{
  "abstract": "Background Vasovagal syncope results from transient cerebral hypoperfusion, but the precise regional fluid shifts preceding syncope remain unclear.Methods In this prospective observational study, 112 adults referred for syncope evaluation underwent 70° head-up tilt testing with simultaneous continuous multi-segmental bioelectrical impedance analysis (BIA) of thoracic, splanchnic, and thigh compartments, alongside beat-to-beat arterial pressure and ECG monitoring. Nineteen datasets were excluded due to missing signals or electrode displacement, leaving 93 participants with analysable data (56 fainters, 37 non-fainters).Results Systolic blood pressure diverged between groups 3 minutes before syncope (p=0.02). In the final 4 minutes of tilt, non-fainters demonstrated adaptive responses: increased splanchnic impedance (+1.4%±0.3%, p=0.001) with stable thoracic impedance, indicating blood autotransfusion from the splanchnic bed to the central circulation. Fainters showed maladaptive responses: no change in splanchnic impedance (−0.5%±0.4%, p=0.09) with increased thoracic impedance (2.9%±0.3%, p=0.02), indicating splanchnic blood pooling. Both groups similarly accumulated fluid in the lower limbs.Conclusions Vasovagal syncope results from failure of splanchnic circulatory compensation rather than excessive lower limb pooling. The splanchnic circulation represents a critical physiological compartment in the pathogenesis of vasovagal syncope.",
  "authors": [
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Mohamed Zuhair"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Nandita Kaza"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Zhuang Liu"
    },
    {
      "affiliations": [
        "Imperial College NHS Foundation Trust, London, United Kingdom"
      ],
      "name": "Philip Eardley"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Melanie Dani"
    },
    {
      "affiliations": [
        "Imperial College NHS Foundation Trust, London, United Kingdom"
      ],
      "name": "Patrisha Tiarborelli"
    },
    {
      "affiliations": [
        "Imperial College NHS Foundation Trust, London, United Kingdom"
      ],
      "name": "Eleonora Battistiol"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Christian Ng"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Amara Thanamayooran"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Michela Sorbini"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Abdul Ali"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Prapa Kanagaratnam"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Ji-Jian Chow"
    },
    {
      "affiliations": [
        "Royal Free London NHS Foundation Trust, London, United Kingdom"
      ],
      "name": "Raj Khiani"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Richard Sutton"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Matt Shun-Shin"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Zachary Whinnett"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Darrel Francis"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Phang Boon Lim"
    },
    {
      "affiliations": [
        "National Heart and Lung Institute, Imperial College London, London, United Kingdom"
      ],
      "name": "Daniel Keene"
    }
  ],
  "title": "511 Beyond lower limb pooling: the critical role of splanchnic autotransfusion in vasovagal syncope",
  "uid": "63a4b518-5bd3-5629-b6f7-7904a38a0190"
}