Complications and Management of Septal Infarction
Septal infarction can lead to life-threatening complications including ventricular septal rupture, which requires urgent surgical intervention for survival.
Ventricular Septal Rupture
Ventricular septal defect (VSD) is a severe complication that can occur following septal infarction, typically appearing early after myocardial infarction with an incidence of about 1-2% of all infarctions 1. With modern reperfusion techniques, the incidence has decreased to approximately 0.2% 2.
Clinical Presentation and Diagnosis
- Severe clinical deterioration is often the first sign, accompanied by a loud systolic murmur (though the murmur may sometimes be soft or absent) 1
- Diagnosis is confirmed by echocardiography, which reveals the location and size of the defect 1
- Color Doppler can depict the left-to-right shunt, while continuous-wave Doppler can estimate right ventricular pressure 1
- Oxygen step-up in the right ventricle can also confirm the diagnosis 1
Prognosis Without Treatment
- Without surgical intervention, mortality is 54% within the first week 1
- Mortality increases to 92% within the first year 1, 3
Management
Initial Stabilization:
- Pharmacological treatment with vasodilators (IV nitroglycerin) may help if cardiogenic shock is not present 1
- Intra-aortic balloon counterpulsation (IABP) is the most effective method for providing circulatory support while preparing for surgery 1
- Newer mechanical circulatory support devices like Impella may serve as a bridge to definitive treatment 4
Definitive Treatment:
- Urgent surgical closure is the primary treatment option and offers the only chance of survival in large post-infarction VSDs with cardiogenic shock 1
- Even without hemodynamic instability, early surgery is usually indicated as the defect may increase in size 1
- Pre-operative coronary angiography should be performed 1
- Bypass grafts are inserted as necessary during the procedure 1
- Percutaneous closure has been reported but requires more experience before being widely recommended 1
Prognostic Factors:
- Poor postoperative outcomes are associated with: cardiogenic shock, posterior location, right ventricular dysfunction, advanced age, and long delay between septal rupture and surgery 1
- Hospital mortality after surgery ranges from 25% to 60% 1
- 95% of survivors achieve NYHA class I or II functional status 1
Other Complications of Septal Infarction
Conduction Disturbances
- Septal infarction can lead to atrioventricular (AV) block, including complete heart block 5
- Arrhythmias are common during early hours after myocardial infarction 1
- Ventricular tachycardia and ventricular fibrillation may occur and are associated with sudden cardiac death 2
Heart Failure
- Septal infarction can contribute to left ventricular dysfunction 6
- Management includes:
- Oxygen therapy 1
- Diuretics (furosemide 20-40mg IV repeated at 1-4 hourly intervals) 1
- Nitrates if no hypotension is present 1
- ACE inhibitors in the absence of hypotension, hypovolemia, or renal failure 1
- For severe heart failure: inotropic agents (dopamine/dobutamine), hemodynamic assessment with balloon floating catheter, and ventilatory support if needed 1
Cardiogenic Shock
- Management includes:
Special Considerations
Timing of Intervention
- Early recognition and intervention are critical for survival 4
- Patients who receive mechanical circulatory support earlier after myocardial infarction have better outcomes 4
Long-term Management
- Biventricular pacing may improve outcomes in patients with severe heart failure after septal infarction and VSD repair 6
- ICD implantation should be considered for patients with recurrent malignant arrhythmias 2