The relationship of gray zone and infarct core in the Iceland MI study
© Mehra et al. 2016
Published: 27 January 2016
Gray zone or infarct heterogeneity, defined as the admixture of necrotic and viable myocardium at the periphery of myocardial infarction (MI), has been noted to be a modulator of cardiac outcomes. Most studies have not reported a direct correlation between infarct core and the zone of heterogeneity. Furthermore, no large population based studies have examined the burden of undiagnosed infarct and infarct heterogeneity.
We report the data from 215 individuals (of the total 950 enrolled in the Iceland MI study) who were found to have myocardial infarction by late gadolinium enhancement on CMR. The infarct core and gray zone assessment was performed by FWHM and 2SD threshold, respectively.
The median infarct core, as a percentage of left ventricular mass was 6.3% (5.4-6.9, 95% CI) and the gray zone was 4.5% (3.8-5.2, 95% CI). The correlation between gray zone and infarct core assessed by Spearman's rank coefficient (rho) was 0.88 (0.80-0.90) P < 0.0001. When gray zone was normalized to total scar size, it had a negative correlation with infarct core, rho of -0.53 (-0.62--0.42), P < 0.0001. Furthermore, non-linear regression with a simple power function fit the relationship between gray zone and infarct size (R2 = 0.74).
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