11 - ECG Recognition I Flashcards
Review of all ECG material
Physiology Exam II - Electrocardiogram I and II
What is a P wave?
deflection from and return to isoelectric line
What physiological event does a P wave correlate with?
atrial myocyte depolarization (phase 0)
What is the normal duration of a P wave?
0.06-0.11 sec
1-2 small boxes
What is a QRS complex?
deflection from and return to isoelectric line
What physiological event does a QRS complex correlate with?
ventricular myocyte depolarization (phase 0)
What is the normal duration of a QRS complex?
0.03-0.12 sec
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What is a PR interval?
beginning of P wave deflection to beginning of QRS complex
What physiological event does a PR interval correlate with?
all electrical events (depolarization- phase 0’s) upstream of ventricular myocytes (atrial myocyte, AV node, bundle, bundle branches, Purkinje fibers)
What is the normal duration of a QRS complex?
0.12-0.2 sec
3-5 small boxes
What is a T wave?
deflection from and return to isoelectric line
What physiological event does a T wave correlate with?
ventricular myocyte repolarization (phase 3)
What is the normal duration of a T wave?
Variable
What is a QT interval?
beginning of QRS complex to the end of the T wave
What physiological event does a QT interval correlate with?
the entire action potential for the ventricular myocytes (depolarization- plateau- repolarization)
What is the normal duration of a QT interval?
variable
roughly half R-R interval
What is the ST segment?
end of the QRS complex to the beginning of the T wave deflection
What physiological event does a QT interval correlate with?
ventricular myocyte plateau phase (phase 2)
What is the normal duration of an ST segment?
Variable (with HR)
What is the sequence of depolarization of the heart?
- SA node
- Atria
- AV node
- Bundle of His
- Bundle branches
- Purkinje fibers
- Ventricles (septum, apex, ventricular free walls)
