4,199
edits
Rate: Difference between revisions
Jump to navigation
Jump to search
m
no edit summary
No edit summary |
mNo edit summary |
||
| Line 9: | Line 9: | ||
'''What is the heart rate?''' | '''What is the heart rate?''' | ||
To answer this question, determine the time between two QRS complexes. Previously, the ECG was registered on a paperstrip transported through an ECG writer at the speed of 25 mm/second. Nowadays, digital ECG registration is common however, the method of determining the frequency remains the same. The ECG paper has a grid with thick lines 5 mm apart (= 0,20 second) and thin lines 1 mm (0,04 second). | To answer this question, determine the time between two QRS complexes. Previously, the ECG was registered on a paperstrip transported through an ECG writer at the speed of 25 mm/second. Nowadays, digital ECG registration is common however, the method of determining the frequency remains the same. The ECG paper has a grid with thick lines 5 mm apart (= 0,20 second) and thin lines 1 mm (0,04 second). | ||
There are three simple methods to determine the heart rate (HR) | |||
{| class="wikitable" | {| class="wikitable" | ||
! | !The square counting method | ||
|- | |- | ||
| | | The '''square counting''' method is ideal for regular heart rates. Use the sequence 300-150-100-75-60-50-43-37. Count from the first QRS complex, the first thick line is 300, the next thick line 150 etc. Stop the sequence at the next QRS complex. When the second QRS complex is in between two lines, take the mean of the two numbers from the sequence or use the fine-tune method listed below. | ||
|} | |} | ||
{| class="wikitable" | |||
!Use a calculator | |||
|- | |||
| Count the small (1mm) squares between two QRS complexes. Hense, the ECG paper runs with 25 mm/sec through the ECG writer, therefore:[[Image:HFformule_en.png|none]]This method works well in case of tachycardia (>100 beats/minute)<br> | |||
|} | |||
{| class="wikitable" | |||
!The marker method | |||
|- | |||
| | |||
Non regular rhythms are best determined with the "3 second marker method" Count the number of QRS complexes that fit in 3 seconds (some ECG writers register this period on the ECG paper). Multiply this number by 20 and find the number of beats/minute. | |||
|} | |||
{| class="wikitable" font-size="90%" align="center" | {| class="wikitable" font-size="90%" align="center" | ||
|+'''The 'square counting' method can be fine-tuned with the following sequence''' | |+'''The 'square counting' method can be fine-tuned with the following sequence''' | ||