Clinical implications of serial changes in ST-segment elevation after reperfusion in patients with anterior acute myocardial infarction

Incidence and Significance of Spontaneous ST Segment Re-elevation After Reperfused Anterior Acute Myocardial Infarction - Relationship With Infarct Size, Adverse Remodeling, and Events at 1 Year

BACKGROUND

Up to 25% of patients with ST elevation myocardial infarction (STEMI) have ST segment re-elevation after initial regression post-reperfusion and there are few data regarding its prognostic significance.Methods and Results:A standard 12-lead electrocardiogram (ECG) was recorded in 662 patients with anterior STEMI referred for primary percutaneous coronary intervention (PPCI). ECGs were recorded 60-90 min after PPCI and at discharge. ST segment re-elevation was defined as a ≥0.1-mV increase in STMax between the post-PPCI and discharge ECGs. Infarct size (assessed as creatine kinase [CK] peak), echocardiography at baseline and follow-up, and all-cause death and heart failure events at 1 year were assessed. In all, 128 patients (19%) had ST segment re-elevation. There was no difference between patients with and without re-elevation in infarct size (CK peak [mean±SD] 4,231±2,656 vs. 3,993±2,819 IU/L; P=0.402), left ventricular (LV) ejection fraction (50.7±11.6% vs. 52.2±10.8%; P=0.186), LV adverse remodeling (20.1±38.9% vs. 18.3±30.9%; P=0.631), or all-cause mortality and heart failure events (22 [19.8%] vs. 106 [19.2%]; P=0.887) at 1 year.

CONCLUSIONS

Among anterior STEMI patients treated by PPCI, ST segment re-elevation was present in 19% and was not associated with increased infarct size or major adverse events at 1 year.

Re-elevation of T-wave from day 2 to day 4 after successful percutaneous coronary intervention predicts chronic cardiac systolic dysfunction in patients with first anterior acute myocardial infarction

This study evaluates the clinical significance of re-elevation of T-wave in patients with ST segment elevation acute myocardial infarction (STEMI) undergoing successful percutaneous coronary intervention (PCI). Resolution of ST elevation within 24 h after reperfusion is associated with better outcome. However, little is known about the serial electrocardiography (ECG) changes and their significance. Seventy-five patients (52 men; 66 ± 1 years) with the first anterior STEMI in whom 12-lead ECG was recorded every day from day 0 to day 8 after PCI were studied. JT interval was quartered (points 1–5), and the deviations from isoelectric line at each point were analyzed in leads V2, V3, and V4. Serial ECG showed ST resolution and T-wave inversion within 2 days after PCI in all patients at the middle of JT interval (point 3), and subsequent re-elevation of T-wave on day 4 in 73 patients (97.3 %). The patients were divided into two groups: Group A (n = 37) with less JT deviation changes (<0.25 mV) from day 2 to day 4 at point 3; and Group B (n = 38) with greater JT deviation changes (≥0.25 mV). Group B had less retrograde collateral flow and longer JT interval in the acute phase, and lower left ventricular ejection fraction (LVEF), worse regional contractility, and higher plasma brain natriuretic peptide levels at 6 months after the onset than Group A (all P < 0.05). The JT deviation change was negatively correlated with and an independent predictor for LVEF in the chronic phase. Re-elevation ≥0.25 mV of T-wave at the middle of JT interval after successful PCI predicts chronic cardiac systolic dysfunction in patients with first anterior STEMI.

Automated assessment of myocardial viability after acute myocardial infarction by global longitudinal peak strain on low-dose dobutamine stress echocardiography

BACKGROUND

Low-dose dobutamine stress echocardiography (DSE) assesses myocardial viability at the early stage of acute myocardial infarction (AMI), but its assessment is subjective and variable. Automated function image (AFI) determines global longitudinal peak strain (GLPS) based on tissue tracking technique. The ability of GLPS obtained by AFI during dobutamine stress to assess myocardial viability after AMI was investigated.

METHODS AND RESULTS

Low-dose DSE at day 3 in 23 consecutive patients with AMI was performed using Vivid 7 (GE Healthcare). Segmental longitudinal peak strain with AFI and obtained GLPS was analyzed. Wall motion score index (WMSI) by echocardiography 1 month later was determined. In 18 patients, left ventriculography was also performed at 3.2±1.5 months later to obtain left ventricular ejection fraction (LVEF) and regional wall motion (RWM, SD/chord). GLPS was improved during dobutamine infusion at 10 µg · kg(-1) · min(-1) (-12.9 ± 3.5% to -15.2 ± 3.6%, P=0.0004). GLPS during dobutamine stress showed good correlations with follow-up WMSI (R=0.47, P=0.02), with peak CK-MB (R = 0.52, P=0.01), with RWM (R = -0.48, P=0.04), and with LVEF (R = -0.54, P=0.02), whereas GLPS at baseline showed no correlations with them. Averaged segmental peak strain at baseline and during stress were correlated with follow-up WMSI (R = 0.50 and 0.43, respectively), but not with LVEF.

CONCLUSIONS

GLPS during dobutamine stress determined by AFI is a promising, objective index to assess myocardial viability on the early stage of AMI.