Left ventricular functional recovery of infarcted and remote myocardium after ST-segment elevation myocardial infarction (METOCARD-CNIC randomized clinical trial substudy)

Abstract

Background: We aimed to evaluate the effect of early intravenous metoprolol treatment, microvascular obstruction (MVO), intramyocardial hemorrhage (IMH) and adverse left ventricular (LV) remodeling on the evolution of infarct and remote zone circumferential strain after acute anterior ST-segment elevation myocardial infarction (STEMI) with feature-tracking cardiovascular magnetic resonance (CMR). Methods: A total of 191 patients with acute anterior STEMI enrolled in the METOCARD-CNIC randomized clinical trial were evaluated. LV infarct zone and remote zone circumferential strain were measured with feature-tracking CMR at 1 week and 6 months after STEMI. Results: In the overall population, the infarct zone circumferential strain significantly improved from 1 week to 6 months after STEMI (− 8.6 ± 9.0% to − 14.5 ± 8.0%; P < 0.001), while no changes in the remote zone strain were observed (− 19.5 ± 5.9% to − 19.2 ± 3.9%; P = 0.466). Patients who received early intravenous metoprolol had significantly more preserved infarct zone circumferential strain compared to the controls at 1 week (P = 0.038) and at 6 months (P = 0.033) after STEMI, while no differences in remote zone strain were observed. The infarct zone circumferential strain was significantly impaired in patients with MVO and IMH compared to those without (P < 0.001 at 1 week and 6 months), however it improved between both time points regardless of the presence of MVO or IMH (P < 0.001). In patients who developed adverse LV remodeling (defined as ≥ 20% increase in LV end-diastolic volume) remote zone circumferential strain worsened between 1 week and 6 months after STEMI (P = 0.036), while in the absence of adverse LV remodeling no significant changes in remote zone strain were observed.

Relationship of Microvascular Obstruction with Global and Regional Myocardial Function Determined by Cardiac Magnetic Resonance after ST-Segment Elevation Myocardial Infarction

“…Huang et al [22] also found that peak troponin is a predictor for the presence of MVO. In addition, like previous research [23] ,…”

“…Our study found that patients with MVO had lower RS and CS in infarct zone than those without MVO, however, the two strains in adjacent and remote zones had no significant differences. Similarly, Podlesnikar et al [23] also found that the infarct zone in patients with MVO had lower CS compared to those without MVO and CS in the non-infarct zone had no significant differences between MVO and non-MVO groups. Therefore, we believe that although MVO will not affect the function of the adjacent and remote zones, the function of infarct zone is extremely reduced by MVO, which will worsen the global LV function of patients with MVO.…”

Five-Year Outcomes and Prognostic Value of Feature-Tracking Cardiovascular Magnetic Resonance in Patients Receiving Early Prereperfusion Metoprolol in Acute Myocardial Infarction

“…In addition, we have previously shown that patients who received early intravenous metoprolol had more preserved global LV strain and infarct zone circumferential strain after STEMI. 16,17 However, in the present analysis we have demonstrated that patients with impaired LV strain, particularly those with impaired GLS, who were treated with early intravenous metoprolol had lower adverse event rates than their counterparts with same degree of LV strain impairment but receiving conventional STEMI therapy. These results strengthen our current evidence of the beneficial long-term prognostic effect of early intravenous metoprolol in STEMI patients with primary PCI and without contraindications to b-blockers.…”

Anterior STEMI associated with decreased strain in remote cardiac myocardium

“…Infarct extent was expressed as the proportion of endocardium involved in the infarction in relation to the total LV endocardial surface as previously described [ 32 ]. Remote myocardium was defined as absence of infarction assessed by LGE [ 25 , 33 ]. Infarct transmurality was expressed in percentage and calculated as the amount of infarcted myocardium divided by the myocardial volume, taken over the area of infarction.…”