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Introduction: Genetics may be involved in the pathophysiology of vasovagal syncope. The 3A/4A polymorphism of the EDN1 gene affects the expression of endothelin-1, and the H323H T/C polymorphism of the EDNRA gene encoding for the endothelin type A receptor has been associated with cardiovascular pathologies. As the endothelin system participates in the regulation of cardiovascular homeostasis, the aim of this study was to analyse the role of these genetic variants in influencing tilt-induced vasovagal syncope., Materials and Methods: We recorded the cardiovascular parameters of 107 otherwise healthy subjects with recurrent unexplained syncope who underwent a head-up tilt test; 58 (54%) fainted., Results: In terms of the EDNRA polymorphism, eight subjects (8%) had the T/T genotype, 41 were heterozygous (38%) and 58 homozygous (54%) for the C allele. Sixty subjects (56%) carried homozygosis for the 3A allele of the EDN1 polymorphism and 47 were heterozygous (44%). The 4A allele was significantly more frequent in the patients who responded positively to the tilt test than in those who did not: the relative odds ratios and confidence intervals at univariate and multivariate analyses were respectively 2.37 (1.07-5.26) and 2.41 (1.05-5.49). Comparisons with a control group further supported these data. Among the tilt-positive patients, the carriers of the 4A allele were more likely to have a vasodepressive pattern than those who were homozygous for the 3A variant., Conclusion: In conclusion, the 3A/4A polymorphism of the EDN1 gene affects susceptibility to syncope, and the 4A variant associated with increased endothhelin-1 expression may promote vasodepressive hemodynamic responses during tilt testing.

Objectives: As the endothelin system participates in the regulation of cardiovascular homeostasis, the aim of this study was to analyse the role of endothelin system polymorphisms in influencing tilt-induced vasovagal syncope., Methods: We evaluated 107 otherwise healthy subjects with recurrent unexplained syncope who underwent a head-up tilt test. All subjects were genotyped for the 3A/4A polymorphism of the EDN1 gene and the H323H T/C polymorphism of the EDNRA gene., Results: Fifty-eight patients (54%) fainted. In terms of the EDNRA polymorphism, eight subjects (8%) had the T/T genotype, 41 were heterozygous (38%) and 58 homozygous (54%) for the C allele. Sixty subjects (56%) carried homozygosis for the 3A allele of the EDN1 polymorphism and 47 were heterozygous (44%). The 4A allele was significantly more frequent in the patients who responded positively to the tilt test than in those who did not: the relative odds ratios and confidence intervals at univariate and multivariate analyses were respectively 2.37 (1.07-5.26) and 2.41 (1.05-5.49). Comparisons with a control group further supported these data. Among the tilt-positive patients, the carriers of the 4A allele were more likely to have a vasodepressive pattern than those who were homozygous for the 3A variant., Interpretation: The 3A/4A polymorphism of the EDN1 gene affects susceptibility to syncope, and the 4A variant associated with increased endothelin-1 expression may promote vasodepressive hemodynamic responses during tilt testing.

Unlabelled: Vasovagal syncope is an exaggerated form of the common faint affecting all age groups. Aetiology is unknown but the tendency for the disease to run in families has previously been noted., Aim: To determine the true prevalence of family history in subjects with a definitive diagnosis of vasovagal syncope made by positive head up tilt with symptom reproduction. To determine the strength of the genetic effect in vasovagal syncope by calculation of sibling (lambdas) and offspring (lambdao) relative risk. Haemodynamic responses to head up tilt were also examined in a sample of first-degree relatives of those with vasovagal syncope., Results: All subjects identified from the Cardiovascular Investigation Unit database with a definitive diagnosis of vasovagal syncope (n = 603) between 1993-2001 were asked to complete a questionnaire. 19% had positive family history for blackouts or faints. From these pedigrees and using a crude estimate of population prevalence, sibling and offspring relative risk was calculated: lambdas = 1080, lambdao = 1356. Eleven first-degree relatives from 6 families attended for head up tilt testing with glyceryl trinitrate (GTN) provocation (4 unaffected, 7 affected). All subjects had symptoms in response to tilt in association with a range of haemodynamic responses., Conclusions: Vasovagal syncope has a strong genetic component. Elucidating underlying genetic mechanisms may lead to more effective, specific treatments.

This report describes an 11-year-old girl with recurrent syncope beginning at the age of 2 1/2 years. Her paternal grandmother, father, and three of her five natural siblings had similar symptoms, often linked to emotional upsets. There were three adopted children from a single family, and none of these had syncope. Prior to referral there was an increase in attacks, some with convulsions, but with no other features of epilepsy. Vasovagal syncope was confirmed. However, continuous electroencephalogram, blood pressure, and heart rate recordings during attacks indicated that in some episodes there was neither cardiovascular change nor epileptiform activity, implying feigned syncope (pseudosyncope) with pseudoseizures. A psychological origin was sought, found, and in part rectified. The separation of vasovagal syncope from pseudosyncope, in the context of the family history, is discussed.