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

• Published in: The American journal of cardiology 2009-08, Vol.104 (4), p.475-479
• Main Authors: Pride, Yuri B., MD, Appelbaum, Evan, MD, Lord, Erin E., BA, Sloan, Sarah, MA, MS, Cannon, Christopher P., MD, Sabatine, Marc S., MD, MPH, Gibson, C. Michael, MS, MD
• Format: Article
• Language: English
• Subjects: Aged; Biological and medical sciences; Cardiology. Vascular system; Cardiovascular; Cardiovascular system; Clinical outcomes; Coronary heart disease; Creatine Kinase, MB Form - blood; Female; Heart; Heart attacks; Humans; Incidence; Investigative techniques of hemodynamics; Investigative techniques, diagnostic techniques (general aspects); Kinases; Male; Medical sciences; Middle Aged; Myocardial Infarction - blood; Myocardial Infarction - drug therapy; Myocardial Infarction - physiopathology; Myocarditis. Cardiomyopathies; Platelet Aggregation Inhibitors - therapeutic use; Predictive Value of Tests; Risk Factors; Stroke Volume - physiology; Tachycardia, Ventricular - epidemiology; Therapy; Thrombolytic Therapy; Ticlopidine - analogs & derivatives; Ticlopidine - therapeutic use; Ventricular Fibrillation - epidemiology
• ISSN: 0002-9149; 1879-1913
• DOI: 10.1016/j.amjcard.2009.04.005

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 ≥40%. Among patients with LVEF ≥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.