A strip of an ECG is 15 s long and has 18 QRS complexes…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A strip of an ECG is s long and has QRS complexes.
- What is the heart rate in beats a minute?
- What is the time of one cycle, in seconds?
Need a reminder? The key ideaShow
The P wave is the depolarisation of the atria. The QRS complex is the depolarisation of the ventricles, and their contraction starts soon after Q. The T wave is the repolarisation of the ventricles, and its end marks the end of the systole. Sympathetic signals and the hormones of the adrenal medulla raise the heart rate and the output. Parasympathetic signals lower them.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. Strip: s. QRS complexes: .
Plan. Each QRS complex is one beat. Scale the count to a minute.
Step 1. The rate. , so beats a minute.
Step 2. The cycle. s.
Answer: beats a minute; s.
Check. This is the usual rate of a healthy heart.
Discussion (0)
Log in to join the discussion.
Loading…