ECG Waveforms Flashcards
what does a single ECG complex comprise of?
individual waves and lines that occur in a specific sequence as a result of depolarization and repolarization
isoeletric line
the baseline of an ECG tracing
waveform
deflection or movement away from the baseline
segment
the line between 2 waveforms
interval
consists of a waveform and a segment
complex
a collection of waveforms ie) QRS complex
what are the components of an ECG?
P wave, PR interval, QRS complex, ST segment, T wave, QT interval
in lead II, which electrode is positive and which is negative?
LL is positive
RA is negative
what does the P wave represent?
atrial depolarization
if the P wave is normal, what would the direction of electrical flow be?
from R to L and down toward positive electrode
P Wave
- location
- amplitude
- duration
- configuration
- deflection
- precedes QRS complex
- 2-3mm high
- 0.06-0.12 seconds
- rounded and upright
- positive and upright in lead II
what does the isoelectric line represent?
after atria are depolarized, wave of depolarization continues towards AV node and junctional tissues and there’s a short pause in electrical flow allowing atria to recover and repolarize
isoelectric line location?
immediately after P wave
what does the PR interval represent?
amount of time it takes for the electrical impulse to leave the SA node, depolarize the atria, and pass through the AV junction
PR interval
- location
- duration
- composed of
- beginning of P wave to beginning of QRS complex
- 0.12-0.20 seconds
- composed of P wave and PR segment