Cardiology Flashcards
What is the physiology behind VF?
Rapid, uncoordinated contraction of ventricles causing QRS to become irregular.
How is VF managed?
Desynchronised cardioversion and CPR in between shocks.
What is pharmacological intervention can be used after 3 unsuccessful shocks to manage VF (refractory VF)?
IV adrenaline (1mg 1:10000) and amiodarone (300 mg).
What is the physiology behind VT? What is seen on ECG?
Rapid contraction of ventricles means body isn’t perfused correctly. Causes a monomorphic broad complex tachycardia.
How do we manage a haemodynamically stable patient in VT?
300 mg amiodarone over 20 minutes then 900 mg over 24 hours.
How do we manage a haemodynamically unstable patient in VT?
chest compressions at a rate of 100-120/minute (30:2 ratio) and delivery of DC cardioversion.
What is seen on ECG for Torsades?
Polymorphic broad complex tachycardia.
How is Torsade’s managed?
2g IV magnesium sulphate
What ECG abnormalities are associated with hypomagnesaemia?
Prolonged QT interval which can convert into Torsade’s.
How do we manage a sinus bradycardia with haemodynamic compromise?
IV atropine 500 micrograms every 3-5 minutes up to 3mg total.
If this fails, convert to transcutaneous pacing.
What medication can be used to manage bradycardia once 3mg of atropine has been used but transcutaneous pacing is not available?
IV isoprenaline
What is the biggest SE of atropine 6-12 hours after administration?
Agitation.
What are the ECG signs of AF?
Irregularly irregular rhythm and lack of p waves.
If someone presents in AF with haemodynamic compromise how is it managed?
Synchronised cardioversion.
Can you cardiovert someone who presents, haemodynamically stable, in AF whose symptoms started 3 days ago?
No - 48 hours is the cut off for cardioversion due to risk of clot. These patients need to be anticoagulated before they can be cardioverted.
What medications can be used for rate control of AF?
1st line is beta blockers (diltiazem if CI),
Can also use digoxin if these are unsuccessful (250mg loading dose followed by 250 mg 6 hours later and then oral OD doses).
What medications can be used to rhythm control someone in AF?
Amiodarone (dangerous long-term SEs),
Class 1c antiarrhythmics - flecainide/propafenone - which are used as ‘pill in pocket’ to take when patients become symptomatic (can only be used in someone with a structurally normal heart).
If someone in AF has a regular HR what is the other pathology occurring?
3rd degree (complete) heart block. Ventricle isn’t receiving atrial signals so irregular rhythm isn’t transmitted so there is a normally ventricular rate.
What is Brugada Syndrome? What are the signs on ECG?
tachyarrhythmias caused by Na channel pathology, often familial.
ECG: concavity and elevation of ST segment in V1-3 and T waves inversion.
Which of the following is associated with life-threatening arrhythmias in someone with Brugada syndrome?
a) Hypotension
b) Hyponatraemia
c) Fevers
C- fevers, accentuating the ECG signs and causing ventricular arrhythmias.
SVT can be categorised into 3 different types, what are these?
- AVNRT (atria-ventricular node re-entry tachycardia)
- Atrial flutter
- Accessory pathways (WPW)
What is seen on ECG for AVNRT? How is it managed?
Narrow complex tachycardia with no P waves.
Management:
1) vagal manoeuvres
2) Adenosine (6, 12, 18)
3) If unsuccessful try synchronised cardioversion (or if haemodynamically compromised)
Why can we not prescribe adenosine for atrial flutter? How do we manage it?
DOES NOT respond to adenosine as it is independent to the ventricle and adenosine blocks AV node (so if you gave it the atria would continue to fire).
Managed with beta blockers and if this is unsuccessful may need synchronised cardioversion.
What is seen on ECG for atrial flutter? What is the rate?
Sawtooth baseline.
Atrial rate around 300bpm, ventricular rate around 150bpm (every other beat transmitted).