EKG Ch. 2 Flashcards
Defining the Intervals (25 cards)
What does the P wave represent?
Atrial depolarization
The P wave indicates the electrical activity that triggers atrial contraction.
What does the PR interval signify?
The period of time in between atrial and ventricular depolarization
It represents the time taken for electrical impulses to travel from the sinus node to the AV node.
What does the QRS complex represent?
Ventricular depolarization
This complex reflects the electrical activation of the ventricles.
What does the ST segment indicate?
The period of time in between ventricular depolarization and repolarization
It represents the plateau phase of the ventricles.
What is the T wave associated with?
Rapid phase of ventricular repolarization
The T wave reflects the return of myocytes to their resting state.
What does the QT interval encompass?
The entirety of ventricular systole
It includes both depolarization and repolarization of the ventricles.
How long does a classic 12-lead EKG represent?
About 10 seconds of time
This duration is critical for analysis and interpretation.
What does one large box on EKG paper represent?
200 ms or 0.2 seconds
This is useful for estimating intervals on the EKG.
What is the baseline of the EKG defined as?
The isoelectric or flat line seen between waveforms
It serves as a reference point for measuring segment elevation or depression.
What is the normal duration of a P wave?
Maximal duration of 120 ms or 0.12 seconds
This is equal to three small boxes on the EKG.
What does a normal PR interval range from?
120 to 200 ms or 0.12 to 0.2 seconds
This corresponds to three to five small boxes on the EKG.
What indicates first-degree AV block in the PR interval?
PR interval greater than 0.2 seconds
This indicates delayed conduction from the sinus node to the AV node.
What is the normal QRS duration?
80 to 120 ms or 0.08 to 0.12 seconds
This is equal to three small boxes or fewer on the EKG.
What does QRS widening indicate?
A delay in conduction through one or both bundle branches
This can reflect underlying cardiac issues.
What does the ST segment represent in relation to the PR interval?
The ventricles’ answer to the PR interval
It allows the ventricles to prepare for the next beat.
What is a clinical point regarding the ST segment?
Deviation of 2 mm above or below baseline indicates a pathologic process
This can signify myocardial injury or ischemia.
What does the T wave represent?
Rapid ventricular repolarization
T wave characteristics can indicate various cardiac conditions.
What can an inverted T wave indicate?
An old infarction or evolving ischemia
This alteration occurs due to scar tissue affecting electrical conduction.
What does a peaked T wave typically indicate?
Electrolyte abnormalities, such as hyperkalemia
This is a critical finding in EKG interpretation.
What is the formula for corrected QT interval (QTc)?
QTc = QT / √RR
This correction accounts for variations in heart rate.
What is the normal range for QTc?
340 to 460 ms or 0.34 to 0.46 seconds
Prolongation can increase the risk of life-threatening arrhythmias.
What does the U wave represent?
A diastolic deflection sometimes seen at the end of the T wave
It is typically less than 1 to 2 mm in height.
What can an upright U wave indicate?
A normal variant or hypokalemia
It may also be more prominent in specific clinical contexts.
What does a widened QRS complex indicate?
Interventricular conduction delay
This can suggest issues within the ventricles.
