Cardiovascular abnormalities accompanying acute spinal cord injury in humans: incidence, time course and severity.

The frequency of cardiovascular abnormalities was evaluated in 71 consecutive patients with acute injury to the spinal cord. Persistent bradycardia was universal in all 31 patients with severe cervical cord injury and less common in milder cervical injury (6 of 17) or thoracolumbar injury (3 of 23) (p less than 0.00001). Marked sinus slowing (71 versus 12 versus 4%, respectively, p less than 0.00001), hypotension (68 versus 0 versus 0%, p less than 0.00001), supraventricular arrhythmias (19 versus 6 versus 0%, p = 0.05) and primary cardiac arrest (16 versus 0 versus 0%, p less than 0.05) were significantly more frequent in the severe cervical injury group. The frequency of bradyarrhythmias peaked on day 4 after injury and gradually declined thereafter. All observed abnormalities resolved spontaneously within 2 to 6 weeks. The primary mechanism underlying these observations appears to involve the acute autonomic imbalance created by the disruption of sympathetic pathways located in the cervical cord. Acute severe injury to the cervical spinal cord is regularly accompanied by arrhythmias and hemodynamic abnormalities not found with thoracolumbar cord trauma. These abnormalities are limited to the first 14 days after injury, a period in which life-threatening disturbances must be anticipated.