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Updated: Jul 15, 2026

Tilt Testing with Combined Lower Body Negative Pressure: a "Gold Standard" for Measuring Orthostatic Tolerance
Published on: March 21, 2013
The Arg389Gly beta1-adrenergic receptor gene polymorphism and susceptibility to faint during head-up tilt test
M F Márquez1, Guadalupe Hernández-Pacheco, Antonio G Hermosillo
1Department of Electrocardiology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico.
Aims:
To investigate the association of the Gly389 allele with positive head-up tilt test (HUT) in a Mexican Mestizo population.
Methods And Results:
HUT results were compared between carriers (one or two copies of the Gly389 allele) and non-carriers (Arg389Arg genotype) of the Gly389 allele of the beta(1)AR gene in 50 patients with unexplained syncope. Thirty-three patients (66%) had a positive HUT. Patients with a positive HUT had a higher Gly389 allele frequency compared with those with a negative test (30.3 vs. 3%; OR 13; pC = 0.012). Moreover, when comparing positive HUT in passive drug-free phase, positive HUT in pharmacological (nitrate) phase, and negative (both phases), a decreasing gradient in the frequencies of the Gly389 allele was found among the three groups: 45.4, 22.7, and 3%, respectively.
Conclusion:
An association of positive tilt table testing to a single nucleotide polymorphism with a Gly to Arg switch at position 389 of the beta(1)AR was found. This polymorphism may contribute to susceptibility to faint during orthostatic challenge.
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