Evaluation of a QRS scoring system in acute myocardial infarction: relation to infarct size, early stage left ventricular ejection fraction, and exercise performance

Validation and derivation of short-term prognostic risk score in acute decompensated heart failure in China

Background

Few prognostic risk scores (PRSs) have been routinely used in acute decompensated heart failure (ADHF). We, therefore, externally validated three published PRSs (3A3B, AHEAD, and OPTIME-CHF) and derived a new PRS to predict the short-term prognosis in ADHF.

Methods

A total of 4550 patients from the Heb-ADHF registry in China were randomly divided into the derivation and validation cohorts (3:2). Discrimination of each PRS was assessed by the area under the receiver operating characteristic curve (AUROC). Logistic regression was exploited to select the predictors and create the new PRS. The Hosmer–Lemeshow goodness-of-fit test was used to assess the calibration of the new PRS.

Results

The AUROCs of the 3A3B, AHEAD, and OPTIME-CHF score in the derivation cohort were 0.55 (95% CI 0.53–0.57), 0.54 (95% CI 0.53–0.56), and 0.56 (95% CI 0.54–0.57), respectively. After logistic regression analysis, the new PRS computed as 1 × (diastolic blood pressure < 80 mmHg) + 2 × (lymphocyte > 1.11 × 10⁹/L) + 1 × (creatinine > 80 μmol/L) + 2 × (blood urea nitrogen > 21 mg/dL) + 1 × [BNP 500 to < 1500 pg/mL (NT-proBNP 2500 to < 7500 pg/mL)] or 3 × [BNP ≥ 1500 (NT-proBNP ≥ 7500) pg/mL] + 3 × (QRS fraction of electrocardiogram < 55%) + 4 × (ACEI/ARB not used) + 1 × (rhBNP used), with a better AUROC of 0.67 (95% CI 0.64–0.70) and a good calibration (Hosmer–Lemeshow χ² = 3.366, P = 0.186). The results in validation cohort verified these findings.

Conclusions

The short-term prognostic values of 3A3B, AHEAD, and OPTIME-CHF score in ADHF patients were all poor, while the new PRS exhibited potential predictive ability. We demonstrated the QRS fraction of electrocardiogram as a novel predictor for the short-term outcomes of ADHF for the first time. Our findings might help to recognize high-risk ADHF patients.

Estimating the extent of myocardial damage in patients with STEMI using the DETERMINE score

Background

Recently, a simple ECG score (DETERMINE score) has been proposed for estimating myocardial scar in patients with ischaemic cardiomyopathy. We sought to evaluate the usefulness of the DETERMINE score for the assessment of myocardial infarct size (IS) as well as microvascular obstruction (MVO), in the setting of ST-elevation myocardial infarction (STEMI).

Methods

This observational study enrolled 423 patients with STEMI (median age 56, 17% women), revascularised by primary percutaneous coronary intervention (PCI). For evaluation of the DETERMINE and Selvester scoring system (an established but complex ECG score for IS estimation), ECG was conducted before discharge (median: 4 (IQR 2–6) days). Cardiac magnetic resonance (CMR) was conducted within a week after infarction for determination of IS and MVO.

Results

Median DETERMINE score of the overall cohort was 8 points (IQR 5–11). A higher DETERMINE score was significantly associated with a larger IS (21% vs 11% of left ventricular myocardial mass (LVMM), p<0.001) as well as larger MVO (1.2% vs 0.0% of LVMM, p<0.001). In linear and binary multivariable logistic regression analysis, the DETERMINE score remained independently associated with IS (OR 1.09, 95% CI 1.02 to 1.17, p=0.014) and MVO (OR 1.12, 95% CI 1.04 to 1.21, p=0.003), after adjustment for Selvester score and clinical indicators of IS (high-sensitivity cardiac troponin T, high-sensitivity C reactive protein, N-terminal pro-B-type natriuretic peptide, TIMI flow pre-interventional and post-interventional PCI, anterior infarct localisation).

Conclusions

In patients undergoing PCI for STEMI, the DETERMINE score provides an easy and inexpensive tool for appropriate estimation of infarct severity as determined by CMR.

Complete versus simplified Selvester QRS score for infarct severity assessment in ST-elevation myocardial infarction

Background

Complete and simplified Selvester QRS score have been proposed as valuable clinical tool for estimating myocardial damage in patients with ST-elevation myocardial infarction (STEMI). We sought to comprehensively compare both scoring systems for the prediction of myocardial and microvascular injury assessed by cardiac magnetic resonance (CMR) imaging in patients with acute STEMI.

Methods

In this prospective observational study, 201 revascularized STEMI patients were included. Electrocardiography was conducted at a median of 2 (interquartile range 1–4) days after the index event to evaluate the complete and simplified QRS scores. CMR was performed within 1 week and 4 months thereafter to determine acute and chronic infarct size (IS) as well as microvascular obstruction (MVO).

Results

Complete and simplified QRS score showed comparable predictive value for acute (area under the curve (AUC) = 0.64 vs. 0.67) and chronic IS (AUC = 0.63 vs. 0.68) as well as for MVO (AUC = 0.64 vs. 0.66). Peak high sensitivity cardiac troponin T (hs-cTnT) showed an AUC of 0.88 for acute IS and 0.91 for chronic IS, respectively. For the prediction of MVO, peak hs-cTnT represented an AUC of 0.81.

Conclusions

In reperfused STEMI, complete and simplified QRS score displayed comparable value for the prediction of acute and chronic myocardial as well as microvascular damage. However, both QRS scoring systems provided inferior predictive validity, compared to peak hs-cTnT, the clinical reference method for IS estimation.

The predischarge electrocardiographic pattern in anterior acute myocardial infarction: relation between evolutionary ST segment and T-wave configuration and prediction of myocardial infarct size and left ventricular systolic function by the QRS Selvester score

Left ventricular systolic function, determined mainly by final infarct size, has a major influence on prognosis after acute myocardial infarction (MI). It was found that infarct size and left ventricular ejection fraction can be predicted using the Selvester QRS-score in patients not receiving reperfusion therapy. We assessed whether the predischarge QRS-score can be used for estimating infarct size and left ventricular ejection fraction in 51 patients with a first anterior MI who had received reperfusion therapy and whether considering the configuration of the ST-segments and T-waves will increase the accuracy of these predictions. All patients had received reperfusion therapy and had predischarge resting 99mTc-sestamibi scan. We determined the Selvester QRS score using the electrocardiograms performed on the same day of the scan. In addition, we divided the patients into 3 groups: A: isoelectric ST and negative T-waves (n = 12); B: ST elevation (> or =0.1 mV) and negative T-waves (n = 23); and C: ST elevation (> or =0.1 mV) and positive T-waves (n = 16). The myocardial perfusion defect extent increased from group A to C (28.5+/-16.4%, 39.4+/-14.8%, and 45.3+/-15.8% in groups A, B, and C. respectively; P = .022). Similarly, the left ventricular ejection fraction decreased (41.7+/-11.6%, 38.4+/-8.1%, and 32.0+/-9.7%, respectively; P = .042) from group A to C. Overall, the correlation between the QRS-score and the myocardial perfusion defect extent (Rho = 0.249; P = .08), and ejection fraction (Rho = -0.229; P = .11) was not good. A statistically significant correlation between the myocardial perfusion defect size and the QRS-score was found only in group A (Rho = 0.599, P = .04). In patients with a first anterior myocardial infarction who underwent reperfusion therapy, the predischarge QRS-score is predictive of infarct size only in those in whom ST elevation resolved completely. In patients with residual ST elevation the Selvester QRS-score is inaccurate in predicting infarct size and left ventricular ejection fraction upon discharge.

Echocardiographic determinants of left ventricular ejection fraction after acute myocardial infarction

OBJECTIVE

This study was performed to determine if factors other than the size of regional dysfunction influence the global left ventricular ejection fraction after acute myocardial infarction.

BACKGROUND

Left ventricular ejection fraction is an important prognostic variable after acute myocardial infarction. Although infarct size is known to affect the subsequent global left ventricular ejection fraction, it remains unclear whether other factors such as site or severity of the wall motion abnormality influence the ejection fraction after acute myocardial infarction.

METHODS

Sixty-nine consecutive patients (mean age 61 +/- 14 years, 46 [67%] male) who did not receive thrombolytic therapy or undergo early revascularization were studied by echocardiography 1 week after Q-wave myocardial infarction. The absolute size of the region of abnormal wall motion (AWM) and the percentage of the endocardium involved (%AWM) were quantitated along with the wall motion score. A severity index was then derived as the mean wall motion score within the region of AWM. Site of myocardial infarction was classified as either anterior or inferior from the endocardial map. Left ventricular ejection fraction was measured by Simpson's method with 2 apical views.

RESULTS

Twenty-nine (42%) patients had anterior and 40 had inferior myocardial infarction. The mean left ventricular ejection fraction was significantly lower in anterior than in inferior myocardial infarction (44.8% +/- 11.5% vs 53% +/- 8.6%; P =. 001). The mean %AWM was greater in anterior than in inferior myocardial infarction (32.1 +/- 15.5 vs 22.4 +/- 14.1; P =.01). The mean wall motion score was greater in anterior than in inferior myocardial infarction (9.8 +/- 6.4 vs 6.4 +/- 4.4; P =.01). The mean severity index did not differ by site. Multiple regression analysis demonstrated that, in descending order of importance, %AWM, extent of apical involvement, and site of myocardial infarction were independent determinants of global left ventricular ejection fraction.

CONCLUSIONS

For myocardial infarctions of similar size, left ventricular ejection fraction is lower when apical involvement is extensive and the site of infarction is anterior. This site-dependent difference may be related to characteristics specific to the apex.

Electrocardiographic evolutionary changes and left ventricular remodeling after acute myocardial infarction: results of the GISSI-3 Echo substudy

OBJECTIVES

The aim of this study was to describe the electrocardiographic (ECG) evolutionary changes after an acute myocardial infarction (AMI) and to evaluate their correlation with left ventricular function and remodeling.

BACKGROUND

The QRS complex changes after AMI have been correlated with infarct size and left ventricular function. By contrast, the significance of T wave changes is controversial.

METHODS

We studied 536 patients enrolled in the GISSI-3-Echo substudy who underwent ECG and echocardiographic studies at 24 to 48 h (S1), at hospital discharge (S2), at six weeks (S3) and six months (S4) after AMI.

RESULTS

The number of Qwaves (nQ) and QRS quantitative score (QRSs) did not change over time. From S2 to S4, the number of negative T waves (nT NEG) decreased (p < 0.0001), wall motion abnormalities (%WMA) improved (p < 0.001), ventricular volumes increased (p < 0.0001) while ejection fraction remained stable. According to the T wave changes after hospital discharge, patients were divided into four groups: stable positive T waves (group 1, n = 35), patients who showed a decrease > or =1 in nT NEG (group 2, n = 361), patients with no change in nT NEG (group 3, n = 64) and those with an increase > or =1 in nT NEG (group 4, n = 76). The QRSs and nQ remained stable in all groups. Groups 3 and 4 showed less recovery in %WMA, more pronounced ventricular enlargement and progressive decline in ejection fraction than groups 1 and 2 (interaction time x groups p < 0.0001).

CONCLUSIONS

The analysis of serial ECG can predict postinfarct left ventricular remodeling. Normalization of negative T waves during the follow-up appears more strictly related to recovery of regional dysfunction than QRS changes. Lack of resolution and late appearance of new negative T predict unfavorable remodeling with progressive deterioration of ventricular function.

A normal electrocardiogram precludes the need for left ventriculography in the assessment of coronary artery disease

OBJECTIVE

To assess whether a normal electrocardiogram can identify good left ventricular function and obviate the need for routine left ventriculography in patients undergoing cardiac catheterization for suspected coronary artery disease.

DESIGN

A prospective study of patients undergoing cardiac catheterisation.

SETTING

A regional cardiac centre.

PATIENTS

The electrocardiograms, coronary angiograms, and left ventriculograms of 391 consecutive patients undergoing investigations for suspected coronary artery disease were entered into the study. Patients with arrhythmias and cardiac pathologies other than coronary artery disease were excluded.

MAIN OUTCOME MEASURES

The electrocardiogram was assessed using a 29 point QRS scoring system, and classified by two cardiologists and a trainee cardiologist as normal or abnormal. Left ventricular function was assessed by digital ventriculography.

RESULTS

The sensitivity, specificity, and negative predictive value of a QRS score of 0 (normal QRS complexes) for discriminating good left ventricular function (ejection fraction > or = 50%) were 92.6%, 41.5%, and 97.2%, respectively. The figures for a normal electrocardiogram as assessed by a doctor were 96.3%, 40.4%, and 98.6% for cardiologist A; 96.3%, 37.4%, and 98.4% for cardiologist B; and 94.4%, 49.6%, and 98.2% for the cardiology trainee.

CONCLUSIONS

If a cardiologist judges the ECG to be normal, left ventriculography is unnecessary and a formal QRS score does not improve reliability of this clinical judgment. Adopting this strategy would save 30-40,000 Pounds in consumables and 65-87 hours of catheter laboratory and staff time for a department catheterising 3000 patients with suspected coronary artery disease annually.

Use of the QRS scoring system in the early estimation of myocardial infarct size following reperfusion

While the QRS scoring system has been established as a convenient tool for estimating infarct size in nonreperfused patients during the chronic stage of myocardial infarction, its applicability to reperfused patients in the acute stage has not been established. To investigate whether infarct size could be estimated by the QRS scoring system soon after reperfusion, we evaluated QRS scores obtained serially 6 hours to 1 month after reperfusion, total creatine kinase release, and left ventricular ejection fraction in 126 patients with acute myocardial infarction who underwent successful reperfusion therapy. A significant correlation was observed between the QRS score obtained after 6 hours and that obtained after 1 month (r = .89). The QRS scores obtained after 6 hours and 1 month were significantly correlated with total creatine kinase release (r = -.65 and r = -.75, respectively) and left ventricular ejection fraction (r = .62 and r = .76, respectively). Thus, the QRS scoring system can be used as a simple and economical method for estimation of infarct size soon after reperfusion.

Pathophysiological analysis of serum troponin T release kinetics in evolving ischemic myocardial injury

The present study measured cardiac troponin T(TnT) for the pathophysiological analysis of evolving ischemic myocardial injury in 35 patients with unstable angina (3: Class IB, 32: Class IIIB) and in 40 patients undergoing coronary reperfusion therapy for acute myocardial infarction. Serum TnT, creatine kinase (CK), CKMB, myoglobin (Mb), and myosin light chain 1 (MLC1) were measured every 2-24 h for 10 days after admission to the CCU. In patients with unstable angina, positive test results were detected in 65.7% for TnT, 20% for CK, 37.1% for CKMB, 60.9% for Mb, and 26% for MLC1. Of the 23 patients with positive TnT, 12 (52.2%) had cardiac events. Of the 12 patients with negative TnT, 11 (91.6%) were event-free. All of the patients who developed cardiac events showed a persistent (n = 10) or delayed elevation (n = 2) pattern 28-120 h beforehand. The sensitivity for predicting cardiac events was 92.3% for TnT, 80% for Mb, 53.8% for CKMB, and 50% for MLC1. In patients with acute myocardial infarction, TnT release kinetics showed 2 peaks after coronary reperfusion therapy. TnT values at the 1st peak significantly correlated with maximum CKMB (r = 0.70, p < 0.05) and early-stage left ventricular wall motion score (r = 0.60, p < 0.05), while 2nd-peak TnT values significantly correlated with maximum MLC1 (r = 0.59, p < 0.05), the T1-SPECT score (r = 0.78, p < 0.05) and left ventricular ejection fraction (r = -0.74, p < 0.05) in the convalescent stage. The 2nd/1st-peak TnT ratio significantly correlated with the nQ/nST elevation index (ratio of the number of leads developing abnormal Q-wave 1 week after the onset to the number of leads showing ST elevation of more than 1 mm at admission) (r = 0.63, p < 0.05) in patients with anterior myocardial infarction. These data indicate that persistent release of TnT reflects progressive irreversible myocardial damage in unstable angina and indicates a risk of future cardiac events. In acute myocardial infarction, the 2nd/1st-peak TnT ratio in patients undergoing coronary reperfusion therapy may be useful for the quantitative evaluation of myocardial salvage.

QRS score as an indicator of myocardial viability after thrombolytic therapy

Electrocardiographic estimation of myocardial injury has, in some studies, correlated poorly with the extent of nuclear perfusion defects at rest and with changes in the left ventricular ejection fraction after acute reperfusion therapy. The authors investigated 16 patients with fatty acid scintigraphy and with the Selvester-Wagner QRS score 2 weeks and 3 months after an anterior myocardial infarction. Segmental uptake on tomographic scans was semiquantitatively classified as low, moderate, or normal. The analysis included a total of 707 segments. QRS scores and the number of segments with low fatty acid uptake did not significantly change during the follow-up period, although the number of segments with moderate fatty acid uptake decreased from 15.9 +/- 5.1 to 12.4 +/- 5.7 (P < .05). The QRS score correlated significantly (rho = .56-.64) with low fatty acid uptake, but not with moderate fatty acid uptake. It is concluded that the QRS score is related to the degree of permanent myocardial injury, even after thrombolysis.

QRS scoring with the Mason-Likar lead system at rest and during ischaemia

The stability of the post-infarction simplified 29-point Selvester QRS score during maximal exercise testing was studied using both standard 12 and Mason-Likar (modified standard, M-L) ECG lead systems. Thirty-eight patients participated in the standard exercise test (mean interval after single infarction 4 months) and a total of 54 patients underwent exercise 201thallium emission tomography with M-L lead system 2 months later. None had electrocardiographic features complicating the scoring. There were no significant differences between the (paired) mean QRS scores, except between the M-L score at rest (2.3 +/- 2.4) and at exercise (3.2 +/- 2.6, P less than 0.01). The correlation coefficient (r) between resting scores was 0.87, between rest and exercise 0.90 (standard leads) and 0.80 (M-L leads). In 78% nuclear imaging revealed ischaemia, but this had no significant effect on the mean scores or correlation between rest and exercise scores. It is concluded that the QRS score is relatively stable during exercise with standard leads if the limb leads are recorded immediately after the exercise. Scoring with the M-L lead system is somewhat inaccurate, especially during exercise, and is not recommended for stratification of clinical risk. The QRS score is protected against ischaemia, which emphasizes its value as an independent prognostic tool.

Prognostic use of a QRS scoring system after hospital discharge for initial acute myocardial infarction in the Framingham cohort

Myocardial infarct size is an important risk factor for survival after acute myocardial infarction (AMI). The purpose of this study was to determine the prognostic value of myocardial infarct size, as estimated by the Selvester 54-criteria/32-point QRS scoring system, in the Framingham cohort. During the first 30 years of the Framingham Heart Study, a total of 384 participants developed an AMI requiring hospitalization; from this group, 243 patients met the following inclusion criteria: (1) no electrocardiographic changes due to a previous infarction, (2) survival greater than 3 days after discharge from the AMI hospitalization and (3) no electrocardiographic evidence of conduction disturbances or ventricular hypertrophy at the time of their final in-hospital electrocardiogram. Univariate and multivariate analyses were performed to test the association of the QRS score, and other associated risk factors, with time until coronary heart disease-related death. QRS score was found to be significantly associated with outcome (p = 0.03), as was the systolic blood pressure before infarction (p greater than 0.001). Both univariate and multivariate analysis showed that a history of systolic hypertension was the variable most strongly associated with coronary heart disease-related death. Thus, identification of AMI survivors at high risk for subsequent mortality can be improved by routine blood pressure measurement before AMI, and QRS scoring of the electrocardiogram taken at hospital discharge.

Diagnostic value of electrocardiographic variables to predict the presence of ventricular late potentials

To test the hypothesis that the presence of ventricular late potentials in the highly amplified, averaged and filtered surface electrocardiogram (ECG) can be predicted from the conventional surface ECG, 211 patients with and without previously documented sustained ventricular tachycardia outside the acute phase of myocardial infarction were studied. The presence of left ventricular akinesia or aneurysm was significantly correlated with the ECG score (based on Q wave duration, R wave duration and amplitude ratio). The mean ECG score in patients without ventricular tachycardia was 3.4 +/- 3.5 points compared with 5.5 +/- 3.9 points (p less than 0.001) in patients with ventricular tachycardia. The presence of late potentials was positively correlated with the ECG score in the whole cohort of patients. This was also the case in the subgroup of patients without a history of sustained ventricular tachycardia. In contrast, in patients with ventricular tachycardia, the presence of late potentials was independent of their ECG score. Using linear discriminant function analyses to predict the presence of late potentials, a history of ventricular tachycardia alone and the ECG score alone had a high predictive power (high standardized coefficients). If combinations of variables were analyzed including estimates of left ventricular function (presence of aneurysm or akinesia; ejection fraction), the ECG score and a history of ventricular tachycardia still ranked highest. The influence of ejection fraction if used in combination with other variables for the prediction of late potentials was relatively small (standardized coefficient of 0.4). In conclusion, the surface ECG can be used in patients previously free of sustained ventricular tachycardia to predict the presence of ventricular late potentials.(ABSTRACT TRUNCATED AT 250 WORDS)

Value of normal electrocardiographic findings in predicting resting left ventricular function in patients with chest pain and suspected coronary artery disease

PURPOSE

Characterization of left ventricular function is important in managing patients with coronary artery disease. Although many methods are available to assess left ventricular function, most are either expensive, invasive, or both. In this study, we examined the ability of normal or near-normal resting electrocardiographic findings to predict resting left ventricular ejection fraction, measured by resting radionuclide angiography, in 874 patients with chest pain and suspected coronary artery disease.

PATIENTS AND METHODS

A retrospective review was undertaken of 4,410 Mayo Clinic patients who underwent rest and exercise radionuclide ventriculography for the evaluation of chest pain and known or suspected coronary artery disease; of these, 874 patients met the inclusion criteria for the current study. A 15-lead electrocardiogram, which was interpreted by the cardiologist or cardiology trainee working in the laboratory, was obtained at the same evaluation as the radionuclide study.

RESULTS

In 590 patients with no previous history of a myocardial infarction and entirely normal resting electrocardiographic results without nonspecific ST-T wave abnormalities, the mean left ventricular ejection fraction was 0.63 +/- 0.004, and 559 patients (95%) had a normal resting ejection fraction (defined as 0.50 or more). Both nonspecific ST-T wave abnormalities (p less than 0.001) and, to a lesser degree, a history of myocardial infarction (p = 0.06) were independent predictors of an abnormal resting ejection fraction. In 185 patients with nonspecific ST-T wave abnormalities and no history of myocardial infarction, the mean left ventricular ejection fraction was 0.61 +/- 0.009, and 85% had a normal resting ejection fraction. In 36 patients with nonspecific ST-T wave abnormalities and a history of myocardial infarction, the mean left ventricular ejection fraction was 0.53 +/- 0.021, and 72% had a normal resting ejection fraction.

CONCLUSION

Thus, an entirely normal result on a resting 12-lead electrocardiogram in patients with suspected coronary disease but no history of a previous myocardial infarction is a reliable (95%) predictor of normal left ventricular function. If nonspecific ST-T wave abnormalities are noted, particularly if there is a history of a previous infarction, the predictive value of the electrocardiographic findings is diminished.

The natural course of electrocardiographic stages of acute inferior myocardial infarction in regard to R/Q ratio group classification

Forty-three patients with their first acute inferior wall myocardial infarction (IWMI) were divided into three groups according to the R/Q ratio in standard lead II. This was done to correlate these groups with the characteristic course of electrocardiographic stages. The R/Q ratio was measured on the ninth day of follow-up study, and the electrocardiographic stages were followed from the onset of the IWMI up until the ninth day. Patients with R/Q greater than 2 (group I) had a more rapid progression through the electrocardiographic stages, along with a better clinical course than patients with a lower R/Q ratio. Patients in group III, with R/Q less than 1, had a slower electrocardiographic stage progression, which correlates well with a more complicated clinical course. Group II was an intermediate group in both the electrocardiographic and clinical course. Rapid stage evolution in the first 12 hours of the IWMI was followed by a more rapid progression through stages during the rest of the follow-up period. It is suggested that the R/Q ratio in lead II can be used as a marker of the severity of IWMI, since it correlates well with the course of electrocardiographic stages. The greater the R/Q ratio, the more rapid the progression of electrocardiographic stages, and the better the clinical course. This may be an additional simple and inexpensive electrocardiographic tool for following the natural course of IWMI.

Does acute-phase beta-blockade reduce mortality in acute myocardial infarction by limiting infarct size?

The mechanism by which early intervention with beta-blockers reduces mortality in acute myocardial infarction is unclear. Therefore the effects of intravenous, followed by oral, metoprolol on indices of infarct size were studied in a double-blind fashion with a median delay of 6.75 hours from onset of symptoms. In 129 patients peak enzyme release and QRS score on the electrocardiogram were assessed, while myocardial perfusion score on thallium-201 scintigraphy was studied in 45 patients. There was a close correlation between all the indices of infarct size. While the correlation coefficients did not appear to be influenced by metoprolol treatment, the slope of the regression was affected. Peak aspartate aminotransferase and lactic dehydrogenase were lower by 11 and 7%, respectively, in the metoprolol-treated group, but no reduction was noted in QRS score or in thallium-201 perfusion defect size in the actively treated group. Thus, it seems likely that early intervention with metoprolol in acute myocardial infarction reduces mortality, not by limiting infarct size, but by some other mechanism.

Prolonged PR interval associated with an abnormal frontal plane QRS axis as an electrocardiographic criterion of left ventricular function

The aim of this study was to investigate whether, in patients who had had one or more myocardial infarctions, the electrocardiographic appearances of prolonged PR interval associated with an abnormal frontal plane QRS axis are correlated with the value of left ventricular ejection fraction. Seventy-three consecutive patients all of whom had had at least one myocardial infarction, were divided into 3 groups: Group A, 22 patients having on their electrocardiogram a prolonged PR interval and an abnormal frontal plane QRS axis; Group B, 15 patients having an abnormal QRS axis as a solitary conduction disturbance; and Group C, 36 patients without conduction abnormalities. The ejection fraction, determined in all patients by gated blood pool imaging, was found to be 30% +/- 8 (mean +/- 1 SD) in Group A, 53% +/- 21 in Group B, and 52% +/- 14 in Group C (P less than 0.001). An ejection fraction of less than 40% was found in 91% of patients in Group A, in 33.33% in Group B, and in 8.33% in Group C (P less than 0.01). Multiple segment ventricular wall contraction abnormalities were found in 50, 6.66, and 11.11%, respectively (P less than 0.001). It can be presumed, therefore, that in patients after one or more myocardial infarctions, this association of conduction abnormalities signifies a severe impairment of ventricular contractility and may identify a subgroup with a high prevalence of severely depressed ejection fraction.

Relationship of QRS scoring system to enzymatic and pathologic infarct size: the role of infarct location

A method for estimating infarct size from 12-lead ECGs has been developed but not extensively validated. To assess its accuracy, ECG scores from 62 patients admitted to the coronary care unit at Barnes Hospital were compared to infarct size calculated from plasma MB creatine kinase (MB-CK) activity. A second cohort of 29 patients enrolled in the Multicenter Investigation of the Limitation of Infarct Size (MILIS) was evaluated as a test set and to provide pathologic correlates. Patients with conduction system disease, ventricular hypertrophy, or multiple infarctions were excluded, as were those in the Barnes group who had undergone thrombolytic therapy. ECGs obtained early (days 3 to 7 in the Barnes group and day 3 in the MILIS group) or late (days 8 to 14 in the Barnes group) were scored manually and by computer. QRS scores from early ECGs of patients with anterior infarctions correlated closely with MB-CK estimates of infarct size (r = 0.71 [Barnes] and 0.85 [MILIS] and with anatomic data (r = 0.78). Enzymatic and pathologic infarct size also correlated well (r = 0.85). Correcting for body surface area by means of total CK-derived infarct size or use of QRS scores from late ECGs did not alter the correlation coefficients. Among patients with inferior infarctions QRS scores corresponded poorly with MB-CK infarct size (r = 0.28 [Barnes] and r = -0.42 [MILIS]) and pathologic infarct size (r = -0.20), despite a significant relationship between pathologic and MB-CK estimates (r = 0.62).(ABSTRACT TRUNCATED AT 250 WORDS)

Development and validation of an automated method of the Selvester QRS scoring system for myocardial infarct size

The Selvester QRS score for estimation of myocardial infarct (MI) size from the standard 12-lead electrocardiogram (ECG) has not yet achieved wide recognition as a valuable tool in the routine assessment of the MI patient, primarily because of the practical limitations inherent to manual application. This study examined the ECGs of 438 patients (105 normal subjects, 161 with "possible" MI and 172 with "definite" MI based on data from cardiac catheterization) to develop software for an automated method of the Selvester system in attempts to overcome the manual constraints. After a comprehensive validation process involving extensive interactions between the manual scorer and the software developer, an automated method of the Selvester system was generated that had a high correlation with manual application (r = 0.94) and was superior regarding time, training, reader bias, reproducibility and precision of measurement. These results indicate that an automated version of the Selvester QRS scoring system would resolve many of the limitations of manual application and would provide a reliable, technically accurate estimate of MI size that could be incorporated into ECG diagnostic programs and used in standard digital ECG machines.

An ischemic index from the electrocardiogram to select patients with low left ventricular ejection fraction for coronary artery bypass grafting

Patients who have a decreased left ventricular (LV) ejection fraction (EF) may be denied coronary by-pass grafting (CABG) because it is assumed that improvement in function is unlikely. If the low LVEF were due to myocardial necrosis, this assumption would be valid. If the dysfunction were due to both necrosis and ischemia, however, then improvement may be possible with CABG. A method capable of identifying such patients would be useful. In this study, an "ischemic index" was determined for 37 patients based on the difference between the presurgical LVEF estimated from the standard 12-lead electrocardiogram by the Selvester QRS score (indicating the extent of dysfunction due to necrosis) and the presurgical LVEF measured from resting multigated radionuclide angiography (indicating dysfunction due to both necrosis and ischemia). It was hypothesized that a high ischemia index, that is, a large discrepancy between estimated and measured LVEF, would be associated with an improved post-surgical measured LVEF. The results showed that patients with an ischemic index of less than or equal to 0 had a mean decrease in LVEF of 8% (p = 0.02) and those with an index between 0 and 10 had no mean change. Patients with an index greater than or equal to 11, however, had a mean increase of 5% (p = 0.02), suggesting that depressed LVEF may improve following CABG among patients whose low function is due primarily to reversible ischemia as indicated by a high ischemic index.

Prognostic value of the simplified Selvester QRS score in patients with coronary artery disease

The relation of the simplified Selvester QRS scoring system for the estimation of myocardial infarct size to survival was studied in 1,915 nonsurgically treated patients with documented coronary artery disease. Electrocardiograms (ECGs) were scored according to a simplified 29 point QRS scoring system. Using Cox model analyses, QRS scores were found to provide strong prognostic information by themselves (p less than 0.0001). Higher QRS scores were associated with lower survival rates. Patients with a score of 0 had a 1 year survival rate of 95% and a 5 year survival rate of 88%; patients with a score of 10 or more had survival rates of 81 and 52%, respectively, at the same intervals. Directly compared with the presence or absence of Q waves on the ECG, QRS scores provided greater prognostic information (p less than 0.001). When compared with 13 individual factors previously shown to provide the greatest independent prognostic information, the QRS score was the third most powerful individual prognostic factor. It did not contribute independent prognostic information in combination with the whole group, but did provide independent information in combination with the six most predictive factors. Its prognostic information overlapped mostly with clinical factors related to heart failure, and combined best with clinical factors related to the severity of ongoing myocardial ischemia. Because it is inexpensive and simple and maximizes the prognostic information from the ECG, the simplified Selvester QRS scoring system can be a useful clinical descriptor for practitioners and clinical investigators.

Enhancement of an old diagnostic tool, the standard 12-lead ECG

The standard 12-lead electrocardiogram (ECG) has long been a reliable clinical tool for diagnosis of myocardial infarction (MI). Minutes may be crucial in the decision regarding urgent interventions for the salvage of severely ischemic myocardium during an acute MI. Besides history and physical findings the ECG may be the only clinical tool immediately available in deciding to initiate acute coronary thrombolysis or balloon angioplasty. Most of the newer techniques are difficult to perform and time consuming, and thus are not immediately available. Recent studies have indicated that there may be important information revealed by the amplitude and direction of the ST-T vectors on the admission ECG that will correlate with the final infarct size which evolves during the next few hours. The Selvester QRS scoring system, based on computer simulations of the human heart activation sequence, uses quantitative information in the 12-lead ECG to estimate the size of an MI. This system, which can be automated, has been examined for specificity in a large database of normals, and validated in a series of comprehensive post-mortem studies, and in other clinical estimates of prognosis and MI size. The QRS scoring system is limited by its inability to differentiate between small MIs and normal myocardium and by the confounding effects on the ECG of ventricular hypertrophy, conduction defects, and multiple MIs. Current studies are expected to overcome most of these limitations. Computer technology further augments the clinical utility of the ECG by providing unique assessment of a patient from individualized demographic and historical characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of cumulated CK release with three vectorcardiographic methods of estimating myocardial infarct size

Infarct size estimated by three vectoracardiographic methods was compared with cumulated CK release in 66 patients admitted to hospital within five hours after onset of myocardial infarction. Infarctional changes in the QRS complex were sequentially computed from a continuous 24-hour recording of Frank lead VCG by: (I)-the integrals of QRS vector differences (QRS-VD) relative to the first recording obtained after hospitalization, (II)-the integral of spatial magnitude during the period of initial abnormal depolarization (IAD), (III)-The sum of R-wave amplitude in leads X and Y and Q-wave amplitude in lead Z (sigma R). From the time-trend curves of cumulated CK release, QRS-VD, IAD and sigma R terminal plateau levels were visually determined representing estimated infarct size (ISCK, ISQRS-VD, ISIAD and IS sigma R). The correlation coefficients were: between ISCK and ISQRS-VD r = 0.62, p less than 0.001, ISCK and ISIAD r = 0.22, p = NS, ISCK and IS sigma R r = -0.22, p = NS. The correlation for ISQRS-VD was significantly better than for ISIAD (p = 0.011) and IS sigma R (p = 0.005). The IAD time-trend curves were inconsistent, falling in 24 and rising in 24 patients. For sigma R the corresponding figures were 56 and 10 patients. Thus, neither IAD nor sigma R have been shown to predict infarct size correctly at an early stage or to describe infarct evolution adequately.(ABSTRACT TRUNCATED AT 250 WORDS)

Indirect measurement of infarct size. Correlative variability of enzyme, radionuclear angiographic, and body-surface-map variables in 34 patients during the acute phase of first myocardial infarction

To gain a correlative perspective of indirect indications of the size of a myocardial infarct, we measured several body-surface electrocardiographic variables and several enzyme and radionuclear angiographic indicators of an infarct's size in 34 patients during the acute phase of first infarction. We found that bivariate correlations ranged widely, from an r value of 0.05 to an r value of 0.92, but were significantly (p less than 0.001) higher when variables from the same technique were correlated (mean r, 0.60 +/- 0.27), as opposed to correlations of variables from different techniques (mean r, 0.27 +/- 0.18). Trivariate comparisons among techniques produced significantly (p less than 0.001) higher r values, but the highest, an r value of 0.76 (total wall motion abnormality score; peak lactic dehydrogenase level; ST-segment integral maximum), indicated that even in this best case, only about 60 percent of the variation of one variable was dependent on or due to the two other variables. These data demonstrate that multiple indirect quantitative indicators of myocardial injury can vary widely in their correlations within the same population of infarcts, and much remains unknown in their relationships during the acute phase. Caution should be exercised, therefore, in their clinical application to predict an infarct's size in individual patients with acute myocardial infarction.

Evaluation of methods of measurement and estimation of left ventricular function after acute myocardial infarction

Using multiple gated cardiac blood pool imaging and single-plane ventriculography from cardiac catheterization, 2 independent measures of left ventricular (LV) ejection fraction (EF) were determined in each of 21 patients. Patients were seen 2 to 6 weeks after their first acute myocardial infarction and were free of electrocardiographic evidence of conduction abnormalities and left or right ventricular hypertrophy. Differences between the 2 measures of LVEF were examined and then compared with the extent of myocardial necrosis estimated from the standard 12-lead electrocardiogram using the complete 54-criteria/32-point Selvester QRS scoring system. Regression analysis yielded an r value of 0.81 (SEE = 8.05) for the overall relation between the 2 measures of LVEF. Correlation coefficients of -0.70, -0.66 and -0.72 were obtained for the relations of radionuclide LVEF, catheterization LVEF and the mean of these 2 determinations, respectively, compared with QRS score. A QRS score 4 or less achieved 100% specificity and that of 8 or less 100% sensitivity for predicting an LVEF greater than 40%. Thus, the Selvester QRS scoring system may be of value in identifying patients with or without markedly impaired LVEF. This risk stratification may be important in reaching optimal postinfarction therapeutic decisions.

A simplified QRS scoring system for the estimation of the severity of acute inferior wall myocardial infarction

Electrocardiographic assessment of the R/Q wave ratio (lead 2) of patients with a first acute inferior wall myocardial infarction (IWMI) offers important indirect quantitative information regarding the severity and extent of the myocardial damage. Eighty-eight consecutive patients with IWMI were investigated by echocardiography and radionuclear angiography. After measuring the R/Q ratio in lead 2 during the ST-wave stabilized stage of myocardial infarction, patients were separated into three groups--group 1 with an R/Q ratio greater than 2; group 2 with an R/Q ratio between 1 to 2; and group 3 with an R/Q ratio less than 1. Utilizing the information thus gathered from the electrocardiogram (ECG) offers a simple and efficient method for early prognosis which merits further investigation.

Limitations of a QRS scoring system to assess left ventricular function and prognosis at hospital discharge after myocardial infarction

The value of a QRS scoring system derived from 12 lead electrocardiograms to estimate left ventricular ejection fraction was assessed in a prospective study of 285 hospital survivors of myocardial infarction. In these patients both the QRS score and ejection fraction were measured by radionuclide ventriculography at discharge. The correlation between ejection fraction and QRS score was weak. In 22 patients who died during six to 12 months follow up the ability of the ejection fraction and QRS score to predict mortality was assessed in terms of sensitivity, specificity, predictive value of a positive and negative test, and efficiency. For ejection fraction less than 40% and a QRS score greater than or equal to 6 sensitivity was respectively 73% and 64%, specificity 73% and 56%, predictive value of a positive test 18% and 11%, predictive value of a negative test 97% and 95%, and efficiency 73% and 56%. Both ejection fraction and QRS score may be used to identify patients at low and high risk during one year follow up, but, contrary to initial expectations, the QRS score appears to be of little value in estimating ejection fraction and is less accurate than ejection fraction in predicting late survival in hospital survivors of myocardial infarction.

Isosorbide dinitrate sublingual therapy for inferior myocardial infarction: randomized trial to assess infarct size limitation

To assess the potential of isosorbide dinitrate sublingual therapy for limiting myocardial infarct size, 41 patients with inferior acute myocardial infarction (AMI) were studied. Twenty patients were randomly assigned to the control group and 21 to the treatment group. Patients in the treatment group received 10 mg of isosorbide dinitrate every 2 hours for 72 hours. To estimate infarct size, QRS scoring, peak creatine kinase (CK) serum levels and CK curves were used. There were no significant differences between the 2 groups in maximal or cumulative activity of CK or QRS score (percent of left ventricle infarcted: 16% in the control group, 17% in the treatment group). In both groups the QRS score increased significantly by 13 hours after AMI, and the increase was highly significant by 19 to 23 hours. Thus, sublingual isosorbide dinitrate at the dosage given did not reduce infarct size in patients with inferior AMI.

Quantitative assessment of left ventricular function after myocardial infarction using the minnesota Q-QS codes for resting electrocardiograms

The electrocardiogram as a quantitative predictor of left ventricular systolic function was investigated in subjects with one myocardial infarction. The first 509 consecutive subjects to enter the Program of Surgical Control of Hyperlipidemia were studied by selective left ventriculography. Electrocardiograms taken during a prior hospitalization of the subjects for acute myocardial infarction were classified according to the Minnesota Q-QS codes. This study showed that the lower (ie, the more significant) Q-QS codes were highly correlated with reduced left ventricular function as measured both by a lower ejection fraction and by a greater number of left ventricular segments showing abnormal systolic motion. In addition, the location of segmental wall motion abnormalities correlated with the electrocardiographic site of the Q-QS code.