Cardiology: PBL / quiz / clinical relevance extras

What medication should you give to a patient having an MI if they have a a high risk of bleeding?

a. Aspirin

b. Aspirin and clopidogrel

c. Aspirin and ticagrelor

d. Aspirin and prasugrel

Aspirin and clopidogrel - it’s important to always give 2 anti-platelets

For suspected stable angina, what 1st line investigation should you do?

ECG

What are the 2 most important investigations in cardiology?

Angiogram and echocardiogram

What investigation should you do for chest pain that isn’t subsiding?

ECG to confirm STEMI

Why can diabetes cause silent MIs (MIs with no pain)?

Diabetes can cause nerve damage so no pain is felt

Name each of the aspects of treating a patient with an MI using the acronym ROMANCE

Reassurance

Oxygen

Morphine

Aspirin (300mg)

Nitrate (GTN)

Clopidogrel

Emetic (anti)

What is right sided heart failure?

What is left sided heart failure?

• Right sided

  • Right side of heart can’t pump → build of blood in right side of heart → builds up in jugular vein and body → fluid overload, builds up in feet (or sacrum if bed bound)

• Left sided

  • More common in valve diseases

  • Left side of heart can’t pump → blood flows back from heart into lungs → pulmonary oedema → shortness of breath, chest pain

  • Build up of water and blood in lungs pushes back into right side of heart → right sided heart failure

What do beta blockers do? / Why are they used to treat/prevent MIs?

Beta-blockers → slow down heart → longer diastole → coronary arteries are supplied during diastole so more blood flow to the heart

What 5 medications do you give for MIs and for how long?

Statin forever

Aspirin forever - other anti-platelet for 1 year

Ace inhibitor forever

Beta blocker forever

GTN as needed (PRN)

What is a murmur?

An extra unusual sound in the heart beat - usually due to blood flowing the wrong way, due to valve issues

What does hypertrophy mean?

When does ventricular hypertrophy happen?

Hypertrophy = enlarged cells

Ventricular hypertrophy occurs in aortic stenosis because more force is needed to push blood through the aortic valve

What is ejection fraction?

% of blood pumped out of ventricles per contraction

What is a systolic murmur, diastolic murmur and pansystolic murmur?

Systolic murmur - valve stuck shut (stenosis)

Diastolic murmur - valve stuck open (regurgitation)

Pansystolic murmur - systolic murmur that lasts the whole duration of systole

How do thiazide diuretics treat hypertension and oedema at the same time?

They remove water from the blood through the kidneys → urine

This reduces high blood pressure and removes excess water so reduces oedema

Which valve does a murmur at the apex of the heart indicate?

It’s the 5th intercostal space, mid-clavicular line

So mitral valve stenosis or regurgitation

What are bibasal crepitations?

Crepitus heard at the bottom of both lungs

What is a PICC line?

Peripherally Inserted Central Catheter

A central line / permanent cannula straight into the heart for administering meds

Is ST elevation seen in acute or chronic cases?

ST elevation is only seen in acute cases so we can call it an acute STEMI

What’s the difference between a STEMI and an NSTEMI?

STEMI means coronary artery is completely occluded - emergency

NSTEMI means coronary artery is partially occluded - less urgent

What are the complication of delayed treatment of MI?

• Heart failure

• Ventricular arrhythmias

• Death

Is heart failure acute or chronic?

Heart failure can be chronic but also can be acute

What is the cardiac arrest arrhythmia?

How is it treated?

Ventricular fibrillation

Treated with defibrillator

What are the complications of MI?

Think DARTH VADER

Death

Arrhythmias

Recurrence

Tamponade

Heart failure

Valve disease

Aneurysm

Dressler’s

Embolism

Rupture

What are the 3 keys to diagnosing ACS (acute coronary syndromes)?

• History

• ECG

• Troponin

MI doesn’t always present as crushing chest pain

How else can it present?

Discomfort may be mild - they could think it’s indigestion

MI can occur with no chest pain (up to 1/3 of patients)

Women, elderly and diabetics are more likely to present in atypical ways

What does pleuritic pain mean?

Pain worse on breathing in

What conditions can mimic MI?

• Pericarditis (inflammation of pericardium)

• Aortic dissection (tear in aorta)

• PE

• Pneumonia

• Oesophageal rupture

What are the limitations of ECGs?

• ECG can be normal in MI (repeat it - it might become abnormal)

• ST elevation can sometimes be normal - there can be a high take off in V2 and V3 in young people

• Certain ECG patterns might look like an MI or hide an MI

• Certain regions of the heart are not well seen by the ECG (e.g. posterior side of left ventricle and right ventricle)

  • ST depression is usually due to angina but if the patient has acute STEMI symptoms it’s likely a posterior STEMI

  • Inferior STEMIs are also associated with posterior or right ventricular STEMI

How do you treat a right ventricular infarction? Are they common?

• Rare on it’s own but common with inferior STEMI (>50%)

• Important to diagnose as management is different from LV infarct

• Impaired RV contractility → reduced RV stroke volume → reduced LV filling → reduced LV stroke volume → hypotension

• To treat, increase the preload by giving fluids → increase stroke volume

What is considered to be an abnormally high troponin level?

How is an acute MI defined/diagnostic criteria?

• An amount of troponin is seen in ~50% of people so abnormal troponin is considered = higher than 99th percentile - this means there’s myocardial injury

• i.e. > 30 ng/l

• So acute MI is defined by acute myocardial injury + at least 1 abnormality from:

  • Symptoms

  • ECG changes

  • Abnormal imaging

How do you determine if someone has chronic or acute high troponin?

Take 2 blood tests with some time between them:

• For chronic myocardial injury, the levels will not fluctuate much

• For acute, it will either rise a lot or fall a lot

How can cocaine cause an MI?

Cocaine can cause intense coronary vasospasm which prevents coronary blood flow → MI

What diseases other than MI scan raised troponin be seen in?

• Sepsis

• Renal failure

• PE

• Myocarditis

• Heart failure

• Cardiomyopathy

So not all patients with high troponin are having an MI

But all patients who are having an MI will have a high troponin

What’s the difference between a STEMI and an NSTEMI?

STEMI - completely occluded artery - emergency

NSTEMI - partially occluded artery - less urgent

What DAPT stand for in terms of treating MIs?

Dual-anti platelet therapy

What do statins do to prevent risk of a further MI?

• Reduce cholesterol levels

• Stabilise plaques

What does 3/52 hx SOB mean?

3 week history of shortness of breath

What coronary artery supplies each part of the heart? - i.e. left main coronary artery, circumflex artery, right coronary artery, right posterior descending artery, right marginal artery

• Left main coronary artery (LMCA) supplies blood to the left side of the heart

  • Left anterior descending artery (LAD) supplies blood to the anterior left side of the heart

  • Circumflex artery (Cx) supplies blood to the posterior and outer side of the heart

• Right coronary artery (RCA) supplies blood to the right side of the heart and SA and AV nodes

  • Right posterior descending artery (RPD) supplies blood to inferior aspect of the heart

  • Right marginal artery (RMA) - supplies blood to lateral right ventricle

• RCA and LAD together supply the septum of the heart

Which ECG lead corresponds to each part of the heart? - i.e. I, II, III, aVR, aVL, aVF, V1-6

II, III, aVF → inferior aspect

I, aVL, V5, V6 → lateral aspect

aVR, V1 → right side

V2, V3, V4 → anterior aspect

What is the pathophysiology of acute coronary syndromes?

• Initial endothelial dysfunction is triggered by factors such as smoking, hypertension and hyperglycaemia

• Results in changes to the endothelium including pro-inflammatory, pro-oxidant, proliferative and reduced nitric oxide bioavailability

• Fatty infiltration of the sub-endothelial space by low-density lipoprotein (LDL) particles

• Monocytes migrate from the blood and differentiate into macrophages

  • These macrophages then phagocytose oxidised LDL, slowly turning into large 'foam cells'

  • As these macrophages die the result can further propagate the inflammatory process

• Smooth muscle proliferation and migration from the tunica media into the intima results in formation of a fibrous capsule covering the fatty plaque

What are the 2 main complications of atherosclerosis?

Once a plaque has formed, complications can develop:

• The plaque forms a physical blockage in the lumen of the coronary artery - this may cause reduced blood flow and hence oxygen to the myocardium, particularly at times of increased demand, resulting clinically in angina

• The plaque may rupture, potentially causing a complete occlusion of the coronary artery - this may result in an MI

Which ECG lead changes correlate to each coronary artery?

What does the mnemonic ROMANCE stand for in terms of acute coronary syndrome treatment?

• Reassure

• Oxygen

• Morphine (10mg IV)

• Aspirin (300mg)

• Nitrates (GTN)

• Clopidogrel (300mg)

• Emetic (anti)

In what circumstances should you give oxygen to a patient having an MI?

Oxygen should only be given if the oxygen saturations are < 94%

C. Aspirin + clopidogrel

B. High cholesterol

C. CAD is the most prevalent heart problem in the UK and globally

A. Take an ECG