Chapter 2: Cardiovascular Flashcards
Classes of Anti-arrhythmic drugs ?
CLASS 1 - membrane stabilising drugs; Na+ blockers
CLASS 2 - Beta-blocker
CLASS 3 - K+ channel blockers
CLASS 4 - Calcium Channel blockers (rate limiting)
OTHER
- adenoside
- digoxin (effective in sedentary patients with non-paroxysmal AF and in patients with associative CHF)
What is included in the CLASS 1 antiarrhthmic drugs?
MEMBRANE STABILISING DRUGS ; Na+ blockers
- disopyramide
- lidocaine
- flecainide/propafenone (c/i in asthma/ severe COPD. Avoid in structural ischameic heart disease)
What is flecainide/propafenone c/i in?
c/i in asthma/ severe COPD. Avoid in structural ischameic heart disease
What is CLASS 2 antiarrhythmic drugs?
BETA-BLOCKERS
- propanolol, bisoprolol etc
What is included in CLASS 3 antiarrhythmic drugs?
K+ CHANNEL BLOCKERS
- amiodarone (4 weeks before and 12 months after electrical cardioversion to increase success)
- sotalol
- dronedarone (hepatotoxicity and heart failure side effects)
What is included in CLASS 4 antiarrhthmic drugs?
CALCIUM CHANNEL BLOCKERS (rate limiting)
- verapamil
- diltiazem (unlicensed)
OTHER antiarrhythmic drugs?
- adenosine
- digoxin (effective in sedentary patients with non-paroxysmal AF and in patients with associative CHF)
What is AF?
- abnormal, disorganised electrical signals fired caused the atria to quiver or fibrillate = rapid and irregular heartbeat
Symptoms of AF?
- heart palpitations = pounding/fluttering
- dizziness, SOB, tiredness
Complications of AF?
stroke and heart failure
Classifications of AF?
LONE
- Single self limiting episode of AF in ‘normal’ patients i.e. those that are defined by a normal clinical history and examination, ECG, chest x ray and echocardiogram
CHRONIC: recurring episodes of AF
- Paroxysmal: when symptoms stop spontaneously without treatment within 2-7 days
- Persistent: when AF is persistently occurring and does not terminate spontaneously, therefore requiring either electrical or pharmacological cardioversion to stop it (> 7 days)
- Permanent: if the cardioversion is not successful or not indicated for that particular patient (present all the time)
POST-OP
- Occurs in a third of patients who have cardiothoracic surgery. This type is associated with greater morbidity, mortality and risks of complications
2 types of control in AF?
RATE CONTROL (controls ventricular rate)
RHYTHM CONTROL (restores and maintains sinus rhythm) - Cardioversion : restores sinus rhythm
Explain cardioversion process
CARDIOVERSION; restores sinus rhythm (RHYTHM CONTROL)
- electrical = direct current
- pharmacological = anti-arrhythmic
- cannot give if symptoms > 48 hours; increased risk of stroke
- electrical preffered if > 48 hours, but should wait until fully anticoagulated for 3 weeks before cardioversion and continue 4 weeks after
- if haemodynamically unstable (perfusion/heart failure) = electrical cardioversion; give parenteral anticoagulant and rule our left atrial thrombus immediately before procedure
For an acute new-onset presentation of AF what would you do?
- life threatening haemodynamic instability: electrical cardiversion
- without life threatening haemodynamic instability:
- <48 hours = rate or rhythm control (electrical or amiodarone/flecainide)
- > 48 hours = rate control (verapamil, beta blocker)
Maintenance drug treatment for AF?
First line = rate control
- betablockers (NOT sotalol)*
- rate limiting CCBs (verapamil, dlitiazem)
- Digoxin
monotherapy –> dual therapy –> rhythm control
Second line = rhythm control
- bbs or oral anti-arrhythmic drug
e.g. sotalol, amiodarone, flecainide, propafenone, dronedarone
(also given if rhythm control is stil required post-cardioversion
Treatment for paroxysmal and symptomatic AF?
- rate or rhythm control = standard bb or oral antiarrhtymic drug
- “pill in pocket” if infrequent episodes - self treatment = flecainide or propafenone restores sinus rhythm if episode occurs
Treatment for atrial flutter?
Similar treatment as AF but catheter ablation more suitable
*A catheter ablation involves passing thin, flexible tubes, called catheters, through the blood vessels to the heart. The catheters record the heart’s electrical activity and can pinpoint where the arrhythmia is coming from. The area of heart muscle at the affected site is then destroyed using either heat (radiofrequency ablation) or by freezing (cryoablation). This creates scar tissue, which doesn’t conduct electricity and so knocks out a trouble spot or acts as a fence around the problem area to prevent the electrical signals from reaching the rest of the heart and causing the arrhythmia.
Stroke prevention: when to give anticoagulant ?
Give if risk of thromboembolic stroke > risk of bleeding (HAS-BLED)
Risk of stroke CHAD2=DS2-VASc
C = chronic heart failure or left ventricular dysfunction
H = hypertension
A2 = age 75+
D = diabetes mellitus
S2 = stroke/TIA/venous thromboembolism history
V = vascular history
A = age 65-74 yrs
Sc = sex i.e. female
Give anticoagulant is 2 or more
male= 0 and female = 1
What anticoagulant given in new onset AF?
parenteral anticoagulant
What anticoagulant given in diagnosed AF?
Warfarin OR NOAC
*NOAC in non-valvular AF with 1 or more rusj factors
What is ventricular tachycardia ?
Ventricular tachycardia (VT) is a fast, abnormal heart rate. It starts in your heart’s lower chambers, called the ventricles. VT is defined as 3 or more heartbeats in a row, at a rate of more than 100 beats a minute. If VT lasts for more than a few seconds at a time, it can become life-threatening.
How should pulseless VT be treated?
immediate defibrillation + CP; IV amiodarone is given refractory to defibrillation
How should patients with unstable sustained VT be treated?
direct current cardioversion. If this fails give IV amiodarone and repeat direct current. If this fails, IV amiodraone should be administered and dc cardioversion repeated
How should stable sustained VT be treated?
IV antiarrhythmic drug (amiodarone preferred). Flecainide, propafenone and lidocaine (less effective) can be used.
If sinus rhythm is not restored, direct current cardioversion or pacing should be considered. Catheter ablation is an alternative if cessation of arrhythmia is not urgent
How should non-sustained VT be treated?
beta blocker
Maintenance treatment for ventricular tachycardia?
For patients at high risk of cardiac arrest
- most patients: cardioverter defibrillator implant (ICD)
- some patients also require a drug: sotalol, bb alone or bb with amiodarone
*ICD sends electrical pulses to regulate abnormal heart rhythms, especially those that could be dangerous and cause a cardiac arrest.
What is torsade de pointes ?
A form of VT associated with a prolonged QT interval
Causes and treatment for torsade de pointes?
Causes: sotalol and other drugs that prolong QT, hyPOkalaemia, and bradycardia
Treatment: Magnesium sulphate
What is paroxysmal supraventricular tachycardia (PSVT)?
Paroxysmal supraventricular tachycardia (PSVT) is a type of abnormal heart rhythm, or arrhythmia. It occurs when a short circuit rhythm develops in the upper chamber of the heart. This results in a regular but rapid heartbeat that starts and stops abruptly.
This will often terminate spontaneosuly or with reflex vagal stimulation such as a valsalva mmanoeuvre, immersing the face in ice-cold water or carotid sinus massage - performed with ECG monitoring
What can be done is PSVT is still present after reflex vagal stimulation or is causing severe symptoms?
IV adenosine (c/i in COPD/asthma)
if ineffective or c/i
Alternative: IV verapamil (avoid in patients recently treated with beta blockers)
- if haemodynamicaly ly unstable = direct current cardioversion
- recurrent episodes = cather ablation OR drugs (rate limiting CCBs, sotalol, flecainide ir propafenone)
What class arrhythmic drug is amiodarone, what is it used to treat and what is the initial loading dose?
CLASS 3 - used in arrhythmias e.g. supraventricular and ventricular arrhythmia
INITIAL LOADING DOSE:
- 200mg TDS for 7 days,
- 200mg BD for 7 days and then,
- 200mg OD as maintenance
Amiodarone side effects
EYES:
- corneal micro-deposits pt counselling = night time glares when driving
- optic neuropathy/ neuritis (blindness). counselling = STOP if impaired vision
SKIN:
- phototoxicity (burning, erythema)
- slate-grey skin on light exposed areas
counselling = shiled skin from light, wide spec SPF for months after stopping
NERVES:
- peripheral neuropathy, counselling = numbness, tingling hands and feet, tremors
LUNGS:
- pneumonitis, pulmonary fibrosis, Counselling = SOB, dry cough
LIVER:
- hepatoxicity. counselling = report jaundice, N+V, malaise, itching, bruising, abdominal pain. 3X raised liver transaminases)
THYROID DYSFUNCTION (contains iodine)
- hyperthyroidism (weight loss, heat intolerance, tachycardia) –> give carbimazole if nec. stop amiodarone
- hypothyroidism (weight gain, cold intolerance, bradycardia). start levothyroxine without stopping amiodarone if essential
Amiodarone monitoring?
- annual eye test
- chest xray before treatment
- LFTs every 6 months
- monitor TSH, T3, T4 before treatment and every 6 months
- blood pressure and ECG (causes hypotension and bradycardia)
- serum K (causes hypokalaemia; enhances arrhythmogenic effect of amiodarone)
Amiodarone interactions?
AMIODARONE HAS EXTREMELY LONG HALF LIFE = 50 days (danger of interactions several months after stopping)
- increased plasma amiodarone concs = grapefruit juice (enzyme inhibitor)
- amiodarone is an enzyme inhibitor = warfarin, phenytoin, digoxin (half dose)
- increased risk of myopathy = statins
- bradycardia, AV block and myocardial depression = bbs, rate limiting CCBs
- QT prolongation = increased risk of ventricular arrhythmia = quinolones, macrolides, TCAs, SSRIs, lithium, quinine, hydroxychloroquine, anti-malarials (chloroquine and mefloquine), antipsychotics (especially sulpiride, pimozide, amisulpride)
What type of drug is digoxin?
Cardiac glycoside: increases force of myocardial contraction (positive ionotrope) reduces conductivity in the AV node (negative chronotrope)
(INCREASE OUTPUT FORCE + DECREASE RATE OF CONTRACTIONS)
high risk drug
Digoxin therapeutic levels?
1-2 microgram/L (Cp 6 hours after dose)
Monitoring is not required during maintenance treatment unless toxicity suspected OR in renal impairment (renally cleared
Digoxin doses?
- loading dose required due to long half life
- maintenance once daily:
- atrial flutter and non-paroxysmal AF in sedentary patients = 125-250 mcg
- worsening or severe HF (in sinus rhythm) = 62.5 - 125mcg
- different dosage forms have different bioavailabiility e.g.
elixir = 75%
tablet = 90%
IV = 100%
Signs of digoxin toxicity
“Slow and sick”.
Risk of toxcitiy in hypO K+, hypO Mg2+, hypER Ca2+, hpoxia and renal impairment
- bradycardia/heart block
- nausea, vomiting and diarrhoea, abdominal pain
- blurred or yellow vision
- confusion, delirium
- rash
Treatment for digoxin toxcitiy ?
WITHDRAW. Correct electrolyte imbalances
Digoxin-specific antibody for life threatning ventricular arrthymias unresponsive to atropine
Digoxin interactions?
- HyPOkalaemia predisposes to digosin toxicity; diuretics (loop/thiazide), b2 agonist, steroids, theophylline (if K+<4.5mmol/L: give K+ supplements OR K+ sparing diuretic preferred)
- increase plasma digoxin conc = toxicity: amiodarone (half digoxin dose), rate limiting CCBs, macrolides, ciclosporin (enzyme inhibitors)
- decreased plasma digoxin conc = subtherapeutic dose: st johns wort, rifampicin (enxyme inducers)
- reduced renal excretion = toxicity (digoxin renally excreted): NSAIDs, ACEis/ARBs
Digoxin interactions acronym ?
CRASED
Calcium channel blockers (verapamin/diltiiazem) Rifampicin Amiodarone St Johns wort Erythromycin Diuretics
2 types of venous thromboembolsim (VTE)?
- Deep vein thrombosis (DVT): a blood clot occurs in a deep vein, usually in calf of one leg
- Pulmonary embolism (PE): detachment of blood clot which travels to the lungs and blocks the pulmonary artery
VTE RISK ASSESSMENT (for all patients admitted to hospital) (12)
- immobility
- obesity BMI >30
- malignant disease
- 60+ years
- personal history of VTE
- thrombophilic disorders
- 1st degree of relative with VTE
- HRT/combined oral contraceptive
- varicose veins with phlebitis (inflammation of vein)
- pregnancy
- crticial care
- significant co-morbidities
Risk of bleeding:
- thrombocytopenia (low platelet)
- acute stroke
- bleeding disorders
- acquired: liver failure
- inherited: haemophilia, Von Willebrands disease
- anticoagulants
- systolic hypertension
What is mechanical VTE prophylaixis?
- compressin stockings - for patients scheduled for surgery continued until sufficiently mobile
Pharmacological VTE prophylaxis ?
- for high VTE risk patients undergoing general/orthopaedic surgery OR admitted to hospital as general medical patients. (if c/i offer mechanical prophylaxis)
PARENTERAL ANTICOAGULANTS:
- low molecular weight herapin OR
- unfractionated heparin in renal failure OR
- fondaparinux
NOACs:
- prophylaxis AFTER knee/hip replacement surgery
- edoxaban: treatment and prevention of recurrent VTE
Durations for VTE prophylaxis?
- general surgery: 5-7 days or until sufficient mobility
- major cancer surgery in abdomen or pelvis: 28 days
- knee/hip replacement sugery: extended duration
Treatment of VTE?
- LMWH OR unfractionated heparin in renal failure . For at least 5 days and until INR at 2 or more for at least 24 hours. Monitor APTT if unfractionated heparin given.
- Start oral anticoagulant at same time; usually warfarin
VTE in pregnancy
- heparins
- LMWH is the preferred choice
- lower risk of osteoporosis and heparin-induced thrombocytopenia
- stop at labour onset. seek specialist advice on continuing after birth
What is APTT?
- Activated partial thromboplastin time
- Blood test that characterizes coagulation of the blood, with a substance added to make it clot faster
- A typical aPTT value is 30 to 40 seconds
- Important to monitor with unfractionated heparin
Heparin types
(parenteral anticoagulant)
- unfractionated heparin activates antithrombin
- low molecular weight heparin inactivate factor Xa
Unfractionated heparin
- standard heparin
- shorter duration of action
- preferred choice if:
= high risk of bleeding
= renal impairment - essential to measure APTT (activated partial thromboplastin time)
Low molecular weight heparin
- tinzeparin
- enoxaparin
- dalteparin
- longer duration of action
- generally preferred choice; lower risk of:
= osteoporosis
= heparin-induced thrombocytopeonia - used in pregnancy
Heparin side effects?
- haemorrhage: withdraw heparin, if rapid reversal required = antidote protamine
- hyperkalaemia: heparins inhibit aldosterone secretion. Higher risk in diabetes and CKD. Monitor before treatment and if >7 days use
- osteoporosis
- heparin-induced thrombocytopoenia: occurs 5-10 days after. Clnical signs: 30% reduction in platelets, skin allergy, thrombosis. Monitoring: before treatment and if >4 days use
What is the reversal antidote for Heparin?
Protamine
Other parenteral anticoagulants?
- heparinoid
- argatroban
- hirudin
- flushes
- epoprostenol
- fondaparinux
What is warfarin?
- oral anticoagulant (high risk drug)
- antagonise actions of vitamin K in blood clotting
- takes 48-72 hours to work
Warfarin doses?
- 5mg initially and monitor every 1-2 days
- maintenance dose: 3-9mg at same time every day
Warfarin monitoring?
- INR every 3 months once stable
Duration of warfarin treatment?
- isolated calf DVT = 6 weeks
- provoked VTE (COCs, pregnancy, leg plaster cast) = 3 months
- unprovoked (e.g. AF) = at least 3 months/ long term
What is the target INR?
- 2.5 = VTE, AF, MI, cardioversion, bioprosthetic mitral valve.
- 3.5 = recurrent VTE in patients recieving antocoagulant and INR > 2
Warfarin patient counselling
- yellow treatment booklet
- anticoagulant alert card
Warfarin interactions?
Changes in INRL
- MHRA/CHM advice: direct acting anti-virals to treat chronic hepatitis C: risk of infection with vitamin K antagonsts and changes in INR; affects efficacy of warfarin. Closely monitor INR
Increased INR = increased risk of bleeding
- MHRA/CH< advice: OTC oral miconazole gel (daktarin) c/i in patients taking warfarin, Closely monitor if miconazole prescribed. Miconazole permanent enzyme inhibitor; increases anticoagulant effect of warfarin
counselling: stop and seek immediate medical attention if any sign of bleeding e.g. nose bleeds or blood in urine
Warfarin side effects?
- Bleeding e.g. nose bleeds <10 mins, bleeding gums, bruising. antidote = vitamin K; phytomenadione
- Calciphylaxis (a serious, uncommon disease in which calcium accumulates in small blood vessels of the fat and skin tissues. Calciphylaxis causes blood clots, painful skin ulcers and may cause serious infections that can lead to death)
- MHRA/CHM advice: warfarin reports of calciphylaxis. counselling: report painful skin rash. Consider stopping if calc diagnosed. risk factor: end stage renal disease
What to do when bleeding on warfarin?
- MAJOR BLEEDING
- stop warfarin
- IV phytomenadione (vit k)
- dried prothrombin complex or fresh frozen plasma
What to do with INR 5-8 + no bleeding ?
- withhold 1-2 dose
- reduce maintenance dose
- measure INR after 2-3 days
What to do with INR 5-8 + minor bleeding?
- omit warfarin
- IV phytomenadione
- repeat if INR still high after 24 hours
- ## restart warfarin when INR < 5
What to do if INR > 8 + no bleeding?
- omit warfarin
- oral phytomenadione
- repeat if INR still high after 24 hours
- restart warfarin when INR < 5
What to do if INR > 8 + minor bleeding?
- omit warfarin
- IV phytomenadione
- repeat if INR still high after 24 hours
- restart warfarin when INR <5
Warfarin and surgery?? (elective/emergncy/high risk VTE and or bleeding)
ELECTIVE
- stop warfarin 5 days before elective surgery
- give oral phytomenadione one day if INR > 1.5
- restart warfain on evening or next day
EMERGENCY
- delay 6-12 hours
- no delay; give IV phytomenadione and dried prothrombin complex
IF HIGH RISK OF VTE
- VTE in last 3 months, AF with previous stroke/TIA, mechanical valve = bridge with LMWH (treatment dose) and stop 24 hours before surgery
HIGH RISK OF BLEEDING
- start LMWH 48 hours after surgery
What are NOACs?
Novel Oral Anticoagulants: inhibits specific clotting factors i.e. thrombin or factor Xa
NOACs examples
- dabigatran - direct thrombin inhibitor, special container - 4 month expiry
- apixaban*
- edoxaban*
- rivaroxaban*
- direct factor Xa inhibitors
USE: increasingly used as an alternative to warfarin.
Advantages: rarely causes bleeding and no monitoring required
NOACs come with patiet alert card
2 classifications of stroke management ?
- ISCHAEMIC = BLOOD CLOT OBSTRUCTS BLOOD SUPPLY
- ischaemic strokes
- transient iscaemic attack (mini strokes) - HAEMORRHAGIC = WEAK BLOOD VESSEL IN BRAIN BURSTS
- intracerebral haemorrhage
Long term stroke management?
TIA : MR dipyridamole and aspirin
ISCHAEMIC STROKE: clopidogrel, in AF-related stroke - review for anticoagulant
BOTH TIA/ISCHAEMIC STROKES: statin irrespective of serum cholesterol, treat hypertension; not with beta blockers unless indicated for another condition
How is intracerebral haemorrhage managed?
- avoid aspirin, statin and anticoagulants (increases risk of bleeding; only give if essential)
- treat hypertension and take care to avoid hypoperfusion
Antiplatelet drug action?
Decrease platelet aggregation and inhibit thrombus formation in the arterial circulation
antiplatalet drugs?
- aspirin
- clopidogrel
- dipyridamole
- cangrelor
- prasugrel
- ticagrelor
- abciximab (monoclonal antibody)*
- eptifibatide *
- tirofiban*
- glycoprotein IIa/IIb inhibitors
Dose of aspirin used in 2nd prevention of CVD?
75mg daily
In what indications is clopidogrel given?
following ACS or PCI
When is dipyridamole given?
2nd preventionn of strokes. Take tabs 30-60 mins before food. Persantin retard capsules special container - 6 week expiry
How are people under 55 initially treated for hypertension (STEP 1)?
ACEi or ARB
*if not c/i or not tolerated: beta blocker
How are people over 55 yrs and/or if patient is of african/carribbean origin initially treated for hypertension ? (step 1)
CCB
*if high risk of heart failure or CCB not tolerated: thiazide like diuretic
Step 2 hypertensive treatment for patients under 55 yrs ?
ADD CCB
*if high risk heart failure or CCB not tolerated: thiazide like diuretic
Step 2 hypertensive treatment for over 55/ of african/carribbean origin?
ADD ACEi or ARB
*ARB preferred in african/carribbean patients
Step 3 in antihypertensive treatment?
ACEi/ARB + CCB +TLD