Maladaptive Cardiac Autonomic Control during a Stress Reactivity Assessment Among Primary Care Patients with Metabolic Syndrome.

Metabolic syndrome (MetS) comprises a constellation of metabolic abnormalities that substantially increase risk for chronic illnesses. Autonomic dysregulation is closely linked to MetS, and while pathophysiological models often address chronic stress exposure, none have examined how such physiological contributions operate situationally, in a clinical setting. We used ambulatory impedance cardiography to examine indicators of cardiac autonomic control (CAC) in a sample of 50 adult primary care patients with and without MetS. Indices of independent sympathetic and parasympathetic cardiovascular control in primary care outpatients were measured during a brief stress reactivity assessment. We compared interdependent CAC features, including cardiac autonomic balance (i.e., sympathovagal reciprocity) and cardiac autonomic regulation (i.e., sympathovagal coactivation) and found significant differences among MetS participants as compared to healthy controls. In particular, cardiac autonomic regulation scores were higher among MetS patients when discussing medication concerns, and cardiac autonomic balance scores were lower among MetS patients when discussing daily stressors. These results suggest that patients meeting criteria for MetS demonstrate momentary variations in CAC depending on personally relevant health topics. The potential for future research is discussed with a focus on prospective data collection to enhance diagnostic procedures and treatment monitoring.