fibrillations Flashcards
define superventricular tachycardia
supreventricular tachyarrthymias with uncoordinated atrial electrical activation and consequently ineffective atrial conduction
what is paroxysmal AF?
recurrent AF that reverts spontaneously
what is persistent AF?
if recurrent AF reverts spontaneously and needs pharmacological/ cardioversion to manage
what are the RF for AF?
age. hypertension, diabetes, obstructive sleep aponea, CAD, valve disease, alcohol, congenital heart disease, lung disease
what is the most common type of cardiac arrhthymia?
atrial fibrillation
how does cardiac remodelling contribute to the pathophysiology of AF?
particularly in the atria
results in structural/ electrical chnages that causes a derrnaged rhythm.
changes in myocytes/ ECM, fibrous tissue deposition
how does the unsynchronised firing pathophysiology result in AF?
initiating triggers from an ectopic focus in the atria - usually pulmonary veins .
what are the consequences of the unsynchronised firing?
turbulent and abnormal blood flow through heart decreasing effectiveness in pumping blood, increasing likelihood of thrombus formation in atria, most commonly left atrial appendage
what manual diagnostic test can you perform to detect AF?
manual pulse palpitations to assess for irregular pulse
describe the clinical presentation of AF
dyspnoea, palpitations, syncope/ dizziness, chest discomfort, stroke/ TIA, anxiety, fatigue, symptomatic hypotension <90mmHg
what do you look for on an ECG showing AF?
irregular RR intervals
absence of distinct repeating P waves
irregular atrial activations
if you suspect paroxysmal AF, would monitoring would you use?
24hr electrical activity monitor
what is the general management of chronic AF?
personalised package of care
stroke awareness
rate control meds
contacts with helplines
psychological advice
up to date education
anticoagulants
networking charities for support
what medications is for stroke prevention in regards to AF management?
direct- acting oral anticoagulant
name some anticoagulants used to treat AF
apixaban, dabigatran, edoxaban, rivaroxaban
if a patient is contraindicated to anticoagulants but need medication for stroke prevention following AF, what do you use?
vitamin K antagonist
if a patient is already using anticoagulants and experienced a MI, what drugs are best to use as well?
anti-platelets
what are 1st line drugs in managing AF (rate and rhythm)
beta blocker
non-dihydropyridine calcium channel blocker - dilitizam/ verpamil
if a patient with chronic AF does little amounts of physical exercise - what drug is best?
digoxin monotherapy
what are second line drug management for AF?
combination of b blocker, diltiazem, dogoxin
what do antiarrthymic drug therapy aim to do?
long term rhythm control
what drugs are antiarrhythmics?
flecainde
propafenone
dronedarone
amiodarone
pill pocket strategy
what antiarrhythhymics do you not give if known ischaemia/ structural heart disease?
class 1c - flecainide/ propafedone
amiodarone is used in patients with AF that always have…?
left ventricular impairment
heart failure
what is the pill pocket strategy?
only taking antiarrhythymic drugs when needed eg after doing something that triggers it eg exercise/ caffeine intake
when would cardioversion be suitable?
AF symptoms presenting >12hrs
when would you start amiodarone before cardioversion?
ideally 4 weeks prior - chronic AF
what is cardioversion?
a device that delivers low-energy shocks to the heart
when would you do left atrial ablation?
if the drugs were unsuccessful
describe left ablation process
uses small burns/ freezes and cause scarring on the inside of the heart to help break up electrical signals
after undergoing cardioversion, how long should be on antiarrhythymics for?
3 months following
what is atrial fibrillation better care?
ABC
Anticoagulants/ avoid stroke
Better symptom management
Cardiovascular and comorbidity optimisation - lifestyle changes
in acute AF and someone is haemodynamically instable, what is best course?
emergency electrical cardioversion
what medications are best to control rate/ rhythm in acute AF?
flecainade/ amiodarone
what drugs are contraindicated for acute AF?
Mg2+/ CCB
what drug types should be given to acutely AF patients?
antiarrthymics and anticoagulants - heparin
what is atrial fibrillation?
heart rhythm problem where atria beats irregularly
what is supraventricular fibrillation?
has electrical signals orginating at or above the AN - defines by narrow QRS <120ms adn a heart rate >100bpm
what is the pathophysiology of supraventricular fibrillation?
orthodromic re-entry phenomenom
tachycardia is secondary to normal anterograde electrical conduction from atria to AVN
signal can also go from ventricles back to atria
narrow QRS - ventricles being activated prior to AVN
how does the ventricles get depolarised before the AVN in supraventricular fibrillation?
may develop an ectopic foci of electrical activity within the atria, AVN, ventricles
impulse conduction - conduction blocks and forms re-entrant circuits
impulse formation - enahnced autorhtyhmaticity (pacemaker away from SAN) or triggered activity activity during repolarisation
what are re-entrant circuits within SVT?
continuous wave of depolarisation in circular path - depolarising wave returns to original site
name 5 examples of SVT rhythyms
sinus tachycardia, atrial tachycardia, atrial flutter, atrial fibrillation, atrioventricular nodal re-entrant tachycardia, atrioventricular re-entrant tachycardia
describe the symptoms of SVT?
anxiety, palpitations, chest discomfort, light-headed, syncope, dyspnea
shock, hypotnesion, signs of HF
can be asymptomatic but tachycardia seen within screening
what are the diagnostic signs on a ECG of SVT?
narrow QRS complex, regular tachycardia
HR - 180-220 bpm
no P waves
what investigation is crucial in SVT?
find initial cause
assess for haemodynamic stability
what symptoms would suggest haemodynamic instabilities?
hypotension, hypoxia, SoB, chest pain, evidence of poor end organ failure perfusion, altered mental status
what is the management for a haemodynamic unstable patient with SVT?
immediate synchronised cardioversion
adensosine
what is the initial management for a haemodynamically stable patient with SVT?
Vagal manoeuvres can be attempted
carotid sinus massage
adenosine
what are valsalva movements?
popping ears motion by holding nose
how do you perform a carotid sinus massage?
patients neck must be extended and turned away - firm pressure applies for linger than 5 seconds
what is the second line management of SVT?
CCB/ B blockers
CCB must by di-hydropidines
if pharmacological actions do not work to treat SVT, what are next options?
catheter ablation
pacemaker
what is ventricular tachycardia?
wide complex tachycardia
>100bpm
what is non sustained VT?
lasts less than 30s and presents tachycardia with tachyarrthymias with >3 beats of ventricular origin
what is sustained VT?
> 30s, haemodynamically unstablility occurs in less than 30s from tachycardia
what is monomorphic VT?
stable QRS morphology
what is polymorphic VT?
has changing or multiform QRS - torsades de pointes
what is bidirectional VT?
beat to beat alteration in QRS frontal plane
linked to digitalis toxicity/ catecholaminergic polymorphic VT
what is the aetiology of VT?
usually ischaemic HD
can be structural HD, channelopathies, infiltrative cardiomyopathy, electrolyte imbalance
illicit drugs
hypokalemia followed by hypomagnesemia
what is the pathophysiology of VT?
enhanced normal automaticity/ abnormal automaticity
what causes the pathology of SVT?
activity triggered by early/ late afterdepolarisation and re-entry
in acute MI - transient ischaemia causes hyperkalaemia and triggers partial depolarisation
injury currents between infarcted tissue and healthy myocardium and triggers spontaneous activity
when history taking how would you differentiate between VF and SVT?
those VF are more likely to be older
what would an ECG show if a patient had SVT?
broad complexes
fast HR
other than ECG, what other tests can be used to diagnosis VT?
stress test
bloods - potassium, magnesium, calcium
how would you manage non sustained VT and asymptomatic?
no therapies
how would you manage non sustained VT but was symptomatic?
b blockers
CCBs 2nd line
how do you manage sustained monomorphic VT that is haemodynamically unstable
advanced cardiac life support
what do haemodynamically stable VT patients need?
antiarrthymic medication
when would a VT patient get an implanted cardiac defibrillator
- ischaemic HD and survive a cardiac arrest
if they have haemodynamically unstable/ sustained VT
