Complications Post-AMI
First 2-3 Days:
- Cardiac arrhythmias
- Cardiac failure
- Pericarditis
Later Complications:
- Recurrent infarction
- Angina
- Thromboembolism
- Mitral valve regurgitation
- Ventricular septal or free wall rupture
Other Late Complications:
- Dressler’s syndrome
- Ventricular aneurysms
- Recurrent cardiac arrhythmias
Pain Management
- Ongoing pain requires prompt revascularization.
- Pain may indicate extension of the infarct or a new infarct.
- Treatment is similar to primary AMI.
- Streptokinase (SK) should only be considered within three days of the original administration.
Left Ventricular Failure
- Oxygen: 4-6L/min continuous
- Frusemide: 40-80mg IV as required
- Morphine: 2.5-5.0mg IV as required
- GTN: 600 microgram or Isosorbide Dinitrate 5 microgram S/L (if SBP >95)
- Mild Left Failure: Few basal crackles, extra heart sound, upper lobe diversion on CXR (common in 40%)
- Rx: Few days of low-dose diuretics + ACEI for prognostic benefits
- Severe Heart Failure and Pulmonary Oedema:
- Rx: Prolonged and powerful diuretics, vasodilators, loop diuretics, sometimes digoxin
- Hypotension and Raised R-Heart Filling Pressures: Common in RV infarcts
- Rx: Volume expansion
- Cardiogenic Shock: Extreme form of heart failure or circulatory collapse
- Rx: Inotropic support (Dobutamine, Dopamine), vasodilators (if SBP >90mmHg), haemodynamic monitoring, ventilation, urgent revascularization, consider ECHO and pericardiocentesis for cardiac tamponade
- Cardiac Rupture: Immediate tamponade, usually fatal within minutes
- Electromechanical dissociation (no pulse or cardiac output despite normal ECG rhythm)
Cardiogenic Shock
- Mortality: Very high
- Management:
- Inotropic support (Dobutamine 2.5-15mg/kg/min IV +/- Dopamine 2-3 microgram/kg/min IV)
- Vasodilators (if SBP >90mmHg)
- GTN 10 microgram/min IV, increase by 10 microgram/min to keep SBP >90mmHg
- Sodium Nitroprusside 0.3 microgram/kg/min IV, increase by 0.3 microgram/min every 5-10 min to keep SBP >90mmHg
- Haemodynamic monitoring
- Ventilation
- Urgent revascularization
- Consider ECHO and pericardiocentesis for cardiac rupture and cardiac tamponade
Right Ventricular Infarction
- Diagnosis: ECG changes confirmed by ECHO
- Rx: Saline fluid challenge (100-200mL/30min)
Pericarditis
- Often occurs post Q wave AMI (transmural), usually 1-4 days post-infarct
- Symptoms: Friction rub, sharp CP aggravated by movement and respiration, pericardial rub
- Common in anterior wall infarcts
- ECG: Generalized ST segment elevation with upright peaked T waves
- Rx: Anti-inflammatory drugs; avoid anticoagulants
Arrhythmias
- VF: Increased HR, AF: Decreased HR
- Ventricular Extrasystoles: May precede development of VF
- Ventricular Tachycardia: May degenerate into VF, Rx: IV lignocaine or synchronized cardioversion
- VF: Rx: Prompt defibrillation (200-360J), recurrences treated with Lignocaine infusions or Amiodarone if poor LV function
- AF: Rx: IV digoxin, amiodarone, treat underlying pathology
- Sinus Tachycardia (Inferior Wall Infarcts): Rx: Elevate foot of bed, IV atropine 600μg
- Conduction Disturbances: Rx: Atropine or temporary pacemaker, permanent pacing if block exceeds 2 weeks
Thromboembolic Disease
- Complications: PE, DVT, CVA
- Long-term Therapy: Considered for patients with large AMI and LVF, akinetic or dyskinetic areas, scar or aneurysm formation
- Mural Thrombus: Confirmed with TOE
Cardiac Rupture
- Typically occurs within 1 week post-AMI
- Cause: Necrotic tissue incompletely replaced by fibrous tissue
Ventricular Aneurysm
- Cause: Stretching of collagen fibers replacing infarcted cardiac muscle
- Presentation: Heart failure, arrhythmias, systemic emboli
- Diagnosis: ECG with persistent ST elevation, echo
- Rx: Anticoagulants, ACEIs, anti-arrhythmics, surgical removal in some cases
Dressler’s Syndrome
- Post-AMI pain not associated with vascular insufficiency
- Symptoms: Pyrexia, pneumonitis, pleurisy, pericarditis (2-10 weeks post-AMI)
- Cause: Autoimmune response to damaged cardiac tissue
- Rx: Anti-inflammatory drugs, steroids may be needed
Valvular Heart Disease
- Cause: Rupture or infarct of papillary muscles or valve leaflets