The relationship between terminal QRS distortion on initial ECG and final infarct size at 4months in conventional ST- segment elevation myocardial infarct patients

Prognostic significance of QRS distortion and frontal QRS-T angle in patients with ST-elevation myocardial infarction

BACKGROUND

QRS distortion (G3I) and frontal QRS-T angle (fQRS-T angle) are both electrocardiographic (ECG) signs of ongoing ischemia and depolarization-repolarization heterogeneity, which always occur in patients with ST-segment elevation acute myocardial infarction (STEMI).

METHODS

We retrospectively collected 592 STEMI patients who underwent coronary angiography and follow-up for 42 months. 1. We divided the patients into two groups according to whether they had G3I on admission, compared the differences in examination data and endpoint events between these two groups. 2. Group patients according to whether the endpoint events happened in hospital, at 12 and 42 months, compare whether there is a difference in fQRS-T angle at the same time point, and find out the predictive cutoff value of all-cause death. 3. Combined G3I and fQRS-T angle together to enhance the predictive value.

RESULTS

G3I and fQRS-T angle are both independent risk factors for all-cause death in STEMI patients within 12 months (G3I P = 0.014, fQRS-T angle P < 0.001) and within 42 months (P < 0.001). The cutoff values of fQRS-T angle for predicting all-cause death are 66.5° at 12 months and 90.5° at 42 months. When G3I and fQRS-T angle are combined used to predict the mortality, the specificity is significantly improved, but the sensitivity decreased.

CONCLUSIONS

G3I and fQRS-T angles are valuable in the prognostic assessment of STEMI patients, especially when combined. These findings help clinicians to identify high-risk patients early for more aggressive treatment.

The prognostic significance of grade of ischemia in the ECG in patients with ST-elevation myocardial infarction: A substudy of the randomized trial of primary PCI with or without routine manual thrombectomy (TOTAL trial)

BACKGROUND

The importance of the grade of ischemia (GI) ECG classification in the risk assessment of patients with STEMI has been shown previously. Grade 3 ischemia (G3I) is defined as ST-elevation with distortion of the terminal portion of the QRS complex in two or more adjacent leads, while Grade 2 ischemia (G2I) is defined as ST-elevation without QRS distortion. Our aim was to evaluate the prognostic impact of the GI classification on the outcome in patients with STEMI.

METHODS

7,211 patients from the TOTAL trial were included in our study. The primary outcome was a composite of cardiovascular death, recurrent myocardial infarction (MI), cardiogenic shock, or New York Heart Association (NYHA) class IV heart failure within one year.

RESULTS

The primary outcome occurred in 153 of 1,563 patients (9.8%) in the G3I group vs. 364 of 5,648 patients (6.4%) in the G2I group (adjusted HR 1.27; 95% CI, 1.04 - 1.55; p=0.022). The rate of cardiovascular death (4.8% vs. 2.5%; adjusted HR 1.48; 95% CI 1.09 - 2.00; p=0.013) was also higher in patients with G3I.

CONCLUSIONS

G3I in the presenting ECG was associated with an increased rate of the composite of cardiovascular death, recurrent MI, cardiogenic shock, or NYHA class IV heart failure within one year compared to patients with G2I. Patients with G3I also had a higher cardiovascular death compared to patients with G2I.

Ischemic QRS prolongation as a biomarker of myocardial injury in STEMI patients

BACKGROUND

Patients with acute coronary occlusion (ACO) may not only have ischemia-related ST-segment changes but also changes in the QRS complex. It has recently been shown in dogs that a greater ischemic QRS prolongation (IQP) during ACO is related to lower collateral flow. This suggests that greater IQP could indicate more severe ischemia and thereby more rapid infarct development. Therefore, the purpose was to evaluate the relationship between IQP and measures of myocardial injury in patients presenting with acute ST-elevation myocardial infarction (STEMI).

METHODS

Seventy-seven patients with first-time STEMI were retrospectively included from the recently published SOCCER trial. All patients underwent a cardiac magnetic resonance (CMR) examination 2-6 days after the acute event. Infarct size (IS), myocardium at risk (MaR), and myocardial salvage index (MSI) were assessed and related to IQP. IQP measures assessed were; computer-generated QRS duration, QRS duration at maximum ST deviation, absolute IQP and relative IQP, all derived from a pre-PCI, 12-lead ECG.

RESULTS

Median absolute IQP was 10 ms (range 0-115 ms). There were no statistically significant correlations between measures of IQP and any of the CMR measures of myocardial injury (absolute IQP vs IS, r = 0.03, p = 0.80; MaR, r = -0.01, p = 0.89; MSI, r = -0.05, p = 0.68).

CONCLUSIONS

Unlike previous experimental studies, the IQP was limited in patients presenting at the emergency room with first-time STEMI and no correlation was found between IQP and CMR variables of myocardial injury in these patients. Therefore, IQP does not seem to be a suitable biomarker for triaging patients in this clinical context.