ECG Flashcards
What do the boxes on an ECG represent?
What are Limb Leads 1,2,3
Bipolar Limb leads
Tell you about the electrical activity in vertical plane of the heart
What are Limb Ledas aVR,aVL,aVF
Augmented Unipolar Limb leads
Tell you about the electrical activity in vertical plane of the heart
What are V1-V6 leads?
Precordial Chest leads
Tell you about the electrical activity in horizontal plane of the heart
What is the most common ECG Lead used?
2
5.Things to consider when interpreting ECG
- Rate
- Rhythym
- QRS
- Sinus P wave present?
- P-R interval
1.How to determine Heart Rate on an ECG
Box Method is (300/no.of boxes between the R wave)
R-Waves across 10 secs and x6
2.How to determine heart rhythym
You can take a card and mark where the R waves are and move along ECG to determine if regular or irregular
3.QRS: Normal/Wide
Greater than 3 small boxes within QRS complex -wide QRS
4.Sinus P wave present?
- P-R Interval?
Differential Charactersitics of Tachycardia
Differntial Charcteristics of Bradycardia
ST elevation requirements + potential reasons for this
1 mm ST segment elevation in any of the leads except V2-V3
2mm in V2-V3
ST Depression requirements + potential reasons for this
J wave requirements + potential reason for this
T wave inversion requiremnts + potential reason for this
Hyperacute T wave requiremnts + potential reason for this
Biphasic T wave requirements + potential reason for this
Flat T wave requirement + potential reason for this
Peaked T wave requirement + potential reason for this
Wide QRS complex requirement + potential reason for this
Pathological Q wave
Low Voltage QRS
R wave
LVH/RVH
Prolonged QT
P-wave/PR Interval & Abnormalities
Cardiac Axis + Abnormalities
ECG Findings for subendocardial ischaemia
What is digitalis effect
From Taking too much Digoxin
Has a curved ST segment
What is an NSTEMI
Non-ST elevation myocardial infarction
ECG findings for a Transmural Infarction
Can also get a pathological Q-wave (>2mm deep + >0.04ms wide)
Pathological Q waves and Infarct Locations
Septal Wall: V1,V2
Anterior Wall: V3,V4
Anterolateral: V3-V6, I, aVL
Subendocardial - None
aVR is not a reliable lead for diagnosing patological Q wave
Other causes of Pathological Q-waves
Bundle Branch Block, Wolff-Parkinson-White Syndrome
Table to describe subendocardial vs Transmural
What is considered a patholoigcal sign of ischaemia
T wave inversion leads V2-V6
____ conduction through the atrioventricular node ensures that ventricles have enough time to fill with blood before contracting.
Slow
Decreased ventricular filling can result from an
increase in conduction velocity at the atrioventricular node.
Increases in conduction velocity at the atrioventricular node can lead to
decreased stroke volume.
The resting membrane potential of cardiac cells is primarily determined by
potassium ions.
Conduction velocity in the heart is slowest at the
AV node
Conduction velocity in the heart is fastest at the
Purkinje fibers
_____ in the ECG corresponds to the atrial depolarization.
P wave
P wave in the ECG corresponds to the
atrial depolarization
The PR-interval in the ECG is the
time from start of atrial depolarization to start of ventricular depolarization (normally <200 msec).
The QRS complex in the ECG corresponds to
electrical ventricular depolarization (normally < 120 msec).
ECG corresponds to the mechanical contraction of the ventricles
QT interval
ECG corresponds to ventricular repolarization
T wave
J point of the ECG corresponds to the
junction between the end of QRS-complex and the start of ST-segment.
The U wave of the ECG is prominent in
hypokalemia and bradycardia.
The lateral leads of the electrocardiogram are leads
I, aVL, V5, and V6.
The inferior leads of the electrocardiogram are leads
II, III, and AVF
Normally, the R wave is larger than the S wave in
lead V4 on electrocardiogram.
The QRS transition zone is usually seen in the chest leads
V3 and V4.
QRS transition zone will shift towards a region of
hypertrophy
Angina caused by vasospasm, or Prinzmetal’s angina, can cause transient in the absence of an infarction.
ST elevation
Ventricular aneurysm can cause persistent
ST elevation in most of the chest leads on electrocardiogram.
_______ causes diffuse ST elevation.
Pericarditis
Significant Q waves on electrocardiogram indicate
necrosis and are diagnostic of infarction.
A large R wave in lead V1 or V2 of electrocardiogram should raise suspicion for a
posterior infarction
ST segment depression in the right chest leads of electrocardiogram should raise suspicion for an
acute posterior infarction.
