Polymorphisms in ß-adrenergic receptors are associated with increased risk to have a positive head-up tilt table test in patients with vasovagal syncope

Abstract Background Vasovagal syncope (VVS) is a frequent clinical condition in which a genetic background seems to be implicated. Considering that the adrenergic receptors (ARs) may play a role in VVS, the present study has as principal aim to determine if the α- and β-AR (ADRA and ADRB) gene polymorphisms are associated with an increased risk to have a positive head-up tilt table (HUTT) test in patients with VVS. Methods: Nine polymorphisms in the ADRA1A (rs1048101, rs1383914, rs574584, and rs573542), ADRB1 (rs1801252 and rs1801253), ADRB2 (rs1042713 and rs1042714), and ADRB3 (rs4994) genes were analyzed using the 5’ exonuclease TaqMan genotyping assay in a group of 134 patients with VVS. Results Under different models, the rs1801252 (OR = 8.63, 95% CI: 0.95-78.72, Precessive = 0.02), rs1042713 (OR = 1.94, 95% CI: 1.02-3.66, Padditive = 0.04), and rs4994 (OR = 2.46, 95% CI: 1.01-6.01, Pdominant = 0.042 and OR = 2.62, 95% CI: 1.04-6.63, Pover-dominant = 0.03) polymorphisms were associated with increased risk for a positive HUTT. All models were adjusted for statistically significant covariates. Conclusion These results suggest that some polymorphisms of the β-AR genes could contribute to a positive tilt test in patients with VVS.

Taquicardia postural ortostática en 15 pacientes: disautonomía compleja / Postural orthostatic tachycardia syndrome (POTS): Report of 15 cases

Background: Patients with postural orthostatic tachycardia syndrome (POTS) report dizziness, lightheadedness, weakness, blurred vision, and fatigue upon standing. The diagnosis of the syndrome is made when an orthostatic intolerance and tachycardia appear in the standing position. Aim: To report 15 patients with POTS. Material and Methods: Review of Tilt test reports in a period of 15 years. Those reports in which orthostatic postural tachycardia and symptoms compatible with POTS appeared, were selected for analysis. Results: We identified 15 patients (3.1% of all positive Tilt test reports) with compatible signs and symptoms. There was a lag of 8 -10 years between the onset of symptoms and the time of diagnosis. Most patients complained of orthostatic intolerance, dizziness and frequent fainting. Orthostatic tachycardia and symptoms occurred on average after 2.9 and 6.1 minutes, respectively,of staying in the standing position. These patients had a high frequency of family history of syncope orpresyncope (66% frequency) and hyper mobility syndrome (53% prevalence). Only 33% of the patients reported relief of their symptoms after being treated (most of them with fludrocortisone). Most patients that reported little or no relief, did not use medications or were treated for a short period. Conclusions: POTS syndrome is uncommon but disturbs quality of life of those who suffer it. Its association with hyper mobility syndromes must be investigated.

A predispodição genética na síncope vasovagal / Neurocariogenic syncope and hereditarity

OBJETIVO: Investigar uma possível predisposição genética para síncope vasovagal. MÉTODOS: Estudo transversal, com 252 indivíduos com história de síncope, submetidos ao teste de inclinação (TI) no Instituto de Cardiologia do Rio Grande do Sul, durante o período de setembro de 2001 a setembro de 2005. Foi analisada a relação entre história familiar positiva para síncope vasovagal e resultado do TI. RESULTADOS: Todos indivíduos foram submetidos ao TI sendo que 126 (50 por cento) casualmente tiveram resultado positivo para síncope vasovagal. História familiar dessa patologia foi identificada em 40 por cento (49/126 casos) dos pacientes com teste de inclinação positivo e em 25 por cento (31/126 pacientes) daqueles que tiveram TI negativo (p= 0,01). CONCLUSÃO: Há uma correlação entre a história familiar de síncope vasovagal e sua ocorrência. É possível que um componente genético possa explicar essa relação.

OBJECTIVE: To investigate a possible familial predisposition in neurocardiogenic syncope. METHODS: Cross-sectional survey with 252 subjects, with positive familial history for syncope, who underwent head-up tilt-test (TT) at Instituto de Cardiologia do Rio Grande do Sul, between September 2001 and September 2005. The relationship between familial history for neurocardiogenic syncope and TT result was analysed. RESULTS: Familial history for neurocardiogenic syncope was identified in 40 percent (49/126 cases) of subjects with positive tilt-test results and 25 percent (31/126 ) of those with negative TT. CONCLUSION: There is a correlation between familial history for neurocardiogenic syncope and its occurence. A genetic component can possibly explain this relationship.