ECG Basics
What does ECG stand for?
Electrocardiogram
Which wave represents atrial contraction?
P wave
What does the PR interval measure?
Time from atrial depolarization to ventricular depolarization
Which node starts the heartbeat?
SA node
What does a flat line on an ECG indicate?
No electrical activity in the heart
What does an ECG measure?
The electrical activity of the heart
Which complex represents ventricular contraction?
QRS complex
What is the flat line between waves called?
Segment
What node slows the signal before the ventricles?
AV node
What does bpm stand for when measuring heart rate?
Beats per minute
What machine records an ECG?
Electrocardiograph
Which wave represents ventricular recovery?
T wave
Which interval measures total ventricular activity?
QT interval
What fibers distribute signals through ventricles?
Purkinje fibers
What does tachycardia mean?
A heart rate that is too fast (over 100 bpm)
Why are ECGs used in medicine?
To detect heart problems and abnormal rhythms
Which wave is usually the largest on the ECG?
QRS complex
Which wave on an ECG represents atrial depolarization?
P wave
What carries signals from the AV node to the ventricles?
Bundle of His
What does bradycardia mean?
A heart rate that is too slow (under 60 bpm)
Where are electrodes placed?
On the chest, arms, and legs
Why is atrial repolarization not visible on ECG?
It’s hidden by the larger QRS complex signal
What can ST elevation indicate?
Possible heart attack
What is the normal adult resting heart rate?
60–100 bpm
What does an irregular rhythm on an ecg usually indicate?
Arrhythmia