Purpose: The purpose of this study was to determine the postural blood pressure response over time, the prevalence of orthostatic hypotension in patients with syncope, and the relationship of orthostatic hypotension to recurrence of symptoms.
Patients and methods: We prospectively evaluated 223 patients with syncope in a standardized manner. Orthostatic responses were measured in a standardized fashion at 0, 1, 2, 3, 5, and 10 minutes or until symptoms occurred. Follow-up was obtained at 3-month intervals. Causes of syncope were assigned by predetermined criteria.
Results: Orthostatic hypotension (20 mm Hg or greater systolic blood pressure decline) was found in 69 patients (31%). The median time to reach minimal standing systolic blood pressure was 1 minute for all subjects. In patients with orthostatic hypotension (20 mm Hg or greater), mean time to reach minimum blood pressure was 2.4 minutes. The vast majority of patients with significant orthostatic hypotension had this finding within 2 minutes of standing. Orthostatic hypotension was common in patients for whom other probable causes of syncope were assigned. The recurrence of syncope was not related to the degree of orthostatic hypotension; however, the recurrence of dizziness and syncope as end-points was lower in patients with 20 mm Hg or greater systolic blood pressure reductions as compared with patients with lesser degrees of orthostatic blood pressure declines.
Conclusion: Orthostatic hypotension is common in patients with syncope and is detected in the vast majority of patients by 2 minutes. Although symptom recurrence on follow-up was lower in patients with more severe orthostatic hypotension, the clinical significance of this finding needs to be further defined by future studies.