Arrhythmias Flashcards by Costanza Cascio

what are the 2 locations for arrhythmias

supra ventricular: SAN, atria, AVN or his

ventricular: ventricular muscle

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name 3 supraventricular tachycardic arrhythmias…

A.fib, atrial flutter, ectopic atrial tachycardia (EAT)

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name 2 supraventricular bradycardic arrhythmias…

sinus bradycardia, sinus pauses

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name 3 supraventricular AVN arrhythmias…

AVN re-entry tachycardia (AVNRT), AV re-entrant tachycardia (AVRT), AV block

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what are 4 ventricular arrhythmias…

ventricular ectopics/ premature ventricular complexes (PVC), ventricular tachycardia, ventricular fibrillation, asystole

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what causes arrhythmias

anatomical: LV hypertrophy, accessory pathways, congenital heart disease
ANS: sympathetic stimulation e.g. stress
metabolic: hypoxia, ischaemic myocardium, electrolyte imbalance
inflammation: viral myocarditis
genetic: e.g. LQTS

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what are the 5 pathological mechanisms that cause arrhythmias

automaticity 
ectopic beats 
triggered activity 
tract pathway 
re-entry

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what does automaticity consist of

occurs if latent pacemaker takes over SAN usually due to tissue damage e.g. hypoxia

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what type of pathological mechanism for arrhythmia is beats that originate in places other than SAN?

Ectopic beats

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“normal AP triggers abnormal oscillations in membrane potentials that reach threshold triggering a sustained train of premature APs” is…

Triggered activity

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what are Tract pathways?

alternate electrical pathways to AVN that are faster than normal conduction

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what type of arrhythmia do tract pathways usually cause

tachyarrhythmias

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what is re-entry?

more than 1 conduction pathway which have different speeds

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what can cause re-entry mechanisms

structural: MI scar, CHD
Functional: conditions that depress conduction velocity or prolong refractory period e.g. WPW syndrome

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in what type of syndrome does pre-excitation (accessory pathway causes AP during repolarisation of heart) occur?

Wolf Parkinson White Syndrome

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what 2 arrhythmias are life-threatening

Vtac & A.Fib

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what are general presenting symptoms of arrhythmias?

asymptomatic, palpitations, SOB, dizziness, pre-syncope, syncope, tachy/brady, SCD, angina

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what ix for arrhythmias?

12 lead ECG, exercise ECG, 24hr ECG

echo

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sinus bradycarda…

how many bpm
aetiology
tx

<60bpm
physiological, drugs, ischameia
tx: acute- atropine, cardiac pacing if haemodynamically compromised

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what does haemodynamically compromised mean?

hypotension etc

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sinus tacycardia…

bpm
aetiology
tx

> 100bpm
physiological, drugs
tx: underlying cause, BBs

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what findings may you find on the ECG of someone with supraventrcular ectopic beats?

narrow QRS complex

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what is the pathological mechanism responsible for supraventricular tachycardias

re-entry, ectopic beats

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what is the tx for supraventricular tachycardias ?

acute: inc vagal tone (valsalva monouvre, carotid massage), slow conduction to AVN (IV adenosine, verapamil)
chronic: BBs, anti-arrhythmic drugs. avoid stimulants

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what is heart block

AVN conduction disease

causes of heart block?

ageing, acute MI, myocarditis, drugs, CHD, post aortic valve surgery

how many degrees of heart block are there?

what does 1st degree heart block mean?

no block, no tx

what are ECG signs of 1st degree heart block

PR interval is long (>0.2secs)

what does 2nd degree heart block mean?

intermittent conduction block at AVN

what are the 2 types of 2nd degree heart block?

Mobitz 1 & Mobitz 2

True/False... | Mobitz 1 shows a fixed PR interval then a dropped beat on ECG

False... Mobitz 1 shows progressive lengthening of PR interval then a dropped beat Mobitz 2 shows a fixed PR interval then a dropped beat

what does 3rd degree heart block mean?

no AP get through to AVN ie. complete heart block

what signs are there on ECG that show 3rd degree heart block?

no correlation between P wave & QRS complex

no tx is given for 1st degree heart block, so for what types of heart block is tx given and what is it?

2nd Degree Heart Block Mobitz 2 & 3rd degree Heart Block | Tx= ventricular pacing

what are the causes of ventricular ectopic or premature ventricular complex?

structural (LV Hypertrophy, HF), metabolic (Ischemia, CHD)

tx for ventricular ectopic or premature ventricular complex?

BBs, ablation of focus

what are causes for ventricular tachycardia?

pre-existing HD e.g. prev MI, cardiomyopathy

what are the 4Ts & 4Hs of reversible ventricular tachycardia?

``` 4Ts= Thrombosis Tension Pneumo Tamponade Toxins ``` ``` 4Hs Hypothermia Hypoxia Hypovolaemia Hyper/Hypokalameia ```

what arrhythmia would a finding of a wide QRS complex (>0.12) be?

Ventricular Tachycardia

what is Tx for acute ventricular tachycardia

unstable: direct current cardioversion (DCC) stable: AAD, amiodarone

what tx is given for torsades de pointes?

IV Magnesium

what is Tx for chronic ventricular tachycardia?

treat underlying, Congestive HF therapy e.g. ACEI, anti-arrhythmic drugs, ICD (implantable cardioverter defibrillator), VT catheter ablation

what are the classes of ventricular tachycardia

monomorphic (1 circuit), | polymorphic (torsades de pointes)

what is V.Fib?

chaotic ventricular activity causing heart to lose its pumping function

what are 2 key sings of v.fib

pulseless, unconscious

what is tx for v.fib

defibrillate & CPR

what is asystole?

absence of ventricular contractions

what are pacemakers usually used for

AVN disease

when is catheter ablation usually used for

re-entry disease e.g. PVC or A.fib

what is the most common arrhythmia?

Atrial fibrillation

what are 3 classes of A.Fib

paroxysmal (<48hrs, recurrent), persistent (>48hrs, cardioverted back to NSR) permanent (inability to restore to NSR)

what is a.fib?

chaotic atrial activity- irregular supra ventricular tachycardia

where does a.fib ectopic foci originate?

ostia of pulmonary vein

what are etiological diseases of a.fib?

HT, HF, Coronary HD, thyroid disease, valvular, congenital HD, cardiac surgery, COPD, septicaemia, pericarditis

what is a common sign of a.fib

irregular pulse

what does ECG show if a.fib present?

>300bpm, irregular rhythm, ventricular rate is variable, absence of p waves but f waves may be present

what is the 4 step tx for A.fib

Terminate AF through cardioversion Control Rate Control Rhythm + Anticoagulants

what are the 3 ways in which AF can terminate?

1. drugs 2. direct current cardioversion (DCCV) 3. spontaneous reversion to sinus rhythm

how do you control rate and hence slow down AVN conduction through Rx?

digoxin, b-blockers, verapamil

how does digoxin work

inc force of contraction of heart by inhibiting ATPase hence inc Ca++ movement into heart

how do you gain control of the rhythm?

restore NSR via amiodarone or DCCV & | maintain NSR via amiodarone, catheter ablation of focus

why MUST anticoagulants be given after A.fib?

A.fib poses an inc risk of thromboembolisms forming

what is the biggest complication of A.fib?

PE and stroke

what is the definition of congestive heart failure?

heart failure due to lost atrial kick and slow filling time

what is atrial flutter?

rapid, REGULAR, atrial tachycardia

True/False... | atrial flutters usually progress to AF?

True!

what is a typical ECG of someone with an atrial flutter?

regular rate with saw tooth F wave

tx for atrial flutter?

radio frequency ablation, BBs, cardioversion, anticoags to prevent thromboembolism

what is cardiac arrest?

cessation of heart

how to recognise someone in cardiac arrest?

unresponsive, no pulse, no breathing

what are causes of cardiac arrest- think ABCDE...

A: CNS depression, blocked airway, swelling, muscle spasm B: dec res drive, lung disorders (e.g. haemothroax) C: 1y- ACS, arrhythmias, drugs, valvular HD. 2y- asphyxia, hypoxia, hypovolaemia, sepsis D: hypoglycaemia E: trauma

how to assess A of ABCDE?

talking?, SOB?

how to assess B of ABCDE?

look, listen, feel - chest expansion

how to assess C of ABCDE?

general exam, BP, pulse, perfusion, bleeding

how to assess D of ABCDE?

AVPU or GCS + Pupils

tx for cardiac arrest

start CPR 30:2 shock if rhythm is VF/pulseless VT every 2 mins administer adrenaline/amiodarone after 3rd shock and thereafter every 3-5mins

when should you not shock?

asystole or PEA (pulseless electrical activity)

True/False... | Cardioversion & Defibrillation are the same thing

True & False... defibrillation is only applied to emergencies and only to VT and pulseless V.Fib Cardioversion given only if pt has a pulse but is unstable or chemical cardioversion has failed however- same in sense that both shock heart to try return arrhythmia back to NSR