The vasovagal tonus index as a prognostic indicator in dogs with dilated cardiomyopathy

Authors

  • Y. Martinez Pereira,

    1. Cardiology Service, Small Animal Teaching Hospital, University of Liverpool, Leahurst, Cheshire CH64 7TE
      *Southern Animal Referral Centre, 248 Wickham Road, Highett, VIC 3190, Melbourne, Australia
      †Cardiopulmonary Service, Hospital for Small Animals, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG
      ‡Veterinary Cardiorespiratory Centre, Martin Referral Services, 43 Waverley Road, Kenilworth, Warwickshire CV8 1JL
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  • R. Woolley,

    1. Cardiology Service, Small Animal Teaching Hospital, University of Liverpool, Leahurst, Cheshire CH64 7TE
      *Southern Animal Referral Centre, 248 Wickham Road, Highett, VIC 3190, Melbourne, Australia
      †Cardiopulmonary Service, Hospital for Small Animals, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG
      ‡Veterinary Cardiorespiratory Centre, Martin Referral Services, 43 Waverley Road, Kenilworth, Warwickshire CV8 1JL
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  • G. Culshaw,

    1. Cardiology Service, Small Animal Teaching Hospital, University of Liverpool, Leahurst, Cheshire CH64 7TE
      *Southern Animal Referral Centre, 248 Wickham Road, Highett, VIC 3190, Melbourne, Australia
      †Cardiopulmonary Service, Hospital for Small Animals, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG
      ‡Veterinary Cardiorespiratory Centre, Martin Referral Services, 43 Waverley Road, Kenilworth, Warwickshire CV8 1JL
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  • A. French,

    1. Cardiology Service, Small Animal Teaching Hospital, University of Liverpool, Leahurst, Cheshire CH64 7TE
      *Southern Animal Referral Centre, 248 Wickham Road, Highett, VIC 3190, Melbourne, Australia
      †Cardiopulmonary Service, Hospital for Small Animals, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG
      ‡Veterinary Cardiorespiratory Centre, Martin Referral Services, 43 Waverley Road, Kenilworth, Warwickshire CV8 1JL
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  • M. Martin

    1. Cardiology Service, Small Animal Teaching Hospital, University of Liverpool, Leahurst, Cheshire CH64 7TE
      *Southern Animal Referral Centre, 248 Wickham Road, Highett, VIC 3190, Melbourne, Australia
      †Cardiopulmonary Service, Hospital for Small Animals, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG
      ‡Veterinary Cardiorespiratory Centre, Martin Referral Services, 43 Waverley Road, Kenilworth, Warwickshire CV8 1JL
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Abstract

Objectives: To investigate the prognostic and diagnostic value of heart rate variability (HRV) using the vasovagal tonus index (VVTI) in dogs suffering from idiopathic dilated cardiomyopathy (DCM).

Methods: Electrocardiographic (ECG) recordings of 369 patients presented to a referral centre between 1993 and 2006 were reviewed.

Results: VVTI values were calculated from 132 dogs. Lower VVTI values were found in patients in International Small Animal Cardiac Health Council (ISACHC) heart failure (HF) class 2 and 3 compared with class 1. VVTI was found to be positively correlated with survival time (ST) in class 2 and 3 patients. When a cut-off value of 7·59 for VVTI was used, the test could differentiate patients in ISACHC HF class 1 versus 2 and 3 with a sensitivity of 89 per cent and a specificity of 62·5 per cent. The ST for patients with VVTI values less than 7·59 was significantly lower.

Clinical Significance: The VVTI is a useful index, obtained from a standard ECG recording that estimates HRV in dogs and does not require any specific equipment for its calculation. It can be useful as a diagnostic tool to assess the severity of HF and is a useful prognostic tool in dogs with DCM.

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