Cardiology Flashcards
Which valvular disorder is most strongly associated with atrial fibrillation?
Mitral stenosis
2/3 of patients develop AF
What are the two treatment approaches to AF?
Rate and rhythm control
When and why is rhythm control used to treat AF?
Young patients
Restoration of sinus rhythm prevents atrial remodelling
What are the 1st, 2nd and 3rd line rate control drugs for AF?
- Beta blockers, non-dihydropyridine calcium channel blockers
- Digoxin
- Amiodarone
When is percutaneous coronary intervention (PCI) vs fibrinolytic therapy used for STEMI?
PCI within 90 minutes of symptom onset
How are unstable angina and NSTEMI differentiated?
No troponin elevation in unstable angina
What causes unstable angina?
Rupture of an unstable plaque → thrombus → partial occlusion of a coronary vessel
The interaction between thrombus formation and endogenous thrombolysis prevents complete vessel occlusion
How does blood vessel occlusion differ in a NSTEMI vs a STEMI?
NSTEMI - complete occlusion of small branches
STEMI - complete occlusion of a main coronary artery
What are 3 late complications of an MI?
- Rupture (LV wall, ventricular septal, papillary muscle)
- Atrial and ventricular aneurysms
- Arterial thromboembolism (due to venous stasis → stroke risk)
- Reinfarction
- Pericarditis
- Congestive heart failure
What are the complications of atrial/ventricular aneurysms following MI?
Arrhythmias (VF)
Rupture → tamponade
Thrombus formation
MI affecting which artery is most associated with mitral regurgitation?
Posterior descending artery → rupture of posteromedial papillary muscle
What is Dressler syndrome?
Pericarditis 2-10 weeks following MI without an infective cause
Autoimmune aetiology
Name two GPIIb/IIIa receptor inhibitors
Eptifibatide
Tirofiban
When is aspirin given in patients with symptoms of ACS?
All patients with possible ACS and without contraindications
300mg orally, as soon as possible after presentations
How long following STEMI is reperfusion therapy (PCI or fibrinolytic therapy) no longer indicated?
12 hours
Which medications are given to all patients with confirmed ACS?
Aspirin 300mg orally
P2Y12 inhibitor (ticagrelor, prasugrel, clopidogrel)
Double anti-platelet therapy
Which ECG leads show an inferior view of the heart?
II, III, aVF (right coronary/marginal artery)
Which ECG leads show the lateral side of the heart?
I, aVL, V5, V6 (left circumflex artery)
Which ECG leads show an anteroseptal view of the heart?
V1, V2 (LAD)
What is a normal ejection fraction?
>55%
Which drug prevents remodelling of the heart following an AMI?
ACEi
When is a bubble study used?
Patent foramen ovale
Atrial septal defect
Which congenital heart disease has a pansystolic murmur?
VSD
Pansystolic murmur over the left lower sternal border
What is the HAS-BLED score?
Way of assessing 1 year risk of major bleeding in patients taking anticoagulants for atrial fibrillation
What is the CHA2DS2-VASc score?
Predictor of stroke risk in patients with atrial fibrillation
Used to determine whether anticoagulant/antiplatelet therapy is required
What are the 5 types of MI?
- Primary coronary event e.g. plaque erosion, rupture, fissuring or dissection
- Supply-demand mismatch
- Sudden unexpected cardiac death
- Associated with PCI or stent thrombosis
- Associated with cardiac surgery
Which beta blockers can be used for heart failure?
Bisoprolol
Carvedilol
Metoprolol XR
What are the potential side effects of amiodarone?
Amiodarone is a BITCH
B - bradycardia/blue man
I - interstitial lung disease
T - thyroid (hyper and hypo)
C - corneal microdeposits (visual haloes and photophobia)/cutaneous
H - hepatic/hypotension
What are the potential side effects of amiodarone?
Amiodarone is a BITCH
B - bradycardia/blue man
I - interstitial lung disease
T - thyroid (hyper and hypo)
C - corneal microdeposits (visual haloes and photophobia)/cutaneous
H - hepatic/hypotension
Which condition is Watson’s water hammer pulse/collapsing pulse associated with?
Aortic regurgitation
Which condition is pulsus alternans associated with?
Advanced LV failure, aortic valve disease
Regular pulse with alternating strong and weak beats
What anticoagulation is given to patients with atherosclerosis?
Aspirin
What anticoagulation is given to patients with acute coronary syndromes?
Aspirin PLUS clopidogrel/prasugrel/ticagrelor
What is the mechanism of hydralazine?
Arteriolar vasodilation
Antihypertensive
What are the two most significant side effects of hydralazine?
Tachycardia
Fluid retention
Give with a beta blocker and a diuretic
What is the most common electrolyte abnormality with ACEi used? Why does this occur?
Hyperkalaemia
ACEi → reduced angiotensin II → reduced aldosterone → reduced urinary potassium excretion
Why do ACEis reduce proteinura?
Angiotensin II usually increases GFR
+ afferent arteriole constriction
++ efferent constriction
ACEis reduce glomerular pressure
Why do patients with bilateral renal artery stenosis have a reduction in GFR with ACEi use?
When renal perfusion is significantly impaired, angiotensin II induces efferent constriction, helping maintain GFR
ACEis block this effect
Because angiotensin II is not used to maintain renal perfusion in healthy patients, they do not have impaired renal function with ACEis
What constitutes a long QT on ECG?
QTc > 440ms
11 small squares or T wave after half the R-R distance
Which drugs are most strongly associated with long QT syndrome?
Amiodarine
TCAs
Haloperidol
Antibiotics e.g. macrolides, fluoroquinolones
Ondansetron
How is blood pressure calculated?
Cardiac output x systemic vascular resistance
What is a measurement of pulmonary capillary wedge pressure used for?
Estimate left atrial pressure
Evaluating the severity of LV failure and quantifying the degree of mitral valve stenosis
Normally 8-10 mmHg
What is an anacrotic pulse (pulsus tardus) and when is it felt?
Low amplitude with slow rise and fall
Prolonged pulse duration
Seen in aortic stenosis
What is bumetanide?
Loop diuretic
What is the mechanism of rivaroxaban/apixaban? What does factor X do?
Factor Xa inhibitor
Factor X cleaves prothrombin, forming thrombin
Thrombin stimulates the conversion of fibrinogen to fibrin
Why is bridging therapy often used with warfarin?
Warfarin inhibits both factor II, VII, IX and X
AND anticoagulants protein C and S
Protein C and S are inhibited immediately but inhibition of clotting factors requires a couple of days
Patients initially have a hypercoagulable state
Why warfarin is not used for acute PE/DVT therapy
From which value is an INR derived?
Prothrombin time
(measure of the extrinsic and common pathways)
Which coagulation pathway does warfarin predominantly act on?
Extrinsic
(prothrombin time/INR measures the extrinsic + common pathways)
Warfarin has a greatest inhibitory effect on factor VII
What are the 4 Hs and 4 Ts of pulseless electrical activity (PEA)?
Hypoxia
Hypovolemia
Hypothermia
Hypo/hyperkalaemia
Thrombosis - coronary or pulmonary
Tamponade - cardiac
Toxins
Tension pneumothorax
What does the breadth of the QRS complex tell you about pulseless electical activity?
Broad: metabolic/ischaemia/LV failure
Narrow: mechanic (poor RV inflow or outflow obstruction)
What is the most common cause of sudden cardiac death in young people, especially elite athletes?
Hypertrophic cardiomyopathy (HOCM)
Systolic anterior motion of the mitral valve is characteristic of which disease?
HOCM
Obstruction → high flow rate during systole → mitral valve is sucked into the ventricle by negative pressure
Pain that is worse when lying flat and better when sitting up is characteristic of what?
Pericarditis
What murmur is heard in mitral stenosis?
Decreascendo diastolic murmur with an opening snap
How are murmurs graded?
What is afterload?
The force or load against which the heart has to contract to eject blood (aortic pressure and systemic vascular resistance)
What is preload?
Stretcing of the myocytes prior to contraction
How do ACE inhibitors help hypertension and heart failure?
- Vasodilation
- Decreased sympathetic activity
- Diuresis
- Inhibits remodelling
What are the actions of angiotensin II?
Vasoconstriction
Increased ADH
Thirst → fluid retention
Stimulates aldosterone
How is blood pressure calculated?
CO x SVR
What is Beck’s triad of cardiac tamponade?
- Hypotension
- Distended neck veins
- Muffled heart sounds
What complications can occur in the first 24 hours following an AMI?
Suddent cardiac death (VF/VT)
Arrhythmias
Acute left heart failure
Cardiogenic shock
What is the most common complication 1-3 days post AMI?
Early infarct-associated pericarditis
What complications occur 3-14 days post AMI?
Papillary muscle rupture
Ventricular septal rupture
Left ventricular free wall rupture
What complications occur 2 weeks to months post AMI?
Atrial and ventricular aneurysms
Dressler syndrome (autoimmune pericarditis)
Arrhythmias
Congestive heart failure
Reinfarction
For how long is dual antiplatelet therapy continued following an ACS?
12 months, then reassess risk of bleeding and risk of discontinuation
Following AMI, which patients should be given beta blockers?
Reduced LV systolic function (ejection fraction < 40%)
Following an ACS, which patients should be given an ACEi/ARB?
Heart failure
LV systolic dysfunction
Diabetes
Anterior MI
Co-existent hypertension
What are indications for revascularisation in patients with stable coronary artery disease?
Activity-limiting symptoms despite optimal medical therapy
Active patients who prefer PCI for improved quality of life compared to medical therapy
Which patients are at a very high risk of further thrombotic events following an ACS?
Haemodynamic instability
Heart failure
Cardiogenic shock
Mechanical complications of MI
Recurrent or ongoing ischaemia
Which patients are at a high risk of further thrombotic events following an ACS?
Rise and/or fall in troponin level consistent with MI
Dynamic ST-segment and/or T wave changes with or without symptoms
GRACE score > 140
Which patients are at an intermediate risk of further thrombotic events following an ACS?
Diabetes mellitus
Renal insufficiency (GFR < 60)
LVEF < 40%
Prior revascularisation
GRACE score 109-140
What PaO2 is an indication for oxygen therapy in ACS?
< 93%
Which P2Y12 inhibitors are preferred in dual antiplatelet therapy?
Ticagrelor and prasugrel
What are the indications for long-term ACEi use following an ACS?
Heart failure
LV systolic dysfunction
Diabetes
Anterior MI
Co-existent hypertension
What are the indications for long-term anticoagulation following an ACS?
Mechanical heart valves
LV thrombus
Chronic AF
CHA2DS2VASC score 2 or more
What are the indications for long-term beta blockers in patients with an ACS?
LVEF < 40%
For how long is dual antiplatelet therapy continued following an ACS?
12 months
Within what timeframe should invasive therapies (PCI/CABG) be commenced in patients with NSTEMI/UA?
Very high risk - 2 hours
High risk - 24 hours
Intermediate risk - 72 hours
What anticoagulation is given to patients with non-valvular AF based on their CHA2DS2-VASc score?
0 = no anticoagulation
1 = no anticoagulation OR treatment with oral anticoagulants
2+ = oral anticoagulation with either warfarin or NOACs
What anticoagulation is given to patients with valvular AF based on their CHA2DS2-VASc score?
Warfarin regardless of score
Valvular AF = patients with mitral stenosis, artificial heart valves and/or repaired mitral valves
What ECG changes are seen in hyperkalaemia?
Tall, peaked T waves
Lengthening of the QRS interval
P wave flattening
Lengthening of PR interval
Shortening of the QT interval
What causes a notched P wave?
Left atrial enlargement
“P mitrale” - enlargement is commonly due to mitral disease
P pulmonale - RA enlargement due to pulmonic disease
Inverted T waves are normal in which leads?
aVR and V1
What are hyperacute T waves?
Broad, asymmetrically peaked T waves
Seen in the early stages of a STEMI, often preceding ST elevation
What are the causes of biphasic T waves?
Myocardial ischaemia - up then down (pictured)
Hypokalaemia - down then up
What is Wellens syndrome?
A pattern of inverted or biphasic T waves in V2-3 that is highly specific for critical stenosis of the LAD
What do the a and v JVP waves reflect?
a wave = atrial contraction
v wave = atrial filling (ventricular contraction)
