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Sublingual nitroglycerin used in routine tilt testing provokes a cardiac output-mediated vasovagal response.
J Am Coll Cardiol. 2004 Aug 04; 44(3):588-93.JACC

Abstract

OBJECTIVES

We set out to determine the effect of sublingual nitroglycerin (NTG), as used during routine tilt testing in patients with unexplained syncope, on hemodynamic characteristics and baroreflex control of heart rate (HR) and systemic vascular resistance (SVR).

BACKGROUND

Nitroglycerin is used in tilt testing to elicit a vasovagal response. It is known to induce venous dilation and enhance pooling. Also, NTG is lipophilic and readily passes cell membranes, and animal studies suggest a sympatho-inhibitory effect of NTG on circulatory control.

METHODS

Routine tilt testing was conducted in 39 patients with suspected vasovagal syncope (age 36 +/- 16 years, 18 females). Patients were otherwise healthy and free of medication. Before a loss of consciousness set in, oncoming syncope was cut short by tilt-back or counter-maneuvers. Finger arterial pressure was monitored continuously (Finapres). Left ventricular stroke volume (SV) was computed from the pressure pulsations (Modelflow). Spontaneous baroreflex control of HR was estimated in the time and frequency domains.

RESULTS

During tilt testing, 22 patients developed presyncope. After NTG administration but before presyncope, SV and cardiac output (CO) decreased (p < 0.001), whereas SVR and HR increased (p < 0.001) in all patients. Arterial pressure was initially maintained. Baroreflex sensitivity decreased after NTG. On Cox regression analysis, the occurrence of a vasovagal response was related to a drop in SV after NTG (hazard ratio 0.86, p = 0.005).

CONCLUSIONS

The cardiovascular response to NTG is similar in vasovagal and non-vasovagal patients, but more pronounced in those with tilt-positive results. The NTG-facilitated presyncope appears to be CO-mediated, and there is no evidence of NTG-induced sympathetic inhibition.

Authors+Show Affiliations

Gisolf J
Department of Physiology, Academic Medical Center, Cardiovascular Research Institute, Amsterdam, The Netherlands. j.gisolf@amc.uva.nl
Westerhof BE
No affiliation info available
van Dijk N
No affiliation info available
Wesseling KH
No affiliation info available
Wieling W
No affiliation info available
Karemaker JM
No affiliation info available

MeSH

Administration, SublingualAdultBaroreflexCardiac OutputDiagnosis, DifferentialFemaleHumansMaleMiddle AgedNitroglycerinProportional Hazards ModelsResearch DesignSyncope, VasovagalTilt-Table TestVascular Resistance

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15358026

Citation

Gisolf, Janneke, et al. "Sublingual Nitroglycerin Used in Routine Tilt Testing Provokes a Cardiac Output-mediated Vasovagal Response." Journal of the American College of Cardiology, vol. 44, no. 3, 2004, pp. 588-93.
Gisolf J, Westerhof BE, van Dijk N, et al. Sublingual nitroglycerin used in routine tilt testing provokes a cardiac output-mediated vasovagal response. J Am Coll Cardiol. 2004;44(3):588-93.
Gisolf, J., Westerhof, B. E., van Dijk, N., Wesseling, K. H., Wieling, W., & Karemaker, J. M. (2004). Sublingual nitroglycerin used in routine tilt testing provokes a cardiac output-mediated vasovagal response. Journal of the American College of Cardiology, 44(3), 588-93.
Gisolf J, et al. Sublingual Nitroglycerin Used in Routine Tilt Testing Provokes a Cardiac Output-mediated Vasovagal Response. J Am Coll Cardiol. 2004 Aug 4;44(3):588-93. PubMed PMID: 15358026.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Sublingual nitroglycerin used in routine tilt testing provokes a cardiac output-mediated vasovagal response. AU - Gisolf,Janneke, AU - Westerhof,Berend E, AU - van Dijk,Nynke, AU - Wesseling,Karel H, AU - Wieling,Wouter, AU - Karemaker,John M, PY - 2004/03/15/received PY - 2004/03/26/revised PY - 2004/04/06/accepted PY - 2004/9/11/pubmed PY - 2004/9/24/medline PY - 2004/9/11/entrez SP - 588 EP - 93 JF - Journal of the American College of Cardiology JO - J Am Coll Cardiol VL - 44 IS - 3 N2 - OBJECTIVES: We set out to determine the effect of sublingual nitroglycerin (NTG), as used during routine tilt testing in patients with unexplained syncope, on hemodynamic characteristics and baroreflex control of heart rate (HR) and systemic vascular resistance (SVR). BACKGROUND: Nitroglycerin is used in tilt testing to elicit a vasovagal response. It is known to induce venous dilation and enhance pooling. Also, NTG is lipophilic and readily passes cell membranes, and animal studies suggest a sympatho-inhibitory effect of NTG on circulatory control. METHODS: Routine tilt testing was conducted in 39 patients with suspected vasovagal syncope (age 36 +/- 16 years, 18 females). Patients were otherwise healthy and free of medication. Before a loss of consciousness set in, oncoming syncope was cut short by tilt-back or counter-maneuvers. Finger arterial pressure was monitored continuously (Finapres). Left ventricular stroke volume (SV) was computed from the pressure pulsations (Modelflow). Spontaneous baroreflex control of HR was estimated in the time and frequency domains. RESULTS: During tilt testing, 22 patients developed presyncope. After NTG administration but before presyncope, SV and cardiac output (CO) decreased (p < 0.001), whereas SVR and HR increased (p < 0.001) in all patients. Arterial pressure was initially maintained. Baroreflex sensitivity decreased after NTG. On Cox regression analysis, the occurrence of a vasovagal response was related to a drop in SV after NTG (hazard ratio 0.86, p = 0.005). CONCLUSIONS: The cardiovascular response to NTG is similar in vasovagal and non-vasovagal patients, but more pronounced in those with tilt-positive results. The NTG-facilitated presyncope appears to be CO-mediated, and there is no evidence of NTG-induced sympathetic inhibition. SN - 0735-1097 UR - https://www.unboundmedicine.com/medline/citation/15358026/Sublingual_nitroglycerin_used_in_routine_tilt_testing_provokes_a_cardiac_output_mediated_vasovagal_response_ DB - PRIME DP - Unbound Medicine ER -