Key result
In nitroglycerine tilt-induced vasovagal syncope, arterial resistance drop drives vasodepressive syncope, whereas reduced venous return drives mixed and cardioinhibitory syncope.
Why the study?
What is the main hemodynamic determinant of hypotension during nitroglycerine tilt-induced vasovagal syncope in patients with syncope of unknown origin?
Observational (n=200)
What is the main hemodynamic determinant of hypotension during nitroglycerine tilt-induced vasovagal syncope in patients with syncope of unknown origin?
The arterial system is the main determinant of blood pressure fall in vasodepressive syncope, whereas reduced venous return drives the fall in mixed and cardioinhibitory vasovagal syncope.
Supports subtype-specific hemodynamics in tilt-induced vasovagal syncope; hypothesis-generating and should not yet change practice.
BACKGROUND: The aim of the study was to assess the main determinant of the fall in blood pressure (BP) responsible for the head-up tilt testing-induced syncope. METHODS AND RESULTS: The study involved 200 patients (mean age 42 ± 3; 81 male) with syncope of unknown origin after the first evaluation. According to the response to the diagnostic tilt test, the population study was divided into four groups: Group I with mixed vasovagal syncope; Group II with cardioinhibitory syncope; Group III with vasodepressive syncope; Group IV: 40 patients with clinical syncope but no tilt-induced syncope. Finger arterial BP (Portapres, TNO, Amsterdam, the Netherlands) was recorded during tilt testing. Left ventricular stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) were computed from the pressure pulsations (Modelflow, TNO, Amsterdam, the Netherlands). During syncopal phase, the TPR decreased significantly in Group III, and increased in Group I and in Group II. CO decreased in Group I and in Group II and did not change significantly in Group III. SV decreased significantly in all groups. CONCLUSIONS: Our data showed that the arterial system appears to be the main determinant of the BP fall in vasodepressive vasovagal syncope; while the impaired constrictive response of the venous system, leading to reduced venous return to the heart, appears to be the main determinant of BP fall in mixed and cardioinhibitory vasovagal syncope.
No takes yet. Share an insight, caveat, or question.
Nigro et al. (2012) conducted an observational in Syncope of unknown origin (n=200). Nitroglycerine head-up tilt testing vs. Comparison among different syncope response groups (mixed, cardioinhibitory, vasodepressive, and no tilt-induced syncope) was evaluated on Determinants of blood pressure fall (total peripheral resistance, cardiac output, and stroke volume). In nitroglycerine tilt-induced vasovagal syncope, arterial resistance drop drives vasodepressive syncope, whereas reduced venous return drives mixed and cardioinhibitory syncope.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: