cardiology

Question 2

Angina - definition

Answer 2

Myocardial ischaemia causes central chest tightness which may radiate to the jaw, teeth, neck or one or both arms. Associated symptoms can include dyspnoea, nausea, sweatiness or fainting. It is usually brought on by exertion, emotion, cold weather and heavy meals and is relieved by rest.

Question 3

Angina - causes

Answer 3

Usually atheroma but rarely anaemia, aortic stenosis, tachyarrhythmias or hypertrophic CM.

Question 4

Angina - 4 types

Answer 4

Stable angina – only induced by significant exercise and always relieved by rest. Unstable or crescendo angina – increases in severity and occurs with minimal exertion or rest. Decubitus angina – chest pain and dyspnoea that is precipitated by lying flat e.g. at night. Variant or Prinzmetal’s angina – a rare form of angina that is caused by coronary artery spasm.

Question 5

Angina - ECG changes

Answer 5

ECG – shows ST depression (ischaemia), flat or absent T waves or evidence of a previous MI. If resting ECG normal consider exercise ECG, thallium scan, cardiac CT or coronary angiography.

Question 6

Angina - conservative management

Answer 6

Modify risk factors – encourage to lose weight, exercise and stop smoking. Ensure HTN and diabetes are well controlled. If serum cholesterol >4 mmol/L - simvastatin 40mg OD at night.

Question 7

Angina - medical management

Answer 7

Aspirin 75 mg OD – reduces cardiac mortality. Atenolol 50-100mg OD – to reduce symptoms but has contraindications – respiratory diseasem LVF, bradycardia or Prinzmetal’s angina. Isosorbide mononitrate 20-40 mg BD for prophylaxis or symptomatic relief with sublingual GTN.

Question 8

Angina - additional medical management

Answer 8

Diltiazem or verapamil – calcium antagonists for patients with contraindications for β blockers. Dihydropyridine – e.g. amlodipine - L-type calcium antagonists that can be added to β blocker. Nicorandil 10-30mg BD – potassium receptor activator used for angina that is still not controlled. Ivabradine – inhibits the pacemaker ‘funny’ current in the SA node and therefore reduces heart rate. It is useful in those that cannot take β blockers and has a similar efficacy. Ranalozine – inhibits the late Na+ current and so prevents calcium overload and ischaemia. Trimetazidine – inhibits fatty acid oxidation - myocardium uses glucose which is more efficient.

Question 9

Angina - PTCA

Answer 9

Indications – poor response or intolerance to medical therapy, previous CABG or post thrombolysis with severe stenosis, symptoms or a positive stress test. Complications – restenosis (30% in 6 months), emergency CABG (3%), MI (2%) or death (0.5%). Stenting – NICE recommends PTCA is accompanied by stenting in 70% of patients. Combined therapy with aspirin and clopidogrel will reduce the risk of subsequent stent thrombosis. IV Glycoprotein IIb/IIIa inhibitors – e.g. eptifibatide can reduce rate of procedure related ischaemic events by preventing platelet aggregation and thrombus formation.

Question 10

Angina - CABG

Answer 10

Indications – to improve survival (left main stem disease or triple vessel disease) or to relieve symptoms (if unresponsive to drugs, unstable angina or if angioplasty unsuccessful). Procedure – the heart is stopped and put onto cardiac bypass. The patient’s own saphenous vein or internal mammary artery (last longer) is used. Prognosis – If angina persists or reoccurs restart anti-anginal drugs and consider angioplasty. It is known that >50% of grafts will close within 10 years but this can be prevented with low dose aspirin.

Question 11

ACS - definition

Answer 11

Common pathology is rupture or erosion of a coronary artery plaque leading to thrombosis. The resulting syndrome depends on whether the coronary artery is totally, partially or transiently occluded: STEMI - ST elevation and +++ troponin. Non- STEMI - no ST elevation and + troponin. Unstable Angina - ST depression or T wave inversion and no or trivial rise in troponin.

Question 12

ACS - risk factors

Answer 12

Non-modifiable – increasing age, male gender and family history of ischaemic heart disease. Modifiable – smoking, hypertension, diabetes, hyperlipidaemia, obesity or sedentary lifestyle.

Question 13

ACS - diagnosis

Answer 13

Criteria include a rise and then fall in cardiac biomarkers e.g. troponin, symptoms of cardiac ischaemia, ECG changes, development of pathological Q waves and loss of myocardium on imaging.

Question 14

ACS - symptoms and signs

Answer 14

Symptoms – central chest pain for >20 mins with nausea, sweatiness, dyspnoea and palpitations. Can be silent in elderly and diabetics – syncope, pulmonary oedema, epigastric pain, vomiting, post-operative hypotension, oliguria, an acute confusional state, stroke or diabetic hyperglycaemia states. Signs – distress, anxiety, pallor, sweatiness, increase or decrease in pulse and blood pressure, 4th heart sound, signs of heart failure, pansystolic murmur (papillary rupture or VSD) or a low grade fever.

Question 15

ACS - investigations

Answer 15

ECG – hyperacute (tall) T waves, ST elevation and new onset left bundle branch block within hours of an infarction. Within days T wave inversion and pathological Q waves will develop. CXR – to look for cardiomegaly, pulmonary oedema or a wide mediastinum in aortic rupture. Bloods – measure FBC, Us and Es, glucose, lipids and serial levels of cardiac enzymes.

Question 16

ACS - cardiac enzymes

Answer 16

Cardiac troponin - most sensitive and specific marker of myocardial necrosis. Levels rise within 3-12 hours from onset of chest pain, peak at 24-48 hours and return to baseline over 5-14 days (if normal after 6 hrs and ECG normal chance of missing MI is 0.3%). Creatinine kinase – there are 3 isotopes (MM, BB and MB) – CK-MB levels rise within 3-12 hours of onset of chest pain, reach a peak at 24 hours and return to normal by 48-72 hours.

Question 17

STEMI management

Answer 17

Give oxygen – 2-4L aiming for SaO2 of >95% (use caution in patients with COPD). Give 300mg aspirin PO and 300mg clopidogrel OD (unless given by GP or paramedics). Give analgesia – 5-10mg morphine IV with 10mg metoclopramide IV. Give GTN – either 2 puffs or 1 tablet sublingually as required Restore perfusion – PCI is the choice within 12 hours. Where PCI is unavailable consider thrombolysis within 5mg atenolol IV unless contraindication and 5mg lisinopril (where SBP >120mmHg) within 24 hours.

Question 18

ACS management

Answer 18

Give 2-4L of oxygen – aim for SaO2 of >95% (caution in COPD). Give analgesia – 5-10mg IV morphine and 10mg IV metoclopramide. Give nitrates – GTN spray or sublingual tablets as required Give Low molecular weight heparin – 1mg/kg enoxaparin BD or fondaparinux (factor X inhibitor). Give β-blockers – 50-100mg OD metoprolol tds (if contraindicated 60-120mg OD diltiazem tds). Give Low molecular weight heparin – 1mg/kg enoxaparin BD. Give IVI nitrates if pain continues – 50mg GTN in 50ml 0.9% saline at 2-10mL/hour. Do an ECG and bloods – if ischaemia, raised troponin or diabetes patient is high risk – do angiography

Question 19

TIMI score and GRACE

Answer 19

Thrombolysis in myocardial infarction (TIMI) score – A – age >65 years, aspirin taken within 7 days or angina >2 times within 24 hours, B – biomarkers e.g. troponin are raised, C - CAD risk factors - >3 present, D – diagnosis of CAD and E – ECG changes - >0.5mm ST elevation. GRACE (global registry of acute coronary events) risk score – this is recommended by NICE.

Question 20

MI or ACS - subsequent management

Answer 20

Bed rest for 48hrs – daily 12 lead ECG should be performed and heart, lungs and legs examined. Address risk factors – stop smoking, encourage exercise, treat HTN, DM and hyperlipidaemia. Aspirin – 75mg OD reduces the risk of vascular events e.g. MI and stroke by 29%. Β-blockade – give 50-100mg metoprolol tds to decrease pulse to ACE inhibitor – 2.5mg lisinopril OD should be given to all patients post MI. Statin – even is cholesterol is normal give 40mg simvastatin OD to all patients post MI.

Question 21

Post MI complications

Answer 21

Cardiac arrest, cardiogenic shock, bradycardia or heart block, tachyarrhythmia’s, ventricular failure, pericarditis, DVT and PE, cardiac tamponade, mitral regurgitation, ventricular septal defect, Dressler’s syndrome or a left ventricular aneurysm.

Question 22

Arrhythmias - definition

Answer 22

A disturbance in heart rhythm - usually benign and intermittent but can lead to cardiac compromise.

Question 23

Arrhythmia’s - causes

Answer 23

Cardiac – myocardial infarction, coronary artery disease, left ventricular aneurysm, mitral valve disease, cardiomyopathy, pericarditis, myocarditis or abnormal conduction pathways. Non-cardiac – caffeine, smoking, alcohol, pneumonia, drugs (β2 agonists, digoxin, L-dopa or tricyclics), metabolic disturbance (K, Ca, Mg, hypoxia or hypercapnia) or phaeochromocytoma.

Question 24

Arrhythmia’s - history

Answer 24

Ask about palpitations – onset and offset, nature (fast or slow and regular or irregular), duration and associated symptoms - chest pain, syncope, hypotension or pulmonary oedema.

Question 25

Arrhythmia’s - investigations

Answer 25

Bloods – FBC, Us and Es, glucose, Ca2+, Mg2+ and thyroid function. ECG – look for signs of ischaemic heart disease, atrial fibrillation, short PR interval (in WPW), long QT (metabolic disturbance, congenital or drugs) or additional U waves (hypokalaemia). 24 hour ECG monitoring – several recordings are needed as arrhythmia may be intermittent. Echocardiography – to look for structural heart disease e.g. mitral stenosis or hypertrophic CM. Provocation tests – exercise ECG, cardiac catheterisation or electrophysiological studies.

Question 26

Narrow complex tachycardia - definition

Answer 26

ECG shows a rate of >100 bpm and the QRS complex duration of (3 small squares).

Question 27

Narrow complex tachycardia - DD

Answer 27

Sinus tachycardia – normal P wave is followed by a normal QRS complex but rate is >100 bpm. Supraventricular tachycardia – the P wave is absent or inverted after the QRS complex. Atrial fibrillation – absent P waves and irregularly irregular QRS complexes are present. Atrial flutter – the atrial rate is usually >300 bpm and the ECG has a ‘sawtooth’ appearance. Multifocal atrial tachycardia – 3 or more P waves morphologies and irregular QRS complexes. Junctional tachycardia – P waves are buried in QRS complexes or occur after them. These include AV re-entry tachycardia (e.g. WPW syndrome) and AV node re-entry tachycardia.

Question 28

Narrow complex tachycardia - management

Answer 28

Give O2 if SaO2 is Continuous ECG monitoring – if it is irregularly irregular treat as AF if regular continue below. If the patient is compromised use DC cardioversion – 100J, then 150J and then 200J. Vagal manoeuvres – carotid sinus massage and the Valsalva manoeuvre. Give 6mg adenosine bolus injection (repeat 6mg once and then give 12mg if required) (lower dose if patient on dipyridamole) Monitor for adverse effects e.g. SBP 200 bpm. If adverse effects use DC cardioversion – 100J, then 150J and then 200J. If no adverse effects use one of the following – 5-10mg IV verapamil over 2 mins, 40mg IV esmolol over 1 min followed by IVI, 500μg IV digoxin over 30 mins or 300mg IV amiodarone over 1 hour.

Question 29

Broad complex tachycardia - definition

Answer 29

The rate is >100bpm and duration of the QRS complexes is >0.12 secs (or >3 small squares).

Question 30

Broad complex tachycardia - DD

Answer 30

Most common cause is ventricular tachycardia (including torsade de pointes) but could also be supraventricular tachycardia with aberrant conduction e.g. AF or atrial flutter.

Question 31

Broad complex tachycardia - management

Answer 31

Oxygen – give high flow O2, connect to cardiac monitor and gain IV access. Are there adverse signs – SBP 150bpm. If yes sedate the patient and perform DC cardioversion – 200J, 300J and finally 360J shock. After shock or if no adverse signs – give 300mg Amiodarone IV in 20-60 mins then 900mg in 24 hours. As an alternative can give 50mg Lidocaine IV over 2 mins – can repeat every 5 mins up to 200mg. If the arrhythmia does not resolve and not yet done sedate the patient and perform DC cardioversion. Correct hypokalaemia and hypomagnesaemia – with 60mmol KCl and 50% magnesium sulphate. Consider maintenance anti-arrhythmic with sotolol if good LV function or amiodarone if not.

Question 32

Atrial fibrillation - definition

Answer 32

An irregular atrial rhythm at 300-600 bpm to which the AV node and ventricles responds intermittently. When the ventricles are not primed reliably by the atria cardiac output falls by between 10 and 30%. The main risk is embolic stroke – warfarin (INR range 2-3) reduces the risk from 4% to 1% per year.

Question 33

AF - causes

Answer 33

Caffeine, alcohol, post-operatively, hypertension, MI or cardiac ischaemia, heart failure, mitral valve disease, pulmonary embolism, pneumonia, hyperthyroidism, hypokalaemia, hypomagnesaemia.

Question 34

AF - clinical features

Answer 34

Symptoms – can be asymptomatic or can cause chest pain, palpitations, dyspnoea or syncope. Signs – irregularly irregular pulse rate, variable intensity of the 1st heart sound and signs of LV failure.

Question 35

AF - investigations

Answer 35

ECG – will shows absent P waves and irregularly irregular QRS complexes. Bloods – for Us and Es (K+ and Mg+), cardiac enzymes (e.g. troponin) and thyroid function tests. Echo – to look for left atrial enlargement, mitral valve disease or poor left ventricular function.

Question 36

AF - acute management

Answer 36

If patient is haemodynamically unstable – give oxygen and IV sedation or GA and perform emergency cardioversion at 100J, then 150J and 300J. If DC cardioversion unavailable give IVI (5mg/kg over 1 hour) or PO (200mg tds) amiodarone or IV flecanide (2mg/kg) over 30 mins . Control ventricular rate – 1st line treatment is a β-blocker e.g. metoprolol (50mg bd) or a CCB e.g. diltiazem (60mg tds) or verapamil (40mg tds). 2nd line is digoxin or amiodarone. Anticoagulation - use LMWH until an assessment for emboli has been made. If patient is high risk (previous stroke, TIA or emboli) then warfarin should be started (INR target range is 2-3). In addition to the above look for associated illness e.g. MI or pneumonia and treat accordingly.

Question 37

AF - chronic management

Answer 37

Rate control – 1st line treatment is a β-blocker e.g. metoprolol (50mg bd) or a CCB e.g. diltiazem (60mg tds) or verapamil (40mg tds). 2nd line is digoxin followed by amiodarone. Anticoagulation – give warfarin (INR target range of 2-3) or 300mg aspirin OD if warfarin contraindicated or risk of emboli is very low. An alternative is dabigatron (direct thrombin inhibitor) – no need for monitoring or dose adjustment and less bleeding but expensive. Rhythm control – if symptomatic, congestive cardiac failure, young patient or first presentation. Use DC cardioversion with 4 weeks pre-treatment with sotalol or amiodarone or medical cardioversion with flecanide (if no structural heart disease) or amiodarone.