Management of Dysrhythmias in Myocardial Infarction
Underlying Causes and General Principles
- Dysrhythmias in myocardial infarction result from ongoing ischemia, reperfusion injury, altered autonomic tone, electrolyte disturbances, acid-base imbalances, hypoxia, and pump failure, according to the European Heart Journal 1, 2
Management Approach by Arrhythmia Type
Ventricular Arrhythmias
- No specific therapy is required for isolated ventricular ectopic beats, even when complex, as their value as predictors of ventricular fibrillation is questionable, as stated by the European Heart Journal 1, 2
- Beta-blockers are the first-line therapy for ventricular tachycardia unless contraindicated, recommended by the European Heart Journal 1, 2, 3, 4
- For hemodynamically unstable VT, immediate electrical cardioversion is indicated, as recommended by the European Heart Journal 1, 3, 5
- Intravenous amiodarone is superior for recurrent sustained VT requiring cardioversion, according to the European Heart Journal 1, 3, 4, 5
Supraventricular Arrhythmias
- Atrial fibrillation complicates 15-21% of myocardial infarctions and is frequently associated with severe left ventricular damage and heart failure, as reported by the European Heart Journal 1, 3, 5, 7, 8
- For well-tolerated AF with controlled ventricular rate, no specific treatment is required beyond anticoagulation, as stated by the European Heart Journal 1, 3, 5, 7
- Beta-blockers are effective for rate control in AF with rapid ventricular rate, recommended by the European Heart Journal 1, 3, 5, 7
Bradyarrhythmias and Conduction Disturbances
- Sinus bradycardia is common in the first hour, especially in inferior infarction, and may be caused by ischemia, reperfusion, or opioids, as reported by the European Heart Journal 1, 3, 4, 5
- For asymptomatic or late sinus bradycardia, no treatment is required, as stated by the European Heart Journal 1, 3, 4, 5
- If accompanied by severe hypotension, IV atropine is indicated, recommended by the European Heart Journal 1, 3, 4, 5, 6
General Management Principles
Priority Interventions
- Early reperfusion therapy is the most important anti-arrhythmic intervention and reduces the risk of ventricular arrhythmias and cardiovascular death, as reported by the European Heart Journal 7, 8, 9
- Urgent angiography with revascularization is indicated if the patient has not received previous reperfusion therapy, recommended by the European Heart Journal 4
Electrolyte Management
- Correction of electrolyte imbalances, especially hypokalemia and hypomagnesemia, is mandatory in patients with VT and/or VF, as stated by the European Heart Journal 4