ECG
What Is The Normal QRS Duration
0.06 to 0.12 Seconds
When Does A Widened QRS Occur
Can occur with conditions where the impulse formation occurs in the ventricles, such as premature ventricular complexes (PVC) and ventricular tachycarida.
What Are Prolonged PR Intervas Associated With
First degree AV blocks and with digoxin toxicity; indicates that the impulse is delayed as it passes through the AV node
How Is The T Wave Measured
Follows the QRS complex and the ST segment. Normally is rounded and smooth.
What Is The Importance Of PR Interval For ECG Interpretation
Helps signal the presence of a conduction delay disturbance such as an AV blcok
What Does A Peaked T Wave Indicate
Hyperkalemia
What Is The Q Wave
If the first deflection is negative, it is called a Q wave. Not everyone has Q waves
What Is The Importance Of The QRS Complex
Interpretation is critiical because of its impoprtance in feflecting ventricular myocardial cell activity. The QRS complex represents ventricular depolarization. so ventricular contraction can be assumed
What Are Short PR Intervals Associated With
Junctional rhythms and indicate that the impulse originated in an area other than the SA node
Where Is The P Wave Located And What Does It Look Like
Located before the QRS complex; Normally upright and rounded; Should be upright in lead II
How Is The PR Interval Measured
Measured from beginning of P wave to beginning of QRS complex.
How Is The QRS Complex Measured
Measured from the beginning of the complex to the end of the complex
How Is The ST Segment Measured
Measured from the end of the S wave to the beginning of the T wave. The deflection should be isoelectric, but may vary 1mm or less
What Does An Inverted T Wave Indicate
Myocardial Ischemia
What Is The PR Interval Duration
Normal Duration is 0.12 to 0.20 seconds
When Do QRS Configuration Variations Occur
Occur with intraventricular conduction delays (IVCD) such as bundle branch blocks
What Do Heavily Notched T Waves Indicate
Pericarditis in adults, but are normal in children
What Does The ST Segment Represent
Represents the time between ventricular depolariation and repolarization (diastole).
What Does A P Wave Represent
Represents time for the passage of the electrical impulse through the atrium causing atrial depolarization (contraction).
What Does The T Wave Represent
Represents time for ventricular repolarization
What DoesThe QRS Complex Represents
Represents time taken for depolarization (contraction) of ventricles (systole).
What Does The PR Interval Represent
Represents time taken for impulse to spread through the atria, AV node and bundle of His, the bundle branches, and Purkinje fibers, to a point Immediately preceding ventricular contraction. This is the time from the beginning of atrial depolarization to the beginning of ventricular depolarization
What Does A ST Segment Depression Indicate
Segment depression (2mm or more below the baseline) may indicate an old myocardial ischemia. Other changes may be seen with pericarditis, pulmonary emboli and electrolyte distrubances.
What is The S Wave
The first negative deflection after the R wave
What Is The R Wave
The first positive deflection. Often is the first waveform after the PR interval
What Is The Importance Of The T Wave
The peak of the T wave represents the vulnerable period of repolarization. This is the period of time when the ventricles are most susceptible to extra stimuli
What Is The Importance Of The P Wave For ECG Interpretation
The presecne of a Pwave indicates that the impulse originated in either the SA node, the atria, or the AV junction tissue. If the P wave is normal, it is referred to as a sinus P wave, meaning that it originated in the SA node.
