Unit 1 Flashcards
PR interval duration
0.12-0.20
P wave duration
0.06-0.10
QRS interval
0.06-0.11
What is the J point
Where QRS complex meets ST segment
QT interval
0.36-0.44
What does QT interval measure?
Time of ventricular depolarization and repolarization
What is the standard signal amplitude?
1.0 mV or 10 small vertical square
View of aVR
Atria and great vessels
View of aVL
Lateral wall of LV
View of aVF
Inferior wall of left ventricle
Anterior leads
V1-4
Lateral leads
I, aVL, V5-6
Inferior leads
II, III, aVF
A normal rate that suddenly accelerates to as rapid rate producing irregularity in the rhythm
Paroxysmal tachycardia
Patterned irregularities
Repeats itself in a cyclic fashion
-sinus dysrhythmia, second degree av block type 2
Totally irregular
-irregularly irregular
A fib
P wave amplitude
0.5-2.5mm
P wave amp >2.5
RAE
P pulmonale
RAE
P wave width >0.10s
LAE
P mitrale
LAE
Saw tooth pattern
Flutter waves; atrial flutter
Inverted P wave originates from?
Lower RA near the AV node, in the LA or the AV junction
Causes of tall QRS complexes
Ventricular hypertrophy, abnormal pacemaker, aberrantly conduct beat
Low voltage QRS
Obese patients, hypothyroid, pericardial effusion
PR interval denotes depolarization of
Heart from the SA node through the atria, AV node, and his-purkinje system
Shorter p waves occur when
The impulse originates in the atria close to the AV junction or in the AV junction
- through abnormal accessory pathways
- preexcitation
Delta wave
WPW
Longer PR interval
Usually AV block
Varying PR intervals
Wandering atrial pacemaker
Normal axis
0 and 90 degrees
LAD degrees
0 to -90
RAD degrees
90-180
Extreme axis deviation degrees
180 to -90
Causes of LAD
LVH, chronic CAD, hyperkalemia, WPW
Causes of RAD
Normal in children and tall thin adults, RVH, pulmonary embolus
Who is likely to have a vertical heart?
Tall thin individuals