Cardiovascular magnetic resonance characterization of peri-infarct zone remodeling following myocardial infarction
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RESEARCH
Open Access
Cardiovascular magnetic resonance characterization of peri-infarct zone remodeling following myocardial infarction Karl H Schuleri1, Marco Centola1,2, Kristine S Evers1, Adam Zviman1, Robert Evers1,3, João AC Lima1 and Albert C Lardo1,4*
Abstract Background: Clinical studies implementing late gadolinium-enhanced (LGE) cardiovascular magnetic resonance (CMR) studies suggest that the peri-infarct zone (PIZ) contains a mixture of viable and non-viable myocytes, and is associated with greater susceptibility to ventricular tachycardia induction and adverse cardiac outcomes. However, CMR data assessing the temporal formation and functional remodeling characteristics of this complex region are limited. We intended to characterize early temporal changes in scar morphology and regional function in the PIZ. Methods and results: CMR studies were performed at six time points up to 90 days after induction of myocardial infarction (MI) in eight minipigs with reperfused, anterior-septal infarcts. Custom signal density threshold algorithms, based on the remote myocardium, were applied to define the infarct core and PIZ region for each time point. After the initial post-MI edema subsided, the PIZ decreased by 54% from day 10 to day 90 (p = 0.04). The size of infarct scar expanded by 14% and thinned by 56% from day 3 to 12 weeks (p = 0.004 and p < 0.001, respectively). LVEDV increased from 34.7. ± 2.2 ml to 47.8 ± 3.0 ml (day3 and week12, respectively; p < 0.001). At 30 days post-MI, regional circumferential strain was increased between the infarct scar and the PIZ (-2.1 ± 0.6 and -6.8 ± 0.9, respectively;* p < 0.05). Conclusions: The PIZ is dynamic and decreases in mass following reperfused MI. Tensile forces in the PIZ undergo changes following MI. Remodeling characteristics of the PIZ may provide mechanistic insights into the development of life-threatening arrhythmias and sudden cardiac death post-MI. Keywords: Cardiovascular magnetic resonance imaging, Myocardial infarction, Late gadolinium enhancement, Periinfarct zone, Myocardial strain
Background Despite substantial progress in risk stratification to identify susceptible patients and therapeutical advances, the risk of sudden death remains the highest in the first 30 days after myocardial infarction (MI) [1,2]. Estimates from recent clinical trials show an annualized suddendeath risk of 8% to 12% in the 3-month period after MI, even with optimal medical therapy [3]. Myocardial scar tissue is one of the most important structural substrates for sudden cardiac death. It has been demonstrated that * Correspondence: [email protected] 1 Johns Hopkins School of Medicine, Division of Cardiology, 1042 Ross Building, Baltimore, MD 21205, USA Full list of author information is available at the end of the article
islands of viable myocardium – surrounded by regions of myocardial scar –can produce the substrate for monomorphic ventricular tachycardia (VT), which is a significant risk factor for sudden cardiac death [4]. Recent studies employing late gadolinium enhance
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