Clinical features of prolonged tilt-induced hypotension with an apparent vasovagal mechanism, but without syncope



      A previous study of electroencephalography (EEG) changes with syncope led to a finding that some young patients develop prolonged periods of tilt-induced hypotension, but they do not lose consciousness. The present study aim was to compare patterns of hemodynamic changes, measures of duration, and sweating between these patients and patients with tilt-induced vasovagal syncope.


      In an observational study, qualitative changes in hemodynamic parameters were compared between patients with prolonged hypotension (n = 30) and with syncope (n = 30). To demonstrate that periods of hypotension far-exceed the typical presyncope period, several parameters were used to compare the durations of events between groups. Differences in sweating patterns were explored.


      Parallels in hemodynamic changes were present in both groups suggesting similar vasovagal mechanisms. Patients with prolonged hypotension had longer durations of hypotension (165 ± 44 versus 57 ± 13 s, p < 0.001), diminished cardiac output (109 ± 38 versus 32 ± 9 s, p < 0.001), and EEG slowing (85 ± 31 versus 9 ± 4 s, p < 0.001) compared to patients with syncope. While all patients generated an increase in sweat rate, those with hypotension only developed a robust sweat response that always preceded the plateau in hypotension compared to 14 (47%) patients with syncope who developed an increase in sweating prior to syncope, p < 0.001.


      Similarities are present among hemodynamic changes with prolonged hypotension and with tilt-induced vasovagal syncope, suggesting a possible vasovagal mechanism for prolonged hypotension. If true, understanding why some individuals develop a vasovagal response that does not culminate in rapid syncope may help to elucidate the physiologic underpinnings of the vasovagal reflex.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Autonomic Neuroscience: Basic and Clinical
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Cooke W.H.
        • Rickards C.A.
        • Ryan K.L.
        • Kuusela T.A.
        • Convertino V.A.
        Muscle sympathetic nerve activity during intense lower body negative pressure to presyncope in humans.
        J. Physiol. 2009; 587 (Pt 20. October 15): 4987-4999
      1. Freeman R, Wieling W, Axelrod FB et al. Consensus statement on the definition of orthostatic hypotension, neurally mediated syncope and the postural tachycardia syndrome. Clin. Auton. Res. 2011 April;21(2):69–72.

        • Fu Q.
        • Verheyden B.
        • Wieling W.
        • Levine B.D.
        Cardiac output and sympathetic vasoconstrictor responses during upright tilt to presyncope in healthy humans.
        J. Physiol. 2012; 590 (April 15): 1839-1848
        • Ganzeboom K.S.
        • Colman N.
        • Reitsma J.B.
        • Shen W.K.
        • Wieling W.
        Prevalence and triggers of syncope in medical students.
        Am. J. Cardiol. 2003; 91 (April 15. (A8)): 1006-1008
        • Ganzeboom K.S.
        • Mairuhu G.
        • Reitsma J.B.
        • Linzer M.
        • Wieling W.
        van DN. Lifetime cumulative incidence of syncope in the general population: a study of 549 Dutch subjects aged 35–60 years.
        J. Cardiovasc. Electrophysiol. 2006; 17 (November): 1172-1176
        • Heyer G.L.
        • Schmittauer C.
        • Islam M.P.
        The clinical and electroencephalographic spectrum of tilt-induced syncope and "near Syncope" in youth.
        Pediatr. Neurol. 2016; 62 (September): 27-33
        • Heyer G.L.
        • Harvey R.A.
        • Islam M.P.
        Sweat patterns differ between tilt-induced reflex syncope and tilt-induced anxiety among youth.
        Clin. Auton. Res. 2016; 26 (August): 295-302
        • Jardine D.L.
        • Melton I.C.
        • Crozier I.G.
        • Bennett S.I.
        • Donald R.A.
        • Ikram H.
        Neurohormonal response to head-up tilt and its role in vasovagal syncope.
        Am. J. Cardiol. 1997; 79 (May 1): 1302-1306
        • Jardine D.L.
        • Ikram H.
        • Frampton C.M.
        • Frethey R.
        • Bennett S.I.
        • Crozier I.G.
        Autonomic control of vasovagal syncope.
        Am. J. Phys. 1998 June; 274: H2110-H2115
      2. Jardine DL, Melton IC, Crozier IG et al. Decrease in cardiac output and muscle sympathetic activity during vasovagal syncope. Am. J. Physiol. Heart Circ. Physiol. 2002 May;282(5):H1804-H1809.

        • Jardine D.L.
        • Wieling W.
        • Brignole M.
        • Lenders J.W.M.
        • Sutton R.
        • Stewart J.
        The pathophysiology of the vasovagal response.
        Heart Rhythm. 2018; 15 (June): 921-929
        • Lewis T.
        A Lecture on vasovagal syncope and the carotid sinus mechanism.
        Br. Med. J. 1932; 1 (May 14): 873-876
      3. Moya A, Sutton R, Ammirati F et al. Guidelines for the diagnosis and management of syncope (version 2009). Eur. Heart J. 2009 November;30(21):2631–71.

      4. Podoleanu C, Maggi R, Oddone D et al. The hemodynamic pattern of the syndrome of delayed orthostatic hypotension. J. Interv. Card. Electrophysiol. 2009 November;26(2):143–9.

        • Serletis A.
        • Rose S.
        • Sheldon A.G.
        • Sheldon R.S.
        Vasovagal syncope in medical students and their first-degree relatives.
        Eur. Heart J. 2006; 27 (August): 1965-1970
      5. Shen WK, Sheldon RS, Benditt DG et al. 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope: a report of the American College of Cardiology/American Heart Association task force on clinical practice guidelines and the Heart Rhythm Society. Heart Rhythm. 2017 August;14(8):e155-e217.

        • Stewart J.M.
        • Medow M.S.
        • Sutton R.
        • Visintainer P.
        • Jardine D.L.
        • Wieling W.
        Mechanisms of vasovagal Syncope in the young: reduced systemic vascular resistance versus reduced cardiac output.
        J. Am. Heart Assoc. 2017 January 18; 6
        • Streeten D.H.
        • Anderson Jr., G.H.
        Delayed orthostatic intolerance.
        Arch. Intern. Med. 1992 May; 152: 1066-1072
        • Streeten D.H.
        • Anderson Jr., G.H.
        The role of delayed orthostatic hypotension in the pathogenesis of chronic fatigue.
        Clin. Auton. Res. 1998; 8 (April): 119-124
        • Vaddadi G.
        • Esler M.D.
        • Dawood T.
        • Lambert E.
        Persistence of muscle sympathetic nerve activity during vasovagal syncope.
        Eur. Heart J. 2010; 31 (August): 2027-2033
      6. van Dijk JG, Thijs RD, vanZwet E et al. The semiology of tilt-induced reflex syncope in relation to electroencephalographic changes. Brain 2014 February;137(Pt 2):576–85.

        • Verheyden B.
        • Liu J.
        van DN et al. steep fall in cardiac output is main determinant of hypotension during drug-free and nitroglycerine-induced orthostatic vasovagal syncope.
        Heart Rhythm. 2008; 5 (December): 1695-1701
        • Wallin B.G.
        • Sundlof G.
        Sympathetic outflow to muscles during vasovagal syncope.
        J. Auton. Nerv. Syst. 1982 November; 6: 287-291