Abnormal heart rate variability in adults with growth hormone deficiency

Area of Science:

• Cardiology
• Endocrinology
• Autonomic Neuroscience

Background:

• Growth hormone deficiency (GHD) is linked to increased cardiovascular mortality and potential cardiac abnormalities.
• Cardiac autonomic dysfunction is observed in non-GHD patients with similar conditions, suggesting its possible presence in GHD.

Purpose of the Study:

• To investigate cardiac autonomic function in patients with GHD using heart rate variability (HRV) analysis.
• To compare HRV parameters between GHD patients and healthy controls to identify potential autonomic imbalances.

Main Methods:

• Power spectral analysis (PSA) of HRV was employed to assess cardiac autonomic tone.
• Key frequency bands analyzed included very low frequency (VLF), low frequency (LF) for sympathetic activity, and high frequency (HF) for parasympathetic activity.
• 14 GHD patients and 19 healthy controls underwent HRV assessment.

Main Results:

• GHD patients demonstrated significantly lower normalized LF power (sympathetic activity) and VLF power.
• GHD patients showed significantly higher normalized HF power (parasympathetic activity).
• The LF/HF ratio, an indicator of sympathovagal balance, was markedly reduced in GHD patients compared to controls.

Conclusions:

• Heart rate variability is demonstrably abnormal in patients with GHD.
• The observed decrease in sympathetic tone and altered sympathovagal balance in GHD patients may underlie their heightened cardiovascular risk.
• These findings suggest reduced central sympathetic tone or altered cardiac autonomic responsiveness as potential mechanisms.