TY - JOUR
T1 - Distinct hemodynamic profiles in patients with vasovagal syncope
T2 - A heterogeneous population
AU - Shen, Win Kuang
AU - Low, Phillip A.
AU - Rea, Robert F.
AU - Lohse, Christine M.
AU - Hodge, David O.
AU - Hammill, Stephen C.
N1 - Funding Information:
Drs. Shen and Low were supported by Program Project Grant PPG NS3 2952 from the National Institutes of Health, which also supported the development of software for data acquisition.
PY - 2000/5
Y1 - 2000/5
N2 - Objective. The objective was to investigate mechanisms of vasovagal syncope by identifying laboratory techniques that characterize cardiovascular profiles in patients with vasovagal syncope. Background. The triggering mechanisms of vasovagal syncope are complex. The patient population is likely heterogeneous. We hypothesized that distinct hemodynamic profiles are definable with provocative maneuvers. Methods. Three groups of subjects were matched for age and gender: 16 patients with a history of syncope and an inducible vasovagal response during passive tilt table testing (70°, 45 min, group I), 16 with a history of syncope, negative passive tilt table testing but positive isoproterenol tilt table testing (0.05 μg/kg per min, 70°, 10 min, group II), and 16 control subjects. Beat-to-beat hemodynamic functions were determined noninvasively by photoplethysmography and impedance cardiography. Results. At baseline, hemodynamic functions were not different among the three groups (supine). In response to tilt before any symptoms developed, total peripheral resistance decreased 9% ± 14% in group I from baseline supine to tilt position but increased 27% ± 18% in group II and 28% ± 17% in controls (p < 0.001). Responses to isoproterenol were not significantly different between group II and controls in supine position. In response to tilt during isoproterenol infusion before any symptoms developed, total peripheral resistance decreased 24% ± 20% in group II and increased 20% ± 48% in controls (p = 0.002). Conclusions. Group I patients may have impaired ability to increase vascular resistance during orthostatic stress. The inability to overcome isoproterenol-induced vasodilatation during tilt is important in triggering a vasovagal response in group II patients. These data suggest that the population with vasovagal response is heterogeneous. Distinct hemodynamic profiles in response to various provocative maneuvers are definable with noninvasive, continuous monitoring techniques. (C) 2000 by the American College of Cardiology.
AB - Objective. The objective was to investigate mechanisms of vasovagal syncope by identifying laboratory techniques that characterize cardiovascular profiles in patients with vasovagal syncope. Background. The triggering mechanisms of vasovagal syncope are complex. The patient population is likely heterogeneous. We hypothesized that distinct hemodynamic profiles are definable with provocative maneuvers. Methods. Three groups of subjects were matched for age and gender: 16 patients with a history of syncope and an inducible vasovagal response during passive tilt table testing (70°, 45 min, group I), 16 with a history of syncope, negative passive tilt table testing but positive isoproterenol tilt table testing (0.05 μg/kg per min, 70°, 10 min, group II), and 16 control subjects. Beat-to-beat hemodynamic functions were determined noninvasively by photoplethysmography and impedance cardiography. Results. At baseline, hemodynamic functions were not different among the three groups (supine). In response to tilt before any symptoms developed, total peripheral resistance decreased 9% ± 14% in group I from baseline supine to tilt position but increased 27% ± 18% in group II and 28% ± 17% in controls (p < 0.001). Responses to isoproterenol were not significantly different between group II and controls in supine position. In response to tilt during isoproterenol infusion before any symptoms developed, total peripheral resistance decreased 24% ± 20% in group II and increased 20% ± 48% in controls (p = 0.002). Conclusions. Group I patients may have impaired ability to increase vascular resistance during orthostatic stress. The inability to overcome isoproterenol-induced vasodilatation during tilt is important in triggering a vasovagal response in group II patients. These data suggest that the population with vasovagal response is heterogeneous. Distinct hemodynamic profiles in response to various provocative maneuvers are definable with noninvasive, continuous monitoring techniques. (C) 2000 by the American College of Cardiology.
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U2 - 10.1016/S0735-1097(00)00567-2
DO - 10.1016/S0735-1097(00)00567-2
M3 - Article
C2 - 10807449
AN - SCOPUS:0034068979
SN - 0735-1097
VL - 35
SP - 1470
EP - 1477
JO - Journal of the American College of Cardiology
JF - Journal of the American College of Cardiology
IS - 6
ER -