Cardiovascular system Flashcards
Why is special care needed when using 2 or more anti-arrhythmic drugs?
The -ve inotropic effects tend to be additive. Care especially needed if myocardial function is impaired
What is the main method of treatment for life threatening new-onset AF?
Emergency electrical cardioversion
What can be used if the AF is non life threatening?
Electrical cardioversion or pharmacological
How can ventricular rate be controlled?
Standard beta blocker, rate limiting CCB (diltiazem or verapamil) as monotherapy
Which beta blocker should not be used for ventricular rate control?
Sotalol
What can be used for rate control after monotherapy fails?
Combo of two drugs: beta-blocker, digoxin or diltiazem
How can sinus rhythm be maintained post-cardioversion?
Standard beta blocker
Or sotalol, flecainide, propafenone or amiodarone
When should verapamil be avoided?
In patients taking beta-blockers: increased risk of severe hypotension and asystole
What is cardioversion?
Procedure where tachycardia or other arrhythmias are converted to a normal rhythm using electricity or drugs
What is used if AF present for more than 48 hours?
Electrical cardioversion
What should be completed ideally before electrical cardioversion?
Anticoagulation at least 3 weeks before and 4 weeks after
What are the two assessments used to assess stroke risk.
CHADVASC (stroke risk)
ORBIT (bleeding risk- newly recommended by NICE in 2021)
How does amiodarone work? (high risk med)
Alters sinus rhythm to restore normal heart beat (has a long 1/2 life and may need loading doses)
How long can side effects occur after stopping amiodarone?
Up to a year due to long 1/2 life
What are the warning signs for amiodarone? (7)
> Corneal microdeposits (reversible on withdrawal, v.common, rare interfere w/vision)
Impaired vision (optic neuritis or neuropathy, STOP to avoid blindness)
Thyroid function (contains iodine so can cause hypo or hyperthyroid. May need to stop treatment to start carbimazole and treat thyrotoxicosis)
Hepatotoxicity (stop if jaundice)
Pulmonary toxicity
Neurological effects (tremor, peripheral neurop)
Phototoxic skin reactions (burning sensation, erythema, persistent slate grey skin colour, use suncream)
What monitoring is required with amiodarone?
> TFT (before treat+ every 6 months) > LFT (before treat+ every 6 months > Serum K+ (before treat) > Chest x-ray (before treat) > ECG w/IV (resus must be available)
Can amiodarone be used in pregnancy?
Has a risk of neonatal goitre- use only if no alt
Can amiodarone be used in breastfeeding?
Avoid- present in milk signif amounts (may cause neonatal hypothyroidism)
What medication can cause severe bradycardia and heart block when given with amiodarone?
Sofosbuvir with daclatasvir or ledipasvir or simeprevir
Which drugs does amiodarone increase the plasma conc of?
- Coumarins
- Dabigatran
- Digoxin
- Flecainide
- Phenindione
- Phenytoin
What medications can cause increased risk of ventricular arrhythmias when given with amiodarone?
- Amisulpride
- Atomoxetine
- Chloroquine
- Citalopram
- Disopyramide
- Escitalopram
- Haloperidol
- Hydroxychloroquine
- Levofloxacin
- Lithium
- Mizolastine
- Mefloquine
- Moxifloxacin
- Phenothiazines
- Pimozide
- Quinine
- Sulpride
- Telithromycin
- Tolterodine
- Tricyclics
Which meds can increase risk of bradycardia, AV block and myocardial depression when given with amiodarone?
> Beta-blockers
Diltiazem
Verapamil
What can occur when simvastatin and amiodarone are given together?
Increased risk of myopathy
What is the important safety feature associated with sotalol?
It can prolong QT interval- leading to life threatening ventricular arrhythmias
What monitoring is required with sotalol?
- ECG and measurement of corrected QT interval
- Serum electrolytes (should be corrected before starting treatment)
How does digoxin work?
Slows down heart rate while increasing force of heart rate contraction
Key facts about PK and PD of digoxin
- Long half life
- May need loading dose
- Therapeutic range 1-2 mcg/L
- Forms have different bioavailabilities: IV (100%), tablet (50-90%), Elixir (75%)
Warning signs of digoxin
- Cardiac (arrhythmias, heart block)
- Neuro (weakness, lethargy, dizziness, headache, confusion, psychosis)
- GI (anorexia, N/V, Diarrhoea, abd pain)
- Visual (blurred/yellow vision)
- Overdose (stop immediately- range= 1.5 to 3mcg/L)
What monitoring is required with digoxin?
- Serum electrolytes (can lead to toxicity if disturbance present)
- Renal function (reduced function= accum of metabolite
- Plasma digoxin (mainly in renal impair, bloods 6hrs after dose)
- Heart rate (should be above 60bpm
Drug interactions with digoxin
- Increased plasma conc with: ciclosporin, diltiazem, itraconazole, lercanidipine, macrolides, nifedipine, quinine, mirabegron, spironolactone and verapamil
- Reduced plasma conc w/ St John’s wort
- Renal function impairing drugs affect digoxin plasma conc
- Concom use with acetazolamide, amphotericin, loop diuretics or thiazide can cause hypokalaemia= increase risk cardiac and digox toxicity
What patients are considered high risk for VTE?
- Substantial reduction in mobility
- Obesity
- Malignant
