Arrhythmia Flashcards
Cardiac causes [6]
Ischemic heart disease
Structural changes
Cardiomyopathy
Pericarditis
Myocarditis
Aberrant conduction pathways (WPW syndrome)
Non cardiac causes [5]
Electrolyte imbalance Metabolic - hypoxia/acidosis/thyroid Caffeine, Smoking, Alcohol Pneumonia, phaeochromocytoma Drugs
Drugs that cause arrhythmia [5]
Levodopa Digoxin Beta 2 agonists (asthma drugs) Tricyclic antidepressants Doxorubicin
Presentation [7]
Palpitations Dyspnoea Chest pain Fatigue syncope/presyncope Pulmonary oedema Can be asymptomatic
Initial mx of arrhythmias [6]
ABCDE
Oxygen
Gain IV access
12 lead ECG
Correct metabolic abnormalities
Classify patient as stable or unstable
Stable vs unstable arrhythmia patient [6]
Signs of shock: Hypotension, Tachycardia Pallor, Peripheral cyanosis Cold, clammy hands and feet, Sweating Confusion Syncope Myocardial ischemia, Heart failure, Pulmonary oedema (fine crackles), Raised JVP
What is a sinus arrhythmia? [3]
Management?
Normal conduction at faster frequency
HR increases inspiration
Decreases expiration
No Rx needed
Causes of sinus arrhythmia [7]
Infection, fever
dehydration, hypovolaemia
pain / exercise
drugs, salbutamol
adrenaline
PE
hypothyroid
MI
What type of tachycardias are there [2]
Supraventricular - narrow complex
Ventricular - broad complex
Sinus
What is sinus arrest? [2]
Management [2]
SA node fails to generate an impulse
No pulse
Mx:
CPR pathway
Adrenaline
What is a narrow complex tachycardia and why? [4]
> 100BPM
QRS <120
Short P wave
Ventricles depolarised via normal pathway so QRS normal
Types of narrow complex tachycardias [5]
Sinus tachycardia
Atrial tachycardia - due to abnormal signal in atria other than SA node
Atrial flutter
AV re-entry tachycardia
(WPW)
AV nodal re-entrant tachycardia = most common cause of paroxysmal (re-entrant point through AV node)
What is WPW [2]
ECG [2]
AV re-entrant tachycardia - another pathway through atrial and ventricle not AV node
As the accessory pathway does not slow conduction AF can degenerate rapidly to VF
ECG:
- short PR interval
- wide QRS complexes with a slurred upstroke - ‘delta wave’
What causes irregular narrow complex [3]
Atrial fibrillation
Ectopic
Atrial flutter with variable block
What is atrial tachycardia [2]
What can cause an atrial tachycardia?
Group of atrial cells act as pacemaker
P wave different (more pointy) but everything else same
Cause: digoxin toxicity
How does WPW present [8]
SVT - associated AF / flutter or tachy Palpitations SOB Dizzy Chest pain Sweating Anxious Syncope
What is associated with WPW [4]
How do you treat WPW [2]
HOCM
Mitral valve prolapse
Ebstein
Thyrotoxicosis
Radiofrequency Ablation = definite
Amiadarone / fliecanide if AF (rhythm control)
What is type A WPW
Type B WPW
Type A: L pathway so RAD
Dominant R in V1
Type B: R pathway so LAD
No dominant R wave
What are adverse signs of supra ventricular tachy which you should assess for [5]
Chest pain (MI) Syncope Shock Heart failure Can be peri-arrest and go into VF or systole = emergency
In a patient with SVT…
What do you do if rate is regular [3]
If rate is irregular what is the most likely problem?
Continuous ECG
Valsalva manœuvre
Carotid sinus massage
If irregular, most likely the diagnosis is AF
What do you do when someone presents in SVT [6]
ABCDE O2 if low sats IV access Bloods Monitor ECG (narrrow/broad QRS) and BP Identify and treat reversible cause e.g. electrolyte
What should you do if someone has adverse signs? [8]
Treat as VT rater than SVT Put out crash call DC shock up to 3 times under sedation Seek expert help Correct electrolyte imbalance IV Amiadarone after shock, 300mg over 10-20 mins Repeat shock IV amiadarone infusion over 24 hours
What do you do for sinus tachy
Not an arrhythmia so no cardio version
Rx = treat cause
If no cause can be found = BB
What do you do if suspect AVRT / AVNRT?
2nd line: [5]
Contraindications of 2nd line [5] (what would you give instead to these patients)
What to do if 2nd line management fails [1]
Block AV node by performing Valsalva or carotid sinus massage (will stop tachy)
IV adenosine (chemical cardioversion) 6mg then 12mg then 12mg if no response
- Need continuous ECG monitoring
- Given as rapid bolus into large proximal vein
- Can cause Brady which is scary but transient - warn patient
- Do ECG during infusion
- CI in asthma / COPD / HF / heart block / severe hypo so give verapamil
- May need to direct cardiovert if doesn’t work
What is the Valsalva manoeuvre [5]
Forced expiration against closed glottis Increases intrathoracic pressure Reduced venous return due to increased atrial pressure Reduced preload Reduced CO
If sinus rhythm after Valsalva is restored what does this suggest?
AVRT
Consider anti-arrhythmia prophylaxis if recurs
What do you suspect if sinus rhythm not achieved with adenosine and what would you do in this case? [2]
Atrial flutter
AF if irregular
SEEK expert help and rate control with BB
Atrial flutter [4]
- characterised by a succession of rapid atrial depolarisation waves.
- ECG: sawtooth appearance
- as the underlying atrial rate is often around 300/min
- the ventricular or heart rate is dependent on the degree of AV block.
For example if there is 2:1 block the ventricular rate will be 150/min
Atrial flutter [2]
- cardioversion
- radiofrequency ablation of the tricuspid valve isthmus is curative for most patients
Atrial fibrillation pathophysiology [3]
Types [3]
- SA node isn’t firing properly = disorganised signal
- Other sites as well as SA node initiate conduction
- CO drops as ventricles not primed reliably leading to HF / increased risk of stroke
Paroxysmal - <7 days and self terminate
Persistent
Permanent - resistant to Rx
What are cardiac causes of AF: valvular [1] and non-valvular [9]
Valvular = MS / prosthetic heart valve issue
Non-valvular
* Ischaemia = most common UK
* Rheumatic = common world wide
* HF
* Hypertension
* IHD
* Cardiomyopathy
* Myocarditis
* Endocarditis
* Surgery
What are non-cardiac causes [8]
Sepsis PE, Bleed Pneumonia Hyperthyroid Alcohol, Caffiene, Drugs Post op Metabolic: Low K / Mg / Ca, Acidosis
Most common causes of AF (SMITH)
SMITH
Sepsis
Mitral valve - S or R
IHD
Thyrotoxicosis
Hypertension
Aetiology Bradycardia
split into extrinsic or intrinsic
Intrinsic
* Idiopathic degeneration - ageing
* Infiltrative disease - sarcoidosis, amyloidosis
* Infectious - endocarditis
* Autoimmune - SLE, RA, scleroderma
* Trauma - valve replacement
Extrinsic
* Increased vagal tone from Vasovagal syncope ir exercise training
* Electrolyte imbalancce - hypo/hyperkaelemia, hyponatremia
* Metabolic - hypothyroidism, hypothermia
* Neurological - raised ICP
Heart block
Bundle branch block
- RBBB
- LBBB
- LAFB
- LPFB
- Bifascicular block
- Trifascicular block
RBBB vs LBBB
One of the most common ways to remember the difference between LBBB and RBBB is WiLLiaM MaRRoW
in LBBB there is a ‘W’ in V1 and a ‘M’ in V6 in RBBB there is a ‘M’ in V1 and a ‘W’ in V6
New LBBB is always pathological. Causes of new LBBB [6]
myocardial infarction
hypertension
aortic stenosis
cardiomyopathy
rare: idiopathic fibrosis, digoxin toxicity, hyperkalaemia
What is the Sgarbossa criteria?
In patients with left bundle branch block (LBBB) or ventricular paced rhythm, infarct diagnosis based on the ECG can be difficult.
1. Concordant ST elevation ≥ 1 mm in ≥ 1 lead
2. Concordant ST depression ≥ 1 mm in ≥ 1 lead of V1-V3
3. Proportionally excessive discordant STE in ≥ 1 lead anywhere with ≥ 1 mm STE, as defined by ≥ 25% of the depth of the preceding S-wave
ECG criteria for LAFB, LPFB
◆ Left anterior hemiblock: left axis deviation, rS pattern inferior leads.
◆ Left posterior hemiblock: right axis deviation, tall R wave in inferior leads.
What is a bifascicular block?
What is a trifascicular block?
- Bifascicular block:
RBBB + left anterior or left posterior hemiblock.
LBBB (due to involvement of both fascicles). - Trifascicular block:
first degree heart block and RBBB
AND
either left anterior or left posterior hemiblock.
Management of peri-arrest bradycardia
◆ IV atropine ± isoprenaline if symptomatic.
◆ Treat reversible causes (e.g. metabolic abnormality or stop offending drug).
◆ Consider pacemaker insertion.
Indications for pacing [7]
- Sinus node disease
- Acquired AV Block
- Congenital AV block
- Neurocardiogenic syncope
- Overdrive pacing for atrial tachyarrhythmias
- Left ventricular outflow tract obstruction in HOCM
- Acquired long QT syndrome e.g., amiodarone overdose
What is considered persistent or permanent atrial fibrillation
persistent (>7 days, but ‘cardiovertable’) or permanent (>7 days + NSR not
possible).
Annual stroke risk
CHA2DS2VASC score
Remember that if a CHA2DS2-VASc score suggests no need for anticoagulation it is important to ensure a transthoracic echocardiogram has been done to exclude valvular heart disease, which in combination with AF is an absolute indication for anticoagulation.
Apixaban 5mg BD lifelong
May be used in conjunction with the CHA₂DS₂-Vasc Score to risk stratify patients for clinically significant bleeding to help guide decisions on anticoagulation in patients with atrial fibrillation.
ORBIT score
- Age >74 +1
- Bleeding history - any history of GI bleed, intracranial bleeding/ haemorrhagic stroke +2
- GFR<60 +1
- Treatment with antiplatelet agents
Management of atrial fibrillation, what factors do you have to consider?
- Age: elderly > rate control. Young symptomatic patients, consider rhythm control
- If young patient and adverse featurse > DC cardioversion
- Onset of symptoms >48h: delay cardioversion until they have been maintained on therapeutic anticoagulation for a minimum of 3 weeks (if considered for long term rhythm control). If elderly then just rate control
