Understanding Cardiac Cycles (i.e, QRS complexes) in an EKG Strip
In an EKG strip, each beat is a QRS complex or cardiac cycle. It is important to often look at specific QRS complexes (cardiac cycles) during the interpretation. So, the first step is knowing how to count QRS complexes (cardiac cycles). Always start at the left and count across as shown below. There are 13 QRS complexes (cardiac cycles) in this EKG strip below.
In an EKG strip I will often ask you to write the triplets on a certain cardiac cycle and tell me the heart rate. In the example below I ask you to write out the triplets from QRS complex (cardiac cycle) 4 to 5 and then tell me the Heart Rate. You see the triplets drawn and the heart rate is greater than 60 beats/min. You could also say the heart rate is less then 75 beats/min or the heart rate is between 60 and 75 beats/min. All are acceptable with the triplets.
In an EKG strip I will often ask you to calculate the Rwave to Rwave heart rate between two QRS complexes. In the example below I would like you to calculate the Rwave to Rwave heart rate between QRS complex 4 and 5. There are 22 small boxes between Rwave #4 and Rwave #5. Thus 22 x .04 is .88seconds. Therefore, .88 divided into 60 is 68 beats/min.
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