Arrhythmias Flashcards
Overview
Abnormal Electrical conduction THEN symptoms then ECG.
IF AF:
- AF ppl. have high risk of stroke BC blood sits in AF in the heart. this can form clots which can go to brain which = Stroke.
- CHA2DSVasc score - F >2 M>1 MEAN u need to give DOAC (stops clot formation) ALT Warfarin.
- Asses bleeding risk with anticoagulants.
AF Treatment:
Rate or Rhythm control. Rate preferred.
- Rhythm can be pharmacologic or non pharmacologic. Rate only pharmacological.
ACUTE AF:
Life threatening (haemodynamically unstable) - Emergency electrical cardioversion.
NON Life threatening - Rate or rhythm.
Cardioversion is a rhythm control strategy. Electrical or pharmacological. AF>48hr electrical preferred. AMIODARONE 4 weeks before and 12 months after electrical to maintain sinus rhythm.
Background
Arrhythmia is any condition where there is abnormal electrical activity of the heart. (abnormal rate&/or rhythm of the heart)
Has many types as below.
HR - 60 to 100 = normal.
- Paroxysmal AF - Eps of AF that stops within 7 days without treatment.
- Pill in pocket Pts have a pill PRN for Paroxysmal AF.
- New onset AF.
Signs and Symptoms / Diagnosis
Dizziness.
Palpitations.
Syncope (faint)
Shortness of breath (dyspnoea).
Chest pain.
Fatigue.
Rarely, and in extreme cases, cardiac arrest.
mnemonic - SAD palpitations (SOB, Abnormally fast/slow or irregular pulse, Dizziness/faint, palpitations)
Diagnosis:
Pulse check then ECG (checks electrical activity of heart)
Causes
Ageing, genetics, HTN, Coronary heart disease, heart valve disease. cardiomyopathy
- Heart conditions number 1 cause
NON-Pharmacological
split into 3 categories.
- Electrical strategies
Direct current cardioversion - this is done with drugs like amiodarone OR electrical shock. MUST BE ANTICOAGULATED and under anaesthesia b4 it. Electrical shock allows SA node to regain control.
- Pacing strategies
Pacemakers - For Bradyarrhythmia’s. placed in collar bone pocket and monitors rate and rhythm and delivers impulses when needed for heart tissue to create a action potential and contract faster.
ICDs (internal cardioverting defibrillator) - Prevents sudden cardiac death from tachyarrhythmia’s. Monitors rate and rhythm. ICD senses VT and delivers impulses very fast rate to regain control then slows down the heart to normal. IF it fails it delivers a electrical shock.
- Ablation therapies
Radiofrequency ablation - First source of arrhythmia’s is found. Catheter with electro node on the end is guided to source site then radiofrequency energy is used to destroy local tissue which destroy abnormal conduction pathways.
Prevents future attacks. Local Anaesthetic is used b4.
Atrial Fibrillation (main 1 for exam)
The atria quivers/Twitches which causes faster/abnormal heart beat.
- Treatment aims to reduce symptoms, prevent complications esp. stroke.
Asses all patients with AF for Stroke and thromboembolism risk.
- Can be managed by either controlling ventricular rate (Rate control) OR trying to restore/maintain sinus rhythm (Rhythm control).
IF they fail then refer
- After drug treatment failure can try ablation strategies.
TREATMENT on Phone (NICE pics) prsc notes here
LIFE THREATENING - New onset AF and life threatening haemodynamic instability (Means unstable blood flow) = Electrical Cardioversion
- (IV heparin b4 ASAP but rule out left atrial thrombus 1st. continue ORAL anticoagulation for 4 weeks after cardioversion)
NON-LIFE THREATENING
Rate or Rhythm control offered if onset <48 hrs.
Rate preferred if onset >48hrs or uncertain.
- B- blocker 1st line for both
RATE CONTROL -GPHC Q. Drugs.
B-blocker (not sotalol) OR Rate limiting CCBs (D or V) OR digoxin (IF NON paroxysmal AF and sedentary or others unsuitable)
- Digoxin also used when AF is with CHF (congested HF)
IF MONO FAILS COMBO = BB D D drugs only. 2 drug FAIL THEN rhythm.
RHYTHM CONTROL drugs:
POST CARDIOVERSION -
B-blocker 1st line OR
Flecainide (AVOID in heart disease) OR
Amiodarone OR
Propafenone (AVOID in heart disease) OR
Dronedarone OR
Sotalol (not as 1st line)
Cardioversion:
- Electrical is with pads and shock/s are sent to restore normal heart rhythm
- Pharmacological (amiodarone/Flecainide) [IF IHD use amiodarone] = They relax the heart, slowing the electrical signals. relaxing blood vessels and making heart work easier and restores regular rhythm.
(BELOW APPLIES TO CV ONLY)
IF AF >48 hrs electrical cardioversion preferred over drug. but delayed until patient anticoagulated for at least 3 weeks. (BC electrical CV can allow clot to travel)
IF anticoagulation for 3 weeks b4 electrical cardioversion not possible (ie haemodynamically unstable) SHOULD rule out left atrial thrombus and give Parenteral anticoagulation (Heparin) ASAP b4 electrical cardioversion. THEN do oral anticoagulation for at least 4 weeks.
Amiodarone can be given 4 weeks before and up to 12 months after
FOR electrical cardioversion.
ACUTE AF + SUS DHF AVOID CCB.
Assessments used in treatment (AF)
HOW TO ASSESS risk of stroke and bleeding:GPHC EXAM Q
Needed to decide when anticoagulation is appropriate in AF.
STROKE: CHA2DS2VASC tool. (NEED TO KNOW WHAT IT STANDS FOR)
C - Congestive HF. H - HTN.
A2 - ages 75 or older.
D- Diabetes.
S2 - Previous stroke, TIA or Thromboembolism.
V - vascular disease.
Age - 65-74
Sc - Sex (Female +1)
- The 2 represents +2.
- Vascular disease meaning Hx MI, Peripheral arterial disease or aortic plaque
BLEEDING RISK:
ORBITE, HASBLED tools. (breakdown on phone)
- HAS BLED 1 or 2 = HAS both conditions.
WHEN TO GIVE ANTICOAGULATION?
When stroke risk is greater than bleeding risk.
- CHA2DS2VASC = 2 or more (1 for M)
NO Anticoagulant when Male = 0 and Female = 1 (GPHC exam Q)
- Some PTs may not need anticoagulant some can i.e. new onset haemodynamically unstable or Life threatening. ESP if not doing cardioversion.
Anticoagulation AF (EXAM Q)
Acutely presenting:
APPLY to life threatening and NON
PARENTERAL anticoagulation: HEPARIN - IF new onset AF and receiving NO or SUB therapeutic anticoagulant UNTILL stroke and bleeding risk assessed and appropriate anticoagulant started.
- NEEDED FOR FAST ACTION TO PREVENT STROKE ETC.
- Used B4 RATE OR RHYTHM.
ORAL Anticoagulant: DOAC (apixaban edoxaban etc) 1ST LINE.
ALT (eg renal impairment) VIT K antagonist (warfarin) (EXAM Q)
Oral anticoagulant are given to confirmed AF pts.
Atrial Flutter
Atria beat faster but regular but AF they beat irregular.
Rate control OR restore sinus rhythm.
RATE
Rate control - ONE of B-Blocker, Diltiazem or Verapamil.
IV B-blocker or Verapamil preferred for RAPID rate control.
Adjunct - Digoxin if needed.
RHYTHM
Conversion to sinus rhythm can be achieved via electrical or pharmacological cardioversion or catheter ablation.
- Duration unknown or >48hrs DONT DO cardioversion UNLESS patient anticoagulated for at least 3 weeks ALT Parenteral anticoagulation and RULE out left atrial thrombus.
Give oral anticoagulant after cardioversion for at least 4 more weeks.
For RAPID rhythm control = Direct current Cardioversion.
Recurrent flutter = Catheter ablation.
Extra:
Flecainide or Propafenone [AVOID IN IHD] can slow atrial flutter = 1:1 conduction to ventricles so is give with Rate control drugs.
Amiodarone can be ALT when other drugs fail.
Ectopic beats
Ectopic = Extra/Skipped beats
If are spontaneous and patient has normal heart then NO treatment needed.
If troublesome then Beta-Blockers can be used and are safer than other drugs.
Paroxysmal supraventricular tachycardia (PSVT)
Will go on it own spontaneously or face in ice cold water or carotid sinus massage. Use ECG with these techniques.
FAIL/Severe symptoms = IV adenosine. ALT IV verapamil (avoid if recent B-blocker use).
FAIL/haemodynamically unstable - Direct current cardioversion.
Recurrent episodes- Catheter ablation or prevention with Diltiazem, Verapamil, B-blocker (inc. sotalol), Flecainide or propafenone.
Arrhythmias after myocardial infarction
For paroxysmal supraventricular tachycardia (PSVT) or rapid irregularity of the pulse BEST TO record ECG 1st.
Bradycardia esp. If complicated by hypotension should give:
IV Atropine
FAIL then IV adrenaline/epinephrine
Ventricular tachycardia
Pulseless ventricular tachycardia (PVT) or ventricular fibrillation (Vf) require resuscitation.
TREATMENT
Unstable sustained ventricular tachycardia, who continue to deteriorate with signs of hypotension or reduced cardiac output:
- Direct current cardioversion to restore sinus rhythm.
- FAIL then IV amiodarone and repeat direct current cardioversion.
Sustained ventricular tachycardia who are haemodynamically stable:
1st line - IV amiodarone
ALT Flecainide, Propafenone, Lidocaine
FAIL then try direct current cardoversion or pacing.
ALT Ablation (shouldn’t be urgent)
Non sustained ventricular tachycardia:
Beta-Blocker
ALL ABOVE:
Once sinus rhythm is restored by the above strategies. Then maintenance may be needed for people with high risk of cardiac arrest
- Implantable cardioverter defibrillator.
B-blockers or sotalol (ALT to b-blocker), or amiodarone (+ a b-blocker), can be used WITH device in some patients;
ALT, Drugs alone when device not appropriate.
Torsade de pointes
Type of ventricular tachycardia with prolonged QT intervals
- caused by drugs, hypokalaemia, severe bradycardia, genetics, stress, hard exercise, sudden noise.
- heart beats irregular usually very fast but not enough O2 pumped around the body, brain is starved of O2 leading to blackouts, falling or death.
It’s self limiting. But can be recurrent and cause impairment/loss of consciousness.
- If uncontrolled can lead to ventricular fibrillation and death.
TREATMENT:
IV magnesium sulfate.
- A beta-blocker (but not sotalol) and atrial (or ventricular) pacing can be considered.
- Anti-arrhythmic can further prolong the QT interval, SO worsen condition.
DRUGS that cause QT prolongation (EXAM Q) MEMORY TRICK:
ABCDDE
Anti-arrhythmic drugs (EXTRA)
SUPRA = ABOVE
1 way to class Anti arrythmitic drugs:
- Supraventricular arrhythmias (verapamil, adenosine, cardiac glycosides)
- Both supraventricular and ventricular arrhythmias (Amiodarone, B-Blocker, Disopyramide, Flecainide, Procainamide, Propafenone)
- Ventricular arrhythmias (lidocaine).
NOTE: Hypokalaemia can increase arrhythmogenic effect of drugs.
Classification based on Effect on ELECTRICAL activity of heart:
Class I: membrane stabilising drugs (e.g. lidocaine, flecainide) Na+ channel blockers
Class II: B-blockers
Class III: amiodarone; sotalol (also Class II) K+ channel blockers
Class IV: CCBs (includes verapamil but not dihydropyridines)
Supraventricular arrhythmias
(Verapamil, Adenosine, Cardiac glycosides [digoxin])
For PSVT adenosine is 1st choice. BC it has very short duration of action (but prolonged in ppl taking Dipyridamole).
Adenosine can be used after B-blocker unlike verapamil.
Verapamil preferred in asthmatics.
Oral cardiac glycosides (digoxin) - slows ventricular response and can used for AF and flutter but IV form not efficient enough for rapid control.
[Digoxin contraindicated in supraventricular arrhythmias linked with conduction pathways.]
Verapamil - effective in SVT. Initial IV dose can be followed by oral treatment (can get hypotension with large doses). AVOID in tachyarrhythmias where QRS complex is wide unless supraventricular origin is proved.
[Contraindicated in AF/flutter linked with accessory conduction pathways (same as cardiac glycosides).]
AVOID in child unless specialist.
IV B-Blocker Esmolol or propranolol can get rapid control of ventricular rate.
Supraventricular and ventricular arrhythmias (Amiodarone, B-Blocker, Disopyramide, Flecainide, Procainamide, Propafenone)
Amiodarone - ESP. used when other are unsuitable. Used for PSVT, nodal and ventricular tachycardia, AF/Flutter, Ventricular Fib.
AND tachyarrhythmias associated with wolf-Parkinson-white syndrome.
USED ONLY in hospital or with specialist. USED IV or ORAL. Advantage of causing little/NO myocardial depression. IV works faster. IV used in resuscitation for ventricular Fib or pulseless tachycardia.
Long half life used OD. Takes Weeks/Months to achieve steady state plasma conc.
B-Blockers - Reduces effect of sympathetic system on automaticity (work auto) and conductivity in the heart. Sotalol used in management of ventricular arrhythmias.
Disopyramide - Used IV for control after MI but impairs cardiac contractility. ORAL form has antimuscarinic AEs so limits use in pts more susceptible to Angle closure glaucoma or with prostatic hyperplasia.
Flecainide - used for serious symptomatic ventricular arrhythmias or junctional re-entry tachycardias or paroxysmal AF. BUT can RARELY cause serious arrhythmias.
Propafenone - Used for Prophylaxis and treatment of arrhythmias and some SV arrhythmias. Can cause weak B-Blocking activity (CAUTION in obstructive airway disease, AVOID if severe).
Ventricular arrhythmias
(Lidocaine)
IV Lidocaine - for ventricular arrhythmias in haemodynamically stable patients and ventricular fibrillation and pulseless ventricular tachycardia in cardiac arrest refractory to defibrillation BUT not 1st choice.
Mexiletine - Life threatening ventricular arrhythmias.
