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NEUROLOGIC Pathologies Linked to Heart


Significant cardiac effects stemming from brain injury are well known, including alteration of cardiac rhythms, cardiac variability, and blood pressure regulation. Neurologic diseases such as parkinsonism, multiple sclerosis (MS), stroke, epilepsy, and tumors can have cardiac effects, although structural abnormalities on conventional MRI may be lacking.
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MS is classically a disease of white matter, although it can also affect gray matter. Autonomic dysfunction is common, affecting as many as 50% of MS patients with symptoms that include orthostatic dizziness, bladder disturbances, temperature instability, gastrointestinal disturbances, and sweating. The effect of autonomic dysfunction on disease activity is unclear. Multiple brainstem lesions are evident on MRI, and may be linked to cardiac autonomic dysfunction. The variability of MS contributes to the difficulty of using imaging to identify culprit lesions.
                 
Stroke causes autonomic dysfunction, with the specific manifestations dependent on the region of the brain involved.
In cases of right middle cerebral artery infarct affecting the right insula, an increased incidence of cardiac arrhythmias, cardiac death, and catecholamine production ensues.Medullary infarcts have been shown to produce significant autonomic dysfunction.

Ictal and interictal cardiac manifestations in epilepsy often precede seizure onset.Common cardiac changes are ictal tachycardia or ictal bradycardia, or both, with no clear relationship to the location or type of seizure. Evidence suggests that heart rate variability changes in epilepsy result from interictal autonomic alterations, including sympathetic or parasympathetic dominance. Investigation of baroreflex responses with temporal lobe epilepsy has uncovered decreased baroreflex sensitivity.

Autonomic dysfunction in the form of orthostatic hypotension has been documented in patients with mass effect from tumors, for example posterior fossa epidermoid tumors, wherein tumor resection results in improved autonomic function.

Cleveland Clinic Journal of Medicine vol. 78 Suppl 1 S69-S74
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