The Journal of Thoracic and Cardiovascular Surgery
Volume 139, Issue 4 , Pages 1026-1032, April 2010

Automatic real-time detection of myocardial ischemia by epicardial accelerometer

  • Per Steinar Halvorsen, MD

      Affiliations

    • The Interventional Centre, Rikshospitalet University Hospital, Oslo, Norway
    • Corresponding Author InformationAddress for reprints: Per Steinar Halvorsen, MD, The Interventional Centre, Rikshospitalet University Hospital, NO-0027 Oslo, Norway.
    • ,
  • Espen W. Remme, MSc, PhD

      Affiliations

    • The Interventional Centre, Rikshospitalet University Hospital, Oslo, Norway
    • ,
  • Andreas Espinoza, MD

      Affiliations

    • The Interventional Centre, Rikshospitalet University Hospital, Oslo, Norway
    • ,
  • Helge Skulstad, MD, PhD

      Affiliations

    • Department of Cardiology, Rikshospitalet University Hospital, Oslo, Norway
    • ,
  • Runar Lundblad, MD, PhD

      Affiliations

    • Department of Cardiothoracic Surgery, Rikshospitalet University Hospital, Oslo, Norway
    • ,
  • Jacob Bergsland, MD

      Affiliations

    • The Interventional Centre, Rikshospitalet University Hospital, Oslo, Norway
    • ,
  • Lars Hoff, MSc, PhD

      Affiliations

    • Faculty of Science and Engineering, Vestfold University College, Horten, Norway
    • ,
  • Kristin Imenes, MSc, PhD

      Affiliations

    • Faculty of Science and Engineering, Vestfold University College, Horten, Norway
    • ,
  • Thor Edvardsen, MD, PhD

      Affiliations

    • Department of Cardiology, Rikshospitalet University Hospital, Oslo, Norway
    • The Faculty of Medicine, University of Oslo, Norway
    • ,
  • Ole Jakob Elle, MD, PhD

      Affiliations

    • The Interventional Centre, Rikshospitalet University Hospital, Oslo, Norway
    • Department of Informatics, University of Oslo, Norway
    • ,
  • Erik Fosse, MD, PhD

      Affiliations

    • The Interventional Centre, Rikshospitalet University Hospital, Oslo, Norway
    • The Faculty of Medicine, University of Oslo, Norway

Received 11 February 2009; received in revised form 8 May 2009; accepted 31 May 2009. published online 31 August 2009.

Objective

Myocardial ischemia may be detected with epicardial accelerometers. We developed and tested automated algorithms for real-time detection of myocardial ischemia by accelerometer measurements in both experimental and clinical settings.

Methods

In 10 pigs, an accelerometer was fixed to the epicardium in the area perfused by left anterior descending coronary artery. Acceleration and electrocardiogram were simultaneously recorded, and the QRS complex was automatically detected for exact timing of systole. Peak circumferential velocity and displacement were automatically calculated from epicardial acceleration signal within 150 milliseconds after peak R on electrocardiography. Global myocardial function was reduced by esmolol infusion, and regional function was altered by temporary left anterior descending occlusion. Automated ischemia detection analyses were tested in 7 patients during off-pump coronary artery bypass grafting. Left anterior descending coronary artery was occluded for 3 minutes before grafting. In both models, echocardiographic myocardial circumferential strain was used to confirm ischemia.

Results

Systolic displacement changed most during left anterior descending occlusion. Negative displacement during ischemia was found in pigs (11.5 ± 2.3 to −1.2 ± 2.8 mm, P < .01); regional hypokinesia was found in clinical study (12.8 ± 8.1 to 3.5 ± 4.4 mm, P < .01). Ischemia was confirmed by echocardiography in both settings. Esmolol infusion induced smaller changes in automated accelerometer measurements than did left anterior descending occlusion (P < .01).

Conclusions

Automatic real-time detection of myocardial ischemia with epicardial accelerometer was feasible. Automated ischemia detection analysis may be used for continuous monitoring of myocardial ischemia during cardiac surgery.

CTSNet classification: 1, 17, 23, 28

Abbreviations and Acronyms: CI, confidence interval, ECG, electrocardiography, LAD, left anterior descending coronary artery, LV, left ventricle, LV dP/dtmax, maximum time derivative of left ventricular pressure, ROC, receiver operating characteristic

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 Disclosures: P.S.H. was recipient of a clinical research fellowship from the Regional Health Authorities. A.E. was a recipient of a clinical research fellowship from the Norwegian Council of Cardio-vascular Diseases. The accelerometer is patented by Rikshospitalet University Hospital; O.J.E., E.F., and P.S.H. are patent holders.

PII: S0022-5223(09)00809-5

doi:10.1016/j.jtcvs.2009.05.031

The Journal of Thoracic and Cardiovascular Surgery
Volume 139, Issue 4 , Pages 1026-1032, April 2010

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