Dunedin-Cardiology Flashcards
How does a vagal manoeuvre help with SVT?
Block the AV node
What is the MOA of adenosine?
ultimately causes AV node block
Acts on A1 receptors on heart- SA and AV nodes
A2 coronary vasodilation
What is a relative contraindication for adenosine?
asthma
What are short RP tachycardia vs long RP tachycardia?
short RP tachycardia: AVRT, AVNRT
Long RP tachycardia: sinus tachycardia, focal atrial tachycardia
What type of circuit is atrial flutter?
macro re-entrant circuit
typically in right atrium around tricuspid annulus
90% counter-clockwise
10% clockwise
Why should you avoid flecainide in atrial flutter?
slows conduction velocity within flutter circuit, relatively minimal effect on AV nodal conduction
if using it, should use with AV nodal blocking agent such as b-blocker to prevent 1:1 conduction
Describe the CHA2DS2-VA score
note, new score has taken out the sex guidelines
List DOACS and their target
Dabigatran- thrombin inhibitor (reversible idarucizumab), renal cleared, p-glycoprotein substrate
Rivaroxoban- Factor Xa inhibitor (reversible andexanet alfa, prothrombin complex partial reversal), primarily hepatic clearance, some renal, metabolised CYP3A4, p-glycoprotein substrate
Apixaban- Factor Xa inhibitor (reversible adexanet alpha), primarily hepatic/biliary clearance, metabolised by CYP3A4, p-glycoprotein substrate
DOAC metabolism interactions
What did the LEGACY Trial suggest?
BMI >27 should loose weight (10% of body weight) if have AF
Also managing sleep apnoea
What are some complications for ablation of AF?
tamponade > CVA/TIA > PV stenosis > phrenic palsy >atrial oesophageal fistula
What is a bifascicular block?
RBBB + block of anterior (LAD) or posterior (RAD) fascicle of left bundle; or LBBB
What is a trifascicular block?
bifascicular block + PR prolongation (ie. AV node)
What are indications for CRT?
Heart failure
ideally SR
LBBB QRS >150ms
LVEF <35%
What is left bundle branch area (deep septal) pacing?
pacing in the left bundle region
thought to be superior
How to treat fascicular VT? “Normal heart” VT Of left ventricle
verapamil, ablation
ECG- tachy, ‘narrow’ RBBB mimicry and LAD
What is the most common cause of sudden cardiac death in athletes?
hypertrophic cardiomyopathy
What are indications for ICD?
Resuscitated VT/VF cardiac arrest not due to reversible cause
Ventricular tachycardia - sustained or symptomatic , not ablatable, associated with:
- severe compromise or
- failed anti-arrhythmias, or
- LVEF <40%
Hereditary cardiac conditions at high risk of sudden cardiac death: hypertrophic cardiomyopathy, long QT syndrome, arrhythmogenic cardiomyopathy, brigade syndrome
What gene gives highest risk in dilated cardiomyopathy?
LMNA gene mutation
Describe congenital long QT syndromes
Describe arrhythmias and their type of circuit
Focal atrial tachycardia –> ectopic atrial focus
Atrial flutter –> intra-atrial macro re-entry circuit
Atrial fibrillation –> multiple small atrial re-entry circuits pulmonary veins
VT –> macro re-entry around myocardial infarct
AVNRT –> re-entrant circuit within or around AV node
WPW –> re-entrant circuit within accessory pathway
What is ejection fraction?
stroke volume/ end-diastolic volume
Stroke volume: end diastolic- end systolic
On echocardiography what is a normal global strain?
More negative is better
abnormal if > -16%
usual < -18%
young people < -20%
What is the indication for cardiac MRI?
infiltrative disease
fairy disease
inflammatory disease (myocarditis)
LV non-compaction
amyloid
sarcoidosis
iron overload/haemochromatosis