B.10 Complications of Myocardial Infarction Flashcards
B.10 Complications of Myocardial Infarction
Primary cause is prolonged myocardial ischemia from coronary artery occlusion, leading to infarction and tissue necrosis
B.10 Complications of Myocardial Infarction
List all complications that can occur in 0-24 hr
Sudden Cardiac Death (SCD)
Arrhythmias
Acute Left Heart Failure
Cardiogenic Shock
B.10 Complications of Myocardial Infarction
0-24 hr
Sudden Cardiac Death
Sudden Cardiac Death (SCD)
- Definition: A sudden death likely triggered by cardiac arrhythmias or hemodynamic failure, occurring in one of two scenarios:
- Following cardiovascular symptoms.
- Within 24 hours of being asymptomatic in patients without prior symptoms.
- Pathophysiology: Fatal ventricular arrhythmias are believed to be the primary underlying cause.
Underlying Conditions
- Coronary artery disease: Present in about 70% of patients over 35 years old.
- Dilated/hypertrophic cardiomyopathy: Other contributions to SCD risk.
- Hereditary ion channelopathies: Includes conditions such as long QT syndrome and Brugada syndrome.
Prevention
- Use of ICD: Consideration of an implantable cardioverter-defibrillator (ICD) to reduce risk.
B.10 Complications of Myocardial Infarction
0-24 hr Arrhythmias
Common causes of death in patients with MI include:
- Ventricular tachyarrhythmias
- Atrioventricular block (AV block)
- Asystole
- Atrial fibrillation
B.10 Complications of Myocardial Infarction
0-24 hr Acute Left Heart Failure
Acute Left Heart Failure
- Can occur with myocardial damage, presenting as:
- Absence of myocardial contraction.
- Pulmonary edema.
B.10 Complications of Myocardial Infarction
0-24 hr Cardiogenic Shock
Cardiogenic Shock
- A critical stage that may follow an acute heart failure episode related to MI.
How it manifests
Heart attack damages the heart muscle
→ A large part of the left ventricle (main pumping chamber) stops working
Heart can’t pump enough blood
→ Blood pressure drops
→ Organs like the brain, kidneys, and skin don’t get enough oxygen
Body tries to help but makes it worse
→ Releases stress hormones → heart beats faster, blood vessels tighten
→ This increases the strain on the already weak heart
Blood backs up into the lungs
→ Causing pulmonary edema (fluid in lungs), shortness of breath
B.10 Complications of Myocardial Infarction
Complications arise due to:
Electrical instability
Mechanical rupture
Inflammatory processes
Hemodynamic compromise
B.10 Complications of Myocardial Infarction
ARRHYTHMIAS
These are the most common early complications and a major cause of sudden death post-MI.
Ventricular Tachycardia (VT) / Ventricular Fibrillation (VF):
→ Sudden cardiac death
→ Immediate defibrillation, IV amiodarone or beta-blockers
→ Consider ICD for secondary prevention
Inferior wall MI with complete (3rd-degree) AV block:
→ May lead to asystole
→ Atropine 0.5–1.0 mg IV, repeat if necessary
→ Consider temporary or permanent pacemaker
Atrial Fibrillation (AF):
→ Common in anterior MI
→ Treat with beta-blockers, heparin, digoxin (if LV dysfunction)
→ Cardioversion if persistent and symptomatic
Life-Threatening
B.10 Complications of Myocardial Infarction
VENTRICULAR FAILURE
Occurs due to loss of functional myocardium, especially if >40% of LV mass is affected.
A. Left Ventricular Failure:
Pulmonary congestion, orthopnea, basal crackles
Cardiogenic shock: Hypotension + cold extremities + oliguria
→ Treat with:
Dobutamine or dopamine (inotropes)
Urgent revascularization (PCI or CABG)
B. Right Ventricular (RV) Failure:
More common in inferior MI
Hypotension, JVD, clear lungs
Avoid nitrates (↓ preload)
Treat with fluids, inotropes
Management Summary:
Mild cases: IV Furosemide to decrease preload
Severe cases:
Nitrates, ACE inhibitors, aldosterone antagonists
Intra-aortic balloon pump (IABP)
LVAD or heart transplant (in end-stage cases)
B.10 Complications of Myocardial Infarction
MECHANICAL COMPLICATIONS
Occur 3–7 days post-MI due to myocardial necrosis and weakening.
Mitral Papillary Muscle Rupture
→ Leads to acute mitral regurgitation → pulmonary edema
→ Presents with new blowing systolic murmur
→ Requires emergency surgery
Ventricular Septal Rupture (VSR)
→ New harsh holosystolic murmur at left sternal border + thrill
→ Biventricular failure, hypotension
→ Treat: Surgery
Free Wall Rupture
→ Sudden collapse, cardiac tamponade, electromechanical dissociation (PEA)
→ Requires urgent pericardiocentesis + surgery
B.10 Complications of Myocardial Infarction
VENTRICULAR ANEURYSM
Develops weeks after transmural MI
Bulging of thinned myocardium → non-contractile wall
Risk of:
Arrhythmias
Thrombus formation → systemic embolism
Heart failure
Echo/MRI shows akinetic wall
Treat with anticoagulation if thrombus present
B.10 Complications of Myocardial Infarction
ACUTE PERICARDITIS
Occurs within 1–4 days post-MI
Symptoms: Pleuritic chest pain, pericardial rub
ECG: Diffuse ST elevation + PR depression
Treat with: → Aspirin or NSAIDs (avoid corticosteroids and anticoagulants early)
B.10 Complications of Myocardial Infarction
DRESSLER’S SYNDROME (Post-MI Syndrome)
Occurs 1–8 weeks post-MI
Autoimmune pericarditis due to myocardial necrosis
Features:
Fever
Pericardial and pleural effusions
Pleuritic chest pain
Pulmonary infiltrates, arthralgia
Treat with:
→ NSAIDs, colchicine
→ Avoid anticoagulation if large pericardial effusion present
B.10 Complications of Myocardial Infarction
1-3 days post-MI
Early Infarct-Associated Pericarditis
- Typically occurs within the first week of a large infarct close to the pericardium.
- Clinical features of acute pericarditis: pleuritic chest pain, dry cough, friction rub, diffuse ST elevations on ECG.
- Treatment: supportive care.
- Complications (rare): hemopericardium, pericardial tamponade.
B.10 Complications of Myocardial Infarction
3-14 days post-MI List all complications
Papillary Muscle Rupture
Ventricular Septal Rupture
Left Ventricular Free Wall Rupture
B.10 Complications of Myocardial Infarction
3-14 days post-MI Papillary Muscle Rupture
Occurrence: Typically happens 3 to 14 days after a myocardial infarction.
Causes: Usually due to acute myocardial infarction.
Most Common Reason: Rupture of the posteromedial papillary muscle due to occlusion of the PDA (posterior descending artery).
Clinical Features:
New holosystolic murmur detected along the 5th ICS in the midclavicular line.
Clinical signs of acute mitral regurgitation may include:
Dyspnea
Cough
Pulmonary crackles
Hypotension
B.10 Complications of Myocardial Infarction
3-14 days post-MI Ventricular Septal Rupture
Occurrence: Usually occurs 3–14 days after myocardial infarction.
Clinical Features:
New murmur characteristic of a ventricular septal defect.
Blood flow shifts from the left ventricle (LV) to the right ventricle (RV) due to a pressure gradient, resulting in increased pressure in the RV and an increase in O2 content in the venous blood.
Most frequently linked to LAD infarction (septal arteries arising from LAD).
Treatment:
Surgical repair and revascularization (often via CABG).
B.10 Complications of Myocardial Infarction
3-14 days post-MI Left Ventricular Free Wall Rupture
- Occurrence: Typically occurs 5–14 days after MI, usually in inferior myocardial infarctions.
- Characteristics: Blood is contained by the pericardium, resulting in cardiac tamponade.
- Clinical Features:
- Sudden onset of hypotension, decreased cardiac output, and increased risk of arrhythmias.
B.10 Complications of Myocardial Infarction
2 Weeks List all Complications
Atrial and Ventricular Aneurysms
Postmyocardial Infarction Syndrome (Dressler’s Syndrome)
Arrhythmias
Congestive Heart Failure
Reinfarction
B.10 Complications of Myocardial Infarction
2 Weeks Atrial and Ventricular Aneurysms
Clinical Features:
Persistent ST elevation post-myocardial infarction (MI) with T-wave inversions.
May present with a systolic murmur and S3 or S4 heart sounds.
Diagnosis:
Echocardiography, which can reveal:
Visual evidence of the pathological protrusion of the myocardial wall.
Complications:
Cardiac arrhythmias (risk of ventricular fibrillation).
Cardiac tamponade.
B.10 Complications of Myocardial Infarction
2 Weeks Postmyocardial Infarction Syndrome (Dressler’s Syndrome)
Occurrence: Typically observed 2–10 weeks post-MI.
Clinical Features:
Symptoms may include pleuritic chest pain, fever, and friction rub.
ECG abnormalities.
Treatment:
NSAIDs (e.g., aspirin) for pain relief.
B.10 Complications of Myocardial Infarction
2 Weeks Arrhythmias
Types may include variations such as atrial fibrillation (A-fib) and atrioventricular block (AV block).
B.10 Complications of Myocardial Infarction
2 Weeks Congestive Heart Failure
Can arise due to ischemic cardiomyopathy.
Associated conditions:
May occur at any time after an MI, especially when LVEF is <40% and when medications such as beta-blockers, ACEIs, ARBs, and MRAs have been initiated.
B.10 Complications of Myocardial Infarction
2 Weeks Reinfarction
Can occur at any point, although the risk increases over time.
