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Electrically induced ventricular arrhythmias in acute myocardial infarction treated with thrombolytic agents
J M McComb1, H K Gold, R C Leinbach
1Cardiac Unit, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
Insights
Predictors of sustained ventricular tachycardia (VT) after acute myocardial infarction (AMI) were identified. Short right ventricular effective refractory period and specific infarct locations were significant factors, guiding antiarrhythmic therapy and improving outcomes.
Area of Science:
- Cardiology
- Electrophysiology
- Internal Medicine
Background:
- Acute myocardial infarction (AMI) survivors face risks of ventricular arrhythmias.
- Programmed ventricular stimulation is used to assess arrhythmia risk post-AMI.
Purpose of the Study:
- To identify predictors of inducible sustained ventricular tachycardia (VT) after AMI treated with thrombolysis.
- To evaluate the role of electrophysiological parameters and infarct characteristics.
Main Methods:
- Ninety-two patients underwent programmed ventricular stimulation 12 days post-AMI.
- Cardiac catheterization was performed to assess coronary anatomy.
- Multivariate analysis identified predictors of sustained VT induction.
Main Results:
- Sustained VT was induced in 22% of patients; nonsustained VT in 13%.
- Predictors included short right ventricular effective refractory period, inferior/posterior AMI site, specific infarct arteries, multivessel disease, and male sex.
- Reperfusion success or residual stenosis did not predict VT induction.
Conclusions:
- Electrophysiological testing can identify VT risk post-AMI.
- Specific patient and infarct characteristics predict VT induction.
- Electrophysiologically guided therapy resulted in low long-term cardiac mortality.
Abstract:
Ninety-two patients underwent programmed ventricular stimulation 12 +/- 3 days after acute myocardial infarction (AMI) treated with thrombolytic agents (streptokinase, recombinant tissue plasminogen activator, or both). Cardiac catheterization was performed in all patients on admission to hospital and was repeated in 97% of them 13 +/- 5 days later. Sustained ventricular arrhythmias--either tachycardia (VT) or fibrillation--were induced in 20 (22%) patients, with nonsustained VT induced in another 12 (13%). Multivariate analysis was used to identify predictors of induction of sustained VT, with short right ventricular effective refractory period (p = 0.0061), site of AMI (inferior or posterior, p = 0.008), infarct-related artery (right or circumflex coronary artery, p = 0.018), multivessel coronary artery disease (p = 0.043) and male sex (p = 0.028) being significant predictors of sustained VT. Neither successful reperfusion, time to reperfusion, nor residual stenosis in the infarct-related artery was significant. All patients in whom VT was induced were treated with electrophysiologically guided antiarrhythmic therapy. Cardiac mortality after hospital discharge was 1% over 30 +/- 16 months.