In order to may be superior to looking at heart rate alone.
A cHR/cSBP ratio of 0.492 beats per minute (bpm)/mm Hg had the best sensitivity and specificity to distinguish neurogenic from nonneurogenic causes, according to results of a prospective study published in Annals of Neurology.
Dr. Lucy Norcliffe-Kaufmann
“If you just look at the heart rate increase alone, of course it is blunted, but it doesn’t really give you the bigger picture that you get when you look at the heart rate in relation to the blood pressure fall,” Dr. Norcliffe-Kaufmann said in an interview.
Neurogenic orthostatic hypotension, which indicates an underlying pathology affecting autonomic neurons, has a much worse prognosis than does nonneurogenic orthostatic hypotension, according to Dr. Norcliffe-Kaufmann and her colleagues, who published the results on behalf of the Autonomic Disorders Consortium.
One key difference between the two groups, they added, is that patients with neurogenic orthostatic hypotension typically have little or no heart rate (HR) increase in the upright position, while patients with nonneurogenic orthostatic hypotension may have marked tachycardia.
Despite the importance of orthostatic HR changes in differential diagnosis, however, there has been no systematic evaluation of HR ranges that may be diagnostic, and proposed ranges have been based on expert clinical experience rather than clinical data, they said.