JCMR 2020; 22.46. Real-time cardiovascular magnetic resonance T1 and extracellular volume fraction mapping for tissue characterization in aortic stenosis-s12968-020-00638-8

s12968-020-00638-8

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This substudy of the METOCARD-CNIC randomized trial examined how left ventricular (LV) function changes after acute anterior ST-segment elevation myocardial infarction (STEMI), using feature-tracking cardiovascular magnetic resonance (CMR). The researchers analyzed 191 patients who had CMR scans at 1 week and 6 months after STEMI, focusing on circumferential strain in the infarct zone and remote myocardium. They also assessed whether early intravenous metoprolol, microvascular obstruction (MVO), intramyocardial hemorrhage (IMH), or adverse LV remodeling affected recovery.<br /><br />Overall, infarct zone circumferential strain improved significantly from 1 week to 6 months, showing functional recovery of the injured myocardium. In contrast, remote zone strain remained stable in the full cohort. Patients who received early intravenous metoprolol had better preserved infarct zone strain than controls both at 1 week and at 6 months, suggesting a lasting cardioprotective effect. Metoprolol did not significantly affect remote zone strain.<br /><br />Patients with MVO or IMH had worse infarct zone strain than those without these findings, but infarct zone function still improved over time in both groups. Remote zone strain was not significantly different according to MVO or IMH status. However, patients who developed adverse LV remodeling showed a worsening of remote zone strain over time, whereas those without remodeling did not.<br /><br />The study concludes that feature-tracking CMR can effectively capture recovery patterns after STEMI and identifies early intravenous metoprolol as providing long-term protection of infarcted myocardium. It also shows that adverse remodeling is associated with deterioration in remote myocardium, highlighting the importance of assessing both infarcted and non-infarcted regions after myocardial infarction.

Keywords

STEMI

left ventricular function

feature-tracking CMR

circumferential strain

infarct zone

remote myocardium

metoprolol

microvascular obstruction

intramyocardial hemorrhage

adverse LV remodeling