Definition and Overview
Post-stroke autonomic dysfunction results from damage to the central autonomic network (CAN), occurring in up to 76% of acute stroke patients. The insular cortex is a key hub -- right insular strokes are associated with sympathetic overactivation while left insular strokes are linked to parasympathetic predominance [1].
Pathophysiology: The Brain-Heart Axis
The insular cortex, hypothalamus, amygdala, and brainstem nuclei form the CAN. Stroke disrupting these structures causes autonomic imbalance affecting cardiovascular, sudomotor, and gastrointestinal function [2].
The brain-heart axis explains cardiac complications of stroke: sympathetic surge can cause myocardial injury (Takotsubo cardiomyopathy), arrhythmias, and QTc prolongation. Cardiac complications are a leading cause of post-stroke mortality [3].
Manifestations
- Cardiovascular: arrhythmias (AF, VT), blood pressure instability, QTc prolongation
- Orthostatic hypotension: impaired baroreflex after brainstem or insular stroke
- Sweating abnormalities: asymmetric sweating patterns
- Thermoregulation: central fever, poikilothermia
- Gastrointestinal: dysphagia, gastroparesis
- Bladder: detrusor overactivity, urinary retention
HRV Changes
Post-stroke HRV is reduced, particularly after right insular stroke. Low HRV in the acute phase correlates with poor functional outcome and increased mortality risk. Serial HRV monitoring may serve as a prognostic marker [4].
Treatment
Acute phase: continuous cardiac monitoring, careful blood pressure management (avoiding both hyper- and hypotension), rhythm monitoring for arrhythmias [5].
Rehabilitation: graded exercise programs, HRV biofeedback, tilt training for orthostatic hypotension. Autonomic function assessment should be integrated into stroke rehabilitation protocols.