Abstract 18987: Wavefront Progression of Necrosis During Myocardial Infarction Revisited: The Wave Expands From Endo to Epi as Well as From Center to Lateral Borders
Background and purpose: The widely accepted wavefront theory of myocardial necrosis during acute coronary occlusion describes its progression as a wavefront from endo towards epicardium. The lateral affection of the myocardium would be predetermined by the location of the coronary occlusion. At the time this phenomenon was firstly described, advanced imaging technology was not available. Current cardiac magnetic resonance (CMR) is able to accurately characterize the necrosis progression in vivo.
Methods: A total of 220 patients with reperfused anterior STEMI (METOCARD-CNIC trial population) were studied. All the patients underwent cine, T2-weighted and late gadolinium enhancement CMR at day 5-7 after STEMI. Endo- and epicardial contours of each LV short axis slice was traced, and each one was divided by 100 cords for analysis. Infarct size was characterized in its 2 dimensions: lateral (defined as the percentage of cords with enhancement in every slice) and transmural extension (percentage of enhancement within each cord, nested in the lateral extension). All slices were weighed according to their relative mass. We compared these parameters between the cardioprotected metoprolol group and the control group.
Results: A strong lineal correlation between transmural and lateral infarct extension was observed (r: 0.88, p<0.001). We found that despite the edema lateral extension was larger than the IS lateral extension, this difference decreased as the transmurality affection increased. Finally, the infarct reduction exerted by metoprolol was derived from both the transmural and lateral extensions of IS.
Conclusions: The transmural and lateral extension of necrosis after myocardial infarction are directly correlated. A proven cardioprotective therapy prevented the necrosis progression in both dimensions. These findings cannot be explained by the classical wavefront theory, suggesting that the necrotic wavefront progresses also in the lateral direction.
Author Disclosures: R. Lorca: None. M. Jimenez-Blanco: None. J. García-Ruiz: None. G. Pizarro: None. R. Fernández-Jiménez: None. A. García-Álvarez: None. L. Fernández-Friera: None. V. Fuster: None. B. Ibanez: None.
- © 2015 by American Heart Association, Inc.