Conduction System

Briefly introduce the conduction system of the heart and EKG (minimum ½ page maximum one page)

Procedure Briefly explain how the experiment performed (not how it must be performed)

Results
Show the EKG tracing from your volunteer. All the peaks and intervals must be properly labeled. Use a table to compare your data with the reference intervals.
What each interval represents? What was the heart rate of the subject?
Show the results of subject’s maximum heart rate (both theoretical and practical one).

Discussion
In this section, you interpret your data; Was the heart rate normal? What is tachycardia and bradycardia? Explain.

Were the intervals in the normal range? (from the table in the result section).
For each interval that you measured, that would be the meaning of abnormal value? For example, if the subject’s ECK was showing an abnormal QT interval, how do you interpret it? Do this for all the intervals.
Was the subject’s practical heart rate close to her/his theoretical heart rate?
Explain these data. For this section of the report, answer the questions in your handout.

Clinical significance
Please briefly explain the clinical significance of EKG and give at least one example of abnormal EKG and explain it.

References
You can use your lab manual (or your lecture book) and the handout.Turnitin.com information for you to upload the report:

Course title: Biology 2120L-009 Spring 2018

Monitoring EKG

INTRODUCTION
An electrocardiogram, or EKG, is a graphical recording of the electrical events occurring within the heart. A typical EKG tracing consists of five identifiable deflections. Each deflection is noted by one of the letters P, Q, R, S, or T. The P wave is the first waveform in a tracing and represents the depolarization of the heart’s atria. The next waveform is a complex and consists of the Q, R, and S deflection. The QRS complex represents the depolarization of the heart’s ventricles. The deflection that represents the repolarization of the atria is usually undetectable because of the intensity of the QRS waveform. The final waveform is the T wave and it represents the repolarization of the ventricles.
Because an EKG is a recording of the heart’s electrical events, it is valuable in diagnosing diseases or ailments that damage the conductive abilities of the heart muscle. When cardiac muscle cells are damaged or destroyed, they are no longer able to conduct the electrical impulses that flow through them. This causes the electrical signal to terminate at the damaged tissue or directed away from the signal flow. The termination or redirection of the electrical signal will alter the manner in which the heart contracts. A cardiologist can look at a patient’s electrocardiogram and determine the presence of damaged cardiac muscle based on the waveform as well as the time interval between electrical events.
In this activity, you will use the EKG sensor to make a five-second graphical recording of your heart’s electrical events. From this recording, you will identify the previously mentioned waveform components and determine the time intervals associated with each.

OBJECTIVES
In this experiment, you will
Use the EKG Sensor to graph your heart’s electrical activity.
Determine the time interval between EKG events.
Calculate heart rate based on your EKG recording.

MATERIALS
Lab Quest
Vernier EKG Sensor
3 Disposable electrode tabs per student

PROCEDURE

Connect the EKG Sensor to the LabQuest by plugging it into the port.
Attach three electrode tabs to your arms, as shown in Figure 1. A single patch should be placed on the inside of the right wrist, on the inside of the right upper forearm (below elbow), and on the inside of the left upper forearm (below elbow).
Connect the EKG clips to the electrode tabs as shown in Figure 1. Sit in a reclined position in a chair or lay flat on top of a lab table. The arms should be hanging at the side unsupported.

When everything is positioned properly, click the green collect/play arrow at the bottom left-hand corner to begin data collection. If your graph has a stable Figure 2 baseline as shown below, continue to Step 5. If your graph has an unstable baseline (figure 3), disconnect the electrode clips from the patient and zero the device. Reconnect the electrode clips and then collect a new set of data by clicking the Green Start.

Figure 2: Stable baseline Figure 3: Unstable baseline

Click and drag on the actual graph itself. As you move the stylus/pointer across the screen, the x values are displayed on the bottom, right. For three heartbeats, identify the various EKG waveforms using Figure 5 and determine the time intervals listed below. Make sure you record the average for each set of time intervals in Table 1.
Figure 5: Sample EKG reading. P-R interval: time from the beginning of P wave to the start of the QRS complex. QRS complex: time from Q deflection to S deflection. Q-T interval: time from Q deflection to the end of the T wave.

Calculate the heart rate in beats/min using the EKG data. Remember to include the time between the end of the T Wave and the beginning of the next P Wave. Use the total number of seconds for one full heart cycle in the equation. Record the heart rate in Table 1.

Formula used to Calculate Heart Rate

(# beats)/minute⁡〖=(# beats)/(x sec) x (60 seconds)/(1 minute)〗

OR

(# beats)/minute⁡〖=(# complete waveforms)/(x sec) x (60 seconds)/(1 minute) x (1 beat)/(1 complete waveform)〗

Print a copy of your EKG. Identify and label the various waveforms.
DATA

Table 1
Interval Time (s)
P-R 0.15
QRS 0.10
Q-T 0.34
Table 2 Standard Resting Electrocardiogram Interval Times
Interval Time (s)
P-R 0.12 to 0.20
QRS Less than 0.10
Q-T 0.30 to 0.40