Sinus node dysfunction in patients with Fontan circulation: could heart rate variability be a predictor for pacemaker...

Area of Science:

• Cardiology
• Pediatric Cardiology
• Autonomic Nervous System Function

Background:

• Sinus node dysfunction (SND) is a significant cause of morbidity in patients following Fontan surgery.
• Heart rate variability (HRV) quantifies autonomic regulation of the heart and is linked to SND in adults.
• Understanding HRV changes in Fontan patients with SND is crucial for monitoring and management.

Purpose of the Study:

• To investigate if 24-hour electrocardiographic (ECG) recordings can detect changes in HRV in Fontan patients with SND.
• To compare HRV parameters between Fontan patients with and without SND, and with healthy controls.

Main Methods:

• Compared HRV from 24-h ECG recordings in four groups: Fontan patients with SND requiring pacemakers (n=12), Fontan patients with SND without pacemaker indication (n=11), Fontan patients without SND (n=90), and healthy controls (n=66).
• Analyzed HRV using the Poincaré plot index SD2 and the very low-frequency (VLF) component.

Main Results:

• Both SND groups exhibited significantly higher SD2 and VLF HRV components compared to healthy controls and Fontan patients without SND.
• Fontan patients with SND requiring pacemakers showed a trend towards reduced SD2 and VLF compared to those with SND but no pacemaker (p=0.06).
• These findings suggest altered autonomic regulation in Fontan patients with SND.

Conclusions:

• Fontan patients with SND demonstrate significantly altered HRV compared to controls.
• A trend of reduced diurnal HRV in severe SND requiring pacemakers may indicate further autonomic compromise.
• HRV analysis shows potential as a valuable tool for monitoring the development of SND in Fontan patients.