Cardiovascular Assessment Flashcards
Wenckebach
Type I
Going, Going, Gone (PRI Interval)
AV node “getting tired” and delays are longer each time until a beat is not conducted
Results in a specific pattern in the PRI: longer, longer, (longer)…then a dropped beat
Lateral injury
Leads I, aVL, V5, V6
Lead 3
Lead three has perpendicular movement to the dominant electrical current in the heart (from base to apex) therefore flattened more not as high of a deflection.
Wolff-Parkinson White Treatment
Treatment is ablation therapy which is usually done via radiofrequency and an intracardiac catheter
Pulseless Electrical Activity
PEA can be any rhythm on the monitor that is pulseless and not Vtach, Vfib or asystole
There is typically a reversible cause!
Frontal Plane
While the electrodes are RA, LA, RL and LL they are often placed in the corresponding positions on the anterior chest wall.
This is more convenient and reduces artifact due to movement.
All 6 frontal plane leads (limb leads) use a combination of the same three electrodes attached to the arms and legs
Sinus Rhythms
All originate in the sinus node and therefore all have upright, round P-waves throughout the strip. There is one P wave per QRS.
Differences in Sinus Rhythms
- Rate: differentiates NSR from sinus brady from sinus tachy
- Regularity: sinus arrhtymia is irregular
Sinus Rhythms:
- Normal sinus rhythm
- Sinus bradycardia
- Sinus tachycardia
- Sinus arrhythmia
How to measure rate when irregular
take the number of QRSs in 6 seconds and multiply by 10
Asystole
Flatline
Sinus Tachycardia
Atrial Tachycardia
Usually between 150-250 bpm
the p wave is flattened, peaked, and diaphasic and may be hidden
If the p wave is hidden it is a SVT
Wandering Pacemaker
The QRS will be consisent but the p wave will change shape and where it is located (sometime might not be there)
Premature Ventricular Contraction
Will have a normal underlying sinus rhythm and then a random wide QRS complex in the middle of the rhythm
Define underlying rhythm
3rd Degree Heart Block
P Wave and QRS Complex have no relation
Atria depolarizing as normal but no signal gets through; either junction or ventricles takes over pacing of ventricles (at inherent rate and associated QRS width)
These two events (atrial and ventricular depolarization) occur simultaneously but independently, thus, the apparent PRI is random and unrelated to the QRS
Idioventricular Rhythm
Will be regular
BPM is 20-40
No p wave
The QRS is greater the 0.12 (wide) and bizarre
First Degree Heart Block
The PRI interval is long
No dropped beats
Ventricular Tachycardia
150-250 bpm
Will look like a bunch of upsidedown U that are all the same shape and rate
Shockable heart rate
Anterior injury
Seen in V3, V4
Lead AVR
AVR=right arm is postive electrode
The direction of electrical activity in the heart is almost exactly opposite to this vector
This results in negative deflections on the ECG
Trigeminy PVC
Every third beat is a PVC
Junctional Rhythms
Originate in junction, and retrograde conduction in atria
Inverted or absent p-wave
PVC
Wil have an underlying rhythm and then there is a wide intrupting QRS
Normal PRI
0.12-0.20
ECG Y-axis
The y-axis represents voltage
1 mm= 0.1 mV
Second Degree Heart Block (Mobitz II)
When there is a PRI it will be constant but every so often a P wave will just not be there
AV node is unreliable results in dropped beats without warning; can be random or in a pattern (e.g. every third beat)
Accelerated Junctional
P wave is inverted and rate is 60-100 with bpm
Leads I, II and III
These are bipolar leads, meaning there are 2 electrodes (positive and negative) to record the tracing
Supraventricular Rhythm
Technically in order to classify the type/origin of the tachycardia you need to be able to see the p-wave
At rates greater than 150 bpm it is unlikely that you will be able to see p waves as they will be hidden in the t wave
SVT is a descriptive term applied to tachycardias that cannot be differentiated because the P waves are not able to be visualized
Quadrigeminy PVC
Every fourth beat is a PVC
Types of PVC
Unifocal
Bifocal
Couplet
Run
Bigeminy
Trigeminy
Quadrigeminy
Bifocal PVC
Different shapes and different foci
Junctional Escape Rhythm
P wave is inverted and rate is 40-60 with bpm
Unifocal PVC
Same shape and focus
How do you find the QRS Complex
Look for the biggest QRS complex on a frontal plane lead and use the lead to determine.
Note: If the biggest deflection is negative then the axis is directly opposite of that l
Left Axis Deviation:
Lead I: positive and Lead II: negative
Causes:
- Abdominal obesity
- Ascites
- Third trimester pregnancy
- Left ventricular hypertrophy
- LBBB
Run PVC
4 or more PVC together
Each of the 12 Leads:
View the electrical activity of the heart from different angles
Have both a positive and negative component
Monitor specific parts of the heart.
Always done from the point of view of the positive electrode in that lead
V1
4th intercostal, right sternal border
QRS Axis
The QRS axis is the direction of the electrical current during depolarization of the ventricles
Normally lead 1 and 2 are positive meaning the majority of QRS will be positive (above isoelectric sign), if this is not true than there is an axial deviation
Right Axis Deviation
Lead I: negative and Lead II: positive
Causes:
- Cor Pulmonale
- RV hypertrophy
- PE
- RBBB
ECG X-axis
The x-axis is a representation of time
1 mm (1 little square) = 0.04 s
5 mm = 0.20 s
Ventricular Rhythm
Originates outside normal conduction pathway, resulting in a wide bizarre QRS
AV Node acs as a one way valve and thus no depolarization of the atria occurs and no p-wave are visualized
Pulseless Electrical Activity (PEA)
Will be no electrical activty on the ECG monitor
Is any pulseless rhythm except for V fib, V tach, or asystole
Leads AVR, AVL and AVF
These are unipolar leads (records only from one electrode)
The center of the heart will be the negative reference point
All precordial (chest) leads are unipolar
Called augmented leads as the ECG machine must amplify the signal
These signals are created by making one of the limb leads positive and the other limb leads negative
Gives a horizontal view of the heart
Very useful in diagnosing the location of an MI
Premature Junctional Contraction
P Waves will be inverted
Underlying Rhythm
Different Types of Tahycardia
Sinus Tachycardia 100 – 160 bpm
Atrial Tachycardia 150 – 250 bpm
Atrial Flutter (atrial rate) 250 – 350 bpm
Junctional Tachycardia 100 – 180 bpm
Lead AVF
Foot is positive electrode
Septal injury
V1, V2
V4
5th intercostal, mid-clavicular line
Idioventriculat Rhythm
20-40 bpm
no p wave
Amplitude of R Waves from V1-V6
From V1-V6 the amplitude of R waves should increase and the amplitude of S waves should decrease
LEAD 2
This is the most commonly monitored lead
Direction of heart’s electrical activity is towards the positive electrode \ results in the most positive deflection for all ECG activity
QRS Height
QRS will change in height between different leads
All 6 frontal plane leads (limb leads) use a combination of the same three electrodes attached to the arms and legs!
If electricity flows towards the positive electrode it results in an upright image on the ECG
If the electricity flows towards the negative electrode (or away from the positive) it results in an inverted image on the ECG-a negative deflection is seen
What do you think happens when the electrical impulse travels perpendicular to this axis? Perpendicular=straight line=no deflection
Wolff-Parkinson White
A congential malformation resulting in a accessory atrioventricular pathway which allow the AV nose to activate ventricles prematurely
The risk is the potential rapid ventricular response
Atrial fibrillation will occur in 1/5 to 1/3 of WPW patients
More common in men
Premature Atrial Contraction (PAC)
Will have an ectopic beat that intruppts the underlying regular rhythm
The P wave of the premature beat will look different than that of the underlying rhythm (this also may change the PRI interval as well)
Einthoven’s Triangle
Named after an early pioneer in electrocardiography
The vector direction of Leads I, II and III form a triangle
When is an ST elevation consider pathological
If it occurs in two or more anatomical continguous leads
12 Lead ECG
A 12 lead ECG has 4 limb electrodes, and six chest electrodes.
6 are STANDARD limb leads
6 are PRECORDIAL (chest) leads.
Sinus Tachycardia
Rate is over than 100 bpm
P wave before very QRS
PRI is 0.12-0.20
QRS is less than 0.12
Direction of Heart
From the base of the heart (Upper) the apex if in a RIGHT TO LEFT direction
Think apex is nearer the armpit, base is closer to the breast bone.
For a normal healthy heart the direction is always the same
V6
5th intercostal, mid-axillary line
R and S waves in V3 or V4
In V3 or V4 the R and S waves should be approximately equal size
Atrial Flutter
Atrial rate between 250-350
Sawtooth patteren
QRS will be between 0.12-0.20 and all the same shape
Normal Sinus Rhythm
Rate between 60-100
PRI is between 0.12-0.20
QRS less than 0.12
V3
placed between V2 and V4
Couplet
2 PVC together
Sinus Bradycardia
Rate is less than 60 bpm
P wave before very QRS
PRI is 0.12-0.20
QRS is less than 0.12
Wolff Parkinson White ECG
Patient is usually in as normal sinus rhythm but re-entry causes a tachycardia
PR is usually < 0.12s
QRS complex > 0.11
Has a characteristic “slur” (delta wave)
Where do most myocardial infarctions occur?
Most myocardial infarction occur in the left ventricle which is why most leads look at the left ventricle
Ventricular Fibrillation
Shockable heart rhythm
Completely irregular
Bigeminy PVC
Every Second beat is a PVC
V2
4th intercostal, left sternal border
Atrial Tachycardia
Bpm will usually be between 150-250
The shape of the p wave will be flattened, peaked, or diaphasic and can blend into the T wave
Unlike atrial flutter will still and an isoelctrical baseline (stright line where they originate from)
Premature Atrial Contraction
Will have an ectopic beat that will intrupt the underlying rhythm (it is a premature p wave). In order for a premature beat to be considered an PAC there must be an upright P wave.
Remeber to name the uderlying rhythm
Atrial Rhythms
Impulse originate in atria
Funny p waves (peaked, notched, flattened, or biphasic)
Wandering Pacemaker
60-100 bpm (may be slower)
The p wave keeps changing
V5:
placed between V4 and V6
How to measure Rate
Count the little square between a QRS complex and then divide by 1500
Paroxysmal SVT
PSVT = paroxysmal SVT, it occurs and ends without warning
Normal QRS
Less than 0.12
Junctional Tachycardia
P wave is inverted and rate is 100-180 with bpm
ECG Recording
All ECG will use the same paper which runs through the at the same speed (25 mm/sec)
Small Squares- 1 mm2
Lead AVL
Again=perpendicular to hearts electrical activity so… flattened view.
Tip to remember= a means augmented V means voltage R=right,L=left,F=foot!!
So AVL means positve electrode is Left, where is the positive electrode for avF?
Atrial Fibrillation
No true P wave only a squiggly line
QRS will be between 0.12-0.20 and all the same shape
Inferior injury
Leads II, III, aVF
Pulseless Rhythms
There are 4 pulseless rhythms
- Ventricular Tachy
- Ventricular Fib
- Asystole
- PEA
First Degree Heart Block
the PRI will be more than 20 secs
Sinus Arrhythmias
Will look like a normal rhythm wilth P waves, PRI, and QRS
The distinguishing factors rhythm and time between beats will vary as a person inhales and exhales (will be a regular irregular pattern)
The rate will usually be between 60-100 but can be slower
LEAD I
Goes toward the positive therefore + deflection on ECG
Remember electrical flow through the heart goes from base to apex!!!!
Heart Blocks
Delay in conduction to the ventricle or may block it completely
