Integrated Electrocardiography-Heart Rate Variability (ECG-HRV) Analysis in Neurologically Symptomatic Individuals Without Cardiac Symptoms: A Data-Driven Retrospective Observational Study of Electrocardiographic-Autonomic Associations.

Background and objective Neurocardiac interaction is bidirectional, with neurological disorders influencing cardiac electrophysiology through the autonomic nervous system (ANS) pathways. Patients may present with central nervous system (CNS) manifestations, autonomic symptoms, or both. Despite the absence of overt cardiac symptoms, subtle autonomic disturbances may precede clinically detectable cardiovascular dysfunction. This study aimed to evaluate cardiac electrophysiology using heart rate variability (HRV) and electrocardiography (ECG) data from neurologically symptomatic but cardiac-asymptomatic individuals; to assess correlations between ECG parameters and HRV indices; and to determine the utility of HRV for early detection of neurocardiac risk in this population. Methods Artifact-free five-minute ECG recordings were analyzed using LabChart Version 8 (ADInstruments, Bella Vista, Australia) to derive HRV and ECG parameters. HRV assessment included both time-domain and frequency-domain measures, while ECG analysis comprised heart rate, PR interval, QRS duration, QT interval, and corrected QT interval (QTc). Demographic and clinical information were retrieved from departmental records for a total of 314 subjects. Following data quality assessment and exclusion of recordings with artifacts or incomplete data, HRV and ECG analyses were conducted on 278 subjects. Statistical analyses were performed using Jamovi macOS Pro (Version 2.6.45) and Statistics Kingdom, a freely accessible online statistical platform. Depending on the distribution and nature of the data, analyses included Spearman rank correlation, Welch's t-test, and one-sample and two-sample t-tests. Results ECG findings demonstrated largely preserved cardiac conduction and repolarization parameters across the cohort, although inter-individual variability in repolarization amplitude was observed. In contrast, HRV analysis revealed subtle autonomic dysregulation, including among subjects presenting predominantly with autonomic symptoms, suggesting impaired parasympathetic modulation despite normal ECG findings. Several HRV indices differed significantly from normative reference values, indicating altered autonomic regulation. Conclusions HRV is a sensitive, noninvasive tool for detecting early autonomic dysfunction in neurologically symptomatic adults, irrespective of the underlying neurogenic presentation. While conventional ECG parameters remain largely preserved in cardiac-asymptomatic individuals, HRV can identify subclinical neurocardiac alterations that may not be evident on routine electrocardiographic assessment. These findings support the integration of HRV into neurological evaluation protocols to facilitate early neurocardiac risk stratification and preventive cardiovascular care.