[ECGmadeasy][arrhythmias] Flashcards
(79 cards)
1
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extra beat supraventricular arryhthmias bradyarryhthmias ventricular arryhthmias
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yes
3
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yes
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smoking alcohol caffiene
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Mg2+ Ca2+ K+
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thyroid disease
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phaechromocytoma thyroid disease
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hypoxia hypercapnia
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pneumonia
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metabolic acidosis
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palpitations chest pain syncope/pre-syncope
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hypotension pulmonary oedema
13
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depolarisation begins at the sinus node
14
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the place in the heart where depolarisation occurs
15
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P waves present? P+QRS wave relationship (should be 1 QRS per P) width of QRS
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less than 120 ms
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most frequent depolarisation (SA node usually has the highest frequency of discharge)
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Lead in which the P wave is most easily seen.
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AVN atria (anywhere) Ventricles (anywhere)
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junctional nodal
21
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sinus atrial junctional *the depolarization waves spreads normally through His*
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Normal as the depolarisation wave is spreading normally through the bundle of His. i.e. it is the same if the initiation is at the AVN/atrial/SA node
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Depolarisation spread through the purkinje fibres (slower/abnormal)
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Repolarisation is also abnormal.
25
[arrhythmias]: what does a narrow QRS relate to
supraventricular arrhythmia \*with a few exceptions
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[arrhythmias]: what does a wide QRS relate to
ventricular arrhythmia
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[arrhythmias]: what are the only supraventricular arrhythmias which have broad QRS complexes (3)
Wolff-Parkinson-White (WPW) Supraventricular + LBBB Supraventricular + RBBB
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[arrhythmias]: what does fibrillation mean?
activation of the atria/ventricles is totally disorganised.
29
[arrhythmias]: what is extrasystole
early single beats
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[arrhythmias]: what prevents competition between areas of the heart which normally initiate depolarisation (SAN) and abnormal but failsafe areas?
the SAN has the highest intrinsic frequency of depolarisation
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[arrhythmias]: What is the depolarisation rate of the SAN
70bpm
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[arrhythmias]: What is the depolarisation rate of the junctional region
50bpm
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[arrhythmias]: what is the depolarisation rate of the ventricles
30bpm
34
[arrhythmias]: what are 'escape rhythms'
slow and protective rhythms which initiate depolarisation if SAN fails. 'escape from their normal inhibition'
35
[arrhythmias]: What is this?
Explain why.
Atrial escape.
Initial sinus beat. Then failure to depolarise.
There is atrial 'escape' of SAN inhibition.
Abnormal P wave seen (depolarisation starts elewhere in atrium).
Normal QRS complex - normal His.
Returns to sinus.
36
[arrhythmias]: What is this?
Why?
Junctional escape.
No P wave in junctional as atria do not contract or hidden by QRS.
QRS normal width.
This cannot be ventrucular as there is normal QRS width.
Cannot be atrial escape as no abnormal P wave.
37
[arrhythmias]: What is the most common cause from ventricular escape?
Complete heart block
38
[arrhythmias]: .... results when the rate of an ectopic ventricular pacemaker exceeds that of the sinus node.
Accelerated idioventricular rhythm (AIVR)
39
[arrhythmias]: What is this?
Why?
Ventricular escape
3 sinus beats. SAN failure.
No atrial or nodal escape. Single wide and abnormal QRS. Abnormal T wave.
Sinus rhythm restored.
40
[arrhythmias]: What is this?
Why?
Complete heart block.
Normal P waves.
Abnormal QRS (due to ventricular escape).
No relationship between P an QRS.
41
[arrhythmias]: What is this?
Why?
AIVR
3 sinus beats.
SAN failure.
Ventricular escape - continuous regular rhythm with wide QRS and abnormal T waves.
42
[arrhythmias]: What is an extrasystole?
the accompanying heartbeat to any earlier than usual depolarisation. ('ectopic' = abnormal location)
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[arrhythmias]: what is the difference between an 'extrasystole' and an escape beat?
escape = late
Extrasystole = early
44
[arrhythmias]: The 1st arrow is sinus. What is the 2nd arrow and why?
Junctional/nodal extrasystole.
No P wave.
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[arrhythmias]: the first arrow is sinus. what is the 3rd arrow and why?
Atrial extrasystole. Abnormally shaped P wave.
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[arrhythmias]: Ventricular systoles can be of no importance - when would you suspect that ventricular asystole is pathogenic.
Abnormal QRS complex early in the T wave of the preceding beat. (?ventricular fibrillation?)
47
[arrhythmias]: What is this showing and why?
Ventricular extrasystole.
5 sinus beats.
early abnormal beat close to abnormal T wave.
48
[arrhythmias]: What is this ECG showing and why?
ventricular extrasystole.
'R on T' phenomenon.
i.e. ventricular extrasystoles have occured at the peak of the preceding sinus beats.
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[arrhythmias]: what is happening if: an early QRS has followed an early P wave
Atrial extrasystole
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[arrhythmias]: what is happening if: the QRS looks slightly different each time.
supect ventricular problem - supraventricular tend to produce the same shaped QRS complexes.
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[arrhythmias]: If the T wave is NOT the same way up as in the normal beat what does this suggest
ventricular beat
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[arrhythmias]: If the T wave is the same way up as in the normal beat, but there is extra/escape beat what does this suggest
supraventricular beat.
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[arrhythmias]: what effect does a supraventricular extrasystole have on the regularity of the P wave
it resets the P wave cycle (i.e. it does not come at the expected time)
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[arrhythmias]: what effect does a s ventricular extrasystole have on the regularity of the P wave
No effect - the P wave comes at the expected time.
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[arrhythmias]: what is the fastest the atria can depolarise in atrial tachycardia
c. 200/min
(above this you get AV block - which differs from 2nd degree as the AVN is functionin properly)
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[arrhythmias]: What is this and why?
Atrial tachycardia.
150/min. P wave superimposed on T waves. QRS are the same as the first 3 sinus beats.
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[arrhythmias]: what is atrial flutter?
atrial rate \> 250/min
no flat baseline between P waves. ('sawtooth' appearance')
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[arrhythmias]: what is atrial flutter with a 2:1 block
atrial contracting at 250/min with 2:1 block = ventricular contraction at a rate of 125/min
59
[arrhythmias]: What is this and why?
Atrial flutter.
P waves at a rate of 250/min (sawtooth)
4:1 block
ventricular activation at 75/min
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[arrhythmias]: what is this and why?
Atrial flutter (250/min) with 2:1 block = ventricular rate of 125/min.
(T waves cannot be identified)
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[arrhythmias]: If P waves are seen very close to the QRS complex (before/after/or not at all) this indicates ....
Junctional
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[arrhythmias]: What is this and why
QRS are essentially normally shaped. No P wave. Regular QRS. Tachycardic. = Junctional tachycardia
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[arrhythmias]: supraventricular tachycardias can respond to ... through vagal nerve stimulation
carotid sinus pressure
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[arrhythmias]: carotid sinus pressure results in what 2 effects (2)
Reduced frequency of SAN discharge
Increase in the delay of conduction in the AVN
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[arrhythmias]: by applying carotid sinus pressure you increase the block between atria and ventricles, why might this be important?
May make identification of underlying patholgy clearer. E.g. atrial flutter on image
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[arrhythmias]: what causes ventricular tachycardia
high frequency ectopic ventricular depolarisiation focus
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[arrhythmias]: in what 3 circumstances would you see a wide and abnormal QRS
ventricular tachycardia (ectopic focus) and R/LBBB
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[arrhythmias]: What is this and why?
Ventricular tachycardia
Broad QRS complexes
T waves difficult to identify
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[arrhythmias]: How do you distinguish between ventricular tachycardia and supraventricular tachycardia with BBB/WPW (3)
1. if QRS is wider than 160 ms it is usually ventricular in origin
2. if the QRS is very irregular thatn it is probably AF with BBB
3. Does the patient have BBB in sinus rhythm as well (if you can see it - the QRS will be the same shape)
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[arrhythmias]: the extrasystoles and exscape beats are what category of arrhythmia
bradycardia
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[arrhythmias]: atrial/ventricular tachys and flutter are wht type of arrhythmia
tachycardia
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[arrhythmias]: what does fibrillating indicate?
no focal point of depolarisation - muscel fibres are contracting independently.
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[arrhythmias]: in atrial fibrillation why do you get normal shaped QRS complexes despite multiple signals of varying intensity from the entire atrium
AVN threshold - all or none conduction. Irregularly timed but of regular shape.
74
[arrhythmias]: What is this and why?
Atrial fibrillation
No P waves
irregular baseline
Irregular QRS
Normal shaped QRS
(looks a bit like flutter in lead v1 - normal)
75
[arrhythmias]: What is Wolf-Parkinson-White syndrome underlying pathology
presence of an accessory conducting bundle between the atria and ventricle - WITH NO AVN TO PAUSE CONDUCTION. (usually it runs down the left side of the heart).
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[arrhythmias]: in WPW syndrome there is a 'pre-excitation' as a depolarisation wave reaches the ventricles before the main wave. what would be seen on ECG
Short PR interval
Delta wave on QRS (early slurred upstroke of QRS - 2nd part is normal - main depolarisation catches up )
77
[arrhythmias]: what is the clinical importance of the WPW anatomical abnormality
Paroxysmal tachycardia
(depolarisation down the His then back up accessory to reactivate the atria = 're-entry' circuit = sustained tachycardia.
78
[arrhythmias]: what is this and why
Sustained tachycardia in the WPW syndrome (re-entry tachycardia - no P waves)
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