Nonspecific dizziness: frequency of supine hypertension associated with hypotensive reactions on head-up tilt.

The clinical syndrome of supine hypertension associated with orthostatic hypotension (OH) in given individuals is recognized by specialists, but is underdiagnosed in the community. The objective of this study was to assess supine hypertension associated with hypotensive reactions on head-up tilt (SH-HRT) among patients evaluated for nonspecific dizziness. Consecutive patients with nonspecific dizziness were studied with a 10-min supine 30-min head-up tilt test. Supine hypertension (SH) was diagnosed when supine systolic blood pressure (SBP) was > or = 140 mmHg and/or supine diastolic blood pressure (DBP) was > or = 90 mmHg. Hypotensive reactions on tilt (HRT) were diagnosed when SBP decreased by > or = 30 mmHg on tilt and/or DBP decreased by > or = 15 mmHg. Of 430 patients tested, 42 (9.8%) had SH-HRT. The median age was 67 years; 37 had a pretest diagnosis of hypertension, with treatment. The median supine BP was 162/90 mmHg; the median nadir BP on tilt was 118/78 mmHg. Four SH-HRT patterns were recognized: (I) SH with typical neurogenic OH (n = 6), (II) SH with vasovagal reaction on tilt (n = 4), (III) SH with sustained HRT (n = 28), and (IV) SH with mixed orthostatic-vasovagal reaction on tilt (n = 4). Dizziness on tilt occurred in 25% of patients category III (SH with sustained HRT), while appearing universally in other SH-HRT patterns. In conclusion, nonspecific dizziness may be the chief complaint in patients with SH-HRT, a disorder often unrecognized by clinicians. Different patterns of SH-HRT on HUTT may reflect different aberrations in cardiovascular homeostasis and may require differentiated management strategies.