CRPS is a chronic pain condition that typically develops after an injury, surgery, or trauma, most often affecting a limb. The pain is disproportionate to the initial injury and is accompanied by sensory, motor, and autonomic changes. While CRPS is primarily known for its effects on the limbs, it is a systemic disorder that can impact body functions far from the original site. CRPS can affect the heart because the syndrome disrupts the body’s fundamental systems that regulate cardiovascular function.
The Role of Autonomic Nervous System Dysfunction
The primary mechanism linking CRPS to systemic issues, including the heart, is a widespread dysfunction of the Autonomic Nervous System (ANS). The ANS manages all involuntary bodily functions, such as breathing, digestion, blood pressure, and heart rate. This system is divided into the sympathetic nervous system (“fight or flight”) and the parasympathetic nervous system (“rest and digest”).
In CRPS, there is an imbalance, often characterized by sustained overactivity of the sympathetic nervous system, acting like a constant stress response. This imbalance causes sympathetic nerves to send inappropriate signals, including those feeding the heart’s cardiac plexus. Studies show CRPS patients have a significantly increased resting heart rate and a noticeable reduction in Heart Rate Variability (HRV).
HRV measures the subtle fluctuations in the time intervals between heartbeats, and its reduction indicates autonomic imbalance. A lower HRV suggests the heart cannot efficiently adapt its rhythm to changing demands, reflecting the body’s sustained state of stress. This autonomic dysregulation is systemic, affecting how the nervous system controls the body’s internal environment.
Specific Cardiovascular and Circulatory Manifestations
The systemic ANS dysfunction translates into several specific cardiovascular and circulatory changes. One direct manifestation is heart rate instability, often presenting as tachycardia or palpitations (fast or irregular heartbeats). This is a direct consequence of sympathetic hyperactivity constantly pushing the heart to beat faster at rest.
Fluctuations in blood pressure are also commonly reported, particularly issues related to postural changes. Orthostatic intolerance, which can manifest as light-headedness, dizziness, or fainting (syncope) upon standing, affects a significant number of CRPS patients. This occurs because the ANS cannot effectively constrict blood vessels to prevent blood from pooling in the lower extremities, resulting in a sudden drop in blood pressure.
The autonomic dysregulation also causes distinct circulatory changes in the affected limb. Sympathetic nerves control blood vessel diameter, and their dysfunction leads to abnormal vasoconstriction or vasodilation. This results in changes in skin temperature (warmer or colder) and skin color (mottled, red, or blue). Swelling (edema) is also common, as dysregulated blood flow and capillary leakage allow fluid to accumulate in the tissues.
Clinical Assessment and Treatment Approaches
Clinical assessment for cardiovascular involvement begins with evaluating vital signs and a detailed patient history regarding symptoms like light-headedness or palpitations. Physicians look for orthostatic hypotension by measuring blood pressure and heart rate while the patient is lying down and immediately after standing up. Specialized tests, such as a tilt-table test, may be used to confirm orthostatic intolerance or other autonomic issues.
A tilt-table test monitors heart rate and blood pressure while the patient is gradually tilted upright, diagnosing disorders where the body struggles to maintain blood flow to the brain. Monitoring HRV through a 24-hour Holter electrocardiogram (ECG) provides objective data on the degree of autonomic imbalance. These assessments help rule out primary heart conditions and confirm that symptoms stem from CRPS pathology.
Management requires a multidisciplinary approach targeting the root cause of the ANS dysfunction. Non-pharmacological strategies include physical therapy to improve circulation and mobility, and lifestyle adjustments like increasing fluid and salt intake to manage orthostatic intolerance. Pharmacological treatments may stabilize heart rhythm or blood pressure, especially for severe orthostatic hypotension. Treatments like stellate ganglion blocks, which interrupt overactive sympathetic signals in the neck, are sometimes used to alleviate pain and associated autonomic symptoms.