Excerpt from Lesson 8
Ventricular Tachycardia (V Tach, VT)
Ventricular tachycardia occurs when an irritable or "ectopic focus" in the ventricles overrides the higher pacemaker site and takes control of the heart.
Ventricular tachycardia is defined as a series of three or more consecutive PVC's. The causes are the same as PVC's: electrolyte imbalance, overuse of caffeine or alcohol, acid-base imbalance, drug-initiated ventricular irritability.
What are the Key Identifying Features of Ventricular Tachycardia?
The key identifying EKG features of Ventricular Tachycardia are easy to learn! This rhythm is very unique and recognizable.
The rate is rapid (around 150-250 beats per minute) However, nobody stops to actually calculate the rate when you see this rhythm march across your monitor!!
The rhythm consists only of QRS complexes, which are wide and bizarre (They look just like the QRS' you see with PVC's.)
Before I summarize the Key features of Ventricular Tachycardia below, let me tell you a TRUE story (names have been changed to protect the innocent) to help you remember how to recognize Ventricular Tachycardia.
My good
friend, Ginny, was working in an area hospital's ICU during graduate
school. The ICU had an SICU (Surgical Intensive Care Unit) on one
side and a CCU (Coronary Care Unit) on the other side. One
shift, she was working on the SICU side of the unit, and there was
another nurse, Sally, working on the CCU side. Sally was orienting a
new nurse, Margaret, to the CCU.
Sally had to leave the unit for a little while
and told Ginny to watch out for Margaret while she was gone. Of
course, no sooner had Sally left the unit until Margaret called to
Ginny, "Hey Ginny, my patient is doing something funny on the
monitor."
Ginny thought, "Well, OK, something funny. It could be
movement artifact or it could be something serious." Ginny, not
wanting to sound worried, said "OK, Margaret, what does it look like
to you?" Margaret said, "Well it looks like ghosts holding hands to
me."
Ginny immediately got this vivid picture in
her mind of Ventricular Tachycardia. She knew she had something to
worry about and jumped right on it!
This true story will help you remember what Ventricular Tachycardia looks like. However, let me warn you: if you see Ventricular Tachycardia in the clinical setting, and say "Hey that patient has ghosts holding hands" everyone and I mean EVERYONE will think you are crazy and will NOT KNOW WHAT YOU ARE TALKING ABOUT! (You may have to use your imagination a little to identify with this story). J
Ghosts holding hands
Summary of Key Identifying EKG Features Of Ventricular Tachycardia
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Rate: Atrial rate cannot be determined. Ventricular rate is 150-250 beats per minute. If the rate is below 150 beats per minute is considered a slow VT. If the rate exceeds 250 beats per minute it is called Ventricular Flutter (Really doesn't matter what you call it, the clinical significance is the same.)
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Rhythm: Usually regular, although it can be slightly irregular.
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P Waves: None of the QRS complexes will be preceded by P waves. You may see dissociated P waves intermittently across the strip (but not usually.)
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PRI: None
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QRS Complex: Wide and bizarre, measuring at least .12 seconds. Often difficult to differentiate between the QRS and the T wave.
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S-T Segment: Different from the underlying rhythm.
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T Wave: T wave deflection is opposite than that of QRS complex.
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