Abstract
Syncope in the elderly may be caused by an apparent hypersensitivity in the high pressure baroreflex control of heart rate and blood pressure - carotid sinus hypersensitivity.
Previous studies have found ambiguous results regarding the baroreceptor sensitivity in patients with carotid sinus hypersensitivity ranging from reduced to increased sensitivity compared to controls. We wanted to establish whether measures of baroreflex sensitivity and autonomic function differed between patients diagnosed with carotid sinus hypersensitivity and age matched controls.
We included 36 patients (12 women; 74 +/-10.2 years) with carotid sinus hypersensitivity and 26 controls (14 women; 72 +/-3.6 years). RR-intervals and blood pressures were measured continuously in the supine and head-up tilted position and during active change to the upright posture. The same parameters were measured during the Valsalva maneuver and deep breathing at 0.1 Hz. From these measurements we derived indices of baroreflex sensitivity and heart rate variability.
We found differences between groups with respect to the tachycardia ratio (p = 0.037) reflecting vagal withdrawal during the Valsalva maneuver and the adrenergic baroreflex sensitivity index (BRSa; p = 0.026) during the same maneuver. We could not demonstrate any significant difference between groups with respect to other measures of cardiovagal or adrenergic baroreceptor control and the response to head-up tilt was comparable between the two groups.
We conclude that only minor differences in autonomic baroreceptor control could be found between patients with carotid sinus hypersensitivity and their controls. Our findings seem to reflect the ambiguous results obtained by others and have led us to suggest that the signals behind the established parameters of cardiovagal baroreflex sensitivity may not follow the same neuronal pathways as those responding to the crude external pressures applied during carotid sinus massage
Previous studies have found ambiguous results regarding the baroreceptor sensitivity in patients with carotid sinus hypersensitivity ranging from reduced to increased sensitivity compared to controls. We wanted to establish whether measures of baroreflex sensitivity and autonomic function differed between patients diagnosed with carotid sinus hypersensitivity and age matched controls.
We included 36 patients (12 women; 74 +/-10.2 years) with carotid sinus hypersensitivity and 26 controls (14 women; 72 +/-3.6 years). RR-intervals and blood pressures were measured continuously in the supine and head-up tilted position and during active change to the upright posture. The same parameters were measured during the Valsalva maneuver and deep breathing at 0.1 Hz. From these measurements we derived indices of baroreflex sensitivity and heart rate variability.
We found differences between groups with respect to the tachycardia ratio (p = 0.037) reflecting vagal withdrawal during the Valsalva maneuver and the adrenergic baroreflex sensitivity index (BRSa; p = 0.026) during the same maneuver. We could not demonstrate any significant difference between groups with respect to other measures of cardiovagal or adrenergic baroreceptor control and the response to head-up tilt was comparable between the two groups.
We conclude that only minor differences in autonomic baroreceptor control could be found between patients with carotid sinus hypersensitivity and their controls. Our findings seem to reflect the ambiguous results obtained by others and have led us to suggest that the signals behind the established parameters of cardiovagal baroreflex sensitivity may not follow the same neuronal pathways as those responding to the crude external pressures applied during carotid sinus massage
| Originalsprog | Engelsk |
|---|---|
| Artikelnummer | 2 |
| Tidsskrift | EC Cardiology |
| Vol/bind | 2 |
| Udgave nummer | 1 |
| Sider (fra-til) | 50-59 |
| Antal sider | 10 |
| Status | Udgivet - 2015 |