Arrhythmias and ECG Changes Flashcards
Describe the tachycardia algorithm
ABCDE assessment
If adverse features (shock, syncope, HF, MI) emergency synchronised direct current cardioversion
If haemodynamically stable, management defers on if the tachycardis is narrow (QRS>120) or broad complex (QRS<120)
For regular narrow, vagal manoeuvres is first line, followed by IV 6mg adenosine, followed by further 12mg
For irregular narrow, if <48 hours rhythm control and rate control if >48 hours
What is atrial fibrillation?
Disorganised atrial activity resulting in irregularly-irregular AV node stimulation and therefore disregular ventricular response
What are the types of AF?
First detected episode
Paroxysmal
- <7 days, typically <24 hours
- Episodes terminate spontaneously
Persistent
- >7 days
- Amenable to cardioversion
Permanent
- >7 days
- Not amenable to cardioversion
What are the causes of atrial fibrillation?
HTN
Lung disease
- PE, Pneumonia
Ischaemic heart disease
Heart failure
Rheumatic heart disease
Hypoxia
Alcohol/Caffeine
Hypercapnia
Mitral stenosis
Atrial septal defect
Thyrotoxicosis
Sepsis
Metabolic abnormalities
Describe the presentation of atrial fibrillation
Palpitations
Fatigue
Chest pain
Dizziness
Dyspnoea
Irregularly Irregular pulse
Apical to radial pulse deficit
What ECG signs are seen in atrial fibrillation?
Absent P waves
Irregular QRS complex, but normal shape, so therefore an irregular rate
What is involved in rate control of AF?
ABCD
B Blocker, first line
- Bisoprolol
- Contraindicated in asthma, hypotension
CCB, first line
- Verapamil
- Contraindicated in HF
Digoxin, second line
- Used in hypotension or co-existent HF
- Contraindicated in younger patients because it increases cardiac mortality
When should rate control be offered in AF?
Offer rate control as the first-line strategy to people with AF, except in people
- Whose AF has a reversible cause
- Who have heart failure thought to be primarily caused by AF
- With new-onset AF
- For whom a rhythm control strategy would be more suitable based on clinical judgement
What is involved in rhythm control of AF?
AF = Amiodarone and Flecainide
Amiodarone
- Older sedentary patients
Flecainide
- Young patients with structurally normal hearts
Direct current cardioversion
- If acute/<48 hours can be cardioverted with sedation
- If >48 hours patient has to be anticoagulated for 3 weeks before cardioversion
What is the mechanism of amiodarone?
Blocking potassium channels which inhibits repolarisation and hence prolongs the action potential
Give adverse effects of amiodarone
Thyroid dysfunction, both hypothyroidism and hyper-thyroidism
Corneal deposits
Pulmonary fibrosis/pneumonitis
Liver fibrosis/hepatitis
Peripheral neuropathy, myopathy
Photosensitivity
‘Slate-grey’ appearance
Thrombophlebitis and injection site reactions
Bradycardia
Lengths QT interval
What score assesses the risk of stroke in AF?
CHAD VASC 2
What factors does the CHADS VAS score take into consideration?
C point for congestive cardiac failure
H 1 point for hypertension
A2 2 points if the patient is aged 75 or over.
D 1 point if the patient has diabetes mellitus.
S2 2 points if the patient has previously had a stroke or transient ischaemic attack (TIA)
V 1 point if the patient has known vascular disease
A 1 point if the patient is aged 65-74
S 1 point if the patient is female
What are the groups of anticoagulants?
Vitamin K Antagonists
DOAC (direct oral anticoagulant)
- Direct thrombin inhibitors
- Direct factor Xa inhibitors
Low molecular weight heparins
When are anti-cogulants used in AF?
Males who score 1 or more or females who score 2 or more should be anticoagulated
What anticoagulants are used in AF?
Warfarin
- Requires cover with LMWH for 5 days
- Only drug lisenced for valvular AF
DOACS
- Patients are not covered if they miss doses
- Use if require anticoagulation but unable to carry out regular monitoring
LMWH
- Rare option in those who cannot tolerate oral
When should anticoagulation be started for patients with AF after a stroke?
2 weeks
What is the mode of action of warfarin?
Inhibits thromboxane
Give side effect of warfarin
Haemorrhage
Teratogenic, although can be used in breastfeeding mothers
Skin necrosis
Purple toes
What has to be monitored with warfarin?
INR (International normalised ration)
The ratio of the prothrombin time for the patient over the normal prothrombin time
What is the INR target for AF?
2.5
What drugs can increase INR (inhibitors of P450 system)?
STICKFACE.COM
Sodium valproate
Ticlodipine
Isoniazid
Cimetidine
Ketoconazole
Fluconazole
Alcohol, Amiodarone
Ciprofloxacin
Erythomycin
Sulfonamides
Chlorampenicol
Omeprazole
Metronidazole
What drugs can decrease INR (inducers of the P450 system?)
BS CRAP GPS
Barbituates
St John’s wort
Carbamezapine
Rifampicin
Alcohol (chronic)
Phenytoin
Griseofluvin
Phenobarbital
Sulphonylureas
How do you manage INR of 5.0-8.0 with no bleeding?
Withhold 1 or 2 doses of warfarin
Reduce subsequent maintenance dose
How do you manage INR of 5.0-8.0 with minor bleeding?
Stop warfarin
Give intravenous vitamin K 1-3mg
Restart when INR <5.0
How do you manage INR >8.0 with no bleeding?
Stop warfarin
Give vitamin K 1-5mg by mouth, using the intravenous preparation orally
Repeat dose of vitamin K if INR still too high after 24 hours
Restart when INR < 5.0
How do you manage INR >8.0 with minor bleeding?
Stop warfarin
Give intravenous vitamin K 1-3mg
Repeat dose of vitamin K if INR still too high after 24 hours
Restart warfarin when INR < 5.0
How do you manage major bleeding with high INR?
Stop warfarin
Give intravenous vitamin K 5mg
Prothrombin complex concentrate,if not available then FFP
How do you manage INR <2?
Increase dose of warfarin and start LMWH
How long before surgery should warfarin be stopped?
In general, warfarin is usually stopped 5 days before planned surgery, and once the person’s INR is less than 1.5 surgery can go ahead
What is the preferred NOAC used in AF for renal impaired patients?
Apixaban