Electrocardiography and blood pressure

Transcription

1 Electrocardiography and blood pressure Effects of body posture, breathing and physical activity on the human circulation Analysis and evaluation of the recorded data ELUP students Experiment was accomplished by: Teacher:... Date:... Subject s profile Name:... Height:... Age:... Weight:... Gender: male / female

2 Goals of the practical lesson (brief definition in a few sentences) 2 Introduction (can be continued on a separate sheet if needed) 1. Fundamentals of the ECG and blood pressure measurement (summary of the most important facts in regard to the analysis of the practical data) 2. Methods and materials (schematic enumeration) 3. Technical details of the practical exercises (preparation of the subject, settings of the recording system, explanation of the exercises)

3 A. Data and Calculations I. Blood pressure measuring 3 Measure the systolic and diastolic blood pressure and pulse (BPM) and give them accordingly in the table! Calculate the pulse pressure and the arterial mean pressure! (measured on the left arm) systole [Hgmm] diastole [Hgmm] pulse pressure [Hgmm] arterial mean pressure [Hgmm] pulse [beat/min] lying down sitting standing up after exercise, standing II. Examination of the ECG components Magnify a characteristic cardiac cycle from the recording and attach it to the report! Mark the components specified in the table on the magnified recording segment! ECG component Which event of the heart cycle occurs during this component? P wave PQ interval QRS complex ST segment T wave QT interval TQ interval Number of the attachment:

4 period time [; sec] III. Normal sinus arrhythmia during deep inhalation-exhalation 4 III/1. Measure the duration (period time; ) of the cardiac cycles during at least 2 consecutive inspiratory and expiratory epochs. Select the area between the consecutive R peaks using the I-beam cursor. Fill the table with as many cardiac cycle data as belong to each respiration epoch. III/1. inhalation I. exhalation I. inhalation II. exhalation II. Cardiac cycle III/2. Plot the durations of the consecutive cardiac cycles (period time, ) on the graph below. On the graph, X axis shows the number of the consecutive cardiac cycles, while Y axis shows the period time () of the cardiac cycles. Mark the onset of the inhalation and exhalation epochs on the graph. III/1. Sitting, deep inhalation / exhalation number of consecutive heart cycles Number of the attachment:...

5 period time [; sec] IV. Effect of sudden stand-up (circulatory reflex) 5 IV/1. Select the area between the consecutive R peaks by the I-beam cursor. Measure the duration of the cardiac cycles (period time, ), then plot the values on the graph below. On the graph, X axis shows the number of the consecutive cardiac cycles, while Y axis shows the period time () of the cardiac cycles. Mark the time point of the stand-up on the graph and on the attached recording! IV/1. Lying down Cardiac cycle Immediately after standing up Standing position (late aftereffect) IV/2. VI/1. Effects of sudden stand-up number of consecutive heart cycles Number of the attachment:...

6 V. Effect of physical activity V/1. Compare the results obtained immediately before and after physical activity. Analyze 8 consecutive cardiac cycles and measure the duration of the cycles ( - period time). Select the area between the consecutive R peaks by the I-beam cursor. Calculate the mean of the individual durations and the difference between the minimal and maximum values (maxmin). Calculate the heart rate in BPM (beat per minute). 6 V/1. Cardiac cycle immediately before the physical activity mean maxmin Number of the attachment:... immediately after the physical activity BPM:... Number of the attachment:... BPM:... V/2. Analyze 5 consecutive cardiac cycles and measure the duration ( delta time) of the ventricular systole (QT segment) and the ventricular diastole (TR interval- between the end of the T wave to subsequent R peak). Calculate the mean. Number of the attachment:... immediately before the physical activity QT interval (ventricular systole) TR segment (ventricular diastole) immediately after the physical activity QT interval (ventricular systole) TR segment (ventricular diastole) duration () [...] Cardiac cycle mean () [...]

7 B. Data summary and conclusions 7 1. Effects of the respiration (normal sinus arrhythmia) Summarize the results in the table below. Mean period time () [...] seated, deep inhalation seated, deep exhalation Does breathing influence heart frequency? Explain your answer. 2. Effect of sudden stand-up and different body postures Summarize the results in the table below. (mean) [...] before standing up (control segment) during the first five cycles after standing up (early aftereffect) during the 10th-15th cycles after standing up (late aftereffect) BPM (mean) a) How does heart frequency change after sudden stand-up? Was there a difference between the first seconds of the stand-up (early aftereffect) and during the later period (late aftereffect)?...

8 8 b) How did mean arterial pressure, pulse pressure and pulse rate change when the subject changed his/her body position? c) Explain the function of the circulatory reflex discussed in a) and b). d) Sudden change of the body position from lying to standing often causes dizziness or mainly in the elderly - fainting. How can you explain this phenomenon?

9 9 3. Effect of physical activity Summarize the ECG results in the table below. BPM (mean) QT interval (mean) [...] TR segment (mean) [...] immediately before the physical activity immediately after the physical activity How does physical activity influence the duration of the ventricular systole and diastole? Describe the physiological background of the observed changes. How did muscle exercise influence mean arterial pressure, pulse pressure and pulse rate? Systolic or diastolic blood pressure values were changed to higher extent upon the exercise? What is the explanation for this? According to the observed changes, was the subject well-trained for physical exercise? Explain your answer!

10 C. Definitions ECG:... Systole:... Systolic pressure:... Diastole:... Diastolic pressure:... Arterial mean pressure:... Pulse pressure:... Respiratory sinus arrhythmia: Bainbridge reflex:... Baroceptor reflex:... Peripheric resistance:

11 VI. Determination of the cardiac axis (optional task) 11 VI/1. Determination of the direction of the R-wave Mark the polarity ( + or - ) of the R-wave in the table below. Lead R-wave + - Einthoven I (CH 1) Einthoven II (CH 40) Einthoven III (CH 3) VI/2. Determination of the amplitude of potential changes accompanied by ventricular depolarization Analyze 5 consecutive cardiac cycles and measure the amplitude of the R-wave from the baseline in case of Einthoven I (CH 1) lead and Einthoven III (CH 3) leads, respectively. For this, use the (delta, amplitude) measurement and select the area between the R peak and the baseline before the QRS complex by the I-beam cursor. Calculate the mean value. As the (delta amplitude) measurement computes the amplitude difference between the start- and the end point of the selected area, polarity of the measured value will be determined by the selection order of the end points. Attach the magnified, analyzed recording segments to the lab record and note the number of the attachments. 1. Lying position: Einthoven I (CH 1) Einthoven III (CH 3) amplitude ( ) [...] Cardiac cycle mean amplitude [...] Number of the attachment: Standing position: Einthoven I (CH 1) Einthoven III (CH 3) amplitude ( ) [...] Cardiac cycle mean amplitude [...] Number of the attachment:...

12 VI/3. Determination of the direction and amplitude of the electrical cardiac axis 12 Construct the electrical axis of the heart using the mean amplitude of the R waves in case of Einthoven leads I and III. When constructing the vector, take care of the calibration bar (1 mv amplitude should correspond to the length of the segment - 2 cm). 1. Lying position: 1 mv Mean electrical axis (angle):... amplitude:...mv 2. Standing position: 1 mv Mean electrical axis (angle):... amplitude:...mv

13 VI/4. Effect of body posture on the direction of the electrical axis of the heart 13 Draw the mean electrical vectors corresponding to the lying and standing positions, respectively, on the figure below. Use different colours to mark the vectors corresponding to the different body postures. pathological left deviation pathological right deviation left dev. right dev. no deviation Normal and disordered QRS main axis positions in the hexaxial reference system Body posture Position of the cardiac axis [º] Range lying standing a) Was there a difference in the direction of the QRS main axis lying vs. standing? b) Explain the results! Yes c) Enumerate some physiological or pathological conditions which can change the direction of the electrical axis. (pathological) left axis deviation: (pathological) right axis deviation:.... No