12. Supraventricular Tachycardias Flashcards
1
Q
How are the diff types of supraventricular tachycardias distinguished from one another?
A
By diffs in P wave configuration and by the regularity of the QRS complexes
2
Q
List the different supraventricular tachycardias.
A
- Sinus tachycardia
- Supra-ventricular tachycardia
- Atrial flutter
- Atrial fibrillation
- Multifocal atrial tachycardia
3
Q
Characterize a sinus tachycardia.
A
- Diastolic interval b/t T and P waves is so close it forms a double humped T-P wave
4
Q
What characterizes all supraventricular tachycardias?
A
- Rapid hr
- Narrow QRS
- Altered or missing P waves
5
Q
What is a paroxysm?
A
“Fit” w/ a sudden onset and abrupt ending
6
Q
What is an atrial flutter? Characteristics of EKG?
A
- Atria are trapped in a reciprocating tachycardia, usually 300/min
- Rapid cycles of atrial depolarization and repolarization produce saw-toothed “flutter waves” in the baseline
- “Rate flavors” equivalent to 150, 100, and 75 bpm due to AV node blocking conduction so only every 2nd, 3rd, or 4th flutter wave passes to the ventricle
7
Q
What is atrial fibrillation? Cause? Characteristics of EKG?
A
- Atria no longer produce a coherent, unified contraction
- Multiple small populations of myocytes depolarize randomly throughout atria
- Atria “shiver” w/ uninterrupted, random electricle activity that never produce a contraction
- EKG: absence of P waves, quivering baseline, irregular rate
8
Q
What does axis shift towards? Away from?
A
- Shifts toward hypertrophy or bundle branch block
- Shifts away from infarction
