MI complications (from Acute coronary syndromes) Flashcards Preview

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Flashcards in MI complications (from Acute coronary syndromes) Deck (31)
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1
Q

There are 2 types of MI complications that are immediately life threatening

What are they?

A

Mechanical complications - structural

Ventricular arrhythmic complications - functional

2
Q

Aside from mechanical complications & VA complications, what complication can arise from MI?

A

LV thrombus

less threatening but still needs treated

3
Q

What is meant by mechanical complications of MI?

A

Tearing or rupture of infarcted myocardium.

15% of all AMI deaths

3 main complications:

  • Free Wall Rupture - 10-12%
  • Papillary Muscle Rupture - 1-2%
  • Rupture of IVS (VSD) - 1-2%
4
Q

What is a free wall rupture?

A

Type of mechanical complication of MI, where the wall of the heart tears

85% occur in the first week and 1/3 in first 24 hours

LAD territory most common, but always at the edge of the infarcted area.

Leads to haemopericardium & acute tamponade

5
Q

What is the outcome of free wall rupture?

A

Sudden EMD death unless adhesions or false aneurysm contain pericardial effusion

If possible urgent echo, pericardiocentesis and drainage with pigtail catheter.

If survives initial episode immediate surgery but rare.

6
Q

Who is most at risk of a free wall rupture?

A

More common in:

Elderly
Females
Hypertensive
Anterior MI

7
Q

What is a Septal wall rupture?

A

Type of mechanical complication, when the intraventricular septum tears

Anterior MI = Apical septal rupture
Inferior MI = Basal septal rupture

Most patients have multi-vessel Coronary artery disease

8
Q

What is a papillary muslce rupture?

A

Mechanical complication in which the papillary muscles controlling the heart valves tear

Type of MI determines which one is ruptured:

  • Inferior MI (PDA) - post/med muscle
  • Ant/lat MI (LAD Cx) - ant/lat muscle
9
Q

What is the prognosis of papillary muscle rupture?

A

Nae good

Complete trans-section is incompatible with life

Mortality high with medical Rx:

  • 33% die immediately
  • 50% die 24hrs
  • Only 6% live > 2 months
10
Q

What 2 mechanical complications can occur together?

A

Papillary muscle rupture & Septal rupture

Sudden major haemodynamic compromise

Generally happens within a week of MI

11
Q

What are the symptoms of Papillary muscle & septal rupture?

A

Symptoms:

  • Sudden severe breathlessness (MVR)
  • Autonomic activation eg sweating, nausea & vomiting
  • Chest pain
12
Q

What are the signs of papillary muscle & septal rupture?

A

Shock, tachycardia, pulmonary oedema

Harsh systolic murmur:

  • Septal rupture at left septa edge = right chest murmur
  • Mitral valve muscle rupture = back murmur (may be absent)

Right parasternal heave

Palpable thrill

Elevated JVP

13
Q

How would you differentiate between Septal rupture & Papillary muscle rupture?

A

Papillary muscle rupture:

  • tends to cause more SOB & oedema (Mitral valve)
  • Inferior MI

Septal rupture:

  • JVP more elevated
  • Anterior MI
14
Q

What are the investigations for mechanical complications of MI?

A

Echo

Right catheter

Left catheter

15
Q

What would you look for an echo that would indicate mechanical complications of MI?

A

Prolapsing mitral leaflet +/- chunk of muscle.

Broad MR jet into normal sized LA.

Septal rupture (VSD) - easily missed.

RV size, function and pressure is a strong predictor of outcome with septal rupture (VSD)

16
Q

What would mechanical complications of MI show on a right heart catheter?

A

Step up in O2 sats with septal rupture (VSD)

Confirms Diagnosis and quantifies shunt

Large v waves on wedge with acute MR

17
Q

What is the purpose of investigating mechanical complications of MI with a left heart catheter?

A

Establish coronary anatomy

Better localisation of pathology

18
Q

How is papillary muscle rupture and septal rupture managed?

A

Medical management only temporary:

1) I.V. Nitrates if SBP > 90mmhg
2) Inotropes if SBP < 90mmhg

3) IABP (balloon pump):
- Reduce afterload
- Augment DBP

Call cardiac surgeons

19
Q

How is papillary muscle rupture & septal rupture surgically treated?

A

Mitral valves are usually replaced rather than repaired.

Septal rupture = repair with pericardial or synthetic patch.

Coronary artery bypass if needed & possible.

If survive acute episode long term prognosis is good.

20
Q

What are the types of Ventricular arrhythmic complications?

A

Ventricular tachycardia (VT)

Ventricular fibrillation (VF)

21
Q

What is Ventricular tachycardia?

A

Broad complex, regular, generally rapid tachycardia.

Initiated by ventricular premature beat, sustained by re-entry loop

22
Q

What is ventricular fibrillation?

A

Irregular, ineffectual ventricular fibrillating activity

Multiple wavelets of electrical activity

23
Q

Following an MI, when can Ventricular tachycardia occur?

A

Can occur at any time after an MI

24
Q

What causes ventricular tachycardia?

A

The effects of the MI:

  • VT may be driven by ischaemia and/or myocardial damage from the MI
25
Q

Is ventricular tachycardia always symptomatic?

A

No

In some, it can be haemodynamically tolerated, despite the poor ventricular function

26
Q

If a patient has sustained Ventricular tachycardia, what must be done?

A

If sustained, urgent cardioversion required, usually electrically but also possible by amiodarone or pacing.

Medical therapy +/- implantable cardioverter-defibrillator (ICD) with anti-tachycardia pacing

27
Q

How would Ventricular fibrillation show up on an ECG/EKG?

A

P-waves and QRS complexes are not present

Heart rhythm is highly irregular

The heart rate is not defined (without QRS complexes)

28
Q

Why is ventricular fibrillation a medical emergency?

A

Can deteriorate into V-fib arrest (asystole)

29
Q

What type of MI is more likely to lead to a LV thrombus?

A

Apical/antero-apical MI

With resulting significant LV dysfunction

30
Q

How long does it take after an MI before an LV thrombus occurs?

A

Seen after 48 hours

This is why early echos done in CCU should be repeated if above infarct pattern

31
Q

What medication is given to those with an LV thrombus?

A

Warfarin (anti-coagulant) for 6/12