Rhythm recognition Flashcards
What patients needs ECG monitoring started immediately? What are some common presentations?
Unexplained syncope, especially during exercise; syncope + structural heart disease, syncope + abnormal ECG (esp prolonged QT)
In a collapsed patient, what type of cardiac rhythm technology should you use?
Defib (right clavicle, left mid axillary line). You are looking only for rhythm analysis - record abnormal on strip.
Then go for ECG.
At rest, the cells of the heart are polarised with what amount of difference?
90mV
The PR interval represents what?
AV node delay
How do you measure the PR interval?
What is the normal interval time?
Start of the P wave to the first deflection of the QRS complex
0.12-.2s (3-5 small squares)
What is the normal QRS?
<0.12s or <3 small squares on 25mm / s paper
How to read the rhythm strip?
1) Is there electrical activity
2) What is the Ventricular rate
3) Is the QRS reg or irreg
4) Is the QRS broad or narrow
5) Is atrial activity present
6) Is the atrial activity and ventricular activity related
What if there is doubt between asystole and fine VF?
Don’t defib
What is a normal heart rate?
What is bradycardia?
What is tachycardia?
60-100
<60
> 100
How do you calculate rate?
Count 30 squares and times by 10
Or
Count 15 squares and times by 20
If more than three (triplet) occur in rapid succession, what is this considered?
tachyarrythmia
When ectopic beats happen alternately to normal beats, what is this called?
bigeminy
If you cannot see atrial activity, do you guess?
No
What is the length of a normal p wave?
<0.12 sec
If the monitor shows VF? what now?
check the patient. if the patient is conscious, this ain’t VF
What can look like VF?
Polymorphic VT
Pre-excited AF
But, if the patient ain’t conscious, they are both a form of pVT and need shocking
What is the safest rule for broad complex tachycardia?
Consider as VT and treat as VT
Torsades often arises in what patient class?
Those with prolonged QT or low K or low Mg
Do NOT give QT prolonging medications like amiodarone
What is PEA
What are some treatable examples?
A normal looking ECG that would otherwise normally lead to cardiac output but isn’t
Treatable examples: fluid / blood loss, tamponade, tension pneumo, PE
What causes bradycardia (less than 60BPM)?
Drugs, normal variant, SA Node, failure of AV conduction
What is a normal PR?
0.12-0.20s
What is first degree block?
> 0.20s. It represents a delay through AV conduction. It can be normal like in athletes
What is second degree block?
When some, but not all, P waves are conducted to the ventricles
What is the complications of Mobitz Type 2?
Complete AV block
Asystole
What causes Mobitz Type 1 AV block (also called Wenckebach AV block)?
Delay of AV conduction
It can be caused by:
Normal variant, MI, Medications (dig, ca+ blockers, amiodarone, beta blocker), myocarditis
What is the difference between Type 1 and Type 2 second-degree HB?
Type 1: Progressive prolongation of P-QRS interval until P wave occurs with no QRS following
Type 2: Constant PR interval but sometimes QRS does not follow P waves
What is complete HB?
No relationship between P waves and QRS complex. The ventricular rate is determined by where the pacemaker orginates.
What is an idioventricular rhythm?
30-40 BPM. The rhythm orginates from the ventricles
Accelerated idioventricular rhythm is common of?
After succesful PCI or thrombolysis.
What is an agonal rhythm?
Slow, irregular, wide complexes
What is AF?
Disorganised electrical activity in atria. No recognisable P waves.
What is atrial flutter?
What are common causes?
Atrial activity of ~300min. (Often found in II, III, AVF)
The ventricular rate is determined by AV conduction (2:2, or 3:1 block)
If conduction is constant, then the HR will be regular.
Atrial flutter often arises out of the right atrium and is linked to PE, COPD, CCF, Congenital heart disease
Where does broad complex tachycardia orginate?
Below the bifurcation of the bundle of His or a SVT that has a bundle branch block
What might VT degenerate to?
VF
What is the safest broad complex tachycardia tx strategy?
Treat as VT unless good evidence of SVT
How to measure QT interval?
From beginning of QRS complex to the end of the T wave
