© 2005 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved.
Familial vasovagal syncope
Electrocardiology Department, Instituto Nacional de Cardiología "Ignacio Chávez" México, D.F., Mexico
Manuscript submitted 14 January 2005. Revision received 25 July 2005. Accepted after revision 7 May 2005.
*Corresponding author. Instituto Nacional de Cardiología "Ignacio Chávez", Subdirección de Investigación, Juan Badiano 1, Sección XVI, Tlalpan 14080, México, D.F., México. Tel.: +52 55 5573 2911x1178, 1411; fax: +52 55 5573 0926. E-mail address: yog_14080{at}yahoo.com (M. Cárdenas).
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Abstract |
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 Top Abstract IntroductionFamily with syncopeSyncope in monozygotic twinsTreatment of VVSDiscussionReferences |
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Vasovagal syncope (VVS) is a common clinical problem characterized by transient episodes of loss of consciousness due to abnormal autonomic activity. This paper describes two groups of monozygotic twins, from different families, affected by VVS and a family with several members with this condition. Their clinical characteristics, haemodynamic response to tilt, treatment, and outcome are described.
Key Words: vasovagal syncope, familial syncope, head-up tilt test
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Introduction |
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TopAbstractIntroductionFamily with syncopeSyncope in monozygotic twinsTreatment of VVSDiscussionReferences |
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Vasovagal syncope (VVS) is a common clinical problem, characterized by transient episodes of loss of consciousness due to abnormal autonomic activity [1]
. It occurs most frequently in young people and is associated with premonitory signs and symptoms. The pathophysiology of this condition is not completely understood, often resulting in difficult diagnosis and treatment [2–5]. Clinical descriptions of familial VVS are scarce [6–11]. This article reports several members of a family affected by VVS, their clinical characteristics, response to head-up tilt test (HUT), treatment, and outcome. Two groups of monozygotic twins with VVS, from different families, are also described. |
Family with syncope |
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TopAbstractIntroductionFamily with syncopeSyncope in monozygotic twinsTreatment of VVSDiscussionReferences |
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The index case was a 20-year-old female with a 4 year history of recurrent syncope from a Mexican mestizo family (Fig. 1). She had palpitations, dizziness and weakness that sometimes were prodromal for an impending syncopal event. A drug-free HUT at 70° was positive at 20 min with a mixed haemodynamic response. The remaining family members, with the exception of the mother, had recurrent syncope and a positive HUT. Demographic data, HUT results, and treatment are shown in Table 1. Cardiac and neurological diseases were excluded in all subjects.
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Syncope in monozygotic twins |
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TopAbstractIntroductionFamily with syncopeSyncope in monozygotic twinsTreatment of VVSDiscussionReferences |
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Table 2 shows the clinical findings in the two monozygotic sets of twins. One set was male, the other female. Patients had recurrent syncope, with signs and symptoms suggestive of VVS. There was no history of syncope in parents or relatives of the boys but the mother of the girls gave a history of syncopal attacks. HUT at 70° was positive in two passive tests performed in each male twin and with a drug challenge (isosorbide dinitrate 5 mg SL) in the females (Table 2). The mother of the girls also had a positive passive HUT test. All showed a mixed haemodynamic response. Cardiac and neurological diseases were excluded in all subjects.
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Treatment of VVS |
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TopAbstractIntroductionFamily with syncopeSyncope in monozygotic twinsTreatment of VVSDiscussionReferences |
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In all patients an increased consumption of water (2 l/d) and salt (1 g/d) was recommended. Only three patients were treated with ß-blockers because of syncope recurrence. During a mean follow-up of 13.6 months (range 9–24 months), no recurrences of syncopal episodes were observed.
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Discussion |
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TopAbstractIntroductionFamily with syncopeSyncope in monozygotic twinsTreatment of VVSDiscussionReferences |
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Cases of familial syncope have been reported [6–
11]. Cooper et al. described VVS in mother and daughter [10]. A case-control study by Camfield and Camfield showed that among children with VVS, a significant proportion had a parent or sibling with syncope, an association not seen in control subjects [6]. Mathias et al. reported a familial tendency for VVS, confirmed with HUT at 45° [8]. They observed a positive family history of VVS in 90% of their group under the age of 20 years (27 of 30 children). In their series, most patients with adult-onset VVS did not have a family history of syncope. In the present communication, familial adult-onset of VVS confirmed with HUT is described. All had mixed haemodynamic responses during the test according to the Brignole et al. classification [3]. Two sets of monozygotic twins with recurrent syncope belonging to two different families are also reported. A positive HUT confirmed a vasovagal origin. There was a history of syncopal attacks in the mother of the girls who also had a positive HUT test.
There are no published molecular genetic studies in VVS. It is difficult, if not impossible, to define only by familial pedigrees, when familial syncope has a genetic basis or is due to the high frequency of this symptom in the general population. According to Mathias et al., most adult-onset patients with VVS did not have a family history. In those with a family history, 73% had a parent or a child but only 27% had other relatives with syncope. This result does not exclude, but makes less likely, an autosomal dominant inheritance. It is possible that the inherited tendency to faint is multifactorial, with genetic, psychological, and environmental factors. Molecular genetic studies should be performed to answer these questions. Recently, a mutation resulting in a deficiency of the noradrenaline transporter was found in a family with postural orthostatic tachycardia syndrome, a disease associated with postural syncope [12]. Impairment of synaptic noradrenaline clearance could potentially result in a state of excessive sympathetic activation in response to physiological stimuli [13].
This report suggests the possibility of a genetic influence in VVS, underlining the importance of investigating this condition in first degree relatives of patients and the importance of future molecular genetic studies.
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References |
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TopAbstractIntroductionFamily with syncopeSyncope in monozygotic twinsTreatment of VVSDiscussionReferences |
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[1] Soteriades E, Evans J, Larson M, et al. Incidence and prognosis of syncope. N Engl J Med 2002; 12: 878–885.
[2] Hermosillo A, Márquez M, Jáuregui-Renaud K, Cárdenas M. Orthostatic Hypotension 2001. Cardiol Rev 2001; 9: 339–347.[CrossRef][Medline]
[3] Brignole M, Menozzi C, Del Rosso A, et al. New classification of haemodynamics of vasovagal syncope: beyond the VASIS classification. Europace 2000; 2: 66–76.
[4] Hermosillo AG, Márquez MF, Jauregui-Renaud K, et al. Tilt testing in neurocardiogenic syncope: isosorbide versus isoproterenol. Acta Cardiol 2000; 55: 351–355.[Medline]
[5] Jaúregui-Renaud K, Márquez MF, Hermosillo AG, et al. Paced breathing can prevent vasovagal syncope during head-up tilt testing. Can J Cardiol 2003; 19: 698–700.[Medline]
[6] Camfield PR and Camfield CS. Syncope in childhood: a case control clinical study of the family tendency to faint. Can J Neurol Sci 1990; 17: 306–308.[ISI][Medline]
[7] Mathias CJ, Bleasdale-Barr K, Alam M. Familial fainting-observations in three families, including one with adopted children. Clin Autonom Res 1995; 5: 105.
[8] Mathias C, Deguchi K, Bleasdale-Barr K, Kimber J. Frequency of family history in vasovagal syncope. Lancet 1998; 352: 33–34.[ISI][Medline]
[9] Mathias CJ, Deguchi K, Bleasdale-Barr K, Smith S. Familial vasovagal syncope and pseudosyncope: observations in a case with both natural and adopted siblings. Clin Auton Res 2000; 10: 43–45.[CrossRef][ISI][Medline]
[10] Cooper CJ, Ridker P, Shea J, Creager MA. Familial occurrence of neurocardiogenic syncope. N Engl J Med 1994; 331: 205.
[11] Lewis SL and O'Toole M. Familial occurrence of neurocardiogenic syncope. N Engl J Med 1994; 331: 1529.
[12] Shannon JR, Flattem NL, Jordan J, et al. Orthostatic intolerance and tachycardia associated with norepinephrine-transporter deficiency. N Engl J Med 2000; 342: 541–549.
[13] Alehan D, Ayabakan C, Özner S. Heart rate variability and autonomic nervous system changes in children with vasovagal syncope. Pacing Clin Electrophysiol 2002; 25: 1331–1338.[Medline]
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