Abstract
BackgroundExpansion of the myocardial extracellular volume (ECV) is a surrogate measure of focal/diffuse fibrosis and is an independent marker of prognosis in chronic heart disease. Changes in ECV may also occur after myocardial infarction, acutely because of oedema and in convalescence as part of ventricular remodelling. The objective of this study was to investigate changes in the pattern of distribution of regional (normal, infarcted and oedematous segments) and global left ventricular (LV) ECV using semi-automated methods early and late after reperfused ST-elevation myocardial infarction (STEMI).MethodsFifty patients underwent cardiovascular magnetic resonance (CMR) imaging acutely (24 h–72 h) and at convalescence (3 months). The CMR protocol included: cines, T2-weighted (T2 W) imaging, pre−/post-contrast T1-maps and LGE-imaging. Using T2 W and LGE imaging on acute scans, 16-segments of the LV were categorised as normal, oedema and infarct. 800 segments (16 per-patient) were analysed for changes in ECV and wall thickening (WT).ResultsFrom the acute studies, 325 (40.6%) segments were classified as normal, 246 (30.8%) segments as oedema and 229 (28.6%) segments as infarct. Segmental change in ECV between acute and follow-up studies (Δ ECV) was significantly different for normal, oedema and infarct segments (0.8 ± 6.5%, −1.78 ± 9%, −2.9 ± 10.9%, respectively; P < 0.001). Normal segments which demonstrated deterioration in wall thickening at follow-up showed significantly increased Δ ECV compared with normal segments with preserved wall thickening at follow up (1.82 ± 6.05% versus −0.10 ± 6.88%, P < 0.05).ConclusionFollowing reperfused STEMI, normal myocardium demonstrates subtle expansion of the extracellular volume at 3-month follow up. Segmental ECV expansion of normal myocardium is associated with worsening of contractile function.
Highlights
Expansion of the myocardial extracellular volume (ECV) is a surrogate measure of focal/diffuse fibrosis and is an independent marker of prognosis in chronic heart disease
Patients with triple vessel disease were more prevalent in the group that showed a rise in ECV in normal segments (1 patient versus 7 patients, P = 0.05)
The present study demonstrates that 1) in reperfused ST-elevation myocardial infarction (STEMI), normal myocardial segments show a subtle expansion of the ECV between baseline and 3 month follow-up; 2) oedematous and infarcted segments show a significant reduction in ECV at follow up; 3) normal segments that demonstrate deterioration in segmental function at follow-up show a substantial increase in delta-ECV from baseline to follow up; 4) acute infarct ECV demonstrates the best association with the number of segments with functional recovery (Fig. 3) and 5) high acute normal myocardial segmental ECV is associated with adverse left ventricular (LV) remodelling at follow-up
Summary
Expansion of the myocardial extracellular volume (ECV) is a surrogate measure of focal/diffuse fibrosis and is an independent marker of prognosis in chronic heart disease. Changes in ECV may occur after myocardial infarction, acutely because of oedema and in convalescence as part of ventricular remodelling. The objective of this study was to investigate changes in the pattern of distribution of regional (normal, infarcted and oedematous segments) and global left ventricular (LV) ECV using semi-automated methods early and late after reperfused ST-elevation myocardial infarction (STEMI). The chronic phase of LV remodelling involves compensatory myocyte hypertrophy and alterations in ventricular geometry to distribute the increased wall stresses more evenly [4]. Pre-clinical studies have speculated that the ‘normal’ non-infarcted myocardium undergoes changes due to increased wall stress [5, 6]. There is limited evidence to support these concepts in humans It remains unknown if these changes in tissue composition of normal myocardium have any impact on regional contractility
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
