EXAM #1: VENTRICULAR PRE-EXCITATION & ARRHYTHMIA Flashcards
What is the definition of ventricular pre-excitation?
Early stimulation of the ventricles via an accessory pathway
What is the eponym for an accessory pathway in the heart?
Bundle of Kent
What is the clinical consequence ventricular pre-excitation?
Predisposes to re-entrant supraventricular tachyarrhythmias
What are the ECG manifestations of pre-excitation?
1) Short PR-interval (less than 0.12sec or three small boxes)
2) Delta wave
What is the classic triad for the WPW pattern?
1) Widened QRS
2) Short PR interval
3) Delta wave
What is the difference between WPW pattern and WPW Syndrome?
Syndrome= development of tachyarrhythmias
What will WPW mimic?
1) Bundle branch block
2) MI
When WPW converts into PSVT, what happens to the delta wave?
Delta wave will disappear
What four things will cause a tall r-wave in V1?
1) RVH
2) RBBB
3) WPW
4) Dextrocardia
What are the requirements for re-entry?
1) Bifurcated pathway
2) Different refractory periods in the two pathways
3) Unilateral slow conduction
What is “disturbed automaticity?”
Alterations in sympathetic and parasympathetic activity that change heart rate
What are three general characteristics of premature beats?
1) Occur early in the cycle
2) Prevent occurrence of next normal beat
3) Generate a pause of varying length
What are the ECG features of atrial premature beats?
1) Abnormally shaped p-wave
2) Normal QRS
3) NO COMPENSATORY PAUSE
What is the most common cause of a pause on an ECG?
Nonconducted atrial premature complex
What are the ECG features of a Junctional Premature complex?
1) No p-wave
2) Normal QRS
What does bigeminy mean?
Groups of two
How can you tell atrial premature complexes from 2nd degree AV block?
1) 2nd degree block will have a p-wave with a dropped QRS complex
2) P-p interval will be constant for 2nd degree AV block
What are the ECG characteristics of PVCs?
1) Wide QRS
2) No p-wave
3) T-wave opposite of QRS
4) Compensatory pause is usual
What does the “R on T” phenomenon refer to?
R-wave that occurs during the T-wave
This is BAD–leads to VT and VF
What is a Grade 0 classification of PVCs?
None
What is a Grade 1 classification of PVCs?
Less than 30/hour
What is a Grade 2 classification of PVCs?
30+ an hour
What is a Grade 3 classification of PVCs?
Multiform
What is a Grade 4A classification of PVCs?
2x consecutive
What is a Grade 4B classification of PVCs?
3x consecutive
What is a Grade 5 classification of PVCs?
R-on-T
What are the characteristics of LVP?
Upright in V1
What are the characteristics of a RVP?
Down in V1
What are the clinical consequences of a LVP?
More clinically concerning:
- IHD
- More likely to cause V-fib in MI
