Predictive Value of Serial ECGs in Patients with Suspected Myocardial Infarction

The electrocardiogram (ECG) is an important diagnostic tool for patients with suspected acute myocardial infarction (AMI). Current guidelines recommend serial ECGs in case of persisting symptoms. We aimed to analyze the predictive value of ischemic ECG-signs in patients with suspected AMI. Patients presenting to the emergency department with suspected AMI were included. All patients with ST-elevation AMI were excluded from analyses. Patients received 12-lead-ECG and high-sensitive Troponin T (hs-TnT)-measurement at admission and after 3 h. Four groups were defined: no ischemic signs in either ECG; new ischemic signs in the second ECG; resolved ischemic signs in the second ECG; and persistent ischemic signs in both ECGs. Patients were followed for 2 years to assess the composite endpoint of all-cause-mortality, AMI, and coronary revascularization. Using a 30-day landmark analysis, a Cox regression with ischemic signs as the variable of interest, adjusted by cardiovascular risk factors, was calculated. Of 1675 patients, 1321 showed no ischemic signs, in 25 new-, in 92 resolved- and in 237 patients, persistent ischemic signs were documented. Patients with persistent ischemic signs had significantly worse outcomes, compared to those without. Compared to no ischemic signs, adjusted hazard ratios for the combined endpoint were 0.81 (95% CI 0.20, 3.31; p-value = 0.77) for new-, 0.59 (95% CI 0.26, 1.34; p-value = 0.21) for resolved-, and 1.47 (95% CI 1.102, 2.13; p-value = 0.041) for persistent ischemic signs. In patients with suspected AMI, persistent ischemic ECG-signs are predictive of a higher rate of all-cause-mortality, AMI, and revascularization.

ST-segment abnormalities are associated with long-term prognosis in non-ST-segment elevation acute coronary syndromes: The ERICO-ECG study

INTRODUCTION

We aimed to identify whether ST-segment abnormalities, in the admission or during in-hospital stay, are associated with survival and/or new incident myocardial infarction (MI) in 623 non-ST-elevation acute coronary syndrome participants of the Strategy of Registry of Acute Coronary Syndrome (ERICO) study.

MATERIALS AND METHODS

ERICO is conducted in a community-based hospital. ST-segment analysis was based on the Minnesota Code. We built Cox regression models to study whether ECG was an independent predictor for clinical outcomes.

RESULTS

Median follow-up was 3years. We found higher risk of death due to MI in individuals with ST-segment abnormalities in the final ECG (adjusted hazard ratio: 2.68; 95% confidence interval: 1.14-6.28). Individuals with ST-segment abnormalities in any tracing had a non-significant trend toward a higher risk of fatal or new non-fatal MI (p=0.088).

CONCLUSIONS

ST-segment abnormalities after the initial tracing added long-term prognostic information.

Assessment of myocardial infarct size with body surface potential mapping: validation against contrast-enhanced cardiac magnetic resonance imaging

BACKGROUND

Assessment of myocardial infarct (MI) size is important for therapeutic and prognostic reasons. We used body surface potential mapping (BSPM) to evaluate whether single-lead electrocardiographic variables can assess MI size.

METHODS

We performed BSPM with 120 leads covering the front and back chest (plus limb leads) on 57 patients at different phases of MI: acutely, during healing, and in the chronic phase. Final MI size was determined by contrast-enhanced cardiac magnetic resonance imaging (DE-CMR) and correlated with various computed depolarization- and repolarization-phase BSPM variables. We also calculated correlations between BSPM variables and enzymatic MI size (peak CK-MBm).

RESULTS

BSPM variables reflecting the Q- and R wave showed strong correlations with MI size at all stages of MI. R width performed the best, showing its strongest correlation with MI size on the upper right back, there representing the width of the "reciprocal Q wave" (r = 0.64-0.71 for DE-CMR, r = 0.57-0.64 for CK-MBm, P < 0.0001). Repolarization-phase variables showed only weak correlations with MI size in the acute phase, but these correlations improved during MI healing. T-wave variables and the QRSSTT integral showed their best correlations with DE-CMR defined MI size on the precordial area, at best r = -0.57, P < 0.0001 in the chronic phase. The best performing BSPM variables could differentiate between large and small infarcts at all stages of MI.

CONCLUSIONS

Computed, single-lead electrocardiographic variables can estimate the final infarct size at all stages of MI, and differentiate large infarcts from small.

Comparative prognostic value of T-wave inversion and ST-segment depression on the admission electrocardiogram in non-ST-segment elevation acute coronary syndromes

BACKGROUND

ST-segment depression (STD) is predictive of adverse outcomes in non-ST-segment elevation acute coronary syndromes (NSTE-ACS), but there are conflicting data on the incremental prognostic value of T-wave inversions (TWIs) on the admission electrocardiogram.

METHODS

Admission electrocardiograms of 7,343 patients with NSTE-ACS from the Global Registry of Acute Coronary Events (GRACE) and ACS I registry were independently analyzed at a core laboratory and stratified by TWI and STD status. We performed multivariable analyses to determine the independent prognostic significance of TWI and tested for interaction between TWI and STD for adverse outcomes.

RESULTS

Patients with TWI and/or STD had a higher prevalence of cardiovascular risk factors, higher Killip class, and higher GRACE risk scores. Among the 2,708 patients with available angiographic data, rates of 3-vessel or left main disease were similar between patients with TWI and those without TWI/STD. After adjusting for other established prognosticators, TWI did not independently predict in-hospital (adjusted odds ratio 1.03, 95% CI 0.75-1.42, P = .85) or 6-month mortality (adjusted odds ratio 1.02, 95% CI 0.80-1.30, P = .88); STD remained a strong independent predictor. There was no interaction between TWI and STD for these outcomes. No contiguous lead groups or cumulative number of leads with TWI provided independent prognostic information.

CONCLUSIONS

TWI is associated with other high-risk clinical features but is not an independent predictor of adverse short- and long-term mortality in NSTE-ACS. T-wave inversion does not provide additional prognostication beyond the GRACE risk model, and its concomitant presence does not alter the prognostic value of STD.

An early and simple predictor of severe left main and/or three-vessel disease in patients with non-ST-segment elevation acute coronary syndrome

Clopidogrel should be initiated as soon as possible in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) except those who urgently require coronary artery bypass grafting (CABG). The present study assessed the ability to predict severe left main coronary artery and/or 3-vessel disease (LM/3VD) that would most likely require urgent CABG based on only clinical factors on admission in 572 patients with NSTE-ACS undergoing coronary angiography. Severe LM/3VD was defined as ≥75% stenosis of LM and/or 3VD with ≥90% stenosis in ≥2 proximal lesions of the left anterior descending coronary artery and other major epicardial arteries. Patients were divided into the 3 groups according to angiographic findings: no LM/3VD (n = 460), LM/3VD but not severe LM/3VD (n = 57), and severe LM/3VD (n = 55). Severe LM/3VD was associated with a higher rate of urgent CABG compared to no LM/3VD and LM/3VD but not severe LM/3VD (46%, 2%, and 2%, p <0.001). On multivariate analysis, degree of ST-segment elevation in lead aVR was the strongest predictor of severe LM/3VD (odds ratio 29.1, p <0.001), followed by positive troponin T level (odds ratio 1.27, p = 0.044). ST-segment elevation ≥1.0 mm in lead aVR best identified severe LM/3VD with 80% sensitivity, 93% specificity, 56% positive predictive value, and 98% negative predictive value. In conclusion, ST-segment elevation ≥1.0 mm in lead aVR on admission electrocardiogram is highly suggestive of severe LM/3VD in patients with NSTE-ACS. Selected patients with this finding might benefit from promptly undergoing angiography, withholding clopidogrel to allow early CABG.