NCLEX-PN

STEP 5: MEASURE THE QRS INTERVAL

The “QRS” complex is a measure of ventricular depolarization . This complex has a series of 3 deflections that reflect the current associated with right and left ventricular depolarization. By convention the first deflection in the complex, if it is negative, is called a “Q” wave . The first positive deflection in the complex is called an “R” wave . A negative deflection after an “R” wave is called an “S” wave .

A second positive deflection after the “S” wave, if there is one, is called the “R” wave. Some “QRS” complexes do not have all three deflections. Regardless of the number of waves present, they are all “QRS” complexes. The “QRS” interval is generally less than 0.10 seconds. Anything greater than 0.10 seconds may be classified as ventricular beats or bundle branch blocks and furthermore classified as “wide”. Questions to ask in this step are as followed:

●​ What is the length of the “QRS”: Interval? (> or = 0.10 seconds?) ●​ Are there any dropped “QRS” complex? (P waves present but no QRS?)

This five-step process is a very rapid process to analyze an ECG and make a rapid interpretation of a rhythm and provide prompt treatment to the client. An EKG can tell us a significant amount of data and this 5-step process is a brief introduction to interpreting cardiac rhythms. Sinus Rhythms Sinus rhythms originate in the sinoatrial (SA) node of the heart. There are five types of sinus rhythms :

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