Relation between myocardial infarct size and ventricular tachyarrhythmia among patients with preserved left ventricular ejection fraction following fibrinolytic therapy for ST-segment elevation myocardial infarction.

Abstract

In the era of early reperfusion therapy for ST-segment elevation myocardial infarction, preserved left ventricular (LV) function is common. Despite preservation of LV ejection fraction (LVEF), there remains a spectrum of risk for adverse cardiovascular events, including ventricular tachycardia (VT) and ventricular fibrillation (VF). Larger infarct size has been independently associated with death, VT/VF, and heart failure in the post-myocardial infarction population. It was hypothesized that infarct size, as estimated by peak serum creatine kinase (CK)-MB concentration, would be associated with the incidence of VT/VF in patients with preserved LV function after ST-segment elevation myocardial infarctions. The Clopidogrel as Adjunctive Reperfusion Therapy-Thrombolysis In Myocardial Infarction 28 (CLARITY-TIMI 28) study enrolled 3,491 patients with ST-segment elevation myocardial infarctions who underwent fibrinolytic therapy. The association between estimated infarct size (ratio of peak CK-MB to the upper limit of normal), the LVEF (measured using left ventriculography or echocardiography), and the incidence of VT/VF through 30 days was assessed. A total of 1,436 patients underwent assessments of LV function, of whom 1,133 had adequate CK-MB for analysis. The median LVEF in this group was 55% (interquartile range 45% to 65%), and most patients (n = 814 [87.1%]) had LVEF > or =40%. Among patients with LVEF > or =40%, the ratio of peak CK-MB to the upper limit of normal was significantly associated with the incidence of VT/VF through 30 days (2.2%, 3.7%, and 5.5% across tertiles, respectively, p = 0.041 for trend) and the incidence of the composite of cardiovascular death, heart failure, shock, and VT/VF through 30 days (3.7%, 6.0%, 8.5%, respectively, p = 0.018 for trend). In conclusion, in patients with ST-segment elevation myocardial infarction with preserved LV function after reperfusion therapy, larger infarct size, as estimated by peak serum CK-MB concentration, is significantly associated with VT/VF as well as other adverse clinical outcomes.

• Authors: Yuri B Pride, Evan Appelbaum, Erin E Lord, Sarah Sloan, Christopher P Cannon, Marc S Sabatine, C Michael Gibson, TIMI Study Group
• Journal: The American journal of cardiology (Am J Cardiol) Vol. 104 Issue 4 Pg. 475-9 (Aug 15 2009) ISSN: 1879-1913 [Electronic] United States
• PMID: 19660597 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Platelet Aggregation Inhibitors
• Clopidogrel
• Creatine Kinase, MB Form
• Ticlopidine

Topics

• Aged
• Clopidogrel
• Creatine Kinase, MB Form (blood)
• Female
• Humans
• Incidence
• Male
• Middle Aged
• Myocardial Infarction (blood, drug therapy, physiopathology)
• Platelet Aggregation Inhibitors (therapeutic use)
• Predictive Value of Tests
• Risk Factors
• Stroke Volume (physiology)
• Tachycardia, Ventricular (epidemiology)
• Thrombolytic Therapy
• Ticlopidine (analogs & derivatives, therapeutic use)
• Ventricular Fibrillation (epidemiology)