Dr. Michael J. Rosner

828.684.1076 – 80 Doctors Drive, Suite 4, Hendersonville, NC 28792-7209

Glossary

Dysautonomia
Any abnormality of the functions of the autonomic nervous system. These include control of blood pressure, heart rate and rhythm, swallowing, gastric and bowel motility, bladder function and many others. These are generally functions over which we have little or only partial voluntary control.
Neurocardiogenic Syncope
Fainting brought about by rapid drop in blood pressure, usually as the result of abnormal neurological control. It is similar to neurally mediated hypotension and orthostatic intolerance. A tilt table examination may help with the diagnosis.
Neurally Mediated Hypotension
One of several dysautonomias characterized by inappropriately low blood pressure usually as the result of ineffective neurological control of vasoconstriction.
Orthostatic Intolerance
Low blood pressure and/or heart rate abnormalities precipitated by rapid postural changes such as bending forward and then up, standing rapidly or going from lying flat to standing. Also is characterized as a dysautonomia because the problem usually relates to abnormal cardiovascular control by the autonomic nervous system.
Positional Orthostatic Tachycardia Syndrome (POTS)
Intense tachycardia (rapid heart beat) precipitated by a change in posture. Blood pressure may decrease or increase. Patients may feel faint, nauseated, anxious and afraid, short of breath and may have chest pain or mistakenly diagnosed as having a “panic attack.”
Tachycardia Induced Hypotension
Blood pressure should increase when heart rate increases significantly. If blood pressure falls with increased heart rate, Tachycardia Induced Hypotension may be present. This can be tested for by using drugs which increase heart rate (such as isoproterenol or dobutamine) and observing the blood pressure response. This may be done routinely as “phase 2” of a tilt table examination.
Tilt Table Test
A test where a patient is placed flat and the blood pressure is monitored. The patient is then raised to nearly standing (usually about 70 degrees) and the blood pressure response measured. The normal response should be an increase in blood pressure. The test is “positive in phase1” if blood pressure drops by 10 mm Hg or more. The patient is usually observed in the upright position for 10-30 minutes though each practice may vary in the details of the technique. If blood pressures do not drop or the changes are equivocal, induced tachycardia may be used and the blood pressure observed: if it drops by 10 mm Hg or more the test is positive.
The test may be considered more “positive” if symptoms that duplicate those occurring in everyday life are reproduced.
This test is usually conducted by a cardiologist with monitoring of the EKG in an environment where cardiac resuscitation can be performed since it may stimulate abnormal heart rhythms and other changes.