Phys: EKG Basics Flashcards
Order of impulse transduction through the heart:
SA -> AV -> bundle of His -> purkinje fibers
Order of fastest to slowest impulse:
Pukrinje -> atria -> ventricles -> AV node
P wave represents:
Atrial depolarization
QRS complex represents:
Ventricular depolarization
T wave represents:
Ventricular repolarization
Why is atrial repolarization not seen in an EKG?
It is hidden by the QRS complex
PR interval
0.12-0.20 seconds
QRS interval:
0.06-0.11 seconds
QT interval:
0.36-0.44 seconds
If the PR interval is > 0.20 then what does the pt likely have?
1st degree AV block
If the QRS interval is > 0.12 then what does the pt most likely have?
A bundle branch block
How many leads are on an EKG?
12, 6 limb and 6 precordial
What two division can the 6 limb leads be divided into?
-3 bipolar or standard leads
-3 augmented leads
3 bipolar or standard limb leads:
I, II, III
3 augmented limb leads:
aVR, aVL, AVF
What are the 6 precordial leads?
V1, V2, V3, V4, V5, V6
What do the leads do?
Allows us to view the electrical activity of the heart from that direction (multiple leads allow entire heart to be viewed in three dimension)
Current in the heart flows from ___ to ____
-to +
What is the normal, mean QRS vector?
60 degrees
Einthoven’s law:
The electrical potential of any limb quells the sum of the other two
What is seen in a first degree AV block?
PR interval > 0.20
Two types of seconds degree AV block:
-mobitz type 1 (wenckebach)
-mobitz type 2
What’s is seen in a mobitz type 1 or weckebach:
PR gets longer and longer and longer until it eventually doesn’t come back (dropped beat)
What is seen in a mobitz type 2?
PR interval stays the same with some dropped beats
What is seen in a third degree AV block?
Atrial rate greater than ventricular rate which leads to AV dissociation
How to calculate heart rate?
Take the # of R waves seen in a 6sec interval and multiply by 10
Wolff-Parkinson white syndrome:
-most common type of ventricular pre-excitation syndrome
-heart beast very fast causing blood to not reach certain parts of the body
-bypasses the rate-slowing AV node
-SHORTENED PR INTERVAL
EKG changes in STEMI:
-ST segment elevation
-total vessel occlusion
EKG changes in NSTEMI:
-non-ST elevation
-partial vessel occlusion
What does hyperkalemia lead to?
-irregular heartbeats
-ventricular tachycardia
What is seen on an EKG in hyperkalemia?
-TALL T wave
-prolonged PR interval
-flattened or absent P waves
-widened QRS complex
What is seen on an EKG in hyokalemia?
-QT prolongation
-U waves that mimic atrial flutter
-T wave flattening
What rhythm is seen?
Normal sinus rhythm
What is seen?
Sinus bradycardia
What is seen?
Sinus tachycardia
What is seen?
Sinus Arrhythmia
What is seen?
Sinus arrest or SA block
What is seen?
Atrial flutter
What is seen?
Atrial fibrillation
What is seen?
Pre-excitation syndrome
What is seen?
First degree AV block
What is seen?
Mobitz type 1
What is seen?
Mobitz type 2
What is seen?
Ventricular tachycardia
What is seen?
Ventricular fibrillation
What is seen?
Ventricular asystole
What is seen?
Atrial pacemaker
What is seen?
Electronic pacemaker spikes
What is seen?
AV sequential pacemaker (dual chamber)
What is seen?
Muscle tremor
