Tachycardia Flashcards
Identify the atrial tachyarrhythmias
PACs
SVT (WPW, AVNRT, Atrial Tachycardia)
Atrial Flutter
Atrial Fibrillation
Identify the ventricular tachyarrhythmias
PVCs
Ventricular Tachycardia
Torsades de Pointes
Ventricular Fibrillation
What happens in Premature Atrial Contraction (PAC)
Early atrial depolarizations
Premature atrial contraction (PAC)
P wave morphology may be different (comes from a different site)
May be nonconducted
If in a pattern: Bigeminal or Trigeminal.
Premature atrial contraction (PAC) treatment
Usually self limited and not symptomatic.
Sinus Tachycardia
In adults: HR>100 bpm but rarely over 200 ppm.
P wave always followed by a QRS in a 1:1 fashion.
Why does sinus tachycardia occur
a physiological response to stress or other stimuli.
Supraventricular Tachycardia (SVT)
Narrow QRS complex
HR at 140-240 bpm.
Abrupt onset and offset.
P wave is usually buried in the QRS but if you can see it, morphology is different.
What commonly causes Supraventricular Tachycardia (SVT)
An accessory pathway: Within the AV node=AV nodal reentry tachycardia 2/3 of patients, Outside the AV node/through the bundle of Kent=AV reentrant tachycardia 1/3 of patients.
Treatment for supra ventricular tachycardia (SVT)
Adenosine
What happens in an AV nodal reentry tachycardia?
A premature beat (PAC) arrives while the accessory pathway is still in refractory. It activates the AV node, slowly (cause its continuing to repolarize). Reaches the ventricle, the accessory pathway has recovered, transmits the signal retrograde to the atria. Then the atria reactivate the ventricle through the AV node.
What makes an accessory pathway named a concealed pathway?
If the patient has SVT via an accessory pathway but has a normal EKG.
What makes an accessory pathway named a Wolff Parkinson White?
If the patient has an SVT via an accessory pathway and has a delta wave on the resting/sinus EKG.
What is pre-excitation
If you see a delta wave on resting/sinus EKG.
Wolff Parkinson White
Narrow PR interval in sinus.
Accessory pathway leads to SVT.
What is the definition of Wolff Parkinson White?
Patient must have SVT symptoms and a delta wave on EKG.
What happens in WPW?
Pre-excitation of the ventricle in the location of the accessory pathway (delta wave), while also conduction through the AV node while in sinus rhythm. When tachycardia, the delta wave disappears.
What are the two pathways present in a dual AV nodal physiology?
Slow (slow conducting) pathway with a fast recovery time.
Fast (fast conduction) pathway with a slow recovery time.
What is the normal AV nodal physiology?
Only one pathway present: Fast conducting pathway with slow recovery time.
What happens in AV nodal reentry tachycardia?
Normal impulse conducted through the fast pathway.
PAC occurs, conducted through the slow pathway (fast is still in refractory).
When the conducted PAC reaches the end of the slow pathway, the fast pathway is recovered and transmits the signal retrograde to the atria, setting up look tachycardia.
Treatment for AVNRT
Adenosine
AVNRT
HR 180-220 bpm.
Regular.
When in tachycardia, cannot see P wave.
No delta waves.