Impact of age on the vasovagal response provoked by sublingual nitroglycerine in routine tilt testing

Bart Verheyden (1) , Janneke Gisolf , Frank Beckers , John M Karemaker , Karel H Wesseling , Andre E Aubert , Wouter Wieling

1 Cardiovascular Diseases

Nitroglycerine (NTG) is used in routine tilt testing to elicit a vasovagal response. We hypothesized that with increasing age NTG triggers a more gradual blood pressure decline due to a diminished baroreflex buffering capacity. The purpose was to examine the effect of NTG on baroreflex control of blood pressure in patients with distinct age-related vasovagal collapse patterns. The study groups consisted of 29 patients (16-71 yrs, 17 females) with clinically suspected VVS and a positive tilt test. Mean finger arterial pressure (MAP) was monitored continuously (Finapres). Left ventricular stroke volume (SV), cardiac output (CO) and systemic vascular resistance (SVR) were computed from the pressure pulsations (Modelflow). Spontaneous baroreflex control of heart rate (BRS) was estimated in the time domain. In the first 3 minutes after NTG, blood pressure was well maintained in all patients. This implies an adequate arterial resistance response to compensate for steeper reductions in SV and CO with increasing age. Heart rate (HR) increased and the BRS decreased after NTG. The rate of MAP-fall leading to presyncope was inversely related to age (r = 0.51, p = 0.005). Accordingly, patients with a MAP-fall > 1.44 mmHg/s (median) were generally younger compared to patients with a slower MAP-fall (30 ± 10 yrs vs. 51 ± 17 yrs; p = 0.001). The main determinant of the rate blood pressure drop on approach of presyncope was the rate of fall in HR (r = 0.75, p < 0.001). It is concluded that, in the older patients, sublingual NTG provokes a more gradual blood pressure decline compared to the younger. This gradual decline cannot be ascribed to failure of the baroreflex buffering capacity with increasing age. Age-related differences in the laboratory presentation of a vasovagal episode depend on the magnitude of the underlying bradycardic response.

Mots clés: Medicine

Bart Verheyden, Janneke Gisolf, Frank Beckers, John M Karemaker, Karel H Wesseling, et al.. Impact of age on the vasovagal response provoked by sublingual nitroglycerine in routine tilt testing. Clinical Science, 2007, 113 (7), pp.329-337. ⟨10.1042/CS20070042⟩. ⟨hal-00479366⟩