Effect of Early Metoprolol During ST-Segment Elevation Myocardial Infarction on Left Ventricular Strain: Feature-Tracking Cardiovascular Magnetic Resonance Substudy From the METOCARD-CNIC trial.

OBJECTIVES: This study sought to evaluate the effect of early intravenous metoprolol on left ventricular (LV) strain assessed with feature-tracking cardiovascular magnetic resonance (CMR).

BACKGROUND: Early intravenous metoprolol before primary percutaneous coronary intervention (PCI) in ST-segment elevation myocardial infarction (STEMI) portends better outcomes in the METOCARD-CNIC (Effect of Metoprolol in Cardioprotection During an Acute Myocardial Infarction) trial.

METHODS: A total of 197 patients with acute anterior STEMI who were enrolled in the METOCARD-CNIC trial (100 allocated to intravenous metoprolol before primary PCI and 97 control patients) were evaluated. LV global circumferential strain (GCS) and global longitudinal strain (GLS) were measured with feature-tracking CMR at 1 week and 6 months after STEMI and compared between randomization groups.

RESULTS: Patients who received early intravenous metoprolol had significantly more preserved LV strain compared with the control patients at 1 week after STEMI (GCS -13.9 ± 3.8% vs. -12.6 ± 3.9%, respectively; p = 0.013; GLS -11.9 ± 2.8% vs. -10.9 ± 3.2%, respectively; p = 0.032). In both groups, LV strain significantly improved during follow-up (mean difference between 6-month and 1-week strain for the metoprolol group: GCS -2.9%, 95% confidence interval [CI]: -3.5% to -2.4%; GLS: -2.9%, 95% CI: -3.4% to -2.4%; both p < 0.001; the control group: GCS -3.4%, 95% CI: -3.9% to -2.8%; GLS -3.4%, 95% CI: -3.9% to -3.0%; both p < 0.001). When dividing the overall cohort of patients in quartiles of GCS and GLS, there were significantly fewer patients in the first quartile (i.e., the worst LV systolic function) who received early intravenous metoprolol compared with control patients at 1 week and 6 months (p < 0.05 for GCS and GLS at both time points).

CONCLUSIONS: In patients with anterior STEMI, early administration of intravenous metoprolol before primary PCI was associated with significantly fewer patients with severely depressed LV GCS and GLS, both at 1 week and 6 months. Feature-tracking CMR represents a complementary tool to evaluate the benefits of cardioprotective therapies. (Effect of METOprolol in CARDioproteCtioN During an Acute Myocardial InfarCtion [METOCARD-CNIC]: NCT01311700).