Work out cardiac cycle and heart rate

Click For Summary

Discussion Overview

The discussion revolves around calculating the cardiac cycle duration and heart rate based on ECG readings. Participants share their methods and results, focusing on the interpretation of grid lines in ECG images after exercise and at rest.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant calculates the cardiac cycle as 0.45 seconds and the heart rate as 133 bpm based on counting 9 grid lines.
  • Another participant questions the count of 9 grid lines, suggesting it should be 10, leading to a recalculation of the cardiac cycle as 0.5 seconds and heart rate as 120 bpm.
  • There is a clarification about counting lines versus spaces, with participants agreeing that counting lines is necessary.
  • A later contribution mentions a new ECG labeled 'resting' and reports counting 15 grid lines for each cycle, seeking confirmation from others.
  • Another participant confirms counting 15 grid lines as well.

Areas of Agreement / Disagreement

Participants initially disagree on the number of grid lines counted for the cardiac cycle, but later reach a consensus on the counting method. However, the discussion remains unresolved regarding the cardiac cycle and heart rate calculations for the 'resting' ECG, as participants have different counts.

Contextual Notes

Participants express uncertainty about the correct counting method for grid lines and how it affects their calculations. There is also a lack of clarity on the implications of different ECG readings on heart rate calculations.

shadows122
Messages
10
Reaction score
0
I would just like to know if i have worked out one cardiac cycle and heart rate correctly.
I have attached the image of the ecg called 'after exercise'

here are my workings out:

1. CARDIAC CYCLE:
there are 4 cycles so:
9 (grids) x 0.05 = 0.45
9x 0.05 = 0.45
9x 0.05 = 0.45
9x 0.05 = 0.45

average = 0.45 x 4/4 = 0.45

so cardiac cycle = 0.45 seconds

2. HEART RATE:
60/0.45 =133 bpm

are these worked out correctly?
 

Attachments

  • afterExercise.JPG
    afterExercise.JPG
    49.2 KB · Views: 423
  • resting.png
    resting.png
    23.5 KB · Views: 469
Last edited:
Physics news on Phys.org
shadows122 said:
I would just like to know if i have worked out one cardiac cycle and heart rate correctly.
I have attached the image of the ecg called 'after exercise'

here are my workings out:

1. CARDIAC CYCLE:
there are 4 cycles so:
9 (grids) x 0.05 = 0.45
9x 0.05 = 0.45
9x 0.05 = 0.45
9x 0.05 = 0.45

average = 0.45 x 4/4 = 0.45

so cardiac cycle = 0.45 seconds

2. HEART RATE:
60/0.45 =133 bpm

are these worked out correctly?
I'm seeing one heartbeat every 10 grid lines. Are you sure about your 9 grid lines number?
 
berkeman said:
I'm seeing one heartbeat every 10 grid lines. Are you sure about your 9 grid lines number?

Oh, dammit i was counting the spaces between the lines.
So you have to count the lines? then yeah it should be 10.

so its:
1. CARDIAC CYCLE:
there are 4 cycles so:
10 (grids) x 0.05= 0.5
10x 0.05 = 0.5
10x 0.05 = 0.5
10x 0.05 = 0.5

average = 0.5 x 4/4 =0.5

so cardiac cycle = 0.5 seconds

2. HEART RATE:
60/0.5 = 120 bpm

is this right?? :smile:
 
shadows122 said:
Oh, dammit i was counting the spaces between the lines.
So you have to count the lines? then yeah it should be 10.

so its:
1. CARDIAC CYCLE:
there are 4 cycles so:
10 (grids) x 0.05= 0.5
10x 0.05 = 0.5
10x 0.05 = 0.5
10x 0.05 = 0.5

average = 0.5 x 4/4 =0.5

so cardiac cycle = 0.5 seconds

2. HEART RATE:
60/0.5 = 120 bpm

is this right?? :smile:
That's what I got as well. :smile:
 
berkeman said:
That's what I got as well. :smile:

i just uploaded another ECG called 'resting' as i can't tell how many grids there are. I counted 15 ? for each cycle, what about you?
 
shadows122 said:
i just uploaded another ECG called 'resting' as i can't tell how many grids there are. I counted 15 ? for each cycle, what about you?
Yep, I get 15 as well.
 
  • Like
Likes   Reactions: shadows122

Similar threads

Understanding the Cardiac Cycle: Diastole & Systole
  • · Replies 2 ·
Replies
2
Views
3K
Efficiency of Stirling Cycle - Is it the same as the Carnot Engine?
  • · Replies 14 ·
Replies
14
Views
2K
Medical Electrical stimulation of the Vagus nerve may relieve treatment-resistant depression
  • · Replies 1 ·
Replies
1
Views
3K
Weird Power Measurements with a Northern Lights Airforce Airdyne Cycle
  • · Replies 8 ·
Replies
8
Views
2K
ChatGPT Examples, Good and Bad
  • · Replies 458 ·
16
Replies
458
Views
36K
Pulley at an Angle Problem - Newton Forces
  • · Replies 17 ·
Replies
17
Views
3K
Rate of Reaction: Doubling X's Concentration Effect
  • · Replies 1 ·
Replies
1
Views
2K
Signal Generator, Oscilloscope and Capacitor
  • · Replies 4 ·
Replies
4
Views
2K
High School Milankovitch Cycles: Find the 53,300,000 Year Cycle
  • · Replies 7 ·
Replies
7
Views
2K
How is heart rate determined by action potentials?
  • · Replies 1 ·
Replies
1
Views
10K