arrhythmia-therapies Flashcards
give 2 examples of supraventricular arrhythmias?
atrial fibrillation
SVT (junctional)
give 2 ventricular arrhythmias?
ventricular tachycardia
ventricular fibrillation
describe the appearnance of ventricular fibrillation on an ECG
HR-300-600
rhythm- extremely irregular
p wave- absent
what is the action of class IA Vaughn-Williams anti-arrythmia drugs?
fast sodium-channel blockade to delay repolarization and increase AP duration
what is the action of class IB Vaughn-Williams anti-arrythmia drugs?
intermediate sodium channel blockade so accelerate reploarization and decrease the action potential duration
what is the action of class IC Vaughn-Williams anti-arrythmia drugs?
slow sodium channel blockade
what is the action of class II Vaughn-Williams anti-arrythmia drugs?
B-adrenergic receptor antagonism
what is the action of class III Vaughn-Williams anti-arrythmia drugs?
prolong refractriness by potassium channel blockade
what is the action of class IV Vaughn-Williams anti-arrythmia drugs?
calcium channel blockade
what are the Vaughn-WIlliams class IA drugs for arrythmias?
Quinidine. Procainamide, dispyramide
what are the Vaughn-WIlliams class IB drugs for arrythmias?
Lidocaine, mexiletine, tocainide
what are the Vaughn-WIlliams class IC drugs for arrythmias?
Flecainide, propafenone
what are the Vaughn-WIlliams class II drugs for arrythmias?
Atenolol, bisoprolol
what are the Vaughn-WIlliams class III drugs for arrythmias?
Amiodarone, bretylium, sotalol
what are the Vaughn-WIlliams class IV drugs for arrythmias?
Diltiazem, verapamil
what are class Ia anti-arrhythmia drugs used for?
atrial fibrillation, premature atrial contractions, premature ventricular contractions, ventricular tachycardia, Wolff-Parkinson-White syndrome
what are class Ib anti-arrhythmia drugs used to treat?
ventricular dysrhythmias only (premature ventricular contractions, ventricular tachycardia, ventricular fibrillation
what are class Ic anti-arrhythmia drugs used to treat?
severe ventricular dysrythmias
atrial fibrillation/flutter
what are class II antiarrhythmic drugs used to treat?
first line for atrial fibrillation (bisoprolol)
general myocardial depressants for supraventricular and ventricular dysrythmias
what are class III antiarrythmia drugs used to treat?
dysrhythmias that are difficult to treat:
Life-threatening ventricular tachycardia or fibrillation, atrial fibrillation or flutter—resistant to other drugs
Sustained ventricular tachycardia
what are class IV anitarrhythmia drugs used to treat?
paroxysmal supraventricular tachycardia
rate control for atrial fibrillation and flutter
what ais the action of digoxin?
inhibits sodium -potassium pump so is a positive ionotrope
what is digoxin used to treat?
heart failure
atrial dysrythmias
what mjust be monitored when a patient is on digoxin?
potassium levels
drug levels
toxicity
what are the side effects of digoxin (digocin toxicity)?
nausea and vomiting
xanthopsia-yellow haze round objects
tachycardia
arrhythmias: VT and VF
what is the treatment of digoxin toxicity?
stop digoxin
has long half life though and at high levels has a risk of significant arrythmias so use digibind to inactivate.
when is digoxin toxicity more serious?
when potassium levels are low
what is the classic scenario where digoxin poisoning occurs?
elderly on drug for rate control and had impaired renal function so levels of drug build
what is amiodarone used for?
ventricular tachycardia
occasionally in supreventricular tachycardia
what are the side effects of amiodarone?
Thyroid (hypo or hyperthyroidism) Pulmonary fibrosis Slate – grey pigmentation Corneal deposits LFT abnormalities
what does amiodarone interact with?
many drugs, including digoxin
what is the action of adenosine?
slows conduction through AV node
what is adenosine used to treat?
paroxysmal supraventricular tachy cardia, converts it to sinus rhythm
how is adenosise administered?
IV push
what are the side effects of adenosine?
asystole for a few seconds
which drugs are used to treat sinus tachycardia?
class II and IV
which drugs are used to treat atrial fibrillation/flutter?
class Ia, Ic, II, III, IV, digoxin anticoagulation
which drugs are used to treat paroxysmal supreventricular tachycardia?
class Ia, Ic, II, III, IV, adenosine
which drugs are used to treat AV block?
atropine
which drugs are used to treat ventricular tachycardia?
class I, II, III
which drugs are used to treat premature ventricular complexes?
class II, IV, magnesium sulfate can be benign and not drugs not required
what are the drugs used to treat digitalis toxicity?
class Ib
magnesium sulfate
digibind
what are the indications for anticoagulation?
atrial fibrillation
DVT/PE
after surgery
immobilisation- prophylaxis is those at high risk of DVT
which anticoagulants are given in AF patients?
warfarin direct oral anticoagulants -Dabigatran -Rivaroxaban -Apixaban -(Edoxaban)
what conditions are arterial thrombi associated with?
MI. strokes, ischaemia
what are conditions are venous thrombi associated with?
congestive heart failure, cancer, surgery
which drugs interact with warfarin, incvreasing warfarin activity?
aspirin, sulfonamides
cimetidine, disulfiram
oral antibiotics
which drugs interact with warfarin, promoting bleeding?
aspirin
heparin and antimetabolites
which drugs interact with warfarin, decreasing warfarin’s activity?
barbiturates
phenytoin
vitamin K
cholestyramine
how is warfarin therapy monitored?
international normalised ratio (INR)- the number of times longer blood takes to clot when on warfarin. Should be 2.5-4.0
what are the adverese affects of warfarin?
bleeding teratogenic (so avoid 1st and 3rd trimester causes retro placental and fetal intracerebral bleeding
what are the CHADS2 score?
used for warfarin bleeding risk: congestive heart failure 1 hypertsension 1 age >/= 75 years 1 diabetes mellitis 1 stroke or TIA 2
what are the characterstics for an ideal anticoagulant?
oral no need for monitoring no interaction with food or drugs given once or twice a day/fixed dose irrespective of body weight/age as affective as warfarin safer than warfarin
