Lab+Assignment+9+ECG-Heart+Sounds

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The Electrocardiogram and Heart Sounds Names of all group members present: Group members NOT present: ******All assignment questions are in red (do not change this) ****** Lab 9 Assignment (15 pts total) Exercise 1: The ECG in a Resting Subject Aim: To measure the ECG in a resting individual. Approximate Time: 15 minutes Procedure 1. Click on the Record button. The signal should begin scrolling across the screen. 2. Click on the AutoScale button at the upper margin of the ECG channel. • If the signal on the ECG channel is upside down when compared to trace, click on the downward arrow to the left of the channel title and select the Invert function. The trace should now look similar to the one in the figure. 3. When you have a suitable trace, type Resting ECG in the Mark box. Click the mark button to attach the comment to the data. Record for a minute or two. 4. Click Stop to halt recording. 5. Select Save As in the File menu, type a name for the file. Click on the Save button to save the data file. Data Analysis 1. Scroll through the recording and find a section of data with Ten (10) good ECG cycles in succession . 2. Use the Display Time icons to adjust the Display Time of the Main window to show the complete ECG cycles on the Main window. 3. Data can be collected from the Main window.

4. Once the cursors are placed in the correct positions for determining the amplitudes and the beat period on each ECG cycle, the values of these amplitudes and the time interval can be recorded in the data table. • Place the cursors at the locations used to measure the amplitudes and period of the ECG cycles. 5. Use the mouse to click on and drag the cursors to specific points on the ECG recording to measure the following (measure at least 5 ECG cycles): • The R-wave amplitude . To measure the R-wave amplitude, place one cursor on the Q wave that precedes the R-wave and the second cursor on the peak of the R-wave. The value for V2-V1 on the ECG channel is this amplitude. • The P-wave amplitude . To measure the P-wave amplitude, place one cursor on the baseline that precedes the P-wave and the second cursor on the peak of the P-wave. The value for V2-V1 on the ECG channel is this amplitude. • The T-wave amplitude . To measure the T-wave amplitude, place one cursor on the baseline that precedes a P-wave and the second cursor on the peak of the T-wave that is in the same cycle as that P-wave. The value for V2-V1 on the ECG channel is this amplitude. • The beat period , which is the time interval between two adjacent R-waves. To measure the beat period, place one cursor on the peak of an R-wave and the second cursor on the peak of the adjacent R-wave. The value for T2-T1 on the ECG channel is the beat period. Figure HH-2-L2: ECG recording displayed in the Analysis window. Lines and labels were added to indicate the locations where cursors should be placed to measure the amplitudes of R (Q-R), P (Baseline-P), and T (Baseline-T) waves.

6. Calculate the following values and insert your results into the data table: • The average amplitudes of the P-wave, the R-wave, and the T-wave. • Measure within your selected 5 ECG cycles the beat period (R to R), then calculate the average of the 5 beat periods. • Converted the average beat period to seconds. • Then calculate the average heart rate, which is expressed in beats per minute and calculated from the average beat period in seconds by using the following equation: Heart Rate (beats/minute) = 60 seconds/minute # seconds/beat 7. Have the subject color their answers for activity effort in red for the short questionnaire to assess health enhancing physical activity ( SQUASH 1 ) by Wendel-Vos et al. 2003. Following the Score Key based on the effort they listed, assign the appropriate score in the far right column. (Ex: Low intensity walking for leisure has a score of 1). Sum the intensity scores for all activities Data Table 1: (0.5 point) ECG cycle Subject #1 Name: 1 2 3 4 5 Average (of the 5) P-wave amplitude 0.1034 R-wave amplitude .3324 T-wave amplitude Beat Period (ms) Average Beat Period (seconds) Average Heart Rate (bpm) 105

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SQUASH 1 – Identify subject’s effort for each activity during an average week. If an activity category is not applicable, score the effort as a 0. (0.25 point) Commuting Activities Effort Score Key (Low/Moderate/Intense) Assigned Score based on Effort Walking to/from work or school Low/Moderate/Intense 1/2/3 Bicycling to/from work or school Low/Moderate/Intense 4/5/6 Leisure Activities Walking Low/Moderate/Intense 1/2/3 Bicycling Low/Moderate/Intense 4/5/6 Odd jobs Low/Moderate/Intense 1/2/3 Sports/Exercise Low/Moderate/Intense (1-3)/(4-6)/(7-9) Household Activities Low: (e.g. cooking, washing dishes, ironing, child care) Intense: (e.g. scrubbing floor, walking with heavy shopping bags) Low/Intense 2/5 Activities at Work and School Low/Intense 2/5 Sum of Intensity Scores Questions 1. Make a box plot of the data for the P, R, and T amplitudes and paste the image below (1 point)

2. Conduct a One-Way ANOVA using the data to compare the P, R, and T wave amplitudes (1 point). • What is your null hypothesis? There is no difference in p, r , and t wave amplitudes between trials. • Using the ANOVA Results: What is your p -value and your alpha? Our p-value was .990768 and our alpha was 0.05 • Do you reject or fail to reject your null hypothesis? We fail to reject our null hypothesis. 3. If your ANOVA detected statistical significance, conduct a post-hoc assessment. For this assignment the post-hoc is to conduct multiple t-tests for each comparison and apply a Bonferroni Correction. Include what type of t test you used, and the results of each comparison with the correction. If your ANOVA was not significant, explain why you think this was the case. (1 point) Looking at our data between trials, each had different numbers all within the same range but varied a decent amount. 4. Based on your statistical analysis and with the support of your data visualized in the graph in question 1, which wave has the largest amplitude? Explain why. (0.5 point) Based on the data that we collected the T wave has the largest amplitude. This is because the T wave can be fairly wide compared to the QRS complex, which is normally “larger”. Though in this case the T wave reading being so large can also point to abnormalities in the heart. Exercise 2: ECG Recordings from Other Subjects

Aim: To measure heart rate from all students. Approximate Time: 15 minutes per subject Procedure 1. Disconnect the lead wires from the wrists and ankle of the first subject. 2. Place new ECG electrodes on another subject . Record the ECG from the second subject, as described in Exercise 1. 3. Repeat this exercise on additional subjects (3 total) to complete Data Table 2 and Data Table 3. At the beginning of each recording, type the name of the subject on the Marks line and click on the Marks button to identify the recording. Measure the amplitudes of the ECG waves and beat periods of the other subjects as you did in Exercise 1. Have each subject fill out a SQUASH form. 4. Copy and paste the calculated averages from subjects 1 – 3 into Data Table 4 Data Table 2: (0.5 point) ECG cycle Subject #2 Name: 1 2 3 4 5 Average (of the 5) P-wave amplitude 0.012 0.054 0.051 .109 .066 R-wave amplitude 0.920 0.901 .907 .817 .865 T-wave amplitude 0.330 0.346 .416 .397 .341 Beat Period (ms) 620 510 500 510 455 Average Beat Period (seconds) Average Heart Rate (bpm) 147 SQUASH 2 – Identify subject’s effort for each activity during an average week. If an activity category is not applicable, score the effort as a 0. (0.25 point) Commuting Activities Effort Score Key (Low/Moderate/Intense) Assigned Score based on Effort Walking to/from work or school Low/Moderate/Intense 1/2/3 2 Bicycling to/from work or school Low/Moderate/Intense 4/5/6 4 Leisure Activities Walking Low/Moderate/Intense 1/2/3 1

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Bicycling Low/Moderate/Intense 4/5/6 4 Odd jobs Low/Moderate/Intense 1/2/3 1 Sports/Exercise Low/Moderate/Intense (1-3)/(4-6)/(7-9) 8 Household Activities Low: (e.g. cooking, washing dishes, ironing, child care) Intense: (e.g. scrubbing floor, walking with heavy shopping bags) Low/Intense 2/5 2 Activities at Work and School Low/Intense 2/5 2 Sum of Intensity Scores 24 Data Table 3: (0.5 point) ECG cycle Subject #3 Name: 1 2 3 4 5 Average (of the 5) P-wave amplitude 0.064 0.038 0.329 0.164 0.097 R-wave amplitude 0.532 0.532 0.370 0.485 0.340 T-wave amplitude 0.224 0.211 0.292 0.189 0.273 Beat Period (ms) 530 570 765 630 600 Average Beat Period (seconds) Average Heart Rate (bpm) 97 SQUASH 3 – Identify subject’s effort for each activity during an average week. If an activity category is not applicable, score the effort as a 0. (0.25 point) Commuting Activities Effort Score Key (Low/Moderate/Intense) Assigned Score based on Effort Walking to/from work or school Low/Moderate/Intense 1/2/3 2

Bicycling to/from work or school Low/Moderate/Intense 4/5/6 4 Leisure Activities Walking Low/Moderate/Intense 1/2/3 2 Bicycling Low/Moderate/Intense 4/5/6 4 Odd jobs Low/Moderate/Intense 1/2/3 1 Sports/Exercise Low/Moderate/Intense (1-3)/(4-6)/(7-9) 8 Household Activities Low: (e.g. cooking, washing dishes, ironing, child care) Intense: (e.g. scrubbing floor, walking with heavy shopping bags) Low/Intense 2/5 3 Activities at Work and School Low/Intense 2/5 2 Sum of Intensity Scores 26 Compiled Subject Data Table 4 (0.25 point) Average Data Value Subject 1 Subject 2 Subject 3 P-wave amplitude 0.1034 0.0584 0.1384 R-wave amplitude 0.3324 0.882 0.4518 T-wave amplitude 0.5876 0.366 0.2378 Heart Rate 105 bpm 147 bpm 97 bpm SQUASH Intensity score 23 24 26 Questions 1. Make a bar graph of the average P, R, and T wave amplitudes (Y axis) comparing the three subjects as series. The x- 1 2 3 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Average P-wave, T-wave, R-wave of each subject P-wave amplitude R-wave amplitude T-wave amplitude Subject Amplitude (mV)

axis should be each wave as shown in the example below. Make sure all labels are present and complete. (1 point) 2. Evaluate your graph above first, do the P-waves of different subjects have the same amplitude? The QRS complexes? The T-waves? What are some explanations for these differences? Include any sources referenced. (0.5 point) The p-wave of each subject is not the same but they are very similar. The QRS complexes differ the most between all of them. There also doesn’t seem to be any similarities in the T- wave amplitude between subjects . The variations may be due to age, gender, or heart health (differences in electrical conduction of heart) or other anatomical factors. 3. For each subject, determine the wave with the largest amplitude and record below. Is this result the same for all individuals? What are some factors that could explain this outcome? (0.5 point) Subject 1: T-wave Subject 2: R-wave Subject 3: R-wave The result is not the same for each person and this could be due to heart health, fitness levels, ECG lead placement etc. 4. Now conduct a One-Way ANOVA on only the T-wave amplitude data to determine if there is a statistical difference for this wave amplitude between subjects . Be sure to use the data from all five cycles, not the average amplitude. Include the specific ANOVA used, your p- value, alpha, your null hypothesis and your conclusion for each. (1 point) • What is your null hypothesis? Our null hypothesis is that there is no difference in wave amplitude between subjects. • Using the ANOVA Results: What is your p -value and your alpha? Our p-value is .805209 and the alpha is 0.05. • Do you reject or fail to reject your null hypothesis? We fail to reject our null hypothesis 5. If your ANOVA detected statistical significance, conduct a post-hoc assessment. For this assignment the post-hoc is to conduct multiple t-tests for each comparison and apply a Bonferroni Correction. Include what type of t test you used, and the results of each comparison with the correction. If your ANOVA was not significant, explain why you think this was the case. (1 point)

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The reason the ANOVA was not significant was because each subject had very different values for their P, R, and T waves. This could be due to a lot of different reasons, like someone could have had a higher resting heart rate. Or someone’s heart could have to pump harder than anothers which would change the amplitude of the waves. 6. Is the heart rate the same for each individual? What may contribute to the similarities or differences in heart rate amongst these subjects? (0.5 point) No, the heart rates of each subject are fairly different. This could be due to overall cardiovascular health or regular exercise which can decrease the resting heart rate. Or one of the subjects that’s heart rate was higher could have been walking around before we took their heart rate. 7. How do the summed SQUASH intensity scores compare between the subjects? Is there an obvious correlation between heart rate and the SQUASH intensity score for each subject? What about between the largest wave amplitude and each subject’s score? (0.5 point) There isn’t an obvious correlation between the heart rate and the SQUASH intensity scores collected. There also doesn’t seem to be a correlation between the largest wave amplitude and the SQUASH score.

Exercise 3: The ECG and Heart Sounds Aim: To study the phasing of heart sounds to the ECG. Approximate Time: 15 minutes Procedure 1. Place the head of the stethoscope on the left side of the subject’s chest and listen for the heart sounds. Move the stethoscope head to different positions until heart sounds are heard clearly such as the positions depicted below. Heart sounds can also be heard by placing the stethoscope over the arteries in the neck. 2. At the same time or with an assistant, firmly place the heart sound microphone on one of the four auscultation areas nearby. Take care to minimize hand motion or any other sounds that may contribute to “noise” or interference. Figure HH-8-L1: Positions of the auscultation areas on the chest: 1-Aortic, 2-Pulmonic, 3- Tricuspid, 4-Mitral. • Aortic, which is located in the second intercostal space at the right sternal margin, #1 on the figure • Pulmonic, which is located in the second intercostal space at the left sternal border, #2. • Tricuspid, which is located at the lower left sternal border, #3. • Mitral, which is usually located in the fifth intercostal space, at the apex beat, #4. 3. Click on the Record button. The signal should begin scrolling across the screen 4. The person holding the stethoscope head on the subject’s chest with one hand should be holding the event marker in the other. Click the event marker when you hear the “lub”, or first heart sound, and release it when you hear the “dub”, or second heart sound. 5. Click on the AutoScale All button.

• If the heart sound recording is noisy, click the heart sound monitor against the chest more firmly or hold it in place with an elastic bandage (Ace wrap) or belt. Also, have the subject hold his or her breath during the recording. 6. After recording for thirty to forty-five seconds, click Stop to halt recording. 7. Select Save in the File menu on the LabScribe window. Data Analysis 1. Scroll through the recording and find a section of data with 10 exemplary ECG waveforms, cardiac sound cycles and consistent responses on the event marker channel, in succession. 2. Use the Display Time icons to adjust the Display Time of the Main window to show the complete ECG/heart sound cycles on the Main window. Figure HH-2-L3: ECG and event marker recordings displayed in the Analysis window. Lines and labels were added to figure to indicate the locations where cursors should be placed to measure the time intervals between the R-wave and the “lub” and the T-wave and the “dub”.

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Figure HH-8-L3: The ECG and heart sounds displayed in the Analysis window. The cursors are placed at the beginning and the end of the second S1 heart sound in the window and the margins of the S1 and S2 sounds of the fourth ECG cycle are marked. 3. Use the mouse to click on and drag the cursors to specific points on the ECG recording to measure the following: • The R-Lub Interval , which is the time interval between the peak of an R-wave and the onset of the event mark. The onset of the event mark indicates the occurrence of the first heart sound or “lub”. Record the value for T2-T1 of either channel in Data Table 4 . Measure this time interval for five total ECG cycles. • The T-Dub Interval , which is the time interval between the peak of a T-wave and the offset of the event mark. The offset of the event mark indicates the occurrence of the second heart sound or “dub”. Record the value for T2-T1 of either channel in Data Table 4 . Measure this time interval for five total ECG cycles. • The S1 Duration , which is the first heart sound. Place one cursor at the beginning of the first S1sound wave and the second cursor at the end of the same S1 sound wave. Record the value for T2-T1 of the Heart Sounds channel in Data Table 4 . Measure this time interval for five total ECG cycles. • The S2 Duration , which is the second heart sound. Place one cursor at the beginning of the first S1sound wave and the second cursor at the end of the same S1 sound wave. Record the value for T2-T1 of the Heart Sounds channel in Data Table 4 . Measure this time interval for five total ECG cycles. 5. Calculate the following values and type your results into the Data Table 5 below. • The average R-Lub interval. • The average T-Dub interval. • The average S1 duration. • The average S2 duration. Data Table 5: (1 point) ECG cycle 1 2 3 4 5 Average R-Lub Interval 105 110 285 295 155 190 T-Dub Interval 615 760 880 955 730 788 S1 Duration 715 865 810 840 775 801 S2 Duration 525 475 510 465 540 503

Questions 1. Why does the lub sound occur around the peak of the R-wave? (0.5 point) The “lub” sound is a reaction to the closure of the AV valves of the heart and will appear at the time ventricular depolarization occurs which the R wave represents. 2. How does the average duration of the S1 compare to the average R-lub sound?.9 (0.5 point) The average S1 duration is x4 bigger than the average R-lub sound. 3. Why does the dub sound occur around the peak of the T-wave? (0.5 point) The dub sound occurs around the peak of the T-wave because that is when the ventricles are relaxing and the semilunar valves are closing. This is because of the change in blood pressure. 4. How does the average duration of the S2 compare to the average T-dub sound? (0.5 point) The average S2 duration is a little over half of the average T-dub sound. 5. How does the size of the S1 signal compare to the S2? Explain why you are seeing this pattern. (0.5 point) The average S1 signal is much higher than the average S2 signal. This is because the lub sound itself is typically longer than the dub sound. The closing of the AV valve is longer, which corresponds with the S1 signal. 6. Is the time delay between the R-wave and the lub sound always the same for each cycle? What about between the T-wave and the dub sound? What is an explanation for variation if it is present? (0.5 point) The time delay between the two is not always the same for either; the variation may be due to certain physiological conditions and can be influenced by: heart rate, cardiac conduction, ventricular function, valve function, respiratory cycle or age and health.

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