ECG Flashcards
What is an ECG used for
An ECG is used to measure the rate and regularity of heartbeats, as well as the size and position of the chambers, the presence of any damage to the heart, and the effects of drugs or devices used to regulate the heart, such as a pacemaker.
P wave is
The P wave represents the wave of depolarization that spreads from the SA node throughout the atria, and is usually 0.08 to 0.1 seconds (80-100 ms) in duration.
The period of time from the onset of the P wave to the beginning of the QRS complex is termed the
P-R interval
ranges from 0.12 to 0.20 seconds in duration.
This interval represents the time between the onset of atrial depolarization and the onset of ventricular depolarization
If the P-R interval is >0.2 sec it means
there is an AV conduction block, which is also termed a first-degree heart block if the impulse is still able to be conducted into the ventricles.
The interval represents the time between the onset of atrial depolarization and the onset of ventricular depolarization is called ?
P-R interval
The QRS complex represents?
ventricular depolarizatio
The duration of the QRS complex is ?
normally 0.06 to 0.1 seconds
the QRS complex is prolonged (> 0.1 sec),
conduction is impaired within the ventricles. This can occur with bundle branch blocks or whenever a
ventricular foci (abnormal pacemaker site) becomes the pacemaker driving the ventricle. Such an ectopic foci nearly always results in impulses being conducted over slower pathways within the heart, thereby increasing the time for depolarization and the duration of the QRS complex.
ST segment
is the time at which the entire ventricle is depolarized and roughly corresponds to the plateau phase of the ventricular action potential.
The ST segment is important in the diagnosis of ?
ventricular ischemia or hypoxia because under those conditions, the ST segment can become either depressed or elevated.
The T wave represents ?
ventricular repolarization
Q-T interval is ?
the time for both ventricular depolarization and repolarization to occur, and therefore roughly estimates the duration of an average ventricular action potential.
The Q-T interval can range from?
This interval can range from 0.2 to 0.4 seconds depending upon heart rate.
A typical ECG tracing of the cardiac cycle (heartbeat) consists of
a P wave, a QRS complex, a T wave, and a U wave,
The baseline voltage of the electrocardiogram is known as the?
isoelectric line.
