Arrhythmias Flashcards
What are the causes of arythmmia?
VT – Electrolyte abnormalities, Ischaemic heart disease, cocaine, cardiomyopathy, MI, Heart failure
SVT – Ischaemic heart disease, thyrotoxicosis, caffeine, alcohol, smoking
AF - Ischaemic heart disease, thyrotoxicosis, caffeine, alcohol, smoking, mitral valve disease, hypertension, lung disease, post op, pericardial disease, cardiomyopathy, infection
What are the main types of Arrhythmia?
Bradycardia - Heart block is caused by AVN problems whereas sinus bradycardia or sick sinus syndrome are caused by the atrial problems
Sinus Bradycardia - Normal Sinus Rhythm but heart rate <100bpm.
1st degree Heart Block - prolonged PR interval, no treatment needed
2nd degree Heart Block type 1 - Prolonged PR until QRS - No treatment
2nd degree Heart Block type 2 - Different pattern to P and R waves, e.g. 2 P waves to each QRS
3rd Degree pacemaker - Random P an QRS rates. Each have their own rate. - Required pacemaker
Narrow Complex Tachycardia: QRS<3ss and >100bpm. These are caused by Supraventricular Problems
Sinus tachycardia
Atrial flutter
Atrial Fibrillation
AVRT (Circuit loops within accessory pathways during conduction)
AVNRT (Circuit loops within the AV node causing rapid pulsation)
Wolfe Parkinson White
Broad Complex Tachycardia: Q>3ss and >100bpm. These are caused by Ventricular Problems
Ventricular Tachycardia
Ventricular Fibrillation
Torsade’s De Pointes
Any narrow complex tachycardia + bundle branch block
What will you find/ask about in a history of Arrhythmia?
Symptoms: Palpitations Chest pain Syncope/Dizziness/Black outs Hypotension Heart Failure - Pulmonary Oedema Sudden Cardiac Death Fatigue/Nausea Can be Asymptomatic
Risk Factors: Family history of early cardiac death Cocaine/Caffeine/Alcohol use Previous MI/IHD Any underlying hyperthyroidism, ask about symptoms
Specific questions to ask in a history taking:
Frequency of symptoms
Are they constant or paroxysmal?
Aggravating factors - Anything that brings them on (specifically caffeine and stimulants)
Are they regular or irregular (get them to tap it out)?
Are the symptoms present now?
Onset of symptoms with exercise is a red flag
Ask about stress/anxiety as this can be a cause
Do they have a specific start/end - Cardiac palpitations have set time they start and stop, but others e.g. anxiety do not have a set time they start/stop and come on gradually?
Differentials
Panic Attacks - Palpitations follow feelings of panic, can be hard to differentiate. May feel numbness tingling in the mouth and fingers
What will you look for/find in an examination of a patient with a suspected Arrhythmia?
End of the bed:
Look for any oedema indicating heart failure
Hand:
Feel pulse – To assess rate, rhythm, character. Irregularly irregular think AF, regularly irregular think ventricular ectopic
Pale palmar creases may indicate precipitating anaemia
Fine tremor – Indicates thyrotoxicosis or anxiety
Neck:
Raised JVP in underlying RHF
Face:
Pale conjunctiva may indicate precipitating anaemia
Chest:
Listen for any murmurs or signs of valve disease/IHD
Pulmonary crackles in underlying LHF
What are the investigations you will order in suspected arrhythmia?
Bedside:
ECG - Looking for an arrhythmia or underlying heart condition e.g. Previous MI, Heart Failure
Glucose - Rule out Hypoglycaemia and assess cardiovascular risk
Bloods:
FBC – Looking for Anaemia or infection (can precipitate AF)
U&E - Electrolyte disturbances cause arrhythmias
Ca2+ and Mg2+ - Electrolyte disturbances cause arrhythmias
TFT’s - Thyrotoxicosis can cause arrhythmias
LFT’s – Find out why
Imaging:
CXR - Looking for Heart Failure
Echo - Look at structural changes e.g. mitral stenosis or cardiomyopathy
Special Tests:
24-hour ECG monitoring - to look for paroxysmal AF and other intermittent arrhythmias
Exercise stress ECG - To look for any coronary artery disease
Cardiac catheter - To look for any coronary artery disease
What is the treatment of an arrhythmia ?
Resuscitation:
A-E approach
Get IV Access/Give O2 to maintain sats of 94+ /Attach 12 lead ECG
Assessment with AMPLE history and brief examination
Get help - Cardiovascular registrar on call/Consider calling 2222
Frequent Observations - Constant
If pulseless begin the arrest protocol
Regular Narrow Tachyarrhythmias Vagal Manoeuvres Adenosine – 6mg, 12mg, 12mg Get help Antiarrhythmics – Amiodarone, Flecainide, B-Blocker If unstable DC cardioversion
Irregular Narrow Tachyarrhythmias
Control rate with IV beta blocker or IV digoxin
If <48 hours since onset cardiovert with Dc or drugs
If >48 hours treat as chronic AF
If Atrial flutter – Definitive treatment with radiofrequency catheter ablation instead of cardioversion and stop blood thinners 6 weeks after
Broad Complex Tachyarrhythmias
Amiodarone/lidocaine – Pharmacological cardioversion
Manage Mg2+/K+ levels as required – Give magnesium sulphate 2 g IV over 10 min in Torsade’s de pointes
If unstable DC cardioversion
Bradycardias:
HR <40 or <60 and symptomatic - IV Atropine (every 3 mins) and adrenaline
Long term treatment with Dual chamber Pacemaker
Identify and treat any reversible causes e.g. electrolytes
Lifestyle:
Give advice about driving where appropriate
Reduce cardiovascular risk – Stop smoking, improve diet, increase exercise
Avoid precipitating factors e.g. alcohol/caffeine
