to healthy controls, respectively. There was no significant difference in HRV between the children operated with LT and EC, although there was a tendency of lower HRV parameters for the patients with EC compared to patients with LT.
Conclusions: A new finding in this study was the significantly lower HRV parameters found in children with extra cardiac conduit as compared to healthy controls. Another interesting finding was the tendency to lower HRV among patients with extra cardiac conduit as compared to those with lateral tunnel - a finding that needs to be further investigated.