Arrhythmias Flashcards
What are the main types of arrhythmias? (5)
- AFib
- Atrial flutter
- Paroxysmal SVT
- Arrhythmias after MI (paroxysmal tachycardia, rapid irregularity, bradycardia)
- VTach (pulseless v-tach or VF)
What treatment is required for ectopic beats?
If spontaneous and the patient has a normal heart, treatment is rarely required and reassurance will suffice
If they are particularly troublesome, beta-blockers are sometimes effective and may be safer than other suppressant drugs
What are the treatment goals in the management of AFib? (3)
Rate control
Rhythm control
Stroke prevention
What is the management of life-threatening hemodynamically unstable new-onset AFib?
Emergency electrical cardioversion WITHOUT delaying to achieve anticoagulation
What is the management of non-life-threatening hemodynamically STABLE new-onset AFib (<48 hours)?
Rate OR rhythm control
What treatment is preferred for management of non-life-threatening hemodynamically STABLE new onset AFib presenting after 48 hours or if duration is uncertain?
Rate control (and anticoagulation)
What is the cutoff for cardioversion in patients with acute AFib?
48 hours
- if less than 48 hours, rate or rhythm control
- if more than 48 hours, rate control only (no cardioversion before anticoagulation)
What are the options for chemical cardioversion in the treatment of AFib? (2)
- Amiodarone (preferred if there is structural heart disease)
- Flecainide
What are the options for urgent rate control in AFib? (2)
- IV beta-blocker
2. IV verapamil
When is electrical cardioversion preferred to chemical?
If AFib has been present for more than 48 hours, electrical cardioversion is preferred and should not be attempted until the patient is fully anticoagulated for AT LEAST 3 weeks
- if this is not possible, parenteral anticoagulation should be commenced, and a left atrial thrombus ruled out immediately before cardioversion
** prior to cardioversion, offer rate control as appropriate
What may be offered to patients with AFib in the interim before cardioversion is performed?
Rate control
Is it necessary to continue oral anticoagulation after cardioversion?
Yes, for at least 4 weeks
For patients receiving cardioversion for AFib with onset >48 hrs, how long should they be anticoagulated first?
At least 3 weeks
Rate control the preferred first-line drug treatment strategy for AFib EXCEPT in patients with… (4)
- New-onset AFib
- Atrial flutter suitable for an ablation strategy
- AFib with a reversible cause
- If rhythm control is more suitable based on clinical judgement
What are the main options for controlling ventricular rate? (2)
- Beta-blocker (not sotalol)
- Non-dihydropyridine CCB (diltiazem or verapamil)
- Digoxin is usually only effective for controlling the ventricular rate at rest, and should therefore only be used as monotherapy in predominantly sedentary patients with non-paroxysmal atrial fibrillation.
When a single drug fails to adequately control the ventricular rate, what drug combinations can be offered?
A combination of two drugs including a beta-blocker, digoxin, or diltiazem
If ventricular function is diminished, what drug combination is preferred for controlling ventricular rate?
Beta-blocker + digoxin
What drug is preferred for managing AFib in patients with heart failure?
Digoxin
What drug may be used to maintain sinus rhythm in patients with AFib post-cardioversion?
A beta-blocker
- If a standard beta-blocker is not appropriate or is ineffective, consider an oral anti-arrhythmic drug such as sotalol hydrochloride, flecainide acetate, propafenone hydrochloride, or amiodarone hydrochloride
What drug may be used before and after electrical cardioversion for AFib to increase success of the procedure and maintain sinus rhythm?
Amiodarone 4 weeks before and continuing for up to 12 months after
What ‘rhythm control’ drugs should be avoided in patients with known ischemic or structural heart disease? (2)
- Flecainide
- Propane one
- Consider amiodarone hydrochloride in patients with left ventricular impairment or heart failure.
Which ‘rhythm control’ drug is preferred in patients with LV impairment or HF?
Amiodarone
How is paroxysmal AFib defined?
Episodes of AFib that self-terminate within 7 days, usually within 48 hours, without any treatment
What is the ‘Pill-in-pocket’ strategy for PAFib?
The person self-manages paroxysmal AFib by taking anti arrhythmic drugs only when an episode of atrial fibrillation starts
To which patients is the ‘Pill-in-pocket’ strategy for AFib offered? (4)
Patients who:
- Have no history of LV dysfunction, or valvular or ischemic heart disease AND
- Have a history of infrequent symptomatic episodes of PAFib AND
- Have a SBP > 100 and a resting HR >70 bpm AND
- Are able to understand how to, and when to, take the medication
In which patients should the risk of stroke be calculated using the CHADS-VASc stroke risk score? (3)
- Symptomatic or asymptomatic paroxysmal, persistent, or permanent AFib
- Atrial flutter
- Continuing risk of arrhythmia recurrence after cardioversion back to sinus rhythm or catheter ablation
What is the CHADS-VASc score?
Estimator for stroke risk in patients with cardiac arrhythmias
C- CHF H- HTN A- age >75 (2 points) D- DM S- stroke/TIA/thromboembolism (2 points)
V- vascular disease (prior MI, PAD, aortic plaque)
A- age 65-74
Sc- sex female
When should bleeding risk be assessed with the ORBIT bleeding risk score?
- When considering starting anticoagulation in people with AFib AND
- When reviewing people already taking anticoagulation
What is the ORBIT score?
An estimator of bleeding risk for people taking anticoagulation for atrial fibrillation, similar to HAS-BLED score
O- older age (age 74 or more) R- reduced hemoglobin/anemia B- bleeding history I- insufficient kidney function T- treatment with antiplatelet
1 point for each risk factor
0-2 is low risk
3 is intermediate risk
4-5 is high risk
How do you interpret the score of the CHADS-VASc scoring system for patients with AFib?
0: no antithrombotic therapy
1: consider anticoagulation with a DOAC, taking into account bleeding risk
2+: offer anticoagulation with a DOAC, taking into account bleeding risk
A 30 year old woman with atrial fibrillation is being considered for stroke risk prevention. She has a CHADS-VASc score of 1. Should she be offered a DOAC for anticoagulation?
No; her 1 point is due to being female, therefore her stroke risk is very low and anticoagulation is not justified
Which drugs may be offered to patients with Paroxysmal AFib whose symptoms persist after standard beta-blocker therapy OR for whom beta-blocker therapy is inappropriate? (5)
Oral anti-arrhythmics:
- Dronedarone
- Sotalol
- Flecainide
- Propafenone
- Amiodarone
*vs in select patients with INFREQUENT episodes of symptomatic PAF, who may be offered the ‘pill-in-pocket’ approach with flecainide or propafenone
What is the HAS-BLED score?
A tool for assessing bleeding risk prior to and during anticoagulation
H- HTN (SBP >160)
A- abnormal renal or liver function (1 point each)
S- stroke
B- bleeding tendency
L- labile INR (time in therapeutic range <60%)
E- elderly (>65)
D- drugs (eg concomitant aspirin, NAIDs) or alcohol (1 point each)
Score:
0-2 indicates low risk
3+ indicates high risk
Can anticoagulation treatment be withheld solely because of the risk of falls?
No
What is the preferred form of anticoagulation for stroke prevention in patients with AFib?
DOACs: apixaban, dabigatran, edoxaban, rivaroxaban
*except in patients with valvular heart disease in whom warfarin is preferred
Can aspirin be offered as monotherapy for stroke prevention in AFib?
No
What can be offered for stroke prevention in patients with AFib in whom anticoagulation is contraindicated or not tolerated?
Left atrial appendage occlusion may be considered
What should be offered to patients with new-onset AFib who are receiving sub therapeutic or no anticoagulation therapy pending assessment and initiation of appropriate anticoagulation?
Parenteral anticoagulation eg LMWH
To which patients with AFib should oral anticoagulation be offered? (3)
Anticoagulation should be offered to patients with confirmed diagnosis of AFib in whom
- Sinus rhythm has not been successfully restored within 48 hours of onset
- There is a high risk of recurrence including history of recurrence, structural heart disease, history of prolonged AFib (more than 12 months), history of failed attempts at cardioversion
- The risk of stroke outweighs the risk of bleeding
What are the treatment goals for management of Atrial flutter? (2)
- Controlling ventricular rate OR
- Attempting to restore and maintain sinus rhythm
*AFlutter generally responds less well to drug treatment than atrial fibrillation
What are the options for achieving sinus rhythm in patients with Atrial flutter? (3)
- Electrical cardioversion (by cardiac pacing or direct current)
- Pharmacological cardioversion
- Catheter ablation
Is anticoagulation required in patients with a history of Atrial flutter lasting more than 48 hours?
Yes, if the duration of Atrial flutter is unknown or has lasted >48 hours, cardioversion should not be attempted until the patient has been fully anticoagulated for at least 3 weeks
- oral anticoagulation should be given after cardioversion and continued for at least 4 weeks
If anticoagulation is not possible for 3 weeks prior to cardioversion in the treatment of Atrial flutter, what should be done instead?
Parenteral anticoagulation should be commenced and a left atrial thrombus ruled out with echo immediately before cardioversion
What is the treatment of choice in cases of Atrial flutter where rapid conversion to sinus rhythm is necessary eg hemodynamic compromise?
Direct current cardioversion
What is the treatment of choice for recurrent atrial flutter?
Catheter ablation
What is the role of anti-arrhythmic drugs in the management of atrial flutter?
Limited to none; anti-arrhythmic drugs are not always successful
Flecainide or propafenone can slow atrial flutter, resulting in 1:1 conduction to the ventricles, and should therefore be prescribed in conjunction with a ventricular rate controlling drug such as a beta-blocker, diltiazem hydrochloride [unlicensed indication], or verapamil hydrochloride. Amiodarone hydrochloride can be used when other drug treatments are contra-indicated or ineffective
Do patients with atrial flutter need to be assessed for stroke risk and the need for thromboprophylaxis?
Yes, choice of anticoagulant is based on the same criteria as for atrial fibrillation
What are non-pharmacological options for managing paroxysmal SVT? (4)
- Often terminate spontaneously
- Reflex vagal stimulation eg valsalva maneuver
- Immersing the face in ice-cold water
- Carotid sinus massage
**performed with ECG monitoring
If initial efforts to terminate paroxysmal SVT are unsuccessful, what medication should be offered?
IV adenosine 6mg given over 2 seconds with cardiac monitoring (into central or large peripheral vein)
Followed by 12 mg after 1-2 min if required
If adenosine is ineffective or contraindicated, what other medication can be tried to terminate paroxysmal SVT?
Verapamil
*should be avoided in patients recently treated with beta-blockers
What cardiac drug should be avoided in patients taking beta-blockers?
Verapamil
What should be considered if paroxysmal SVT fails to terminate with vagal maneuvers and drug treatment?
Consider an arrhythmia of ATRIAL (not ventricular) origin such as focal atrial tachycardia or atrial flutter
What intervention is indicated in patients with paroxysmal SVT and hemodynamic instability?
Direct current cardioversion
When is direct current cardioversion indicated in patients with paroxysmal SVT? (2)
- Hemodynamically unstable patients
2. When vagal maneuvers and medication fail to restore sinus rhythm (and an alternate diagnosis has not been found
What are the treatment options for recurrent episodes of paroxysmal SVT?
- Catheter ablation (treatment)
- Prevention with drugs:
- diltiazem
- verapamil
- beta-blockers (sotalol, flecainide, propafenone)
What are the most common arrhythmias occurring after MI? (2)
- Paroxysmal tachycardia (supraventricular or ventricular)
- Bradycardia
Less common but important: VF (risk highest in the first hour)
What is the treatment of choice for bradycardia following MI?
IV Atropine 500 mcg every 3-5 min; max 3 mg per course
*particularly if bradycardia is complicated by hypotension
(Atropine is an antimuscarinic, therefor it decreases the parasympathetic tone of the heart to increase HR in the treatment of bradycardia)
What should be done in patients with post-MI arrhythmias before the initiation of anti-arrhythmic drugs?
Obtain an ECG
What drug should be administered to post-MI patients with bradycardia and high risk of asystole?
IV Adrenaline infusion 2-10 mcg/minute, adjusted according to response
What is the treatment of choice for post-MI patients with bradycardia and hemodynamic instability who have failed to respond to atropine?
After atropine is attempted, IV adrenaline infusion should be administered 2-10 mcg/min adjusted according to response
Which ventricular tachycardias require resuscitation? (2)
- Pulseless ventricular tachycardia
2. Ventricular fibrillation (VF)
What is the management of patients with unstable VTach who have signs of hypotension or reduced cardiac output?
- Should receive direct current cardioversion to restore sinus rhythm
- If this fails, IV amiodarone and repeat DC cardioversion
What is the management of patients with sustained VTach who are hemodynamically stable?
IV antiarrhythmics
FIRST LINE:
- amiodarone
SECOND LINE:
- flecainide
- propafenone
- lidocaine
*if sinus rhythm is not restored direct current cardioversion or pacing should be considered
Can catheter ablation be used in the treatment of VTach?
Yes, if cessation of arrhythmia is not urgent
What is the treatment of choice for non-sustained VTach?
Beta-blockers
What intervention should be offered to patients who remain at high risk of cardiac arrest following restoration of sinus rhythm after VTach?
Maintenance therapy:
- Implantable cardioverter defibrillator (most patients)
- beta-blockers OR sotalol, amiodarone (in combination with standard beta-blocker) can be used in addition to ICD OR alone if ICD is not appropriate
What is torsade de pointes?
A form of ventricular tachycardia associated with a long QT syndrome (usually drug-induced, but other factors including hypokalemia, severe bradycardia, and genetic predispositions are also implicated)
What are the some drugs commonly associated with drug-induced long QT syndrome and torsade de pointes? (6)
- Macrolides
- Ondansetron
- Quinolones
- Methadone
- Antihistamines
- Flecainide
What is the treatment of choice for torsade de pointes?
FIRST LINE:
- IV magnesium sulfate
SECOND LINE:
- beta-blocker but NOT sotalol and atrial pacing
**anti-arrhythmics can further prolong the QT interval, thus worsening the condition
What is the major concern with torsades de pointes?
If not controlled, it can progress to VF and sometimes death
Episodes are usually self-limiting but are frequently recurrent and can cause impairment or loss of consciousness
Which anti-arrhythmic drugs are primarily used for treatment of supraventricular arrhythmias? (4)
- Adenosine (paroxysmal SVT)
- Verapamil (preferable to adenosine in asthma)
- Digoxin (but contraindicated in WPW)
- Beta-blockers (eg. esmolol or propranolol)
*goal of treatment is to slow ventricular rate by decreasing rate of SA node (beta blocker, adenosine) OR decreasing ventricular response (digoxin, verapamil, adenosine)
Which drugs can be used in the treatment of both supraventricular and ventricular arrhythmias? (6)
- Amiodarone
- Beta-blockers
- Disopyramide
- Flecainide
- Procainamide
- Propafenone
Which antiarrhythmic drugs are used ONLY in ventricular arrhythmias? (2)
- Lidocaine, may be used in VTach (hemodynamically stable), VFib, pulseless VTach in cardiac arrest refractory to defibrillation
* HOWEVER, no longer the anti-arrhythmic drug of choice - Mexiletine (life-threatening ventricular arrhythmias)
Which arrhythmia may be treated with verapamil?
SVT
What type of drug is verapamil?
CCB, reduces cardiac contractility and propagation of electrical impulses through the heart; also decreases coronary and systemic vascular tone
What are the major contraindications of verapamil? (10)
- Concomitant use of beta-blockers (risk of heart block)
- Atrial flutter or Atrial fibrillation associated with WPW or other accessory conducting pathways
- Bradycardia
- Cardiogenic shock
- HF with reduced EF
- Hypotension
- Second- or third-degree AV block
- Sick sinus syndrome
- SIBO-atrial block
- History of significantly impaired LV function
**should not be used in children with arrhythmias without specialist advice as it may accelerate supraventricular arrhythmias with dangerous consequences
What are the main side effects of verapamil? (5)
- Constipation
- Bradycardia
- Heart block
- Heart failure
- Hypotension
What is the main drug interaction to look out for when using verapamil?
Beta-blockers; when used together may cause HF, bradycardia, and even asystole due to compounded negatively inotropic and chronotropic effects
What are the Class I anti-arrhythmic drugs according to the Vaughan Williams classification? (8)
- Procainamide (1A)
- Quinidine (1A)
- Disopyramide (1A)
- Phenytoin (1B)
- Lidocaine (1B)
- Mexilitine (1B)
- Flecainide (1C)
- Propafenone (1C)
What are the Class II anti-arrhythmic drugs according to the Vaughan Williams classification?
Beta blockers
What are the Class III anti-arrhythmic drugs according to the Vaughan Williams classification (4)
- Amiodarone
- Sotalol (beta-blocker, also class II)
- Dofetilide
- Ibutilide
What are the Class IV anti-arrhythmic drugs according to the Vaughan Williams classification?
Non-dihydropyridine calcium channel blockers ie verapamil, diltiazem
Adenosine is the treatment of choice for terminating which arrhythmia?
Paroxysmal SVT
Which drug may prolong the half-life of adenosine?
Dipyridamole
Which drugs may prevent the action of adenosine? (2)
- Caffeine
2. Theophylline
Can adenosine be used after beta-blockers?
Yes, unlike verapamil
Can adenosine be used to treat patients with asthma?
No, asthma is a contraindication. Verapamil is used instead
What are the contraindications of adenosine? (7)
- Asthma
- COPD
- Decompensated HF
- Long QT syndrome
- Second- or third- degree AV block
- Sick sinus syndrome (unless pacemaker fitted)
- Severe hypotension
What are the common side effects of adenosine? (6)
- Breathlessness
- Chest discomfort (but discontinue use if pain)
- Arrhythmias
- AV block, asystole
- Bradycardia
- Sinking feeling, sense of ‘impending doom’
What electrolyte imbalance enhances the arrhythmogenic (pro-arrhythmic) effect of many antiarrhythmic drugs?
Hypokalemia
** Most drugs that are effective in countering arrhythmias can also provoke them in some circumstances; moreover, hypokalaemia enhances the arrhythmogenic (pro-arrhythmic) effect of many drugs
What is digoxin?
A cardiac glycoside that slows the ventricular response in cases of Afib and Atrial flutter
Rarely effective for rapid control of ventricular rate
Contra-indicated in SV arrhythmias associated with accessory conducting pathways eg WPW
Digoxin may be used to treat which arrhythmias? (2)
- Atrial fibrillation
2. Atrial flutter
What are the contraindications of digoxin? (4)
- Ventricular arrhythmias
- Second- and third-degree heart block
- SV arrhythmias associated with accessory conducting pathways eg WPW
- Myocarditis
Which abnormalities increase the risk of digitalis toxicity? (8)
- hypercalcemia
- hypokalemia
- hypomagnesemia
- hypoxia
- Recent MI
- Severe respiratory distress
- Sick sinus syndrome
- Thyroid disease
**use caution when prescribing digoxin
What are the notable side effects of digoxin? (7)
- Bradycardia
- Visual disturbance (blurry or yellow vision)
- Cardiac conduction disorders
- Cerebral impairment
- GI disorders
- Dizziness
- Rash
What drug interactions should be monitored when using digoxin?
- Loop and thiazide diuretics (hypokalemia may increase risk of digitalis toxicity)
- Amiodarone
- CCBs
- Spironolactone
- Quinine
- Steroids
- Beta blockers (increase risk of bradycardia)
* *many many more drug interactions!
2-6 increase the plasma concentration of digoxin and thereby increase the risk of toxicity
For which arrhythmias can beta-blockers esmolol and propranolol be used?
Ventricular and supraventricular
For which arrhythmias can amiodarone be used?
Supraventricular and ventricular, particularly when other drugs are ineffective or contraindicated
- paroxysmal SVT
- ventricular tachycardia
- AFib
- AFlutter
- VF
- tachyarythmies associated with WPW
**Should ONLY be initiated under hospital or specialist supervision
What is the main cardiac advantage of amiodarone?
Causes little to no myocardial depression
What are the indications of IV amiodarone? (2)
Cardiopulmonary resuscitation for
- VF
- Pulseless tachycardia refractory to defibrillation
What is the half-life of amiodarone? (Long or short?
Very long, extending to several weeks; many weeks or months may be required to achieve steady-state plasma concentrations
*this is particularly important when drug interactions are likely
What are the important drug interactions to consider with patients taking amiodarone? (6)
MANY drug interactions including:
- Digoxin
- Diltiazem and verapamil
*doses should be halved if amiodarone is started in order to avoid bradycardia, AV block, and heart failure
- Diuretics
- Steroids
* these may cause hypokalemia (increase risk of torsade de pointes) - Anticoagulants
- Isoniazid
* amiodarone is a CYP450 inhibitor, increases lifespan of drugs)
What are the main contraindications to using amiodarone? (4)
- Severe conduction disturbances (unless pacemaker is fitted)
- Sinus node disease (unless paced)
- Sino-atrial heart block and sinus bradycardia (except cardiac arrest)
- Thyroid dysfunction
What are the main side effects of amiodarone? (6)
- Hypotension
- Lung toxicity
- Hepatotoxicity
- Photosensitivity and grey skin discoloration
- Arrhythmias
- Thyroid disease ie hyperthyroidism
What is the mode of action of beta-blockers in the treatment of arrhythmias?
Attenuation of the effects of the sympathetic NS on automaticity and conductivity within the heart
Which beta-blocker is particularly useful in the management of ventricular arrhythmias?
Sotalol, unlike most beta-blockers which are mainly indicated in supraventricular arrhythmias
What is disopyramide?
Class IA anti-arrhythmic that decreases the inward Na current to make the heart more resistant to abnormal activity
For which arrhythmias can disopyramide be used?
Ventricular and supraventricular arrhythmias, particularly after MI
What are the main disadvantages of disopyramide?
- Impairs cardiac contractility
- Has antimuscarinic effects
- Prolongs the QT interval
What are the contraindications of disopyramide?
- Bundle branch block associated with 1st degree AV block
- Pre-existing l’on gQT syndrome
- 2nd and 3rd degree AV block or bifascicular block (unless paced)
- Severe heart failure (unless secondary to arrhythmia)
- Severe sinus node dysfunciton
What are the main cautions when using disopyramide?
- Atrial flutter or atrial tachycardia with partial block
- Acute porphyrias
- Elderly
- HF
- Myasthenia gravis
- Prostatic enlargement (antimuscarinic effects)
- Susceptibility to angle-closure glaucoma (antimuscarinic effects)
For what arrhythmias are flecainide and lidocaine used?
- Serious symptomatic ventricular arrhythmias 2. Junctional re-entry tachycardias
- Paroxysmal AFib
What is a potentially severe complication of lidocaine?
Methemoglobinemia, especially when used with benzocaine
What are the main contraindications for flecainide?
Structural heart damage
- abnormal LV funciton
- atrial conduction defects
- bundle branch block
- distal block
- hemodynamically significant valvular heart disease
- HF
- history of MI
- long standing AFib
- 2nd or 3rd degree AV block
- sinus node dysfunction
For which arrhythmias is propafenone indicated?
- Prophylaxis and treatment of ventricular arrhythmias
2. SOME supraventricular arrhythmias (paroxysmal SVT including AFib and Aflutter)
What are the main contraindications of propafenone?
Structural heart disease including
Atrial conduction defects (unless adequately paced); Brugada syndrome; bundle branch block (unless adequately paced); cardiogenic shock (except arrhythmia induced); distal block (unless adequately paced); electrolyte disturbances; marked hypotension; myasthenia gravis; myocardial infarction within last 3 months; second degree or greater AV block (unless adequately paced); severe bradycardia; severe obstructive pulmonary disease (due to weak beta-blocking activity); sinus node dysfunction (unless adequately paced); uncontrolled congestive heart failure with left ventricular ejection fraction less than 35%
What are common side effects of propafenone?
Anxiety Arrhythmias Asthenia Cardiac conduction disorder Dizziness Fever Headache Hepatotoxicity Sleep disorders Altered taste Vision blurring
