Myocardial Infarction Flashcards by Nienke Schouten

How would you define an MI?

A myocardial infarction occurs when blood flow to (a part of) the heart stops or decreases

Cardiac muscle gets damaged
Often occurs in coronary artery
Leads to cell death, which will release troponin

How well did you know this?

Not at all

Perfectly

What symptoms are associated with an MI?

Pain
Sweating, nausea, vomiting
Breathlessness, weakness, fatigue
Loss of consciousness

How well did you know this?

Not at all

Perfectly

What sort of chest pain characterises an MI?

Tightness, pressure and squeezing. Can also be knife-like, tearing or burning

Pain may radiate to left arm, lower jaw, neck, shoulder

How well did you know this?

Not at all

Perfectly

What is Levine’s sign? As seen in an MI?

person localises chest pain by clenching one or both fists over their sternum (historical, but not necessarily accurate)

How well did you know this?

Not at all

Perfectly

What percentage of MIs are silent?

22-64%

How well did you know this?

Not at all

Perfectly

What are risk factors for getting an MI?

Old age
Actively smoking
High blood pressure
Diabetes Mellitus
Total cholesterol, low HDL, high LDL and high triglycerides

Other risk factors include male sex, obesity, alcohol use

How well did you know this?

Not at all

Perfectly

What happens if cardiac myocytes are not supplied with sufficient oxygen?

If the impaired blood flow is sustained, an ischemic cascade is triggered:

Heart cells in the territory of the blocked coronary artery die and do not grow back
Collagen scar replaces heart tissue
Apoptosis of affected cells

How well did you know this?

Not at all

Perfectly

What are the two types of MIs, as described by their location in the cardiac wall?

Ischemia first affects the subendocardial region, which will begin to die within 15-30 minutes after blood loss

This is just below the inner surface of the heart
Most susceptible to damage
Subendocardial infarction

When the MI persists, a transmural infarction can arise

How well did you know this?

Not at all

Perfectly

What are the risks after an MI?

Post-MI, there is myocardial scarring which leads to an alteration in the conduction pathway, putting someone at risk for:

Arrhythmias
Heart block
Aneurysm of the heart ventricles
Inflammation of heart wall

How well did you know this?

Not at all

Perfectly

What is often the cause of an MI?

Atherosclerotic plaques can rupture, leading to the formation of blood clots that block the (coronary) artery

How well did you know this?

Not at all

Perfectly

How is an MI diagnosed?

An MI is defined by increased troponin, as well as one of the following:

Symptoms relating to ischemia
Changes on ECG
Changes in the motion of the heart wall
Demonstration of a thrombus

Blood tests will show elevated troponon I and troponin T

How well did you know this?

Not at all

Perfectly

What are patients who experience a STEMI at risk of?

Patients experiencing acute STEMI are at risk for developing life-threatening arrhythmias like ventricular fibrillation which causes sudden cardiac arrest, sometimes referred to as a “massive heart attack”.

How well did you know this?

Not at all

Perfectly

How do you treat a STEMI?

CPR and defibrillation

How well did you know this?

Not at all

Perfectly

What is characteristic of a NSTEMI?

No elevation of the ST interval - potential depression, as seen on an ECG

Often subendocardial

How well did you know this?

Not at all

Perfectly

What is angina?

Angina is a type of chest pain that results from reduced blood flow to the heart

How well did you know this?

Not at all

Perfectly

What causes angina to flarre up?

The pain is often triggered by physical activity or emotional stress

How well did you know this?

Not at all

Perfectly

What are the symptoms of stable angina?

shortness of breath
nausea
fatigue
dizziness
profuse sweating
anxiety

How well did you know this?

Not at all

Perfectly

What are risk factors for stable angina?

Being overweight, history of heart disease, high lipids, hypertension, diabetes, smoking, sedentary lifestyle

How well did you know this?

Not at all

Perfectly

WHat is unstable angina?

Unstable angina is chest pain that occurs at rest or with exertion or stress. The pain worsens in frequency and severity. Unstable angina means that blockages in the arteries supplying your heart with blood and oxygen have reached a critical level.

How do you manage unstable angina?

giving nitroglycerin or antiplatelet medication

How would you manage a NSTEMI?

300 mg aspirin

Another anti-platelet: ticagrelor, clopidogrel

Antithrombin therapy with fondaparinux sodium should also be offered

What is the prognosis for an MI?

Without treatment, about a quarter of those affected by MI die within minutes, and about forty percent within the first month

Morbidity and mortality from myocardial infarction has however improved over the years due to earlier and better treatment

What includes secondary prevention of cardiovascular events?

For secondary prevention, patients should be offered treatment with an ACE inhibitor, a beta-blocker, dual antiplatelet therapy, and a statin.

Treatment with aspirin should continue indefinitely

How would you manage a STEMI?

Coronary reperfusion therapy (either primary PCI or fibrinolysis) should be delivered as soon as possible in eligible patients with a STEMI

In addition to aspirin, most patients with a STEMI should be offered a second antiplatelet agent

What dose of ramipril, aspirin, ticagrelor and bisoprolol should be given?

Aspirin: 75mg daily Ramipril: 2.5 mg daily Ticagrelor: 60mg daily in combination with aspirin Bisoprolol: 5-10 mg daily

What are non-pharmaceutical ways to manage acute coronary syndromes?

Revascularisation procedures such as percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) are often appropriate, alongside drug treatment, for patients with an ACS

What complications can occur after an acute coronary syndrome?

Arrhythmias Stroke Heart failure

What is the HAS-BLED score?

HAS-BLED is a scoring system developed to assess 1-year risk of major bleeding in people taking anticoagulants for atrial fibrillation (AF)

What parameters are used in the HAS-BLED score?

A calculated HAS-BLED score is between 0 and 9 and based on seven parameters with a weighted value of 0-2: 1. Hypertension (1) 2. Abnormal liver or renal function (2) 3. Stroke (1) 4. Bleeding (1) 5. Labile INR (1) 6. Age > 65 (1) 7. Drugs or alcohol (1)

At what HAS-BLED score would you consider someone high-risk?

A score of ≥3 indicates "high risk", but does not necessarily mean that an anticoagulant cannot be given, as some risk factors may be modified

What is the CHA2DS score?

The CHA2DS2-VASc score is a widely used medical tool used to guide physicians on blood thinning treatment to prevent stroke in people with non-valvular atrial fibrillation Purpose -> risk of stroke

What parameters are used in the CHA2DS score?

CHAD2 score is calculated based on: 1. Congestive heart disease (1) 2. Hypertension (1) 3. Age >75 (2) 4. Diabetes Mellitus (1) 5. Prior Stroke or TIA (2) 6. Vascular disease (1) 7. Agre 65-74 (1) 8. Female sex

At what CHA2DS score do you start treatment? What treatment is appropriate?

NICE guidelines recommend that if the patient has a CHA2DS2-VASc score of 2 and above: 1. oral anticoagulation therapy (OAC) with a vitamin K antagonist (VKA, e.g. warfarin with target INR of 2-3) 2. one of the direct oral anticoagulant drugs (DOACs, e.g. dabigatran, rivaroxaban, edoxaban, or apixaban) is recommended

How would you manage stable angina?

Short-acting nitrate for acute situation 1. Offer either a beta blocker or a calcium channel blocker as first-line treatment for stable angina 2. Combination of two If the person cannot tolerate beta blockers and calcium channel blockers or both are contraindicated, consider monotherapy with one of the following drugs: 1. a long-acting nitrate or 2. ivabradine or 3. nicorandil or 4. ranolazine.

A 45 year old woman presents with acute onset of severe chest pain and has ECG changes of an acute inferior myocardial infarct. She is obese, does not exercise, smokes 20 cigarettes a day and takes the progesterone-only pill. She is under investigation for bullying and harassment at work. Coronary angiography shows a significant atherosclerotic stenosis in her right coronary artery. ``` Which is the most important predisposing risk factor for atherosclerosis? A) Cigarette smoking B) Obesity C) Oral contraceptives D) Physical inactivity E) Stress ```

Cigarette smoking

A 59 year old man has 1 hour of severe central chest pain. A lateral myocardial infarction is immediately apparent on ECG. Which leads are most likely to show reciprocal ST depression? ``` A) aVf and III B) aVL and C) avr and I D) I and V6 E) V5 and V6 ```

Reciprocal depression in leads aVF and III, ST elevation in aVL, I & V5-6 indicate a lateral MI.

A 55 year old man has pain and tightness in his right thigh and calf on exercise, worsening over the past 6 months. The right femoral and popliteal pulses are absent. The left femoral and popliteal pulses are present. ``` Which is the most likely site of the arterial obstruction? A) Aorto-iliac B) External iliac C) Femoropopliteal D) Internal iliac E) Tibial ```

External iliac

A 66 year old woman has heart failure secondary to hypertension. Her current medications are furosemide and lisinopril. Her JVP is not raised, her chest is clear and she has minimal ankle oedema. Her pulse is 76 bpm, regular and BP is 170/100 mmHg. Which is the most appropriate medication to add? ``` A) Bisoprolol fumarate B) Indapamide C) Losartan potassium D) Spironolactone E) Verapamil hydrochloride ```

Beta blockers + AceI are first line for treatment of heart failure to reduce morbidity and mortality - beta blockers reduce adverse remodelling

A 55 year old man has an occupational health check and is found to have an ejection systolic murmur. His pulse rate is 50 bpm and BP 120/80 mmHg. There is a low-volume carotid pulse and no radiofemoral delay. An ejection systolic murmur is heard at the left sternal edge, apex and aortic area, which radiates to the carotid arteries but not to the axilla. There are clear lung bases with no ankle oedema. Investigations: ECG: sinus rhythm, voltage criteria for left ventricular hypertrophy Chest X-ray: normal Which is the most likely diagnosis based on these findings? ``` A) Aortic stenosis B) Coarctation of the aorta C) Mitral regurgitation D) Tricuspid regurgitation E) Ventricular septal defect ```

Aortic stenosis results in an ejection systolic murmur that radiates to the carotid arteries in this fashion. If it was mitral regurgitation it would be a pansystolic murmur radiating to the axillae and not to the carotids.

A 27 year old man develops acute breathlessness and widespread petechiae on an orthopaedic ward. He was admitted with bilateral femoral fractures 2 days ago (following a motorbike accident) and underwent bilateral femoral nailing. He received four units of blood peri-operatively. His temperature is 37.3°C, pulse rate 110 bpm, BP 135/70 mmHg, respiratory rate 25 breaths per minute and oxygen saturation 82% breathing air. Heart sounds are normal and his chest is clear. Investigations: Haemoglobin 120 g/L (130-175) White cell count 17 x 10°/L (3.8-10.0) Platelets 130 x 10°/L (150-400) Which is the most likely cause of his acute symptoms? A) Anaphylactic response to subcutaneous heparin B) Disseminated intravascular coagulation C) Fat embolism D) Pulmonary thromboembolism E) Transfusion reaction

Fat embolism. Platelets not low enough for DIC. Pulmonary embolism wouldn’t have petechiae, transfusion reaction would be quicker and not likely to cause petechiae. Broken femurs increase risk of fat embolism.

A 65 year old man is invited to the abdominal aortic aneurysm screening programme. An ultrasound scan shows his abdominal aorta to be 33 mm in diameter. Which is the most appropriate management plan? ``` A) Reassure and discharge B) Refer for angiography C) Refer for vascular surgery D) Repeat ultrasound scan in 12 months E) Request CT scan of abdomen ```

repeat ultrasound in 12 months - watch and wait. 3.0-4.4cm arrange follow up in one year, if 4.5-5.4 then arrange f.u in three months

A 42 year old man has 1 week of chest pain and shortness of breath. His pulse rate is 125 bpm, BP 77/42 mmHg and oxygen saturation 85% breathing air. Investigations: Chest X-ray: no abnormality CT pulmonary angiogram: massive pulmonary embolus. Which is the most appropriate immediate treatment? ``` A) Intravenous alteplase B) Intravenous heparin (unfractionated) C) Oral dabigatran etexilate D) Oral warfarin sodium Exclude E) Subcutaneous low molecular weight heparin ```

A - Intravenous alteplase – treatment of massive (haemodynamically unstable) PE give systemic thrombolytic therapy. if they are normotensive then give heparin.

A 76 year old woman with hypertension is taking amlodipine 10 mg daily. A 24 hour BP measurement shows a mean BP of 168/90 mmHg. ``` Investigations: Sodium 135 mmol/L (135-146) Potassium 4.0 mmol/L (3.5-5.3) Urea 7 mmol/L (2.5-7.8) Creatinine 100 umol/L (60-120) EGFR 68 mL/min/1.73 m²(>60) ``` Which class of antihypertensive should be added? ``` A) ACE inhibitor B) Alpha blocker C) Beta blocker D) Loop diuretic Exclude E) Thiazide-like diuretic ```

A, ACE inhibitor: stage 2 treatment of hypertension in older or afro-carribean individuals is with ACE inhibitor (based on old guidelines where step 2 is ace/arb, new guidelines said add either ACE or thiazide.

What are surgical options for angina treatment?

coronary artery bypass graft [CABG] or percutaneous coronary intervention

What is a TIA?

A transient ischemic attack (TIA) is a temporary period of symptoms similar to those of a stroke. A TIA usually lasts only a few minutes and doesn't cause permanent damage.

How would you acutely manage a suspected TIA?

Offer aspirin (300 mg daily),