“Simulation of Acute Myocardial Infarction” by Andrews

  • ©Lee T. Andrews



    Simulation of Acute Myocardial Infarction

Program Title:

    Demonstrations and Displays



Project Affiliation:

    Medical College of Ohio


    Acute myocardial infarction (heart attack) is one of the leading causes of death in the United States. This hypermedia document was created to help students better understand the mechanisms leading to acute myocardial infarction (MI) and the functional changes which occur during and after this life-threaten-ing event.

    A three-dimensional computer model was created from magnetic resonance images of normal subjects and patients with MI, aortic stenosis, hypertension, and ischemic heart disease. Multiphasic acquisition provided dynamic information on the behavior of the Quantitative data were gathered on myocardial wall thickness, en-docardial wall motion, and regional ejection fraction in both the normal and the diseased subjects.

    Major anatomical features of the heart were extracted using Image

    Workbench image analysis software. Each interface was identified with a different region of interest contour (ROI). This was done for each of the spatial image planes and for two of the seven temporal phases (end diastole and end systole). Key framing methods were used to produce the inter-frames between diastole and svs-tole to reduce the segmentation effort.

    The ROI’s were sampled using a radial method to reduce the data set to 50 data points per contour and to align each spatial slice. This process was necessary to adhere to the mosaic requirements of MOVIE BYU software. Additional interslice contours were created by splining between adjacent extracted contours to reduce the variability of segmented contours and smooth the surface of the model. In order to accurately simulate the dynamic behavior of the intact human heart, quantitative measurements of the trajectory of each node of the model were required. Dynamic motion was measured for the epicardial and endocardial walls of the ventricles and atria. using a radial method referencing the centroid of the heart. Calculation of the motion of each segment of the myocardium generated a normalized data set for each of the heart’s anatomic regions. These won quantitative data were then used to animate the computer graphics model to show the effects of MI in a very graphic way.

    Students can select a coronary artery and fly inside it to enter a branch with arteriosclerosis. As this unstable region erupts, platelets adhere to the sclerotic le-sion, and the artery closes, causing acute MI. Using the branching capabilities of HyperCard, students can delve more deeply into the quantitative methods used to measure heart performance.Simultaneous presentation of surface electrocardiograms and graphs of myocardial wall thickening demonstrates the dynamic changes that take place during a heart attack. Each section contains an audio track with comments from a physician.

Other Information:

    System Requirements: Mac II, 8 MB RAM, 8-bit color, 27 MB disk storage

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