Ecg & Heart Sounds

ECG & Heart Sounds

Exercise 1: ECG at rest

Study Exercise

Use the Comments panel to indicate on the recording the P-wave, the QRS complex, and the T-wave.

Study Questions

ECG Amplitude and Duration|Component|Amplitude (mV)|Duration (s)|P wave|0.15|0.14|QRS complex|1|0.03|T wave|0.32|0.18||ECG Interval and Rate|Pair|Interval (s)|Heart rate (BPM)|1|2.45|24.5|2|2.36|25.4|3|2.34|25.6||

1. What can you say about the amplitude of the various waves in different cardiac cycles?

The amplitude increased with physical activity and movements. |

2. The P wave and the QRS complex represent depolarization of the atrial and ventricular muscle respectively. Why does the QRS complex have the largest amplitude?

The pressure is higher during depolarization. |

3. In steps 7 and 8 heart rate was calculated based upon the peak-to-peak interval of the R waves. Was there variability between the beats? Would you expect the interval between beats to be identical? Why or why not?

Yes. there was variability between the beats. We would not expect the interval to be identical because there could have been movement artifact from beat to beat. |

4. The range for a normal resting heart rate is 60 to 90 bpm. A trained athlete could have a resting heart rate of 45 to 60 bpm. Why might a very fit person have a slower heart rate than someone of average fitness?

A fit person may have a slower heart rate because they have a higher stroke volume, thus a higher cardiac output. |

Exercise 2: ECG variation

Variation in ECG Component Amplitudes and Durations|

Volunteer|P amplitude (mV)|P duration (s)|R amplitude (mV)|QRS duration (s)|T amplitude (mV)|T duration (s)|

1|-0.098|79.734|0.295|0.999|0.198|0.424|

2|-0.167|1.414|1.48|0.654|0.946|0.041|

|||1.48||||

|||||||

|||||||

Study Questions

1. Are the amplitudes and durations of the various waves in different individuals similar or very different?

They are similar but not identical.|

2. What...