Validation of a novel method of assessing autonomic function using ultrasonography in patients with heart failure: a pilot cross-sectional study

Heart failure (HF) is a common condition associated with poor prognosis, and impaired autonomic regulation is one of its characteristic features,1 making the assessment of autonomic function clinically important. Generally, the standard for assessment of autonomic function is heart rate variability, but it is not suitable for patients with non-sinus rhythm. Since 40–47% of HF patients have non-sinus rhythm,1 autonomic function is often overlooked due to this limitation. To address this issue, we focus on the vagus nerve cross-sectional area (VNCSA), a novel ultrasound-based measure that is easy to assess at the bedside.2,3 This study aimed to determine whether VNCSA reflects autonomic function and is applicable in patients with HF. This was a cross-sectional study conducted at Sagamihara Kyodo Hospital, Japan. The study population comprised two groups: (i) 139 patients admitted at Sagamihara Kyodo Hospital for HF diagnosed according to the Framingham criteria between May 2024 and January 2025, and (ii) 133 healthy community-dwelling adults recruited as volunteers. Exclusion criteria for both groups included a history of cerebrovascular or neuromuscular diseases, advanced diabetes, upper limb orthopaedic disorders, severe cognitive impairment that could hinder participation, and haemodialysis due to dialysis-related factors that markedly influence autonomic function. In addition, the control group excluded individuals with cardiovascular diseases, including HF, myocardial infarction, or a history of cardiovascular surgery. This study was approved by the Ethics Committee of Sagamihara Kyodo Hospital (approval number: No. 284). All participants agreed to participate and obtained an informed consent form before data collection.