Chapter 8 Rhythm recognition Flashcards
Where do the place the colour-coded 3 lead ECG electodes on the patient: White, Black, Red
WHITE for right (right shoulder)
SMOKE OVER FIRE (black left shoulder, red left lower chest)
Place on clean dry skin (can use alcohol wipes, shave hair). Place over bone. Muscle gives artefact
When would you choose to use antero-posterior placement for defibillator pads?
Permanent pacemaker in right precordial chest position
Transcutaneous pacing (reducing thoracic muscle activity)
Chest trauma
Refractory VT/VF
What is the difference between asystole and ventricular standstill?
Asytole - flat (often undulating flat line). Implies ventricular AND atrial asystole
Ventricular standstill: ongoing atrial activity - p waves, atrial flutter or fibrillation but NO ventricular activity. Can try pacing this patient
On a telemetry strip, how can you accurately count the rate for a very fast or irregular rhythm?
Count number of QRS complex in 6 seconds ( 30 large sqaures) and x by 10
What are the three rhythms that a cardiac arrest can be classified into?
1) Shockable: VT, VF
2) Asystole
3) PEA
Atrial fibrillation passed down an accessory pathway may produce a very fast tachyarrhythmia that may be mistaken for?
Polymorphic VT. Rhythm is fast, up to 300 BPM, broad and irregular.
Would not be inappropriate to shock if the patient was not well perfused.
VT may be classified morphologically into two types. What are they?
Monomorphic
Polymorphic
What is a capture beat? What is a fusion beat?
Capture: normal atrial beat is captured during VT. Normal QRS complex amongst VT seen
Fusion: Fusion of normal beat with VT beat
What would an atrial tachycardia with bundle branch block appear like on an ECG?
As a broad-complex tachyarrhythmia
Are polymorphic and torsades de pointe the same?
No, torsade is a type of polymorphic VT (axis of electrical activity changes in a rotational way)
A patient has torsades de pointes. Why would you avoid amiodarone when it is normally used in VT?
This is a specific type of polymorphic VT that is often due to a prolonged QT interval. Amiodarone will worsen the prolongation.
How to you prevent a recurrence of torsade de pointes
Replace potassium
Replace magnesium
Increasing HR by overdrive pacing is HR is slow
Cease and withold any QT prolonging drugs (including amiodarone)
You’re not sure if the rhythm is asystole or very fine VF, should you shock?
No, give CPR. This my increase amplitude and increase success of shock
What are your treatment options for a bradyarrhythmia?
1 ) atropine 500mcg bolus (repeat up to 3mg)
2) Isoprenaline 1-10mcg/min or
Adrenaline 1- 10mcg/min ( or 0.1-1.0mcg/kg/min)
3) Transcutaneous pacing
Is 2nd degree heart block, Mobits type 1 (Wencklebach) always pathlogical? Does it need urgent treatment
Can be normal in highly trained athletes with high vagal tone, outside of this, is usually pathological. Due to ischaemic, medications (beta blockers, Ca blockers, digoxin, amiodarone), myocarditis, following cardiac surgery.
If asymptomatic does not require urgent treatment.
Is the dropped QRS in 2nd degree HB mobits type 2 alway at a regular interval?
No, can be regular but dropped beat can be random, giving an irregular HR.
A patient is described as having an AV block as 2:1 or 3:1. Which rhythms could the patient be in?
Either mobits type 1 or 2 can be described this way.
2:1 implied 2 p waves to 1 QRS. Given the difficulty seeing PR prolongation, it’s hard to tell which rhythm the patient is in.
A patient is described as having an AV block as 2:1 or 3:1. Which rhythms could the patient be in?
Either mobits type 1 or 2 can be described this way.
2:1 implied 2 p waves to 1 QRS. Given the difficulty seeing PR prolongation, it’s hard to tell which rhythm the patient is in.
A patient is in complete heart block HR 40 but they seem to be well perfused. Is this a stable rhythm?
No, risk of abruptly deteriorating into asystole
What is the difference between an idioventricular rhythm and an accelerated idioventricular rhythm
Idioventricular rhythm is arising from the ventricular myocardium, HR 30 -40.
Accelerated means the rhythm is still from ventricular myocardium but with a normal HR, but not fast enought to be VT, usually 50 - 110
Often seen as a reperfusion rhythm post lysis/PCI
How dangerous is an accelerated idioventricular rhythm?
Often seen as a reperfusion rhythm post lysis/PCI.
Usually not a serious risk unless there is haemodynamic compromise or its develops into VT/VF, which is uncommon
How do you distinguish from an accelerated idioventricular rhythm an a junctional rhythm?
Both may have the same HR (50 to 110) however idioventricular will have wide QRS, junctional will be narrow (unless there is a bundle branch block)
What is an agonal rhythm?
Seen in dying patients Slow irregular, wide ventricular complexes of varying morphology.
Usually does not generate a pulse.
Complexes slow and broaden and deteriorate into asystole.
Is atrial flutter always regular?
No, can have variable conduction, producing an irregular rhythm
In atrial flutter, why is a HR or 150 called 2:1 or 3:1 or 4:1?
Because the flutter waves always seem to occur with a rate of 300 bpm.
So if ventricular HR is 150, conduction is 2:1
Where does AF usually originate from on the heart?
The right ventricle. So is a recognised complication of disases affecting the right heart including COPD, major PE, complex congenital heart disease, CCF
Does the rate of VT increase or decrease the risk associate with this rhythm?
Faster VT > 200 BPM is more likely to deteriorate into VF
The Q wave can be difficult to measure due to difficulty detecting the end of the T wave. What is generally the best lead to measure it in?
Lead II
Also lead 1 and V5
Can average over several leads
What happens to the QT interval as the HR increases?
QT interval shortens
When is a QT prolonged?
Men > 430
Female > 450
If > 500 high risk of cardiac arrest and death
What is the risk with long or short QT or brugada syndrome?
Risk of ventricular arrhythmia and death
What would a 2nd degree HB mobites type II look like?
3 p-waves of regular intervals to every 1 QRS complex
