Supraventricular Tachyarrythmias Flashcards
What is ventricular pre-excitation?
Widening of the QRS interval
Abnoramal ventricular activation occurs LATE as a BBB
Ventricular Activation occurs EARLY (PRE-EXCITATION) resulting in a delta wave.
Where can the extra pathway be in pre-excitation?
in the AV node or or via an accessory pathway (budle of kent)
What is the ECG result of pre-excitation?
Short PR (.10 sec)
What are the charicteristics of Wolf-Parkinson-White Syndrome?
Pre-excitation plus the classic supraventricular arrhythmia
Without SVA it’s just the WPW pattern
What other pathology can mimic Ventricular Pre-Excitation?
BBB (Widens QRS) or MI
What Is seen in an inferior MI?
Wide Q wave
Where is the kent bundle located?
In the right AV area.
What type of depolarization gets rid of the Delta wave in Vent. Pre-Excitation
Conduction is via the normal pathway, until the arrythmia converts
Macro re-entrant tachy arrythmia
What can cause a tall upright R wave in lead V1?
- Right ventricular hypertrophy with reversal of the precordial pattern
- Wolf Park White (pre-excitation)
- Dextrocardia (situsinversus)
- RBBB
What does a delta wave look like?
It is a little spike on the upslope of the R wave
What is the most common mechanism of tachy-arrythmias?
Re-entry
What is required for re-entry to take place?
A bifurcated pathway
Different refractory peroid for each pathway
Unilateral slow conduction
What is the mechanism of arrythmias concerning the refractory period?
The refractory peroid can either be lengthened or shortened depending on the slope of the funny current.
What are charicteristics of early beats?
Occur early in the cycle
Prevent occurrence of the next normal
Generate a pause of varying length.
What differentiates Early ATRIAL Beats
Early in cycle
Abnormally shaped P wave(may be difficult to see)
Normal QRS
No compensatory pause
What is the the most common cause of a paue on an ECG?
Non-conducted atrial premature doesn’t conduct to the AV junction or ventricle.
How is a Ventricualr Premature different than atrial?
Has a compansatory pause A-B = B-C
Premature beat has a big irregular R wave with opposite vector as the rest
Atrial A-B > B-C and preceded by a P wave
What is unique about a supreventricular premature?
Premature beat has no P wave
What pathology is associated with “grouped beating”?
2nd Degree AV block (have to be sure theres no prematurity)
What differentiates an AV block from Atrial Prematures?
P wave in prematures are Early compared to the rest.
AV block P waves are in the normal place.
What is distinctive about ventricular prematures?
Wide, bizarre QRS, complexes >.12sec (FLBs)
NO Preceding P wave
ST seg slopes away from QRS
Compensatory pause unusual
What is ventricular bigemeny?
Fixed coupling interval between the normal complexes and the extrasystoles. Strongly supports reentry as mech of arrythmia
What is the worst type of ventricular premature?
R wave found on the Terminal portion of the T wave. (Grade 5)
What arrythmia is the Lown Classification used for?
Ventricular Prematures 0-None 1- 30/hr 3- Multiform 4A- Two Consecutive 4B- 3 or more consecutive 5- R-on-T
