BioEd Online

Teacher Background

Physicians diagnose hearts attacks (acute myocardial infarctions, or MI) based on a patient’s signs and symptoms, physical examination findings, electrocardiogram (EKG or ECG) results, and cardiac enzyme studies. Emergency personnel also assess the heart rate, blood pressure, breathing rate, and general appearance and alertness of the individual in crisis.

Typically, in cases where heart attack is suspected, emergency room personnel will attach wire electrodes, or leads, to the patient’s chest and perform an EKG (a graphical record of the heart’s electrical activity as it contracts and relaxes). Each heartbeat sends an electrical signal that travels from the top of the heart to the bottom, causing the heart to contract and pump blood. These electrical signals set the rhythm of the heartbeat, which produces the familiar jagged-line pattern on an EKG monitor. Emergency room professionals viewing the EKG printout can detect the rate of the heartbeat, abnormal heart rhythms, and the strength and timing of the electrical signals as they pass through each part of the heart. Students learned about this test in the activity, “Introduction to Personal Stories.”

During a heart attack, damaged or destroyed heart muscle cells release chemicals, particularly proteins, called cardiac enzymes, into the bloodstream. Specific tests that measure the blood levels of these proteins can help determine whether a patient has had a heart attack. Normally, very low levels of cardiac enzymes are found in the blood, but the levels rise dramatically when heart muscle is injured or destroyed (as during a heart attack). Physicians usually order repeated blood tests of two cardiac proteins—creatine phosphokinase (CK) and troponin (T)—and compare their levels over time.

CK is an enzyme found in heart, brain, muscle and blood of healthy people. Blood levels of CK rise four to six hours after muscle damage, and peak about 18–24 hours after a heart attack. CK-MB is a form of the enzyme found mainly in heart muscle, so elevated blood levels suggest heart muscle damage. Troponin is released into the bloodstream more quickly (two to six hours after heart cell damage) than CK is, and blood levels of T peak in 12–26 hours. Because T is an “earlier” and somewhat more accurate indicator of cardiac muscle cell damage than CK is, it is the preferred marker for diagnosing heart attack. But both cardiac proteins typically are measured in patients suspected of having MI.

Objectives and Standards

Materials and Setup

Teacher Materials

• Interactive white board or video projector and computer

• Internet access

• Copy of “Teacher Key to Diagnostic Tests and Exam Results”

• Copies of “Diagnosis of a Heart Attack” (add to Reference Folders)

• Copies of “Table of Diagnostic Tests” (add to Reference Folders)

• Diagnostic Test Cards (one set per student team), photocopied onto card stock, cut into sets and stored in zip-top bags

• Copies of the “Medical Team Instruction Sheet” (one per student team)

• Copies of “Patient Diagnosis” sheets for Arturo, Brain and Angela (one set per team)

• Copies of “Arturo: Part Two,” “Brian: Part Two” and “Angela: Part Two” (one set per team)

• Copies of Expert Diagnostic team certificates (optional)

Materials per Student

• Set of Diagnostic Test Cards

• Copy of “Medical Team Instruction Sheet”

• Copy of “Patient Diagnosis” sheets for Arturo, Brain and Angela

• Personal story folders for each character

• Reference folder with a copy of the “Table of Diagnostic Tests” (added to folder previously, in the activity, “Introduction to Personal Stories”) and “Diagnosis of a Heart Attack” (add to folder).

• Copy of “Arturo: Part Two,” “Brian: Part Two” and “Angela: Part Two” (Do not add to the personal story files until after the activity is completed. Students will use this information at the end of the activity.)

Setup

1. Photocopy the Diagnostic Test Cards onto card stock and cut into sets. Make at least one copy per team of the “Table of Diagnostic Tests,” “Diagnosis of a Heart Attack” and Part Two of the personal stories. Do not give students Part Two of the personal stories until they have completed their diagnostic teamwork on each patient. A “Diagnosis Answer Key” is provided to the left.

2. Have students work in teams of four.

3. Note. You may want to allow most of one class period to work through the first case, and follow with the other two cases during a second class period.

Procedure and Extensions

Time: One or two 45-minute class periods

1. Remind students that Arturo, Brian and Angela still are in the emergency room. Project the video, Scientific Decision-making, Part Two (http://www.bioedonline.org/lessons-and-more/resource-collections/scientific-decision-making/) to familiarize students with changes in the EKG and blood tests that are used to identify myocardial infarction (heart attack). Pause the video after the introduction. You will return to the video after student teams have finished diagnosing each patient. Depending on your students, you also may have them read the reference sheet, “Diagnosis of a Heart Attack,” before beginning the activity or as homework the day before.

2. Tell students that they will work in teams, as medical personnel, to diagnose Arturo, Brian and Angela. Provide each team with the updated Reference folder, all three personal story folders (without Part Two for each character), a copy of the “Medical Team Instruction Sheet,” and a set of Diagnostic Test Cards.

3. Read the “Medical Team Instruction Sheet” to the class, ensuring that students understand the diagnosis process. Answer any questions before proceeding.

4. Have students start with Arturo’s case. Project or write the following questions on the board:
   
   What do we know about the patient?
   What information do we need to diagnose his condition?
   
   You may want to work through Arturo’s case as a class, to be sure students understand the process.

5. Students will select diagnostic tests or physical exam results to give them additional information about Arturo’s condition—so that they can arrive at a diagnosis. The information on Arturo’s “Patient Diagnosis” sheet will help them decide which diagnostic tests to order. Inform students that they also may request physical exam results (in the appropriate table on the “Diagnosis Sheet”) to gain further insight into Arturo’s medical condition. Each team may request three results at a time.

6. You will serve as monitor, using the "Teacher Key to Diagnostic Test Results" sheet to fill in the “Results” column for each test requested by student teams. You may want to appoint one or more students to serve as additional monitors.
   
   Note: Students may calculate the CK-MB% of total CK on their own, or request the calculation result (at an additional cost).

7. After all teams have submitted a diagnosis, determine a winner based on the completeness of the diagnosis and time submitted (see “Diagnosis Answer Key,” lesson PDF. In case of a tie, also consider the amount of funds expended. (If you wish to print certificates for members of winning teams, a template is included at the end of this activity.)

8. Have members of the winning team present the evidence they used to reach a diagnosis. The class may question the team’s presentation, with you as moderator. Ask the team, Could you have saved the patient any money by ordering fewer or different tests? Have the team defend its test choices. Allow further classroom discussion as necessary.
   
   OR hold team presentations after all three patients have been diagnosed. Conduct “Grand Rounds” in class (see “Grand Rounds,” lesson PDF), during which time each team presents one of its diagnoses and evidence. Following each team’s report, others in the class may contribute to, or challenge the presentation. If lab coats are available, students should wear them for their Grand Rounds presentations.

9. Have teams repeat steps 4–8 to develop and reach diagnoses for Brian and Angela. Assist the teams as before. Depending on the time required to complete Arturo’s diagnosis, Brian’s case can serve as the start of day two for this activity.

10. After all the teams have made their diagnoses and presented their outcomes, read or have students read Part Two of each personal story. You also may show the next section of the video narrative.
    
    Explain that the additional information includes the emergency room physician’s explanation of tests ordered and the reasoning for them, along with a definitive diagnosis and follow-up for each character.

11. Conclude by having students discuss the cases as a whole. Ask, Were you surprised by any of the diagnoses? At first, did you think all of the patients were having a heart attack? Was cost a factor in any of the diagnoses?

12. You may want to have each team write and submit a report of the tests ordered, and conclusions reached for each patient.

Extensions or Homework

Several kinds of careers are encountered in the personal stories of Arturo, Brian and Angela. Have students research and present different health-related careers to the class. Presentations should include a description of the career, educational requirements to obtain a position in this field, typical duties/responsibilities, and work settings for those who do this job. A partial list of professions involved in the cases is provided (see sidebar, lesson PDF). You can add to this list or allow students to choose a different health-related career, with your approval.

Handouts and Downloads