Anti-arrhythmics Flashcards
A 50 year old woman presents with palpitations and dizziness. She has a Hx of HTN and DM. Her BP is 120/80. ECG shows AF. Management? 1. DC shock 2. medical cardioversion 3. medical cardioversion + heparin 4. anticoagulation + rate control
- Patient is stable and there is no precipitating acute illness.
Consider anticoagulation, rate control and or maintenance of sinus rhythm if AF is paroxysmal.
Which of the following is the MOST important risk associated with AF?
- DVT
- Left arterial thrombus
- Headache
- Chest pain
Left arterial thrombus
5% annual risk of thromboembolic event in persistent / permanent AF
7% risk of thromboembolic event following cardioversion
Thromboembolic risk - CHADS2-VASC score Congestive heart failure -1 HTN - 1 Age >75 - 1 DM - 1 Stroke / TIA - 2 Vascular disease - 1 Age 65-74 - 1 Sex (female = 1)
Score 0-1 : aspirin
Score 2: oral anticoagulation with either warfarin (INR 2-3) or NOAC e.g. damigatran
How do you calculate bleeding risk?
HAS-BLED score Hypertension - 1 Age - 1 Abnormal LFTs, renal function 1,1 Stroke / TIA 1 Bleeding risk -1 Labile INRs 1 EtOH 1 Drugs 1
Score of 3 or more indicates increased 1 year risk of bleed on warfarin sufficient to justify caution or more regular review
Give examples of some new oral anticoagulants
Dabigatran
Rivaroxaban
Apixiban
What are the advantages of NOACS?
No monitoring required
Short half-life
What are the disadvantages of the NOACs?
Unable to monitor
Unable to reverse
A 50 yr old woman presents with palpitations and dizziness. She has hypertension and diabetes. Her blood pressure is 120/80.
What is her CHADS2 score and what should we do?
Score =2
Should prescribe warfarin or NOAC
She is stable so no need to cardiovert. Should rate control - e.g. with beta blocker or CCB
A patient is in acute AF without HF. What drug would you prescribe for rate control?
Beta blocker or CCB (Not both - risk of decreasing HR too much)
2nd line is to add digoxin
A patient is in acute AF with HF. What drug would you prescribe for rate control
Digoxin IV
2nd line - amiodarone IV
Patient is in paroxysmal AF. what drug would you prescribe for rate control
Beta blocker or CCB
2nd line - add digoxin
DIGOXIN. What is MOA? What is it used for?
Increases vagal tone.
Slows AV nodal conduction
Used for rate control in AF (not PAF) with LVF
DIGOXIN. SEs?
Visual disturbances
Arrhythmias
Usually well tolerated
Long Half life - 36hrs so need loading dose.
Toxicity with low K+ and high Ca+
Beta blockers - what vaughan-Williams class? What MOA?
Vaughan-williams class II
I SODIUM CHANNEL BLOCKADE
Reduce phase 0 slope and peak of action potential
II BETA BLOCKADE
Block sympathetic activity; reduce rate and conduction
III POTASSIUM CHANNEL BLOCKADE
Delay repolarization (phase 3) and thereby increase action potential duration and effective refractory period
IV CALCIUM CHANNEL BLOCKADE
Block L-type calcium-channels; most effective at SA and AV nodes; reduce rate and conduction
Block B1 and B2 adrenergic receptors
Slow AV conduction
Used in AF rate control and sinus rhythm maintenance. Also used in HTN, IHD etc.
SEs of Beta blockers
bronchoconstriction
bradycardia
negative inotrope
Non-dihydropyridine CCBs. Examples? MOA?
Diltiazem. Verapamil
Slow AV nodal conduction
Used in AF for rate control and sinus rhythm maintenance. Also used in HTN and IHD