EKG Quiz Flashcards
ST segment represents what?
first phase of ventricular repolarization
T wave represents what?
Final phase of ventricular repolarization
Small squares are how much time?
0.04 seconds
bold squares are how much time?
0.2 seconds
Rate range of atrial foci?
60-80bpm
Rate range of junctional foci?
40-60bpm
Rate range of ventricular foci?
20-40bpm
Cause of sinus arrhythmia?
Parasympathetic and sympathetic activation in response to respiration.
Name of the conduction branch of the left atrium?
Bachmann’s Bundle
What do we call “entrance block”?
Parasystole
Wandering Pacemaker
- pacemaker activity wanders to nearby atrial focus
- cycle length variation
- P’ wave variation
- <100bpm
Multifocal Atrial Tachycardia
- pacemaker activity wanders to nearby atrial foci
- cycle length variation
- P’ wave variation
- > 100bpm
Atrial Fibrillation
- firing of multiple irritable, parasystolic atrial foci at once
- no real P waves (kind of a wavy baseline)
- irregular QRS complexes
Atrial Escape Rhythm
- due to sinus arrest
- P’ waves at a regular rate
- slower rate than sinus pacing (60-80bpm)
Junctional Escape Rhythm
- due to sinus arrest and atrial foci failure or conduction block at the proximal portion of the AV node
- either no P waves or inverted P’ waves (retrograde depolarization)
- lone QRS complexes
- 40-60bpm
Ventricular Escape Rhythm
- due to complete conduction block high in the ventricular conduction system or to downward displacement of the pacemaker (if all foci above fail)
- If the former, there will be P waves regularly, but they’re “overlaid” on top of regularly paced (but slow) QRS complexes at a different rate
- if the latter cause, then there will only be QRS complexes at 20-40bpm
Atrial Escape Beat
- due to transient sinus block
- pause followed by single P’ wave + cycle
- normal pacing resumes
Junctional Escape Beat
- due to sinus block and no atrial response
- pause, followed by QRS w/o P wave
Ventricular Escape Beat
- due to burst of parasympathetic activity, depressing the SA node, atrial foci and junctional foci
- pause, followed by enormous QRS w/o P wave
Premature Atrial Beat (PAB)
- due to an irritable atrial focus
- P’ wave earlier than expected
- P’ is up if in superior portion of atrium or inverted if in lower portion of atrium
- SA node is reset and normal pacing resumes
PAB with Aberrant Ventricular Conduction
- due to premature atrial beat conducted to ventricles when one bundle branch isn’t done repolarizing yet
- P’ wave with slightly wide QRS
- SA node is reset and normal pacing resumes
Non-Conducted PAB
- due to a premature atrial beat that hits the ventricles in a refractory periord
- P’ wave earlier than expected followed by no QRS complex
- SA node is reset and normal pacing resumes
Atrial Bigeminy
- due to an irritable atrial focus that fires after every normal cycle
- SA node is reset producing a span of clear baseline after every couplet
Atrial Trigeminy
- due to an irritable atrial focus that fires at the end of every second normal cycle
- SA node is reset, producing a span of clear baseline after every couplet