Cardiology Flashcards
What do class 1 antiarrhythmics do?
Block Na channels
eg. Flecainide
Prolongs depolarisation - how long the ventricle takes to contract (Prolongs QRS)
What do class 2 antiarrythmic agents do?
Beta blockers
Slow AV node conduction
What do class 2 antiarrythmic agents do?
Potassium channel blockers
Eg. amiodarone, sotalol
Prolong QT
What do class 4 antiarrythmic agents do?
Calcium channel blockers
Prolong AV node conduction
eg. Verapamil
Side Effects of Flecainide?
Tingling and constipation
Proarrhythmic
QRS widening
Milk can decrease GI absorption
Most serious side effect in Sotalol?
QTc prolongation
Bradycardia and lethargy
Which anti arrhythmic is contraindicated in infants <1year?
Verapamil
Also contraindicated in WPW
Which medications are contraindicated in WPW?
Verapamil
Digoxin
What is multifocal atrial tachycardia?
When there are 3 or more different non sinus P wave morphologies?
Tx with Antiarrhythmics class 1 or 3
What is the management of atrial flutter?
Synchronised DC cardioversion
If that doesn’t work Amiodarone or Sotalol
If giving flecainide MUST be given with beta blocker.
What does orthodromic mean?
When the electrical activity goes down through the AV node and then back up through the accessory pathway (narrow QRS complex)
What does antidromic mean?
When the electrical activity goes down through the accessory pathway and then back up through the AV node (broad QRS complex - looks like VT)
What structural abnormality is WPW associated with?
Ebsteins Anomaly
WPW
Antegrade conduction down an accessory pathway.
What is permanent junctional reciprocating tachycardia?
- Variant of AVRT with orthodromic conduction
Hallmarks - Incessant tachycardia (usually slower rate 200bpm)
- Long RP interval
- Inverted P waves inferior leads
Accessory pathway with slow retrograde conduction
(decremental)
You see deep inverted P waves in the inferior leads
What is AV nodal re-entrant tachycardia?
- Re-entrant circuit within the normal AV node
- Typical or atypical
- Slow pathway and fast pathways (dual AV node physiology)
When would you consider giving Verapamil in a child <12months?
Fascicular ventricular tachycardia
Usually more narrow QRS complex with RBBB pattern and superior axis
What is Long QT syndrome?
Delayed myocardial repolarisation.
What is the channel involved in Long QT 1 and 2?
Potassium channel
One - KCNQ1 - Slow potassium channel low function
Two - KCNH2 - Potassium channel low functioning means it takes longer for potassium to repolarise the cell
What is the channel involved in Long QT 3?
Three - SCN5A - Gain of function in sodium channel meaning it stays open causing depolarisation for longer
What does the ECG look like in long QT type one?
Broad T wave
What does the ECG look like in long QT type two?
Flattened T wave
What does the ECG look like in long QT type three?
Peaked T wave that is delayed
What is the treatment for long QT syndrome?
Lifestyle modification - reducing adrenaline surges
B blocker - Nadolol (most effective)
Avoid medications that prolong the QT interval eg. ondansetron
What gene is involved in Brugada syndrome?
SCN5A - loss of function in the sodium channel
Diagnosis of Brugada syndrome?
Diagnosis based on the presence of a spontaneous or drug-induced coved-type ST
segment elevation in V1 or V2 (Type 1 morphology)
* ST elevation ≥2mm
* Gradually descending ST segment
* Terminates with negative T wave
What is the criteria for rheumatic fever?
Two major or one major and two minor manifestations
plus
Evidence of a preceding Group A streptococcus infection
Major:
Carditis (including subclinical evidence of rheumatic valve disease on echocardiogram)
Polyarthritis or aseptic mono-arthritis or polyarthralgia
Sydenham chorea
Erythema marginatum
Subcutaneous nodules
Minor:Fever
ESR ≥30 mm/hr or CPR ≥30 mg/L
Prolonged P-R interval on ECG
Diagnostic criteria for Kawasaki disease?
Fever for 5+ days
Plus 4 of 5 of:
No exudative Conjunctival injection (>90%) - perilimbic sparing
Mucositis - cracked lips, strawberry tongue
Extermity changes (70-98%) - swelling, erythematous, desquamation, beaus lines across finger nails
Polymorphous rash - usually maculopapular
Cervical lymphadenopathy (25-50%) - >1.5cm
How long after IVIG do you need to delay live immunisations for?
11 months
Does IVIG cause raised ESR or CRP?
ESR therefore use CRP to monitor inflammatory response
What type of medication is sildenofil?
Phosphodiesterase type 5 inhibitor which increased cGMP and nitric oxide causing vasodilation
Most common cardiac lesions in 22q11 deletion?
Tetralogy of fallout (35%)
Interrupted aortic arch (20%)
Truncus arteriosus (10%)
What cardiac complication are children with Noonan Syndrome at risk of?
Hypertrophic cardiomyopathy (20%)
Up to 50% have pulmonary stenosis
What do you see on ECG with hypocalcaemia?
Prolonged QTc
What is pulmonary hypertension?
PAP >20mmHg
How do you calculate cardiac output?
Qp (Cardiac output)= VO2/ (Sats PV - Sats PA) x Hb x 1.36
Qs = VO2 /(Sats Ao - Mixed venous Sats) x Hb x 1.36
Qp:Qs
Aosats - MV sats/PV sats - PA sats
What are the ECG findings you would see for a patient with congenitally corrected TGA?
Left axis deviation
Deep Q waves V1, II and III, with no Q waves in the left precordial leads V5 and V6.
(This indicates abnormal depolarisation of the inter ventricular septum from right to left)
