Intro To Cardiac Flashcards
What does a long PR segment indicate??? What drugs can cause this??
Pr segment that’s long (normal: 0.12-0.20 secs) means 1st Degree AV Block!! This is when the time it takes for the impulse from the SA node down to the AV node is way longer than usual.
Drugs that decrease conduction speed like Beta Blockers and Calcium Channel Blocker can cause this!!!
What do you know about the Monitoring leads?
~ consists of 3 electrodes or more (positive, negative, and ground)
* STANDARD LEAD 2 (most common in bedside monitoring) :
1) Provides tallest “R” waves
2) Negative electrode under L clavicle (white)
3) Positive electrode under R breast (red)
- to remember the location of these electrodes: “White on Right, Smoke (black) over Fire (red), Snow (white) over Grads (green)”!
What does P wave mean? What should you see?
Atrial depolarization (or contraction).
- Present
- Upright/ positively deflected in Lead II
- 1 P-wave per QRS
- Morphology (they all should look alike as you look across the EKG)
What does PR segment
mean? What is the normal value? Does it mean If it’s too long? What can causes this??
Time it takes for that impulse to make it from SA node to AV node (or delay at AV node).
- Normal value: 0.12-0.20 secs
- Too long (greater than 0.20 secs) means 1st degree AV Block!!!! Caused by beta blockers and calcium channel blockers that decreases conduction speed!!!!
What does QRS complex mean?
What should you see in a QRS? What’s the normal value?
Ventricular depolarization.
Positively deflected in Lead II, Follows the P-wave, should be 0.04 - 0.10 SECONDS!
What does T wave mean?
What should you see? What does it mean if T wave is elevated/too high?
- Ventricular Repolarization (or relaxation)
- Upright, rounded, and ~0.5 mm amplitude!!!!!!
- If too high, it means HYPERKALEMIA!!!
What does isoelectric line mean?
No electrical activity! It’s the flat baseline from which all the wave form emerged
What does ST wave mean? What does it mean if there’s abnormality???
From S to the end of T should be isoelectric!
Abnormality indicates CARDIAC ISCHEMIC
What’s the normal value for a QRS??
0.04 - 0.10 seconds
What’s the normal value for a PR segment??
0.12 - 0.20 seconds
What is the QT interval? (Including it’s normal value, and what critical period - R on T phenomenon is)
- Should be LESS THAN HALF the distance from one QRS to the next (less than half of the R to R).
- Usually less than or equal to 0.44 sec in length!!!!!
- ***Critical period – R on T phenomenon!! Can be caused by Ondansetron/Zofran!!!!! (Ventricles are recovering/repolarization; and then if let’s say an PVC or premature ventricular contraction which is an ectopic beat happens to fall during THAT ventricular recovery time, it should sent the ventricles into a lethal pathway, LEADING TO V-TACH!!!
WHAT drugs can cause prolongation of QT Interval???
Ondansetron/ Zofran!!!!!
How many seconds is in a small box? How about a big box? How many small boxes are in a big box?
Small box = 0.04 secs each
Big box = 0.20 secs
There are 5 small boxes in 1 big box!
What are the 6 steps in ECG strip interpretation?
- Rate (60-100)
- Count the QRS and times it by 10
- Less than 60 would be Sinus Bradycardia
- More than 100 -150 would be Sinus Tachycardia (remember than >150 is called Supraventricular tachycardia) - Rhythm
- Measure R-R intervals (“Marching out”)
- Regular or irregular?
- If irregular, then is there a pattern or not??? - Analyze the P - wave
1) Present
2) Upright
3) 1 per QRS
4) Monomorphic? meaning that it all should look the same throughout - Measure the PR and QRS
- PR is 0.12-0.20 secs (longer would be 1st degree AV block)
- QRS is 0.04 -0.10 secs - Analyze the ST segment:
- Should be isoelectric. If evaluated/depressed it means CARDIAC ISCHEMIA - Analyze T wave:
- Upright, rounded, and ~0.5 mm amplitude. IF higher, that means HYPERKALEMIA!!!
What are the perspective on Dysrhythmias?
- May be the result of pathology
- IF problematic (meaning tht u can have funny rhythm and still be fine. It becomes problematic when the body is compromising its ability to MAINTAIN perfusion, so you’ll see signs of poor perfusion) :
1) Causing an alteration in PERFUSION!!!!
2) Increasing risk for other conditions
What should YOU do when a rhythm change occurs??
- Is it compromising their ability to maintain perfusion? (if yes, you’d see signs of poor perfusion)
- Is the patient stable or unstable?
- GOLDEN RULE OF STABLE IS SYSTOLIC BP OF 90** - Considering diagnosis & comorbid conditions.
- Investigate:
1) Oxygenation (<92%)
2) Medications
3) Electrolytes
What is a sinus rhythm??
Any rhythm in which depolarization begins at the SA node/pacemaker.
Could there be factors that cause a sinus rhythm to appear irregular?
YES! Ectopic beat – a beat occurring somewhere else in the heart, not where it should originate which is the SA node!
- This can be from the atrium or the junction of the SA and AV node. But most commonly recognized is if it’s from the ventricles, Ventricular Ectopic Beat OR Pre-mature Ventricular Contraction (PVC). This means that you’d see an abnormal, big & wide QRS that appears in the MIDDLE of a normal rhythm!!!
Could there be T wave or ST segment abnormalities with a sinus rhythm??
YES!
- Peak T waves means Hyperkalemia
- ST Elevation (“Tomb stone” appearance) means CARDIAC ISCHEMIA!! Call HCP immediately!!!! This is harder to fix than hyperkalemia so you need to reach out fast!!
Could the QRS width be altered and the rhythm still be a sinus rhythm??
Yes! YOu’d see wider QRS!!
Basically just indicates that when the impulse that started from the SA node made it down to the AV node, got screwed up down in the Bundle Branches!!
THIS IS CALLED BUNDLE BRANCH BLOCK!!!!
What are the 2 characteristics of Sinus bradycardia?
- Same as a regular sinus rhythm but rate is less than 60 !
- All potential alterations can apply! (meaning that you can have sinus bradycardia with a 1st degree AV block, or a ST or T wave elevation, or a bundle branch block, etc)
