ECG Interpretation: Waves, Intervals, Axis, and Abnormalities
15 keer bekeken 0 keer verkocht
Vak
Medical
Instelling
University Of Gujrat
This document is a detailed guide to ECG interpretation, covering every aspect essential for understanding and analyzing electrocardiograms. It provides an in-depth exploration of ECG fundamentals, including waveforms (P, QRS, T, and U waves), intervals (PR, QT), and segments (ST), with specific at...
Introduction to ECG/EKG
An Electrocardiogram (ECG or EKG) is a test that records the electrical activity of the heart over
a period of time using electrodes placed on the skin. It is a crucial tool for diagnosing various
heart conditions by analyzing the heart's rhythm and electrical conduction patterns.
Components of the ECG Waveform
The ECG waveform consists of waves, complexes, intervals, and segments that correspond to
specific electrical events in the cardiac cycle.
1. P Wave
○ What it Represents: Atrial depolarization, which leads to atrial contraction. ○
Details: The P wave reflects the electrical impulse traveling through the atria
from the sinoatrial (SA) node.
2. PR Interval
○ What it Represents: The time from the onset of atrial depolarization to the onset
of ventricular depolarization.
○ Details: It includes the P wave and the PR segment, indicating the conduction
time through the atria and the atrioventricular (AV) node.
3. PR Segment
○ What it Represents: The period between the end of the P wave and the
beginning of the QRS complex.
○ Details: Reflects the delay at the AV node, allowing the ventricles to fill with
blood before they contract.
4. QRS Complex
, ○ What it Represents: Ventricular depolarization, leading to ventricular
contraction.
○ Details: Consists of three deflections:
■ Q Wave: The initial negative deflection after the P wave.
■ R Wave: The first positive deflection after the Q wave.
■ S Wave: The negative deflection following the R wave.
5. ST Segment
○ What it Represents: The period between ventricular depolarization and
repolarization.
○ Details: Normally isoelectric (flat), changes can indicate myocardial ischemia or
infarction.
6. T Wave
○ What it Represents: Ventricular repolarization, the recovery phase of the
ventricles.
○ Details: Represents the ventricles returning to their resting state.
7. QT Interval
○ What it Represents: The total time for ventricular depolarization and
repolarization.
○ Details: Measured from the beginning of the QRS complex to the end of the T
wave.
8. U Wave (occasionally present)
○ What it Represents: Thought to represent repolarization of the Purkinje fibers.
○ Details: Not always visible and its exact significance is not entirely understood.
Isoelectric Lines in ECG
● Definition: The isoelectric line is the baseline of the ECG tracing where there is no net
electrical activity detected.
● Number of Isoelectric Lines: There is essentially one isoelectric line, but it can be
observed during different intervals.
● Occurrences:
○ PR Segment: Represents the isoelectric period after atrial depolarization.
○ ST Segment: Another isoelectric period following ventricular depolarization.
● Significance: Deviations from the isoelectric line during these segments can indicate
cardiac abnormalities such as ischemia or infarction.
Depolarization and Repolarization
● Depolarization: The process by which cardiac muscle cells change their electrical
charge from negative to positive, leading to contraction.
○ Atrial Depolarization: Reflected by the P wave.
○ Ventricular Depolarization: Reflected by the QRS complex.
● Repolarization: The process of returning to the resting negative charge after
depolarization, leading to relaxation.
○ Ventricular Repolarization: Reflected by the T wave.
● Note: Atrial repolarization occurs but is usually obscured by the QRS complex and not
visible on the ECG.
Voordelen van het kopen van samenvattingen bij Stuvia op een rij:
Verzekerd van kwaliteit door reviews
Stuvia-klanten hebben meer dan 700.000 samenvattingen beoordeeld. Zo weet je zeker dat je de beste documenten koopt!
Snel en makkelijk kopen
Je betaalt supersnel en eenmalig met iDeal, creditcard of Stuvia-tegoed voor de samenvatting. Zonder lidmaatschap.
Focus op de essentie
Samenvattingen worden geschreven voor en door anderen. Daarom zijn de samenvattingen altijd betrouwbaar en actueel. Zo kom je snel tot de kern!
Veelgestelde vragen
Wat krijg ik als ik dit document koop?
Je krijgt een PDF, die direct beschikbaar is na je aankoop. Het gekochte document is altijd, overal en oneindig toegankelijk via je profiel.
Tevredenheidsgarantie: hoe werkt dat?
Onze tevredenheidsgarantie zorgt ervoor dat je altijd een studiedocument vindt dat goed bij je past. Je vult een formulier in en onze klantenservice regelt de rest.
Van wie koop ik deze samenvatting?
Stuvia is een marktplaats, je koop dit document dus niet van ons, maar van verkoper shikhapatel. Stuvia faciliteert de betaling aan de verkoper.
Zit ik meteen vast aan een abonnement?
Nee, je koopt alleen deze samenvatting voor €9,89. Je zit daarna nergens aan vast.
