Ecg Flashcards
PR interval
Period between atrial depolarization and start of ventricular depolarization
QRS complex
Ventricular depolarization, atrial repolarization
QT interval
Ventricular depolarization and repolarization
ST segment
Isoelectric period following QRS complex when ventricle is depolarized
T-wave
Ventricular repolarization
P-wave
atrial depolarization
PAC
Early or abnormal P-wave
benign
Ectopic focus initiate impulse before SA node
Atrial flutter
Ectopic focus overrides SA node
atrial tachycardia
Sawtooth appearance T waves not identifiable
Predisposed to thrombosis
Atrial fibrillation
Multiple ectopic foci overriding SA node Repeated uncoordinated depolarizations Irregularly regular P waves not identifiable R-R intervals irregular Predispose to thrombosis
First-degree AV block
Prolonged PR interval
No symptoms
2nd degree AV block
Mobitz I: Progressive prolonged PR interval until one QRS complex is dropped.
Mobitz II: PR intervals are the same followed by a drop of QRS interval. More serious, heart rate is low, cardiac output decreases.
Third-degree AV block
All impulses are blocked at the AV node
No signal transmitted to ventricles
Atria and ventricles are paced independently
Medical emergency
PVC
Premature depolarization the ventricles due to ectopic focus
Tall and wide QRS complex, no P-wave.
Unifocal, bigeminy, trigeminy
Unifocal PVC
one ectopic focus
Bigeminy PVC
Normal sinus followed by a PVC
